psw Posted March 28, 2009 Author Report Share Posted March 28, 2009 Hey...say what you like about me...but leave howard jones out of this! Link to comment Share on other sites More sharing options...
col Posted March 28, 2009 Report Share Posted March 28, 2009 No worries about current, because its in series with the 8ohm driver coil. Aaah, I just revisited your post... what you do is take a loop of wire from just before the driver - some single core bell wire works - and bend it into some shapes putting it between driver and pickup or even in a loop around the pickup (leaving an inch or two gap all round). This is an interesting experiment, and results were occasionally surprising but for it to provide a practical solution it would have to be researched a lot more. Definitely something you should try out though because its quick and easy to play with. there wasn't enough detail! - but in series makes complete sense now! My only thought here is that we're trying to fight EMF that was created using 200+ turns on the main driver - is a simple one or two turn reversed loop up to the job? (also, it's not exactly the most concise, aesthetically pleasing solution ... but nevertheless worth spending a short while toying with) yes, one loop is unlikely to be enough. And having one loop will also make the adjustment require more precision (maybe an impossible amount). It is just a little test to play around with - worth doing though. Maybe you will decide to run with it and develop it further. I've had a totally frustrating night dicking about with a chip with AGC built into it (a TDA7284 - another one of zfrittz6's circuits...I do rate some of the stuff he came up & I'd like to eliminate them from my enquiries first) ...I can't get a peep out of it when I feed it a guitar signal. I now suspect it needs a a buffer opamp between the guitar output & its input (it's actually meant for a tape recorder AGC....the datasheet is awful...also, I feel I should be wearing big flares, with massive hair & listening to music by Howard Jones as I construct the lash up). My only objection to using that chip and others like it is that it's obsolete, so it will get harder and harder to find. cheers Col Link to comment Share on other sites More sharing options...
Hank McSpank Posted March 28, 2009 Report Share Posted March 28, 2009 (edited) I've had a totally frustrating night dicking about with a chip with AGC built into it (a TDA7284 - another one of zfrittz6's circuits...I do rate some of the stuff he came up & I'd like to eliminate them from my enquiries first) ...I can't get a peep out of it when I feed it a guitar signal. I now suspect it needs a a buffer opamp between the guitar output & its input (it's actually meant for a tape recorder AGC....the datasheet is awful...also, I feel I should be wearing big flares, with massive hair & listening to music by Howard Jones as I construct the lash up). My only objection to using that chip and others like it is that it's obsolete, so it will get harder and harder to find. Col Agreed, it wasn't so easy to source (but I only needed a couple)...are there an other alternatives? Using such a device obviously keeps the component count (& complexity) low ..After posting, I gave it another 15 mins & did get the chip to work using a sig gen as an input (proving my theory, it's no good for direct connection to a mag pickup),....one alarming aspect is that it really did markedly as some distortion on to the sine wave as seen on the output (again it was late & I might have slipped up) Edited March 28, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
col Posted March 28, 2009 Report Share Posted March 28, 2009 (edited) I've had a totally frustrating night dicking about with a chip with AGC built into it (a TDA7284 - another one of zfrittz6's circuits...I do rate some of the stuff he came up & I'd like to eliminate them from my enquiries first) ...I can't get a peep out of it when I feed it a guitar signal. I now suspect it needs a a buffer opamp between the guitar output & its input (it's actually meant for a tape recorder AGC....the datasheet is awful...also, I feel I should be wearing big flares, with massive hair & listening to music by Howard Jones as I construct the lash up). My only objection to using that chip and others like it is that it's obsolete, so it will get harder and harder to find. Col Agreed, it wasn't so easy to source (but I only needed a couple)...are there an other alternatives? Using such a device obviously keeps the component count (& complexity) low ..After posting, I gave it another 15 mins & did get the chip to work using a sig gen as an input (proving my theory, it's no good for direct connection to a mag pickup),....one alarming aspect is that it really did markedly as some distortion on to the sine wave as seen on the output (again it was late & I might have slipped up) I think there are other chips (SANYO LA4150), but even more difficult/impossible to source. I have been told that these all-in-one tape recorder ICs do tend to be nasty noisy distorting lumps which ties in with your findings. I've decided to eat my words and start looking again at designing a discrete output stage. After what you've said about the LM386 and the distortion it adds, I figure that if we can get some relatively simple push pull output stage to work, we can tailor the efficiency vs distortion, get the gain exactly as we need and also fine tune the mixed mode aspect. I've no experience in this area, but I've got a good book with a step through with examples including a low power one. I also have found a couple of schematics that include a transistor gain stage with feedback etc. So I guess that I should be able to cobble something together. I'll just have to over engineer the thermal protection and hope for the best from that point of view. This is going to slow development down at my end, but I have some time of work starting middle of next week, so I'll get more done then cheers Col Edited March 28, 2009 by col Link to comment Share on other sites More sharing options...
Hank McSpank Posted March 28, 2009 Report Share Posted March 28, 2009 (edited) I think there are other chips (SANYO LA4150), but even more difficult/impossible to source. I have been told that these all-in-one tape recorder ICs do tend to be nasty noisy distorting lumps which ties in with your findings. I've decided to eat my words and start looking again at designing a discrete output stage. After what you've said about the LM386 and the distortion it adds, I figure that if we can get some relatively simple push pull output stage to work, we can tailor the efficiency vs distortion, get the gain exactly as we need and also fine tune the mixed mode aspect. I've no experience in this area, but I've got a good book with a step through with examples including a low power one. I also have found a couple of schematics that include a transistor gain stage with feedback etc. So I guess that I should be able to cobble something together. I'll just have to over engineer the thermal protection and hope for the best from that point of view. This is going to slow development down at my end, but I have some time of work starting middle of next week, so I'll get more done then cheers Col Well, the TDA7248 has been struck off my list (it's lying in the bin next to it's new buddy ...an LM386!) ...it's *awful* ....when feeding it a pure sine wave via a small Opamp based preamp (TL074) - the sine wave is clean as a whistle out of the TL074 ...it then it feeds into the TDA7248...it comes out of that awful, just awful. End result? (when used with a sustainer & fed with a guitar signal). Fizz & distortion (nicely controlled at that though!) Folks, we're going to need a proper AGC circuit** that yields an output that's as pure as the driven snow...and definitely a threshold circuit too (because the AGC simply will simply try to amplify the background noise when your playing softly...which ends up with a very messy signal being fed to the driver) & I'm now figuring that any such 'proper' circuit it will need too many discreet components to make 6 channels (hex) viable. Therefore at this relatively early stage, it's looking like Hex may have to be 'parked' (& before Pete has a 'told you so' fit...it's not because of the driver...it's down to the high component count likely needed just to get a nice clean signal for *one* channel!). If I can nail a good end to end circuit for one channel, this circuit might scale up to hex using SMT. My 'parking' doesn't mean aborting (it's still the end goal, but I need to see physically small a one channel circuit can be made) And Pete - that doesn't mean I'm going to copy your driver...far from it! I've heard you say on many occasion it must be 0.2mm wire ...well, I have a load of 0.15mm lying around & look forward to proving it needn't be 0.2mm ;-) I'll also be developing my own circuit...as the LM386 is truly terrible (BTW: I don't think it's a valid argument to say the LM386 is a good solution because it's cheap ...here in the UK an LM386 costs about 50p, but a proper class B output power amp is only likely to be £2!) I outlined something similar a long time ago for my 'ideal' sustainer drive signal conditioning. along side the Limiter, there would be an expander to squelch low level signal and noise - anything below threshold would be silenced, anything above amplified to maximum drive - this way you could have a guitar that didn't squeal away all the time and try to jump out of your hands, but you would get strong immediate sustain when you did actually play a note. There were 2 channel compression chips around a few years ago that would have been perfect for this. These days its not so easy as most parts are only smd which is really fiddly or just impossible to solder by hand. This sort of thing might work well if we can get it in a big enough package. I like your line of thinking...(I've not had time to read the datasheet...but I will read it later, & will have a bit of a Google too), after just a few hours of 'sustainer experimenting', it's quite clear that there's not a whole lot of options here ..... Have a low tech 'budget' sustainer (with possible distortion & fizz) Have a rolls royce sustainer (no fizz, even sustain but high component count...therefore probably a chunky cct board) Some hybrid(!) solution - ie going discreet component where no ready IC solution exists, but utilising suitable ICs where we can (the absolute goal .....pure sine wave in = sine wave out ...if this scenario, we can ultimatley feed a guitar signal through the circuit without fear of fizz. Oh dear, I'm going to have to wind myself a larger six string driver now! **Edit: Just cleaned up most of the obvious the bad grammar & typos (that'll be speed typing for you!) I'm just pondering this a little more - perhaps what we need is more of a limiting circuit rather than an AGC circuit - the power amp & driver are essentially a gain circuit - if we limit/control that gain (by limiting the guitar signal fed back into the the power amp), well we've got an AGC by proxy! The signal into our sustainer circuit will always be quite chunky in the great scheme of things & the AGC just raises the moise floor - we might be able to dispense with the threshold if we don't use AGC? Edited March 28, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
col Posted March 28, 2009 Report Share Posted March 28, 2009 Folks, we're going to need a proper AGC circuit that yields an output that's as pure as the driven snow...and definitely a threshold circuit too (because the AGC simply will simply try to amplify the background noise when your playing softly... I know.... ;p I've already made one AGC that has an output that's at least as pure as the driven slush - its good enough for a no fizz sustainer. More recently, I've been working on various simplified ones with fewer components. Also want to improve the controlability and the reaction times somewhat. And Pete - that doesn't mean I'm going to copy your driver...far from it! I've heard you say on many occasion it must be 0.2mm wire ...well, I have a load of 0.15mm lying around & look forward to proving it needn't be 0.2mm ;-) I'll also be developing my own circuit...as the LM386 is truly terrible (BTW: I don't think it's a valid argument to say the LM386 is a good solution because it's cheap ...here in the UK an LM386 costs about 50p, but a proper class B output power amp is only likely to be £2!) hmm, I know for a fact that you can get good (better) results with heavier wire. I do have a concern about using finer wire - even 0.2 wire. That is it will be exceeding recommendations for current load, so you will get more problems with heat losses and possibly other issues related to heating. I've just been going by what the recommendations are for transformer design, but I worked out that 0.31 wire was going to be bang on in that respect, and the 0.28 that I am using is within a reasonable margin. 0.15 may be getting too fine though ? I like your line of thinking...(I've not had time to read the datasheet...but I will read it later, & will have a bit of a Google too), after just a few hours of 'sustainer experimenting', it's quite clear that there's not a whole lot of options here ..... Have a low tech 'budget' sustainer (with possible distortion & fizz) Have a rolls royce sustainer (no fizz, even sustain but high component count...therefore probably a chunky cct board) Some hybrid(!) solution - ie going discreet component where no ready IC solution exists, but utilising suitable ICs where we can. Oh dear, I'm going to have to wind myself a larger six string driver now! An alternative you didn't mention is a dsPIC based system where 6 channels are conditioned (gain, AGC, filtering for harmonic modes) in the digital domain before being fed directly into 3 stereo digital-input class-d amps. If you can work with SMD, this could be very compact with a low component count. cheers Col Link to comment Share on other sites More sharing options...
Hank McSpank Posted March 28, 2009 Report Share Posted March 28, 2009 (edited) That is it will be exceeding recommendations for current load, so you will get more problems with heat losses and possibly other issues related to heating. I've just been going by what the recommendations are for transformer design, but I worked out that 0.31 wire was going to be bang on in that respect, and the 0.28 that I am using is within a reasonable margin. 0.15 may be getting too fine though ? You may be right, but I've got the stuff in my hands (whereas I haven't any 0.2mm or 0.31mm)...from my one string test, the amount of power needed to drive a single string is remarkably low...it'd be interesting to see how the power requirements scale up. An alternative you didn't mention is a dsPIC based system where 6 channels are conditioned (gain, AGC, filtering for harmonic modes) in the digital domain before being fed directly into 3 stereo digital-input class-d amps. If you can work with SMD, this could be very compact with a low component count. Yeah, but I'm a bloke in an uncoverted loft with a few spare components, a scope, a DVM & about a day's PIC programming experience .....in other words at this stage in the game, any 6 channel PIC system &/or SMD is totally out the question! (as I'd imagine it is for most of those passing through this thread ...so I'd not listed it as an option!) Edited March 28, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
Truth_David Posted March 28, 2009 Report Share Posted March 28, 2009 David...With all due respect...I am not sure if you were around at the time of zfrittz6 but his circuit and drivers (at least to good extent) were tried and failed. His response was that the circuit had error, in fact as presented these errors failed for it to work as an amplifier at all. As I recall his results were not all together verifiable...but for all we know maybe it worked in a fashion once the bugs were worked out. OK halt!!!!!!! Pete before we go any further, I am the very person who was translating for Juán zfrittz6. You are taking what he said out of context. He never said that his circuit was incorrect. He was correcting someone else's error and recommending that they start afresh. You obviously never took the time to read my ammended translations fully. Furthermore I received his circuits, can provide links to photographs of both the circuits completed and the coils. However, because of you and Col's patronizing attitude, he chose to simply disappear, and he took the circuits with him and I have since lost contact with him completely. However I still have the coils, and have tested those that survived my experiments (they proved to be extremely fragile and many of them during the soldering process snapped off close to the coil, so were rendered useless.) I think I am the only one to be able to judge whether the circuits worked or not, but due to my total ignorance in terms of electronics I botched it, then sent back the circuits to him for analysis. This coincided with the period during which you accused him basically of false claims to the effectiveness and success of his work - that resulted in his disappearing act, so thank you. I have already explained how the switch idea while clever may in fact have fundamental problems and as far as I am aware failed to be built or shown to actually work! Incorrect assumption also, because Juán fitted the switch to one of his project guitars, and was extremely enthusiastic about the results. However, what would be most instructive would be if you were to attempt to replicate his work and prove it for us. I already stated that I have no electronics knowledge way back. However I do have a friend who would be able to replicate his circuits, but I prefer to hear from someone like Hank whether or not his schematics make sense, so as not to waste anyone's time. Otherwise, I am putting on the patronizing attitude I can tell...some of your suggestions are really wishful thinking. I often do this, and I come up with ideas and even experiment with them. There seems to be some misunderstanding about the ebow for instance or aspects that keep getting overlooked. Scaling the device up for instance means scaling up everything including the distance between the internal driver and pickups...that could be up to six times the size of a conventional ebow right there! Thank you for pointing that out - no doubt this will have been reflected also in the original patents for the e-Bow, in which I seem to recall there was also the idea of a multiple string version? One way of getting a feel for some things is to take things to an extreme. For instance, a completely sealed driver would potentially eliminate all EMI (this was part of zfrittz6's tin can enclosed drivers) but in doing so, it could completely eliminate the EM forces that drive the string! One of the drivers he made for me can be plainly seen to have what he called 'laminations' within the driver coil. Unfortunately it was one of the coils that did not survive my attempts to scrape the wire for soldering. Another approach would be to create something that focuses the field...dual coil drivers are a strategy but can suffer from a lack of projection...one way to help this as col is doing is to widen the gap between the coils. A sound idea, but enlarging the driver. Perhaps it is a better way, or something similar (bi-laterals, alternating hexs) but with some other sacrifices. The last I heard from zfrittz6 he was changing tack towards the use of a cuadruple coil driver. He gave many reasons why he believed this to be the best approach. I shared this information with Hank, perhaps he would not mind interpreting the information in electronics speak, because that task is beyond me I'm afraid. Col and the commercial guys have taken or embarking on this route and in part overcome the sacrifices by allowing the driver to act also as a pickup...either through pre-amplification or transformers to help with impedance matching. Not a bad idea at all really, perhaps a low impedance driver could be built to equal or better the tone of an active or passive pickup (the sustainac I heard wasn't at all "bad")...but for others the need to always have power for the guitar to work and no choice of neck pickup might be too much. I agree, that is a limitation many are forced to live with, especially those with 'active' guitars. And a 9v battery can give up the ghost without much warning, leaving you high and dry in a gigging situation. So in short it can come off as patronizing or "shooting your ideas down in flames" when someone, usually myself, tries to show the shortcomings in them. Then I find my comments (which with all due respect have a fair bit of practical experience behind them) are dismissed in quotes from other unacknowledged parties, and then their apparent shortcomings dismissed as off hand remarks. I think that you have come across as being excessively heavy handed on several occasions, and you have the tendency to make assumptions based upon skimming posts. In all fairness, no-one could be expected to read and assimilate the sheer volume of information that arrives here daily and respond to all of them. But it seems this is what you have chosen to do, and I commend that effort. However the result of this is that inevitably you are having to split your focus in many different directions, and logically you will not be able to maintain the same degree of focus upon all the incoming posts. What I am trying to say is that this is supposed to be a united effort, with each of us contributing towards a common goal. I think there needs to be room for people to express their ideas without judgement or prejudice, even if this arises out of your personal experience and experimentation, otherwise it ceases to be a forum, and becomes simply a monopoly, like the majority of enterprises. For my part, I feel that I am contributing as I am able, partly in order to revitalize myself and maintain my interest and faith that eventually something concrete will come out of this - perhaps a DIY kit that anyone at any level technical skill would be able to fit themselves, or a step by step tutorial for a fully working sustainer project documented like an 'Instructable'. In the meanwhile, I feel that my continuing research and sharing the results of that with the group are a valuable resourse, so I don't feel that there is any reason whatsoever to have to endure a patronizing attitude on the part of any other member of this forum, whether that be you or Col or anyone else here. I was so offended at one point that I left the forum, which is probably why you failed to recognize me when I returned. That was in no way intentional - I did not realize that you did not know who I was, as I had not changed my nick. David L pete Link to comment Share on other sites More sharing options...
psw Posted March 28, 2009 Author Report Share Posted March 28, 2009 Ok... Well, actually I did remember who you were quite clearly as many of your posts repeated your earlier ones in content and desires. I had forgotten that you were zfrittz6's translator, perhaps it was your failure to get the device working even after you had paid the inventor for the product of his work that influenced my memory of the situation which was frustrating for many at the time. If you are "I am the only one to be able to judge whether the circuits worked or not" then all I was able to take away from that experience was that it was not proven to work. There were no audio clips and the circuit was incorrect. That is not to say that it didn't work, but the posts were difficult and asking anything of the designer to explain thins was extremely difficult if not garbled in translation. I did not then, nor now accuse him of false claims, just to verify his results in tangible ways and explain them further. I was not the only one, and if you read this thread, it is not dissimilar to what I am questioned about, accused of, or freely try as best I can to explain. If there were amended translations, they could easily be missed if they were not re-posted as things then as now were going fairly quickly...the only diagrams presented by zfrittz6 were apparently incorrect and I have not seen any correction to them. Still it is many years ago and maybe the problem as you say is more with the translation as to what was trying to be understood. I and many others tried very hard to understand at the time I can assure you. ... The ebow patent does specify details for a proposed hex version built into the guitar. I have pointed people towards this patent. But as far as I can tell it was never built or tested and proposes things like a large "lead" shield to stop EMI getting from the driver to the pickup. I would suggest that lead is not an appropriate material for such a function nor practical. I would also suggest based on further experimentation that there would be numerous other problems yet to be overcome to have this work as intended and described. This is not atypical for patents in an attempt to cover future bases. When I try and explain the ebow to you, that you apparently own, you shut down your understanding it would seem. There are lots of misconceptions about the ebow...like that it is free of EMI and distortion effects that are crucial to attempt something similar or expanding the concept. ... I don't skim read the posts by the way, there are things that I can struggle to understand, there are things that contradict my experience and would like explained. I have lately taken a more back seat to all this as the answer seems to be 'I'll take care of that later' or 'I don't believe that effect matters a tot'...fair enough, neither did I 4 years ago or more. And, maybe there is a work around, or maybe the reasons are hidden because only one aspect is being studied at a time. I too tried that approach, and made big errors in doing so, in my opinion and for reasons I tried to explain. For instance, hank got sustain very well with a signal generator and assumed that it was fine...till it was plugged in. My feeling is that this is a juggling act where you can not completely isolate one thing from another. ... Me and col have got on each others nerves too...so I hope you are not setting up "factions" or "cliches". You may feel that I am "hard" on some and "soft" on others such as col. I think this would be misplaced. Col has done enough work and had enough success and taken in a lot of these things over the time he has been there. He has greatly expanded into areas like AGC discussed from the beginning for which I lacked the ability to do much with, he also has explored and continues to explore the multicoil drivers. As for others who are trying to replicate the results I have achieved, I continue to support them in their endeavors as clearly I feel some responsibility in offering them, to provide such support. This is extremely unusual. Most threads are of the nature of "this is what I made" and leave it at that...I can't think of any that have offered over 5 years of ongoing support here, elsewhere and by email almost every week...as best I can, and in difficult circumstances. ... However, you are right, I can't tell what zfrittz6 was saying except through your translations...and possibly corrections (that I may not have been aware of) and I only have your word and your translations to base an opinion of the results. My recollection was that someone did try and replicate the circuit presented, you seem to be confirming it was not correct as posted (which would explain why it didn't work) and that you own originals that you also were unable to get to work (for whatever reason). You apparently have expertise at hand, and I would think that you would engage them in fixing zfrittz6's devices or your mistakes with them and demonstrate the results. This would be the only conclusive proof and be invaluable to understand more about them should they prove as effective as was claimed. Laminations have been used by col and myself and many others...they may prove a more effective core for reasons you appear ignorant of, but they are no magic bullet. On my designs, there was negligible difference, ferrite was better...did not stop EMI or fizz effects. ... If the zfrittz6 switch was fitted and proved to work, the nature of this installation was never shown or demonstrated. As I mentioned, the only problem with it is that many (including me and sustainaic and fernandes and rose and numerous others) have all found this to be necessary. I didn't want it to be necessary, I didn't see it would be necessary for some time, I have continued to work towards a work around (the only reason I pursued the mid driver for instance that was clearly stated). You will see the same kind of switch on may of my early hex drivers and in the sustain box as something that I wished, and still wish, were possible for "on the fly" feedback...but wishing doesn't make it so! It could be for instance that zfrittz6's drivers were so good that they didn't have any appreciable EMI. It might be that any fizz that could be heard was acceptable to his ears as long as the sustain was achieved (most fizz can be completely hidden by mild distortion or selective hearing). It may be that he did not use two or three pickups on his guitars. Col and perhaps a majority of people here only have single pickup installations, so their devices suffer none of these issues at all. Perhaps his guitar lacked tone controls and was able to rewire the standard switch in such a way to achieve complete bypassing with a standard switch. It is of course entirely possible to wire a super switch selector to function as described without any additional micro switches as I have already posted and as worked out over at GN2 some time ago. Using the unproven, non-replicated word of your translation of zfrittz6's work as a reason for non-bypassing not being an issue is grossly misleading. Perhaps it can be got to work, but there is nothing to say that it will and it contradicts direct experience to date with multi pickup guitars and standard switching. ... But thanks for recalling for myself and everyone your vested interest in zfrittz6's work. I was somewhat puzzled to see it revived so ardently, now I see why this is the case. Maybe we could bring back some of the other history here...how about Wix (and his various psudenoms that have seen him banned in forums the world over) and we get the tread closed...or how about the Chilean forum that attempt to co-opt the work done here as their own. Let's all buy a select EMG and a 100K pot and get perfect sustain, or hook up a PA to a mid rail pickup to avoid my obviously intentional desire to "over complicate things" presumably for my own reasons. Hank and col and others will have their own successes and take the thing in new directions and have to deal with the issues when they become apparent to them. They are doing constructive work towards that aim for which you are not. They may in time fulfill all their goals, or even exceed them, you will not. As long as you are turning to others to fulfill your aims for you, or try and convince us about the virtues of blind faith or roland systems...I fear you will not adequately understand nor be able to contribute constructively in such discussions where there is debate or disagreement or differences of experience or issues to be addressed, nor adequately champion the work of others such as zfrittz6 which (now that you have reminded me) relied entirely on your translations. ... Or lets all just say, well pete, your time has come and gone, I know it's your thread and all, but we feel it's time for you to go...so push off!!! I have agreed that this may be a point...I am considering it honestly...but I suspect others may wish me to stick around to gain from whatever I may have to offer. My achievements have not been in the form of "look what I have done" but more that "you may also do this and I will try to help"...but also in creating a vibrant environment in which things can be enthusiastically debated. If that is unwanted, perhaps I should "push off". Nowadays most correspondence I receive privately is will I make one and sell it at below the cost of materials usually by people who, like you, do not have the abilities to get it to work and thus discredit my results in the process. This is the only reason I am not actually getting any reward from any of this and things like a "kit" has never materialized from me. I suspect that this will be the deterrent to anyone else that contemplates such an endeavor. pete PS...resist the temptation to continually re-quote my entire posts...the moderators have asked about this twice already. Link to comment Share on other sites More sharing options...
Hank McSpank Posted March 28, 2009 Report Share Posted March 28, 2009 (edited) I don't skim read the posts by the way, there are things that I can struggle to understand, there are things that contradict my experience and would like explained. I have lately taken a more back seat to all this as the answer seems to be 'I'll take care of that later' or 'I don't believe that effect matters a tot'...fair enough, neither did I 4 years ago or more. And, maybe there is a work around, or maybe the reasons are hidden because only one aspect is being studied at a time. Since you're referring to me - just one point of order (& just what is it with you, we're never more than a post or two away from contention) ...when I said "it matters not a tot", you need to put it into the context ...ie at that particular time, I was collecting technical data (specifically about power levels to drive each string at different points along the fretboard)...in this instance, the EMI on the guitar output (that you're relating my quote to) did not "matter a tot" - that doesn't mean I think the issue is insignificant....I just feel it's insignificant when measuring power levels. To use my boat analogy ...I'm stress testing to see if the engine is up to the job ...sure, there may be a hulking great whole in the hull ...but at this point 'it matters not a tot' ....I'll get to it - you can be sure I won't I won't put the boat out out to sea until I do. [Hank retires to the poopdeck to ponder how this analogy might be twisted] I'm aware of all the hurdles, but I can't tackle them all in the first few nights of testing ...hence my "I'll tackle that later" quip. You're very quick to jump in prematurely, steering my early findings in such a way that you prop up the bar at the "The Sustainer Arms" & spout off to the new customers (whether they want to hear or not!) - but relax, I will get to each of these hurdles in turn ....we can discuss/debate those particular points when I do. I've covered a lot of ground in a short time - I'm already & starting to hone in on some possible circuit 'solutions', but give me a break! (remember, I'm only about 4 nights into this project & @2.5hrs per night - that's just over one man day...I've got a few years 'breathing space ahead') Not much more to report on the experiments today...I did a little bit more testing earlier this evening, which revealed the TDA7053A (the 'A' here is important - it's the variant with two DC Volume control pins) to be quite a capable power amp chip (Col you might want to hold off building that push/pull output stage - unless you've decided to go that firmly route anyway of course - & would you believe I only went & bought some TIP122/127s trannies this afternoon - doh!). Anyway, with the TDA7053A, I adopted the role of a 'Hank AGC' & tweaked the DC Volume control to the chip while moving between strings & in differnt fretboard position - it worked brilliantly on the Low E to G strings (at all fretboard positions). I saw some HF ripple sumperimposed on the signal as scoped across the driver, but it's worthing noting that my workbench is not a particularly scope friendly enviroment & the HF could be coming from the fluorescent bench lamp, my soldering iron, sig gen RF artefacts etc. The high E & B string proved to be very hard to coax into excitation...& weirdly, cranking up the TDA7053 volume control actually choked the plucked string (& this is with the driver orientated the same way as when exciting all the other just fine)...there's definitely something unique about these two particular strings that'll need a lot more investigation...my gut feeling is that it'll likely need a bespoke driver &/or circuit dedicated just to those two strings (I'm thinking a coil with less impedance, therefore less turns of wire...which obviously takes the DC resistance down...I need to see what i can get away with wrt the TDA7053 in this instance) Edited March 28, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
psw Posted March 28, 2009 Author Report Share Posted March 28, 2009 OK... Well I encourage you to continue to work with the TDA7053...this was one of my amps of choice when we were discussing various alternatives to the LM386. It may be worth referring back to those discussions about this and others that were brought forward back then. Obviously some time ago now. I was attracted to BTL amps, but after a little experimentation, I settled to continue to try and get as much as I could from the much cheaper and more easily available LM386 that was giving reasonable results at the time. ... I don't think I took your words out of context but am resolved to sit back as you are partly right that I can't criticize what is not revealed to me, a perennial problem. I do think that it mattered a great deal and that the crux of the issues involved were more than adequately displayed as soon as it was plugged in and deserves further exploration as there is the appearance of a presumption that it doesn't matter on which a lot of this work is based on. With the sustain with the signal generator, you set up a system even more isolated than an ebow with it's internal driver or running from a hex piezo pickup (which can also suffer squeal by the way). Somehow, the signal generators signal was clearly being heard in the guitars signal although it shared no ground, the other pickups were "de-selected" and there was a fair distance from the bridge pickup and the driver with a very focused single string aperture. How did the signal from the generator get into the guitars signal? Was it coupling magnetically with the bridge pickup? When the bridge pickup was used as the source, did this coupling magically disappear? Could the signal have find it's way through to the other pickups ground has been shown to be the experience of others? These are factors that I felt did matter. I have found them to matter a lot to high string response for instance as I have already noted. I have explained that if they do matter, it would make the zfrittz6 switch untenable as presented on multi pickup guitars. I have explained that by simply disconnecting completely other pickups you may have a solution or clues as to why it might matter, or disprove what I am saying, or qualify it in technical or whatever terms people would like. Every indicator so far seems to confirm my experience however (and a lot of others), and the problems associated with zfrittz6's switch idea still stand till they are resolved...zfrittz6's unqualified enthusiasm not withstanding. ... There also seems to be a misconception of the ebow. The ebow does suffer massive EMI and distortion issues, it uses them as a feature and is disclosed openly in their literature. The rivers signal is heard and sometimes canceled out by the magnetic fields of pickups, selected or not. For instance, rubbing it over the alternating fields of a neck HB to get a tremolo drive effect similar to the sound of a harmonica. Nothing wrong with that, that is what it is intended to do. But it is simply wrong to assume that because the ebow has it's own driver and is self contained it doesn't suffer from EMI and distortion, fizz and all the rest of the issues that we are trying to minimize. This misconception may lead one to think that such a self contained system, say from non-magnetic piezos will solve these things...this I quite strongly see as a fallacy that I once to had shared. But maybe you don't share such beliefs, no amount of skimming or careful reading has made this any clearer in anyone's posts related to thes aspects. ... I have also suggested that the thin coil design was one of many tried specifically to address the high string response issues and have put forward the idea of "speed" of response of such a design. This is a hypothesis or best theory that I can explain it's effectiveness. None the less, deep coils and other ideas displayed very similar results as you are having with high strings. Similarly, different gauges of winding wire were found to exhibit the same flaws, look at G-mikes results in the tutorial. The thin coil is not the only approach I am sure (although the HB driver of col's had thin coils also, as did curtisA's and many other successful installations)...I advocate it as something that I can speak to that works. Many have tried variations yet this continues to be a reliable design principle. Why it works, is still somewhat unexplained...as good or better devices yet to be discovered. ... Similarly, I am one of the few people that have actually worked at hex drivers devoting hundreds of hours in this pursuit. Besides yourself, I don't know anyone else who has been trying it. I can see great difficulties in them, a single driver can not be simply scaled up and expect to work. Yes, it is a necessary step along the road, but it is simply wrong to assume that one in isolation will work the same with five more right up beside them without massive problems. Anytime a magnet or even ferrous material is close to another magnet they are coupled either by attraction or repulsion. We can I assume regard this as something of a "truth" at least enough to make presumptions on that alone, even without doing any practical work. Such issues may well invalidate any data collected on a single string driver in isolation once scaled up. Yes, you can get low EMI and drive power with such devices, but once scaled up, so too are the issues and requirements of distance, and EMI and all the other issues, even ignoring the effects of magnetic coupling or cross talk between close drivers. ... But you are right...it is your voyage of exploration and your chosen craft to sail it...you will discover the reefs and rocks as I did along the way, or perhaps successfully navigate around them where i failed to do so. I am not accusing you of "dragging your heels", your progress has been remarkable, others have been here years and made no progress at all. You said "it matters not a tot" and I suggested that it did and continues to matter. I have tried to explain why. I have appreciated your intentions, but my feeling and experience is that you can not isolate things to collect technical data as by assuming so, the technical data collected may well be invalid...I have put this forward by my own experience and in so doing invalidating much of my work in early part of this thread...I have acknowledged this for some time and always put forward this disclaimer. So...either it does matter, or we disagree...or you will find that it does or it doesn't along the way in due course. I will have to be content with that. Maybe there are things I and others are not privy too that would invalidate any comment from anyone. But I don't think it is out of context at all...just a difference in opinion at this point in time. I think that by plugging the guitar in, it goes some way to indicating how it matters, but again, maybe you disagree. You say I should know that the ideal drive signal is a sine wave, I tend to think a perfectly in phase sample of the actual strings vibration a the the point of driving the string is the ideal drive form. This I am content to allow to take it's own course as it should. ... However, david has a history here and I do take exception to some of his presumptions. Mainly because they have relied upon misunderstandings and have been supported by flawed notions that he takes as gospel. No one should cite the ebow patents hex driver things as being proof of concept. They are simply a concept, full of flaws, included to dissuade others to take the ebow to the next obvious step of a hex version, should it be proved to be possible. It is an idea, but not a proven one at all...typical strategy of all patents. This is in line with other justifications that have been made over some time, quoting as reasoning the off hand opinion of others (unknown) as proof that things are possible, that the patents say so so it must be true, that he alone can verify zfrittz6 work and can supply pics to prove it...even while admitting that all of zfrittz6's posts were filtered through his translations and didn't work in his hands. I am sorry, but I do take exception to this kind of thing because it is grossly misleading to all concerned. If, like me you choose to worry about it later and discover a work around or that it does matter, then at least I am confident that you will. David however will not! Maybe zfrittz6 did, looks like we will never know for sure! Al did in a manner of speaking...others may disagree with the results...it certainly was completely different to what I advocate for the thin coil design (7 watts of remote power and no pickup bypassing on a mid driver), but perhaps works to his satisfaction which is all that really matters. David is apparently looking now to you to save him with validation of his ideas and for you to help him in his aims and likely (like zfrittz6) build it for him...that is the cross I am willing to hand over to you...for me, it became too heavy to bear after a while...I wish you more success and fortitude than I can muster at this point in my life... pete Link to comment Share on other sites More sharing options...
Truth_David Posted March 29, 2009 Report Share Posted March 29, 2009 David is apparently looking now to you to save him with validation of his ideas and for you to help him in his aims and likely (like zfrittz6) build it for him...that is the cross I am willing to hand over to you...for me, it became too heavy to bear after a while...I wish you more success and fortitude than I can muster at this point in my life... I think you have clearly overstepped the mark here Pete - if there is a moderator on this forum you should be disciplined; I thought there were supposed to be rules against public flaming! You really are a nasty piece of work, but clearly you have shown your true colours for all to see. Not only are you willing to publically humiliate other forum members, but you do so with obvious pleasure, even going so far as to talk about me on forum to another member as though I were not 'here', as may be clearly seen from the above post. And just for the record, all Juán asked of me was a roll of 0.020 wire, he made everything for me out of the kindness of his heart, a gesture way beyond you and others like you. And whatever you may think about him, that gains a measure of respect and allegiance from me, which again is something you seem incapable of understanding. Frankly I find your attitude despicable, arrogant, presumptious, conceited and spiteful, and it seems to be way beyond you to be capable of apologising for giving offense - but just remember '...as you sow, so shall you reap'. David L pete Link to comment Share on other sites More sharing options...
psw Posted March 29, 2009 Author Report Share Posted March 29, 2009 I take no pleasure in it and have qualified my statements. I am not a moderator, but if you feel like that bring it to their attention. I did not write as if you weren't there, I address a whole post to you...I was replying to hanks post in this instance and to your comment... ...maintain my interest and faith that eventually something concrete will come out of this - perhaps a DIY kit that anyone at any level technical skill would be able to fit themselves Earlier you mentioned correspondence with Hank which appeared to indicate, along with disparaging remarks about my attitude and cols in the past, that you hoped that this would materialize through his work. You certainly made it clear that it wouldn't be through your own work without clear "instructables" that you were capable of successfully accomplishing (even though I have given over a lot of room to doing just that for the thi9n coil design). If I misconstrued this aspect, i apologize. Also, I have apologized on many occasions. I wonder if you have spent much time on other areas of the forum where people have posted their ideas or efforts in guitar building to unhelpful or off hand one liners, it would appear not. How often have people asked...oh, look for yourself around the forum! As for your accusation of "flaming", I was simply stating that I was not prepared to take on the burden of fulfilling your aims, and if Hank was prepared to, I wish him luck. I did so in a forceful way this is true, but not with foul language or with any other message but that. There can be no misconstruing the message behind your last post and the end results of your last period of "contributing" to this thread. ... Yes, my attitude may offend just as yours clearly did to me on more than one occasion without any sign of letting up. Your current attitude is much the same as it was back then when you chose to leave. I did not forget, I chose to put that aside to see if you had moderated your approach at all. But no, much the same, starts off ok...then it gets spiteful...again! However, arrogant as I am, I started this thread to discuss all manner of related topics and have maintained it for a very long time now...however, it is a thread and some effort that I have maintained to provide the only central point for such discussions and there is nothing more arrogant than to suggest I "push off" my own topic because you don't like my attitude or language. I get no pleasure from this, quite the contrary...but you came here to this thread and asked advice or opinions or help or charity or agreement...or whatever it is that you came for...to contribute I hope...but instead as before it deteriorates to this.... ... Yes...I will not make you a sustainer out of the kindness of my heart, then or now...that does not make me a bad person. In fact I have for some time been trying to work towards something like that, as you no doubt are aware for some time, have tested it with competent installers, and at a cost that would in no way compensate for my time and probably less than materials bought by members on their own...specifically for people like you. Yours and others inability to complete the task has been the only reason that I have not released these things robbing others who could do it of that opportunity for the time being. ... But, as I say...let the moderators decide and if it has deteriorated to such a point, do not be surprised if the thread is closed as a result of your actions or my own choosing. Let your own words speak... You really are a nasty piece of work, but clearly you have shown your true colours for all to see. .... Frankly I find your attitude despicable, arrogant, presumptious, conceited and spiteful, and it seems to be way beyond you to be capable of apologising for giving offense - but just remember '...as you sow, so shall you reap'. As for Juán... And whatever you may think about him I have made it clear, I don't know him, we all tried hard to understand his posts, we were all somewhat enthusiastic...but then it shortly relied on your translations alone. We will no doubt never know about these things as you are the resident expert...I have no opinion about the person at all. he made everything for me out of the kindness of his heart, a gesture way beyond you and others like you. ... that gains a measure of respect and allegiance from me, which again is something you seem incapable of understanding. Well...as I read it...without skimming...it sounds like I'd be your best friend if only I had made you a sustainer in the first place as you requested as I recall. Not withstanding your "respect and allegiance" on this basis, it is hardly the evidence of results that I was seeking or that anyone could work from. I have made it clear, that it was impossible to ascertain at that time or now how or if it worked, and how effective and what manner it was shown to work. That is not a personal slight, a point of fact...it was you that have been promoting his work despite this yet the same things apply. ... But report this, or I will...more than happy to take any penalty that is deemed required. I have always been grateful for the service PG has supplied to make this kind of thing possible, the forum is ultimately theirs and theirs alone. If you think that my dismissal will somehow get you what you desire, I think you are sadly mistaken. As far as other contributors, my motivation has and always will be to help or to comment and lend my observations and experience...I think the majority may be able to attest to that, maybe I am wrong. But that has been and continues to be my only motivation on my own thread, and my prerogative in my opinion. It would be beneficial though that you take that step to involve the moderators by reporting this post for their consideration rather than have me report myself and be accused of some kind of collusion with the powers that be if it backfires on you or the thread is closed down! thanks for your personal input into my being...again pete Link to comment Share on other sites More sharing options...
westhemann Posted March 29, 2009 Report Share Posted March 29, 2009 I think you have clearly overstepped the mark here Pete - if there is a moderator on this forum you should be disciplined; I thought there were supposed to be rules against public flaming! You really are a nasty piece of work, but clearly you have shown your true colours for all to see. Not only are you willing to publically humiliate other forum members, but you do so with obvious pleasure, even going so far as to talk about me on forum to another member as though I were not 'here', as may be clearly seen from the above post. And just for the record, all Juán asked of me was a roll of 0.020 wire, he made everything for me out of the kindness of his heart, a gesture way beyond you and others like you. And whatever you may think about him, that gains a measure of respect and allegiance from me, which again is something you seem incapable of understanding. Frankly I find your attitude despicable, arrogant, presumptious, conceited and spiteful, and it seems to be way beyond you to be capable of apologising for giving offense - but just remember '...as you sow, so shall you reap'. Truth david...This is so far the only TRUE personal attack i have seen in this thread(not that I have read all of it,and I will not)...and it comes from you.PSW,as well as everyone else in this forum,is perfectly within their rights to argue against an idea if they believe it won't work,just as you are allowed to argue that it will work. Seems as if you are the type of person that will get very nasty indeed if you don't get your way....well I guess that is too bad,because in this case you do not get your way... You crossed the line with that post...and you try to hide it from moderator eyes by putting it in quote tags as if you are quoting someone else... Go there again,and you will be put on vacation.If you can't handle that,then do me a favor and don't post. Link to comment Share on other sites More sharing options...
col Posted March 29, 2009 Report Share Posted March 29, 2009 Its a shame this thread seems to be turning into a cat fight again :| I just spent an hour or two reading back through some posts from the time Juan was involved, and it was as I remembered. I normally wouldn't want to add fuel to the fire in this way, but if I don't present things from my POV when dirt starts to fly, I'll get sick of the project and give up on it again - I don't want to do that right now so: ..... Juan(zfrittz) was a cool guy - an electronics repair man, but NOT an engineer/designer (he said himself he had never designed a circuit before). He tried out our ideas, then implemented his own circuit based on those ideas. After some days and weeks of explaining how it worked better than my designs, but was not finished?! and us repeatedly asking him to post some audio clips, he seemed to disappear. Our natural conclusion was that maybe it wasn't as successful he had initially thought. (I would still honestly like to see proof to the contrary though) Throughout this time all the discussion form Juan, Pete, myself and many others was polite, friendly and productive. David on the other hand during this same time period seemed to me to try and take over. Particularly once he had taken on the role of interpreter. He started presenting pre-existing ideas as though they were Juans ideas (just because juan had also had success with them). He also began touting juan as some sort of electronics wizard and used this as a basis for criticising others who disagreed or were sceptical. There was one post where David tried to persuade Pete to join him and Juan as a 3 man team. This was presented in a way that ignored the work others had done on the project. When this request was rightly ignored, the post was repeated with sections emboldened... it was VERY aggressive attempt to try and take over what is very much a community style project, by someone who didn't have anything useful or positive to offer. It is fortunate that the nature of forums like this means we can go back and check if our memories are accurate - on this occasion, sadly, mine were :-| here are some choice examples: (remember that these are from a guy who at that point had not managed to get anything to work sustainer wise, about a guy who was unable or unwilling to provide evidence that any of his ideas worked.) [to Pete] "...I feel that if at all possible you and Juán should team up with me as the translation intermediary if you like, because he has the electronics expertise of a professional - no offense, but it was his job, so he should be good at it. He is also working on a rotary switch option, although he still considers the micro switch to be the best option..." followed a few posts later by: "...Apparently the 6v circuit is much more compact than the 9v one he sent me originally, so when it arrives I will post some picks (with his permission obviously). I feel that if at all possible you and Juán should team up with me as the translation intermediary if you like, because he has the electronics expertise of a professional (I remember you saying a while back that if we had any professional electronics techs in our team, the project would already be done and dusted, well we do, so why don't we make the most of his free contribution to the forum and his clearly altruistic attitude?!) - no offense, but it was his job, so he should be good at it. He is also working on a rotary switch option, although he still considers the micro switch to be the best option..." here's another from a little later that is a fairly typical expample of the "bigging up" that we were subjected to: "And unless my eyes are deceiving me, it also looks as though he has succeeded in combining the driver with a stacked humbucker type s/c, and if that is the case, then he has cracked it! Given that in his last contribution he presented a fully working dual coil driver of extremely small dimensions, I really think he deserves much of the merit for the experimentation now being undertaken by several others....so you might like to also consider his circuitry designs, as unlike others, who are basing their circuits on what is most commonly available, Juán has the electronics expertise to experiment with circuits that are not so commonly used, which is also why he favours the 6v circuits and is therefore also able to drastically minimize the real estate used by the pcbs. That certainly aids in the design of modular and plugin type prototypes, and probably will also bring us closer to Pete's ideal of a modular device that could actually be mounted inside a p/up cover, circuitry and all..." David continued to try to claim credit on behalf of Juan for much of the projects successes - including the work and ideas of others. I imagine that by this time, Juan must have been getting very embarrassed. a sad state of affairs indeed. Col Link to comment Share on other sites More sharing options...
col Posted March 29, 2009 Report Share Posted March 29, 2009 Not much more to report on the experiments today...I did a little bit more testing earlier this evening, which revealed the TDA7053A (the 'A' here is important - it's the variant with two DC Volume control pins) to be quite a capable power amp chip (Col you might want to hold off building that push/pull output stage - unless you've decided to go that firmly route anyway of course - & would you believe I only went & bought some TIP122/127s trannies this afternoon - doh!). I have been aware of the TDA7052A which is just a mono 8pin version of the 7083A. The only problem for me right now is that I'm still developing the whole mixed/current mode amp idea, and it doesn't look so easy to do that with those chips. That's one of the nice things about the LM386 - its innards are quite accessible. I've looked at lots of IC output stages in the last week or two, revisiting many I've already seen to see if any of them would be easy to set up in mixed mode, and so far drawn a blank - that's why I'm looking at a discrete amp as an option. I'll most likely get my most recent mixed mode AGC LM386 design tested before moving on to a discrete output stage. The high E & B string proved to be very hard to coax into excitation...& weirdly, cranking up the TDA7053 volume control actually choked the plucked string (& this is with the driver orientated the same way as when exciting all the other just fine)...there's definitely something unique about these two particular strings that'll need a lot more investigation...my gut feeling is that it'll likely need a bespoke driver &/or circuit dedicated just to those two strings (I'm thinking a coil with less impedance, therefore less turns of wire...which obviously takes the DC resistance down...I need to see what i can get away with wrt the TDA7053 in this instance) some brainstorming - you've most likely thought of this lot already - : some signal with a near 180º phase is getting to the driver (too obvious) : there is a significant DC current through the driver (but if that, why only with those strings?) : some sort of parasitic oscillation is causing a choking effect on the string when the gain is increased (you're the man with the scope, so you would have spotted that already) Are you still using a single string driver? Are you triple sure you didn't inadvertently flip the coil, the magnet or the connections over (I know, I know, but I gotta ask... )? Are you just testing the open strings, or going further up the neck? Are you using the input from a pickup or from a sig gen? From my experience, a separate driver for B & E strings is not required - it is possible to get them to sustain well using a full width 6 string driver coil. Bearing in mind the double whammy of weaker pickup signal and weaker drive force, you really need plenty of gain and a brick-wall limiter. Ideally the limiter is feed forward - that way it takes into account the weakness of the E & B at the driver as well as their weakness at the pickup. Unfortunately, it seems to be easier to setup and tweak a feedback limiter... at least to give a better dynamic range and lower distortion with faster response. cheers col Link to comment Share on other sites More sharing options...
Hank McSpank Posted March 29, 2009 Report Share Posted March 29, 2009 (edited) Post edited/appended - - see footnote: Something quite noteable happened this afternoon. While messing about with scores of permutatiions (driver position, VCC voltage level, signal 'drive' level, driver orientation, height from string etc) with my single sting driver (yes, still on that for now!), I established that under certain conditions, the driver can be anywhere between the bridge & middle pickup with *NO* EMI whatsoever (nada, nothing...guitar output clean as a whistle)...in fact only when I move the driver *directly* over the bridge pickup pole pieces do I then get squeal. this is quite interesting as obviously it means such a driver could be mounted wherever you want on the guitar without having to worry about EMI! (it's early days yet though...perhaps when I add more drivers into the equation such a 'win' will disappear) One other thing I've noticed, when the single string driver is positioned on the G string (& adjusted just at the 'edge of sustain' ...just to make the G sting excite nicely)....it has enough 'reach' to excite the D & the A strings too! (I'd video these scenarios for you all to see, but I've only got a simple point & shoot camera & you wouldn't be able to hear the clarity of the guitar's output - fed into a small amp I knocked up & listened to through headphones) These two observations are quite a revelation to me at least (especially in relation to my first night's testing when I could get rid of EMI with a sig gen input even at a couple of metres from the pickup!) Anyway, it's into the loft (it's after 10.00pm, so again I won't get much done tonight!) Footnote: All sorts of problems tonight (I have a bench tri-PSU, but it whacks out a fair amount of EMI itself, so I knocked up a simple little 7V regulated DC power supply ciruit, but had no ends of problems) IMHO, single string drivers are proving to be *very* handy for honing in on specific areas of Sustain-age! (if you can make one, I encourage you to do so). It's now quite clear that's it's entirely possible to make small coil sustainer & place it anywhere on the guitar & not worry about EMI ...the catch? Only the bottom 4 strings will be squeal free! On the low E through G stings, pure sustain, no fizz, no EMI...next to any pickup you care to place the driver (of course this is only a one string driver & these obs may be negated when a coiuple more are added into the mix, but like I said earlier, this one string driver has some reach!). When the EMI comes into the equation, is when trying to sustain the top two strings...those two strings need significantly more drive (well, for this 8 Ohm coil with 400 windings of 0.15mm at least). This 'extra' drive get's whacked out as fierce EMI...serious amounts of EMI. Quite remarkable really...bottom 4 strings = very little drive needed...very *very* clean sustain signal (& it'll sustain until Kingdom Come)....but sigh, I guess most folks want six strings?!! (sustainers, schmustainers). Ok, now to to Cols earlier points... I have been aware of the TDA7052A which is just a mono 8pin version of the 7083A. Agreed. I'm not even sure how the TDA7053A appeared on the radar here - the mono variant (7052A) you mention is the one to go for. There's a couple of othe manafacturer's mono variants too (ie with DC volume control)....an LM4865 and TEA7530. some brainstorming - you've most likely thought of this lot already - : some signal with a near 180º phase is getting to the driver (too obvious) : there is a significant DC current through the driver (but if that, why only with those strings?) : some sort of parasitic oscillation is causing a choking effect on the string when the gain is increased (you're the man with the scope, so you would have spotted that already) >>near 180º phase - I don't know, I'd need to scope the input & output (had too many probs to get deep down & dirty with this one) >>there is a significant DC current through the driver a quick current check revealed nothing untoward. >>some sort of parasitic oscillation is causing a choking effect on the string when the gain is increased Nope...signal across the coil is is clean (just how have you guys got as far as you have without visibility of the output signal?!) So I've still not fully accounted for the high E & B string 'choking'... & there's invisible stuff here that I can't easily quantify (permananet & elecro-magnetic fields!). My theory is that it's the higher frequencies (top E & B string) fighting against the inductance of the coil, coupled with *possibly* the TDA7053A not having enough firepower for this condition. I now need to make a single coil driver with less windings (need thinner wire) Are you still using a single string driver? Yes, & it's proving a revelation wrt revealing things like the best 'excitation points' along each string. As an aside, if you hold the single string driver over an existing pickup...the string is strangled completely (moog guitar anyone?) Are you triple sure you didn't inadvertently flip the coil, the magnet or the connections over (I know, I know, but I gotta ask... )? Are you just testing the open strings, or going further up the neck? Are you using the input from a pickup or from a sig gen? Yes, I'm sure the coil hasn't been flipped (I have the driver in a holder and simply move the holder across a little above each string in turn) I'm testing everywhere...like I say, the 4 lowest strings will sustain anywhere on the fretboard (open though highest fret) I'm using the guitar not a sig gen (a cheap strat with single coil pickup...I'm figuring if I can get this to sustain EMI free, every other guitar will be a doddle!) - I will revisit the sig gen thoughas input though (if for no other reason ...just to get a handle on why so much EMI) From my experience, a separate driver for B & E strings is not required - it is possible to get them to sustain well using a full width 6 string driver coil. Bearing in mind the double whammy of weaker pickup signal and weaker drive force, you really need plenty of gain and a brick-wall limiter. Ideally the limiter is feed forward - that way it takes into account the weakness of the E & B at the driver as well as their weakness at the pickup. Unfortunately, it seems to be easier to setup and tweak a feedback limiter... at least to give a better dynamic range and lower distortion with faster response. none of that made much sense...off to Google! BTW: Your idea of using a chip like the SSM2166 for the AGC/preamp is a good 'un, but it's pin count is just too high if I was going the hex route (& I'd need six of them at £5.00 each !) There'll not be much updates from me for a day or two, as some parts have now arrived for another project I've on the go ...a homemade CNC, which will really help my sustainer project a little further down the line (eg cutting a custom 6 x 'single string' driver holder from black 3mm acrylic), so over the next day or two, I'll be cracking on with that....... [everyone breathes a sigh of relief] Edited March 30, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
col Posted March 30, 2009 Report Share Posted March 30, 2009 Quite remarkable really...bottom 4 strings = very little drive needed...very *very* clean sustain signal (& it'll sustain until Kingdom Come)....but sigh, I guess most folks want six strings?!! (sustainers, schmustainers). Before you get over excited about remarkable performance, it would be wise to measure the inductance of your coil. If you don't have one, a cheapo inductance meter can be had for maybe £10 - £15. (I bought a cheap, nasty DMM form B&Q that measures inductance !). Then you can go here and quickly check what the impedance will be at different frequencies! Making a rough estimate based on the inductance of a 6 string driver with very thin core, I guess yours would be in the region of 8mH that would put the impedance at 300Hz at about 17ohm, which combined with the weaker pickup signal and the less efficient driving due to thinner strings would all add up to make it need a whole lotta extra drive gain. >>near 180º phase - I don't know, I'd need to scope the input & output (had too many probs to get deep down & dirty with this one) So I've still not fully accounted for the high E & B string 'choking'... & there's invisible stuff here that I can't easily quantify (permananet & elecro-magnetic fields!). My theory is that it's the higher frequencies (top E & B string) fighting against the inductance of the coil, coupled with *possibly* the TDA7053A not having enough firepower for this condition. I now need to make a single coil driver with less windings (need thinner wire) If the string is being actively choked, all I can think is that either it is a 'wolf tone' effect (in which case you would have to increase the gap between the string an the driver and/or pickup) or that your system - circuit+driver+pickup+pickup/driver gap is taking the phase response past 90º (or -90º) near the frequency of the B string ? ..unless the driver is somehow having a negative effect directly on the pickup...?? From my experience, a separate driver for B & E strings is not required - it is possible to get them to sustain well using a full width 6 string driver coil. Bearing in mind the double whammy of weaker pickup signal and weaker drive force, you really need plenty of gain and a brick-wall limiter. Ideally the limiter is feed forward - that way it takes into account the weakness of the E & B at the driver as well as their weakness at the pickup. Unfortunately, it seems to be easier to setup and tweak a feedback limiter... at least to give a better dynamic range and lower distortion with faster response. none of that made much sense...off to Google! hehe, I banged on about the difference between feed-forward and feed-back limiters and how it is particularly significant for a sustainer for quite a while until anyone 'got' it. More recently I've decided to try using the less well suited feed-back variety due to simplicity. My theory is that a normal feedback AGC takes the output of the AGC as the control voltage which is fine except that it can't react quite as well to the variable response of different string/fret combos With a feed-forward topology, the AGC tries to even out the signal that's coming from the pickup rather than the signal that's coming from the AGC circuit - this means that the weaker strings will be driven slightly harder than the more responsive strings - you get a more even response. Where this is even more evident is as you play further up the neck and the gap between driver and strings becomes less - a feedforward AGC will take this into account while a brickwall feedback AGC one will provide exactly the same drive level independant of the different responses of different strings and frets. That's the theory. In practice, I have found it more difficult to get a feedforward AGC to work with low distortion, fast reaction, high compression ratios and wide dynamic range (that last one is a killer BTW) So I'm hoping that a compromise will be 'good enough' - have to wait and see. cheers Col Link to comment Share on other sites More sharing options...
space_ryerson Posted March 31, 2009 Report Share Posted March 31, 2009 That's a great little schematic (but it looks like it was drawn by someone with a crayon!). I'd love to have had some readings for the associated driver coil ...inductcance, DC resistance, wire gauge etc. (DC resistance would be a start....do you have a way of measuring this space_ryerson) Crayon indeed! The DC resistance of the driver is only 9.8 ohms! How do I test inductance? I'm not taking the driver apart, since I don't want to jeopardize it working, but there is some info on windings, etc. in patent 5,123,324. In a prior post in this thread I took shots of both sides of the circuit board, which may be of some help Excellent...just found it http://www.tinyurl.com/clbrhu (I can see they've used a TL074 for U1 & a TL064 for U2)...I can't make out the power transistors Q9 & Q10 though (it'd be helpful if you could eyeball their casings to see what characters they have on them) Since the transformer doesn't work now anyway, if push comes to shove, you could always desolder it & on the damaged side start unwinding it (presumably one side's coil is reading open/short circuit), - keeping a count of the number of windings get a micrometer to establish the wire gauge ....once you have the number of windings & the gauge info to hand - rewind it with replacement wire! Don't laugh, my wife used to do this for a living...& it's as low tech as that! Hey Hank, I had a gander, and Q9 & Q10 on that diagram are Motorola 731 JE172's. I don't know if there is any difference between them and a MJE172. Moving along, I only recognize some of the FETs on the board. There are two '271 p824cf's, one 2n3904a, and one 'P 6241f'. Link to comment Share on other sites More sharing options...
psw Posted March 31, 2009 Author Report Share Posted March 31, 2009 (edited) I always wondered what that vertical black side mounted board is running through the middle of the circuit? Sustainiac and fernandes have more finesses, but mine is smaller Edited March 31, 2009 by psw Link to comment Share on other sites More sharing options...
Hank McSpank Posted March 31, 2009 Report Share Posted March 31, 2009 I'd have to say, if my main flagship product was destined to go in a guitar as the Fernandes system is, I think I'd be able to model it in a fashion that it doesn't look like it was desgned/built in 1952! Haven't they ever hear of SMD & small Molex headers?! Ubelievable. Incidentally, have we seen the Fernandes schematic pass through these parts in the past 300 pages? That sustainer circuit the other day (Floyd Rose?), was really interesting...more please! Link to comment Share on other sites More sharing options...
Hank McSpank Posted March 31, 2009 Report Share Posted March 31, 2009 (edited) (oops double post - can't find a delete post buttong either?) Space_ryson....tks for ID'ing Q8/9 ...I'm not familair with that variant. Also, since this is a push/pull power amp, I'd have expected the transistors to have had slightly different numbers? (one will be a PNP...eg MJE172 & the other NPN such as a MJE182) Edited March 31, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
psw Posted March 31, 2009 Author Report Share Posted March 31, 2009 (edited) Oh...i thought that the posted circuit was supposed to be the fernandes one...there are links to the major patents on page 7 of this thread...most have a lot of this circuitry stuff. The Rose patent is pretty old by comparison and short lived. The sustainiac is probably a bit better from memory with a circuit that goes for 8 pages. Fernades is more secretive and i think the "black board" is something to do with the electronic switching that both have found to be necessary and a problem that was with the earlier versions like the rose...as was switch pop and excessive battery drain. Of course, I was trying to simplfy the concept myself and avoid the complex circuitry...my aim was never to make a "sustainer clone" but a viable DIY alternative, or something better, or just explore the concept. I am not aware of anyone who has been able to completely workout what is in the fernandes and such really...obviously lots of op amps and things, but that really gives little clue. There have been some interesting circuits around in the past that used discrete push-pull transistors as the power stage with an opamp on the front end, low component count and fairly high power if you want. There tends to be a fair bit of crossover distortion and things though and the LM386 is much the same thing in many respects if used right (one error is excessive preamp gain that overloads the input). By far the more limiting factor is the power...a 9v battery is only capable of putting out so much current, the harder it is driven, the sooner it suffers. I have tried other amps, but have generally returned to the LM386, I have not used the F/R but very similar kinds of basic preamp/amps which have also worked for what I do with mine and have worked adequately for others. Having revised some of this thread, I did see some of the pages in which I was actively pursuing alternatives. I had trouble with the 4053's for instance trough over heating and that helped me to recall that under load they suffered and would attempt to shut down in this application. I also did a dual LM386 thing in BTL but also did not work too well for me...but a very interesting application for the chip all the same. If people want to search this thread...the 300 odd pages will condense to 46 if you switch to the outline view on the options view. From this you will see the members post, one line, and where the posts quote another post in a tree like structure. The tread has distinct era's, so if you are aware of members contributions, you will find those kinds of things. Col and curtisA (plus avalon and other's) contributions to dual coil ideas. Newer member should of course look at the tutorials and other links found in my signature for a less confusing introduction perhaps. I've been playing the sustainer a bit today...mine gets a good strong response on all strings and is very clean on lower settings (in which the AGC is active) but it would be improved with a more aggressive AGC. I appreciated the feed forward idea (eventually, it did take a while to get my head around the difference) but with few circuits about and the complexity, I chose the more conventional hard limiting with an ability to over ride it. Generally, I will try and stay out of peoples way for a bit as far as current projects are concerned to allow space for discovery. If anyone requires my assistance they may ask directly on this thread as I will still be notified of any posts and be following the progress with interest...if biting my tongue... pete ps...the part numbers being quoted are not apparently for the circuit displayed which wasn't clear...without the circuit it is difficult to ascertain the function. Sustainiac reportedly use class D amps for instance, so push pull is possible an assumption...the rose patent is very old though a good one to read...fernandes have always tried to disguise their circuitry and approach to some degree. Patents should definitely not be read as an instruction manual or necessarily even describing a product as such. Edited March 31, 2009 by psw Link to comment Share on other sites More sharing options...
Hank McSpank Posted March 31, 2009 Report Share Posted March 31, 2009 (edited) Oh...i thought that the posted circuit was supposed to be the fernandes one I guess I was tripped by space's associated comment... Hi PSW, remember me? I'm the one with the dead yellow transformer on a Floyd Rose Sustainer. Well, I've found out quite a bit more, but could still use some help finding a replacement transformer. After months of sleuthing, a very nice guy on another forum took apart his Jackson PC-1 for me, and told me this was written on the transformer: ...he then went on to do some detective work resulting in the schematic he posted. space, could you go to the final frontier & clarify which schematic you posted a couple of pages back please? Edited March 31, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
col Posted March 31, 2009 Report Share Posted March 31, 2009 ...i think the "black board" is something to do with the electronic switching that both have found to be necessary... Electronic switching is used also because it is cheaper and more compact - it doesn't make sense to have a massive wadge of expensive custom switching hardware when some cheap and compact off-the-shelf switches and a few tiny very cheap transistors will do a better job. I have tried other amps, but have generally returned to the LM386, I have not used the F/R but very similar kinds of basic preamp/amps which have also worked for what I do with mine and have worked adequately for others. Having revised some of this thread, I did see some of the pages in which I was actively pursuing alternatives. I had trouble with the 4053's for instance trough over heating and that helped me to recall that under load they suffered and would attempt to shut down in this application. I also did a dual LM386 thing in BTL but also did not work too well for me...but a very interesting application for the chip all the same. when you tried these alternatives, where did you get the circuits from - were they existing tested designs, or your own designs (or heavy modifiacations)? Newer member should of course look at the tutorials and other links found in my signature for a less confusing introduction perhaps. alternatively, they could dip in to anywhere in the last two thirds of the thread - 99% of the pages have repetitions of extensive summaries of the project ps...the part numbers being quoted are not apparently for the circuit displayed which wasn't clear...without the circuit it is difficult to ascertain the function. Sustainiac reportedly use class D amps for instance, so push pull is possible an assumption...the rose patent is very old though a good one to read...fernandes have always tried to disguise their circuitry and approach to some degree. Patents should definitely not be read as an instruction manual or necessarily even describing a product as such. Class-D amps use push-pull output stages - e.g. there's one in the sustainiac patent circuit. cheers Col Link to comment Share on other sites More sharing options...
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