Hank McSpank Posted March 25, 2009 Report Share Posted March 25, 2009 (edited) Ok, people....we have sustain! My first trial run tonight..... Conditions... An 8 ohm ohm single string driver coil potted with paraffin wax (about 400 turns of 0.15mm around about 1cm of 4mm mild steel 'core', a reasonably powerful ferrite magnet attached on one end, ). The input signal - my PC, running a Function Generator program(test tone generator - http://www.tucows.com/preview/240287) - Sine wave preset at 330hz ( That's good progress. One thing I would suggest is don't use 330Hz as a test frequency - that will potentially give you over optimistic results. A coil with as many turns as yours will likely have a MUCH higher impedance at higher frequencies. e.g an 8ohm 6mH coil (yours may be more than that) will have an impedance of around 14.5 ohms at 330Hz. At 660Hz it would be 26ohms and at 1320 (24th fret?) the impedance would be a whopping 50ohms. A high inductance driver like this will push the strings very hard with relatively low current at the lower frequencies, but struggle badly at the higher frets. To avoid potential dissappointment, it would make sense to test at a higher frequency - say 1000Hz or 1200Hz ? That way you know you will have at least as good a response for the full frequency range of the guitar. Stick a capo of some sort on so you don't have to hold the string down to run the tests. cheers Col Thanks...I only chose 330Hz, just as an initial test frequency, because it's conveniently the frequency of an open top E string (& I started that trial run at about 10.30pm last night & didn't have a whole lot of time). I will be going further up the frets tonight capo in hand (but need to muller a donor guitar pickup for its thinner wire & make a smaller coil first). I'll be carrying out test at all the guitar's extremeties (while supervising the kids bathime tonight, I'll be knocking up a guitar note/fret to frequency mapping table!) Impedance issues aside, I'm also thinking here the difficulty in driving the top strings is more likely to be the fact they're a lot more physically 'taught', but perhaps just as significantly, as we approach the higher regions of the fretboard, we aren't applying the 'drive' near the middle of the string....it's going to be a lot harder to stimulate a fundamental note just for that reason alone (I sound like Duncan Ballantyne! "& for that reason alone...I'm out") ...in a perfect world, the driver should relocate itself to be in the exact half way point of the note being played - some type of track & pulley system on the guitar face for the driver eh? (just kiddin'!) Edited March 25, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
psw Posted March 25, 2009 Author Report Share Posted March 25, 2009 There is the effect that as you fret higher, the string is pushed closer to the driver in the neck position that gives a stronger drive higher up the fretboard. As well as tension, a large part of it seems to be in the amount of ferrous material the driver has to work with. For instance, on my tele if you let the thing play itself, eventually one string tends to predominate. As you would expect that string is generally the low E, if you damp that, the A string, if you damp these two it is generally the G string (although this is probably on a par with the A, the B and D strings have a similar response, and the high e last. A lot seems to be about the mass of the inner core, not the outer windings. I use 10-46 strings...both sustainiac and fernandes recommend this kind of gauge to give the device something to work with. Light 9's may make high b and e strings unresponsive although I may try a set on the tele as it has quite a powerful drive. Part of my approach to the Hex thing in lieu of a fully hexed driver and pickup was the aim of making the drivers compensate fore each string, so a little more drive for the high e and such, even though they were to be chained together in a mono unit. I've always felt that the tension plays a part. I have though tuned strings down a fair bit (while remaining tense and of course the tremolo can produce this effect) which should benefit drive by a lower pitch and less tension...but the string (core) gauge seems to be the bigger factor to the response. ... One other thing that really kills high string response seems to be "fizz" ...if there is grunge in the signal this will effect the ability for the high string to respond. Another factor that I would be looking at in donovan's work is very long driver leads. If you consider that these leads are extending the driver coils for no drive effects is one aspect. Another thing to consider the effect of capacitance and such of these long leads. A long guitar lead will for instance roll off the highs and this kind of effect is probably also detrimental to high string performance. pete Link to comment Share on other sites More sharing options...
Truth_David Posted March 25, 2009 Report Share Posted March 25, 2009 (edited) Hi Pete and everyone. My apologies for not having commented on your replies Pete - if you cannot access the Internet for a couple of days, things tend to move beyond the subject matter pretty quickly. But I have been reading the posts. In fact I believe that this forum - http://music-electronics-forum.com/showthr...8028&page=2 - a part of which you belong to - is discussing what seems to be very pertinent to the last couple of pages of posts, and also bears out what zfrittz6 was saying regarding using a lower voltage psp..... The post is actually based upon a variation of the hex p/up sustainer theme, and this forum is also mentioned. I am thinking that it might be an idea for some of you to collaborate and share ideas and projects with some of these guys, because they sound pretty well up on the technology. Hope you will find this of interest. David L Edited March 25, 2009 by Truth_David Link to comment Share on other sites More sharing options...
psw Posted March 25, 2009 Author Report Share Posted March 25, 2009 You really must try & stop assuming that you've all angles covered & that others haven't - I know what I'm doing ....I'm not here because I'm clueless & want to ponce info off others towards a cheap diy sustainer. Let's ground ourselves here - a sustainer project isn't exactly the inner workings of the Hubble Space telescope reflector - at its most basic, it's a simple low power audio amp driving a simple coil! No, I've pitched my trailer up here to be amongst like minded individuals & share info, with a view to different sustainer designs/avenues - not to be patronised. I could almost stomach the constant "been there..done that" stance you've adopted wrt everything I'm posting...*if* you could give me some tangible technical data, but correct me if I'm wrong, you aborted the hex concept without a replicable solution (& have you ever wondered why - as you keep saying - so many pass through this thread then disappear?!). You've served the internet community extremely well with your thin sustainer driver info, but there are *many* more ways to skin a cat - if all you can now do on this thread is look for the bad in everything that doesn't fit your model, then in your shoes, I'd be wondering if it's time to say let it go. Maybe you are right Hank...my motivation has never been to patronize and I have gone to great lengths to try and help and to point out that I haven't covered all angles...I only spent a year on the hex things before I made the thin driver (around page 40 from memory)...but that means nothing as no one can do everything. A lot, if not most of the Hex things worked, there were many designs, they would not be easily "replicable" no matter what I disclosed about their workings and construction. A lot of what I was working towards was perhaps overly ambitious. A lot of was fulfilled by the simpler designs and compensated in other areas by being compatible with standard guitars, compactness, ease and cost of replication. People pass through this thread after years of presence generally if you have a good look. Others pass through because they fail or don't have the skills or confidence, others come just to ask me specifically if I will make one for them (for which I get weekly emails), LK passed through because he died others stayed for a year or so and then went on with careers, study and other projects. There is no obligation. A very many people come because they are interested and never post nor are even members of PG. About a thousand views have occurred in the last 2 weeks alone. The Hex era was also heavily subscribed to with innovative work being done by many for quite some time. As far as "my model"...the thin coil design has a proven track record as one design that works, that's all. I "push" it because it has been replicated by me in various forms on the same principle (thin, ultra thin, piggyback, etc) and by a very many others with success. This thread exists as the title suggests to discuss all sustainer ideas, that's why I set it up, that's what it does. The bigger frustration is that it doesn't have a short prescriptive answer. To address this, one member decided to jump the gun and present his work as a tutorial (G-Mike) bring the F/R circuit before he had achieved a complete success. I followed with a pictorial of my driver winding process and the piggyback idea as well....and continued developing these simplified forms because they were easily replicable and fulfilled the needs of many here and made a good starting point, if not an end to itself. Still...I can understand how I can come off as 'objectionable' perhaps...a cross I guess I have to bear. It is not my intention but to engage in discussion to further and help. Clearly in that I have and am failing for you. Clearly there is enough information here to show that I have "been there and done that" in many respects (eg. page 2 single coil driver described in full...page 7 use of signal generator to produce drive). Although in recent times I have not been doing "the work" that I used to do, I certainly put in the time and effort and thought into these things. I don't know if there is anything that I could say or offer to you that wouldn't come off as patronizing. If I can through personal experience see flaws in the experimentation, I am over complicating things if I try and work around EMI and phase issues I am being too simplistic....when I present a design that works and a ridiculous amount of support to help others replicate it I am pushing my own barrow. So...pointless to defend myself really, just digging my own hole in doing so. pete Link to comment Share on other sites More sharing options...
Leppard84 Posted March 25, 2009 Report Share Posted March 25, 2009 That was over a year ago, since then I bought a Fernandes, to bypass my own building frustrations, only to break the trim pots on the install. Therefore, I do have a Fernandes circuit board for us to take a look at. I'll try and post some pics tonight after I'm off of work, maybe we can gain some insight into what they are doing and firnd a simpler way of going about it! But it is an idea I like. As for my driver, I finially have one that reads at 10.2 ohms on my DMM!!! Close enough for now, I don't have an oscilliscope like many of you might but I'm diving in full force to aid in testing of circuits. Talk to you all later, ToNy I'd like to see some pics and details on their driver. As for the board, you are not the first to have trouble with the trim pots and there are a few posts on fixing them around the electronics section as I recall that you might want to search out. Sorry you didn't get the project to work, both fernandes and sustainiac make good products...personally I have a bit of a bias for the sustainiac as it seems a bit more flexible in the installation and aftermarket support and as I say, yours is not the first one that has trouble with the trim pots. pete Thanks Pete! That is awesome and excited now, I want to get both working!! Thought I did enough research into Fernandes and Sustainiac but after I broke it and went back the Sustainiac Stealth Plus looks like a smarter buy IMHO. On to the Fernandes de-bugging.... My fernandes was going to fit into my Yamaha Pacifica, as I was looking for a "Phil Collen" style guitar setup, Neck Driver for infinite sustain, single coil in the middle, and a bridge HB. Here is the pic of the top of the circuit-board. There is a connector pin for power, driver pot, driver pickup, pickup selector. Switches are a DPDT on/off for the sustainer and a DPDT harmonic switch with the middle toggle being a blend of both modes. There is a small transformer on it, something with working the driver as a pickup when the sustainer isn't on (which when the sustainer is ON if you set the pickup selector to neck only you will get nothing, no sound). My sustainer works fine in passive mode, it just doesn't sustain the notes (which was why I got it!). There are two op-amps on the board, but I can only read one of them, gotta get my magnifying glass from my grandpa's house, but its 026D JRC H028B. I haven't looked that up yet, and that long black thing, I've never seen anything like before. Luckily it had a stamp on the circuit board telling me what it was, NIC-6338. Hope these are of some help. And I do have a question too... Been wondering about the driver of my sustainer. It has a ez-connect to my board, but I've been wondering what kind of load the fernandes driver runs at. If I use my DMM and test it just like the 10 ohm coil I just wound, would that give me the reading of its load resistance? Thanks didn't have any luck in the preview with posting a pic so for now your gonna have to link to my myspace to see it, here it is link to Sustainer PCB pic (top view) Link to comment Share on other sites More sharing options...
space_ryerson Posted March 26, 2009 Report Share Posted March 26, 2009 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: C9219-A 0543 Seems promising, but after a lot of googling, I couldn't find any info. So, I went and read all of the patents printed on the circuit board (4,907,483/ 5,123,324/ 5,200,569/ 5,233123), which yielded this: Pretty interesting, eh? The mystery transformer is marked as T1. I went and looked at the circuit board, and c9 is 100nf, and r9 is 10k. The sustainer driver/pickup is 34 in the diagram (9.8 ohms in my guitar), and the bridge pickup is 24 (15.4k, also in my guitar). This at least showed me what was going on in the circuit, but I was still unclear, until I read this in patent 5,123,324: Although the pickup coil (of the sustainer driver) provides relatively low voltage signals, these voltages are stepped up by the transformer, so that the system provides output voltages comparable to those achieved with conventional high inductance pickups. This arrangement provides significant cost and performance benefits. Makes sense, and then there's this: (The) transformer is a low-noise transformer such as a nickel core transformer. Transformer may be an autotransformer in which the primary and secondary coils are parts of the same winding. Transformer may be arrange to provide a step up voltage ration of about 15:1 to about 30:1, preferably about 20:1 to about 25:1. Transformer is disposed in relatively close proximity to neck pickup, hence to the coil system thereof. Ok, now I'm much closer, but I don't know where to find a transformer in this ratio range. I went through all of mouser, and couldn't find anything that fit the bill. Any suggestions? There's a lot more about what the transformer does in patent 5,123,324, and a lot of interesting info about the harmonic mode in patent 4,907,483. Any help you guys can give to aid me in finding a replacement transformer would be great! Link to comment Share on other sites More sharing options...
psw Posted March 26, 2009 Author Report Share Posted March 26, 2009 Thamks for the info on the fernandes "mystery" transformer. I had kind of assumed this function as such transformers also feature in things like the Lace alumitones and even the LP recording as I recall. Great to see a good circuit drawn out, I'm sure it will be a valuable reference for many and stimulate ideas. Not sure how much help I can be with it, but as fortune has it, you and Leppard84 could perhaps compare stuff on this one. For instance, a suitable replacement might be found if the working transformer was measured from his. I dare say something similar even if it has to be wired hanging off the board might suffice...I can't see any reason you could harm anything by trying. Interesting to note they require a 4pdt like mine for the on off and bypassing functions...but perhaps people with more knowledge and skills can take apart the diagram and explain it more fully. With any luck we'll have fixed at least 2 of these things and provided information for future reference as it is not the first time this kind of thing has come up, and probably not the last. Thanks... pete Link to comment Share on other sites More sharing options...
Hank McSpank Posted March 26, 2009 Report Share Posted March 26, 2009 (edited) 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) Ok, here's my take -the transformer 'T1' is *only* used to crank up the driver coil signal level it can also be utilised as a traditional magnetic pickup - it's not used in the sustaining aspect of the circuit at all. Therefore if you're saying your sustainer doesn't work because of transformer 'T1' being faulty - then T1 is *not* your problem...ie you have a fault elsewhere. If you're saying your system doesn't work with the driver being used as a traditional guitar pickup coil...then yes, space_ryerson, you'll need a 25:1 step up transformer (that said, if it's also not sustaining too, it'll likely be be the driver coil - have you have done a DC resisiatnce check?). Here's how I interpret it *roughly* - The normal guitar signal comes in from the bridge pickup, it is then buffered/split by a high input impedance/low output impedance unity gain circuit (Q3)...the original bridge pickup signal is then fed out of the 'out' leg.... the signal to be fed to the driver coil, then start's it's journey up into U1A. They've used a lot of components, but essentially here's the chain.... bridge pickup -> unity gain (non inverting) buffer -> non inverting preamp (though the phase compensation looks a bit lightweight) -> driver signal 'strength' & AGC circuit -> harmonic mode switch (ie reverse polarity of signal feeding driver) -> Class B push/pull power amp -> driver coil. (BTW: the 'busy' switching going on around S1, is just because they have so many permutations (eg coil 34....can be used as a sustain/driver coil or traditional pickup coil) - we don't need anywhere near as many switching permutations! In fact S1 can all but be eliminated for our basic sustainer (we just need a power switch & harmonic switch) Some observations They use dual rail ...something which after my experiments last night, I'm now beginning to lean towards myself (I think it's pretty essential to have 0V DC on the +ve driver connection in the absence of an input signal...this isn't the case with an LM386 output, therefore blocking cap needed - bit it's better to have 0V there in the first place) They use a bit of 'threshold' circuitry, both to conserve power & stop EMI when the bridge pickup input signal falls below a preset level (makes complete sense & I've not seen much reference to that aspect on here) Probably the most significant part of the design for me, is the fact they've used dual rail with a Class B push/pull design for the power amp. Also, it's worth noting they've not gone overboard with trying to lock the phase of the input signal with the driver signal. A lot of their circuitry is bordering on overkill for hobbyists & can be removed for replica test purpose. For example...do we really need a battery indicator?!(it's useful, but not essential...when the sustained signal goes weak/feeble...change the battery!) Also, in a workshop enviroment - if, like me, you have a dual rail bench PSU - you can obviously bin the bits in the top left - & if you don't want to utilise the sustainer driver as a pickup, you can bin T1 & all its associated connections (inc the S1 aspect)! space_ryerson - is there any chance you could note down what characters the following components have on their casing... Chip U1 (it's a quad opamp...just like to know which variant they used) Chip U2 (ditto) Transistors Q9 & Q10 I'm still not totally clear what the battery connections are (it looks like two batteries are being used - 2 x 9V PP9s?)...VCC is the positive rail & VEE is the negative rail. Well, after a further night's experimentation, I'm starting to really hate that LM386...it truly is a pig of a little chip. It distorts the signal terribly (which I reckon accounts for the 'fizz' many speak of on here). I've revisted & edited my test results from two nights ago (specifically about disregarding distortion - bad info is worse than no info!). I did use a TDA7053A power amp chip to drive the coil ...the output was *much*, much better as observed on a scope...but ran out of time. By the way, it'd be nice to have us all the same language, so here's my take (& once agreed it should be in a FAQ) EMI = Electro-Magnetic Interference (audible hum induced into the bridge pickup from the sustain driver magnetic field - same frequency as the signal being applied to the driver ) Fizz = Audible distortion (sounding like ...erhm fizz!) as heard on the guitar 1/4" jack socket output ...cause unknown (though Pete mentioned that he thinks it's the sound of EMI being mixed in with the pure note? I don't think it's this) String flux (maybe I have the term wrong here) = The idea that the metal guitar strings themselves are acting as a 'conduit' for the driver's magnetic field back into the bridge pickup. I have an open mind on this one - at one stage last night I was thinking about knocking up a unique string 'metal metal string...fishing gut...metal string' (the fishing gut being inserted between the neck pickup & middle pickup to break the possibility of magnetism travelling along the wire to the bridge pickup!) I think it's important we all talk the same language & make sure we can account for every one of the above (else how can we elimante them) RE the Fizz... well, using an LM386, I noticed that when I had fizz, if I took the VCC down from 9-12V to about 5.5V it disappeared....below 5V, the fizz changed timbre. I reckon the fizz may be down to high frequency distortion as produced by that nasty LM386. Comments? Edited March 26, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
Truth_David Posted March 26, 2009 Report Share Posted March 26, 2009 I just thought I would add another link in which the Vibesware Guitar Resonator appears. I don't know whether you remember a few posts back, when I was postulating the idea of somehow having the driver above the strings? I seem to remember someone shooting me down in flames pretty rapidly....well I had actually forgotten that it has already been done by this company Vibesware, and it seems to work. In my opinion it is vastly overpriced, but it seems well constructed. Anyway, for those interested in a hexaphonic system, it might be that such a system might be somehow made to work with individual strings, by sensing which strings are being struck by the plectrum, then using the hexaphonic system to send the message to the controller as to which strings to excite into sustain. It is only an idea, and I have little idea how it might be possible to implement, perhaps as silly as any of my previous ideas, but perhaps it will serve as a catalyst towards a different approach? Another interesting fact is that Vibesware state that their product should only be used on the fretboard itself, as when brought into proximity with the p/ups it will produce squealing and howling. Given that this is precisely the most difficult of the issues this project seems to be dealing with, perhaps this might offer a different approach, by literally avoiding the issue? I look forward to hearing your feedback (pun intended )..... David L Link to comment Share on other sites More sharing options...
Hank McSpank Posted March 26, 2009 Report Share Posted March 26, 2009 (edited) I just thought I would add another link in which the Vibesware Guitar Resonator appears. I don't know whether you remember a few posts back, when I was postulating the idea of somehow having the driver above the strings? I seem to remember someone shooting me down in flames pretty rapidly....well I had actually forgotten that it has already been done by this company Vibesware, and it seems to work. In my opinion it is vastly overpriced, but it seems well constructed. Anyway, for those interested in a hexaphonic system, it might be that such a system might be somehow made to work with individual strings, by sensing which strings are being struck by the plectrum, then using the hexaphonic system to send the message to the controller as to which strings to excite into sustain. It is only an idea, and I have little idea how it might be possible to implement, perhaps as silly as any of my previous ideas, but perhaps it will serve as a catalyst towards a different approach? Another interesting fact is that Vibesware state that their product should only be used on the fretboard itself, as when brought into proximity with the p/ups it will produce squealing and howling. Given that this is precisely the most difficult of the issues this project seems to be dealing with, perhaps this might offer a different approach, by literally avoiding the issue? I look forward to hearing your feedback (pun intended )..... David L Thanks for that David....I'd never heard of the system. Their approach is quite innovative. I joked just yesterday that what's really needed is a way of moving the 'point of sustain' (tracks & rails on the guitar!)...but that's essentially what they're doing (albeit the guitar is doing the moving!). Also with mounting it off the guitar, it eliminates 80% of the problems....phantom power, EMI, the guitarist get to keep the original pickups etc. It's a great implementation & a bit of a slam dunk for the competition methinks (though the price is a bit chunky!) I see they're also releasing a harminic footswitch in May. No doubt this will allow the guitarist to select which 'harmonic' he wants to fade in (something I'm hoping to be implementing along the line)...this is quite revolutionary as sustain with "on demand harmonics" are the holy grail ...yet are bit of a lottery at the moment! Edited March 26, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
Truth_David Posted March 26, 2009 Report Share Posted March 26, 2009 Thanks for that David....I'd never heard of the system. Their approach is quite innovative. I joked just yesterday that what's really needed is a way of moving the 'point of sustain' (tracks & rails on the guitar!)...but that's essentially what they're doing (albeit the guitar is doing the moving!). Also with mounting it off the guitar, it eliminates 80% of the problems....phantom power, EMI, the guitarist get to keep the original pickups etc. It's a great implementation & a bit of a slam dunk for the competition methinks (though the price is a bit chunky!) I see they're also releasing a harminic footswitch in May. No doubt this will allow the guitarist to select which 'harmonic' he wants to fade in (something I'm hoping to be implementing along the line)...this is quite revolutionary as sustain with "on demand harmonics" are the holy grail ...yet are bit of a lottery at the moment! You're welcome......one thing I don't understand, although I have yet to receive their reply on this question - is that according to them it only works with the guitar plugged in to their connection box. But as far as I am aware this sort of system should be capable of effecting the strings directly, exciting them into sustain, or am I mistaken? Why should I believe this? Because the e-Bow does this, even on an acoustic guitar with metal strings (not even necessarily steel or nickel strings), and I imagine that any of these systems will work in the same way. They themselves state that it is working as an electromagnet. Another restriction is the fact that there is only a mono output from the device, whilst I believe stereo would be far better, in order to send non-effected signals and effected signals separately to a board or outboard processors. However, where I see this technology going is hexaphonic, so that the output from each string could be individually processed. As already mentioned, an existing hex p/up via a V-guitar system such as the VG-8,88 or 99 would already process each string individually, but unless there were some sort of string detection going on before the signal got to the hex p/up, it could become difficult to control. I wonder whether one could not design some sort of movement sensor into the driver, so that it was capable of detecting which strings were actually being played. I imagine that the Moog Guitar must be employing such technology already, but here we are talking thousands of dollars as opposed to probably an nth of that going the DIY route.... Another perhaps more original idea: If it were not for the sheer impracticality of it, I would envision some sort of hand held device, possibly even in the form of a plectrum, which was capable of either sensing the string being struck or alternatively actually exciting the string(s) as they are struck. Before you laugh, remember that it is actually possible to do this to some extent with an e-Bow. It is certainly not easy, and almost impossible to achieve whilst holding a pick. In fact I got so frustrated by that that I began to experiment with actually using the e-Bow as a picking device - horribly clumsy, but after all, that is what would be the ideal application - it would concentrate the focus of the effect upon what was being picked whilst leaving the other fingers free to fingerpick or tap or whatever. Well that is what I would do anyway....except that I would ideally like to be able to do this with an acoustic guitar too. David L Link to comment Share on other sites More sharing options...
space_ryerson Posted March 26, 2009 Report Share Posted March 26, 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. Also, the driver has a metal shield on the side facing the bridge of the guitar, which I feel is there to shield the rest of the guitar from EMI. Ok, here's my take -the transformer 'T1' is *only* used to crank up the driver coil signal level it can also be utilised as a traditional magnetic pickup - it's not used in the sustaining aspect of the circuit at all. Therefore if you're saying your sustainer doesn't work because of transformer 'T1' being faulty - then T1 is *not* your problem...ie you have a fault elsewhere. If you're saying your system doesn't work with the driver being used as a traditional guitar pickup coil...then yes, space_ryerson, you'll need a 25:1 step up transformer (that said, if it's also not sustaining too, it'll likely be be the driver coil - have you have done a DC resisiatnce check?). You are 100% correct. The sustainer portion works just fine (great, in fact!) without the transformer, but when the circuit is off, the neck pickup isn't functioning. I can tell the transformer is visually damaged, so I'm just trying to find a replacement, but not having much luck. Reading the scanned patents in google patents for this, namely 4,907,483 and 5,123,324, really illuminated to me how the Floyd Rose Sustainer works. It's dense reading, but explains why they chose to use quad op amps, etc. The phase lag sections, and how harmonic mode is achieved were also very intriguing. Link to comment Share on other sites More sharing options...
Hank McSpank Posted March 26, 2009 Report Share Posted March 26, 2009 (edited) You're welcome......one thing I don't understand, although I have yet to receive their reply on this question - is that according to them it only works with the guitar plugged in to their connection box. But as far as I am aware this sort of system should be capable of effecting the strings directly, exciting them into sustain, or am I mistaken? Why should I believe this? Because the e-Bow does this, even on an acoustic guitar with metal strings (not even necessarily steel or nickel strings), and I imagine that any of these systems will work in the same way. I'm not sure I understand what you're getting at. Their solution is essentially a string driver...it needs an input (ie there is no pickup circuitry in their device). This is why they're saying their device must be connected 'first in the chain' of effects ...so they can send the unadulterated guitar signal to their driver coil to stimulate the strings. It really is a very clever workaround/solution to all the nasty by-products that sustainers have. 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! Edited March 26, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
space_ryerson Posted March 26, 2009 Report Share Posted March 26, 2009 That's not a bad idea. I'm definitely driven enough to sit down and count windings The only trouble is that I can't seem to figure out how to take the transformer apart. I'll take some pics when I get home tonight. I'll also look up what Q9 and Q10 are for you. Link to comment Share on other sites More sharing options...
Truth_David Posted March 26, 2009 Report Share Posted March 26, 2009 I'm not sure I understand what you're getting at. Their solution is essentially a string driver...it needs an input (ie there is no pickup circuitry in their device). This is why they're saying their device must be connected 'first in the chain' of effects ...so they can send the unadulterated guitar signal to their driver coil to stimulate the strings. It really is a very clever workaround/solution to all the nasty by-products that sustainers have. OK, now I understand, thank you for clarifying that point..... BTW I really appreciate the work you are doing on this, and I encourage you on your midi driver quest. David L Link to comment Share on other sites More sharing options...
lvs Posted March 26, 2009 Report Share Posted March 26, 2009 (edited) Probably the most significant part of the design for me, is the fact they've used dual rail & gone the push/pull route for the power amp. This latter point is especially interesting, they've chosen a bog standard Class B configuration which will yield some degree of crossover distortion. For example applying a pure sine wave into that stage, will yield a distorted output sugnal across the coil, looking something like this... ... however there is also feedback from the output of the transistor PP stage back to the input of the preceding opamp. During crossover a feedback voltage appears at the input of the opamp, which in turn makes the opamp send a signal through it's output that counteracts the distortion considerably. The quicker (better slew rate) the opamp can make it's output react, the better this works. I ran a little SPICE sim and the output has surprisingly low THD, with the output sine not deformed as far a I could see. When the feedback line is disconnected from the PP stage and reconnected to the opamp's output (giving a classic inverting opamp circuit running into a class B PP), you get the distorted curve like shown here in the quote. Hope this helps a bit to understand that stage better, surely not meant to embarrass anyone. About supplying the circuit symmetrically, one advantage I can think of is it can help against on/off switch pops. Edited March 26, 2009 by lvs Link to comment Share on other sites More sharing options...
Hank McSpank Posted March 26, 2009 Report Share Posted March 26, 2009 (edited) ... however there is also feedback from the output of the transistor PP stage back to the input of the preceding opamp. During crossover a feedback voltage appears at the input of the opamp, which in turn makes the opamp send a signal through it's output that counteracts the distortion considerably. The quicker (better slew rate) the opamp can make it's output react, the better this works. I ran a little SPICE sim and the output has surprisingly low THD, with the output sine not deformed as far a I could see. When the feedback line is disconnected from the PP stage and reconnected to the opamp's output (giving a classic inverting opamp circuit running into a class B PP), you get the distorted curve like shown in post #4508. Hope this helps a bit to understand that stage better, surely not meant to embarrass anyone. About supplying the circuit symmetrically, one advantage I can think of is it can help against on/off switch pops. :-) nice to have your input. The negative feedback is indeed a clever 'workaround' I'd overlooked wrt to the crossover distortion (I was focusing on the 0V DC at the emitters under quiescent conditions - which is another important purpose the negative feedback fulfills - I've since ripped that crossover part out of my post, as like I say, bad info is worse than no info!). I'd love spend some time & get a handle on that SPICE sim - is it intuitive to use? Edited March 26, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
psw Posted March 26, 2009 Author Report Share Posted March 26, 2009 (edited) I am familiar with the pickup makers forum, and them with my work. Although not fully credited, way back I supplied the links to Micheal Brooks and some of the Sustainer history stuff (on yet another forum)...what they missed was the really old sustainer patents...like this one from 1892... Each string of a piano effectively fitted with it's own ebow and predating transistors of course. ... http://www.vibesware.com/ Interesting...like an ebow on a stick! There is a lot that's not being said I suspect....what happens if you wanted to play high up the neck with a standard guitar with a neck pickup...the device would need to be forward of the fretting and so essentially over the pickup...hmmm I see they're also releasing a harminic footswitch in May. No doubt this will allow the guitarist to select which 'harmonic' he wants to fade in (something I'm hoping to be implementing along the line)...this is quite revolutionary as sustain with "on demand harmonics" are the holy grail ...yet are bit of a lottery at the moment! I don't follow this...Uli is sustaining harmonics it would seem...but all the sustainers including mine create harmonics "on demand"...the only caveat is that the harmonics generated, while completely predictable, are not selectable...the "mix" control comes a little closer perhaps. Maybe like ebow and us, they are going to offer the opportunity to reverse the signal to create harmonics (more likely) or a variable filter (so effectively a wha as in the "mix" control...but their advantage is that they can move the driver along the string. This is of course exactly what I recommend people do for the testing of the DIY devices before installing them...test the system well away from the pickups so that you know that it works. ... As for the "definitions" I don't really agree about them really...I think col might have come up with the term "fizz" but is a part of EMI effects as is the string flux idea which is one way that a drivers signal might be sensed by a pickup. Speaking to the "problems" with my simple design and those of sustainiac and fernandes and similar (ebow does suffer the same things but it is treated as a feature btw) there are assumptions or misunderstandings I think about perceived problems with this approach. I am not advocating it as perfect by any means, there are reasons to pursue the hex drive idea if that is the direction you are prepared to go...as far as I can see largely to do with a quest for improved polyphonic drive and perhaps less manual muting. EMI and "fizz" problems only exist where the system is not working properly or you intend or like that effect (as with an ebow for instance where the driver gets close to the pickup itself). The device works by emitting electromagnetic radiation causing the strings to vibrate. If this radiation gets into the pickup it will create oscillation feedback (squeal) or cancellation effects, or distortions and howls. Move the driver right away (over the neck) and these will not exist. So, the challenge is to have the EM radiation focused enough to drive the string and not get into the pickups. Where it does, EM interference occurs. EMI can leak through by magnetic coupling, there is no doubt that the strings will be magnetized by the drivers signal and this can be sensed by a pickup if it is enough to travel along the string to the sensing coils...ie string flux...you can see it in the models, you can set up experiments to hear the effect. "Fizz" is a friendly term for mild distortions that can creep in, yet not have undue effects on the sustaining of the strings. This occurs when there is excessive drive signals (so my circuits and the F/R can display this at the higher gains quite easily...cols heavily AGC things far less if at all I suspect). I generally set my circuits to a gain that is just shy of squeal and then manually control drive. I also note that in my guitars, the weakening of the battery creates more of a fizz effect...so, distortions created by a diminishing headroom seems to make this a lot worse. This and other experiments lead to the idea that clean headroom is one strategy to at least minimize or eliminate possible fizz effects. Others may actually find "fizz" not that objectionable, more like and ebow and completely masked by a dirty sound...and actually seek out these extreme driving effects. Other things not discussed and a concern of cols as I recall at one point...is the artificial way in which the driver tends to excite the strings...to some ears it can lack the character of the original guitar. I used to worry more about that kind of thing, but having played the things for a few years now, I kind of expect it to sound like that...and to my ears it sounds just like natural loud amp feedback that also locks on to a particular mode of vibration. ... I just want to put out there that people like myself and col do have sustain on all strings, that it is polyphonic (but the response is not even and one string will tend to predominate in a chord (typically the lower strings) over time...and even that can be controlled a little with creative damping) that EMI is not an issue with a successful system except in the form of "fizz" and this "fizz" is only an issue if you drive the strings hard with a lot of power, the driving amp is struggling or distorted, and there is no limiting (like AGC) to tone things down. As for the LM386...maybe it is not the ideal amp...enough pages have been spent debating and looking into alternatives. However, it is a solid, cheap, easily obtainable and dependable design for what it does and these are the reasons that it is still around and the darling of the DIY crowd and powers the ebow. But just one of very many approaches that people could take. ... Again...I am more than happy to post clips of my guitar's characteristics...what it can do, the limitations, what "fizz" sounds like on my guitar at higher settings, what a sustained chord sounds like...you name it! ... Basically, we all have different aims and aspirations for the thing...mine sounds a bit different from a sustainiac and gives a more powerful and raw feedback like effect, but with a lot of control. That's what it is designed to do, that's what it does. Problems of "fizz" and other EMI are intrinsic in this project, balancing it all to create the effect that you desire is the challenge. Sustainiac, Fernandes, Brooks, Col, Me and a lot of people over the years through this thread have been able to produce sustain and predictable harmonics on all strings to their satisfaction, or at least in a musically useful way. pete ps...i might add also, that something that sounds like "fizz" on my guitar is that even with a medium action and a low drive, the strings do vibrate hard enough to crash into the frets quite a bit..lower strings more than others...the proof that this is what is being heard is that you can hear it "acoustically" and it is less or not at all on higher strings or on highest frets. Edited March 26, 2009 by psw Link to comment Share on other sites More sharing options...
Hank McSpank Posted March 26, 2009 Report Share Posted March 26, 2009 (edited) I don't follow this...Uli is sustaining harmonics it would seem...but all the sustainers including mine create harmonics "on demand"...the only caveat is that the harmonics generated, while completely predictable, are not selectable...the "mix" control comes a little closer perhaps. Maybe like ebow and us, they are going to offer the opportunity to reverse the signal to create harmonics (more likely) or a variable filter (so effectively a wha as in the "mix" control...but their advantage is that they can move the driver along the string. Perhaps it's my terminology - I mean definable/controlled harmonics on demand. eg "I want a fifth harmonic?" seventh harmonic etc? At the minute, you can get the fundamental, octave (& fifth?) quite easy - flick a switch & wait for it to arrive'...but it's not exaclty controlled (vs fading in/out a desired harmonic with say a footpedal)...that's what I mean by 'on demand'. As for the "definitions" I don't really agree about them really...I think col might have come up with the term "fizz" but is a part of EMI effects as is the string flux idea which is one way that a drivers signal might be sensed by a pickup. Well, if we're all to row together in the same direction...we need to agree a common name for each bad by-product, agree it's cause & then we can work towards treating it. I don't think it's good to simply bundle fizz in with 'general EMI' it' might be getting into the guitar signal via EMI, but it s derivative thereof...if we know what's causing it, we can 'handle' it. I'd already noticed that there's more fizz below 5V, a different type of fizz above 9V - this fizz can be heard in amongst the other more predominant EMI. "Fizz" is a friendly term for mild distortions that can creep in, yet not have undue effects on the sustaining of the strings. Yes, but other than a general observation that the fizz creeps in more as the battery fades...what's the technical explanation? This occurs when there is excessive drive signals (so my circuits and the F/R can display this at the higher gains quite easily...cols heavily AGC things far less if at all I suspect). but that wouldn't be the case when the battery is dying (when youve said fizz is especially prevelant) Other things not discussed and a concern of cols as I recall at one point...is the artificial way in which the driver tends to excite the strings...to some ears it can lack the character of the original guitar. I used to worry more about that kind of thing, but having played the things for a few years now, I kind of expect it to sound like that...and to my ears it sounds just like natural loud amp feedback that also locks on to a particular mode of vibration I'd noticed the string 'excites' way differently to the way a string moves when it's plucked - this does indeed yield a different timbre. As for the LM386...maybe it is not the ideal amp...enough pages have been spent debating and looking into alternatives. However, it is a solid, cheap, easily obtainable and dependable design for what it does and these are the reasons that it is still around and the darling of the DIY crowd and powers the ebow. But just one of very many approaches that people could take. Well, there's now one less LM386 in operational use - it's been retired in this household for the foreseeable future...I may come back to it after I've carried out some experiments with dual rails output stages, but for now....it's filed under "euuuugh". Edited March 26, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
lvs Posted March 26, 2009 Report Share Posted March 26, 2009 (edited) I'd love spend some time & get a handle on that SPICE sim - is it intuitive to use? I use SIMetrix. As far as I remember Rod Elliott once gave it a good rap at his website, and with the intention in the back of my head to learn to use a SPICE simulator some time, I downloaded it. I'm not positioned to say in what aspects it's "better" or "worse", because that would imply "compared to what" and I simply don't know how it compares to other simulators. It took me some time to get used to the GUI (and it's small bugs here and there) but it goes fast now. The free version is limited in the number of components, but most of the time it's enough for my small stuff. And then yeah, it's like a plane with a thousand knobs in the cockpit from which I had to sort out the ones useful for my purposes. But that wasn't too counter-intuitive, considering I seldom had a look in the manual. But better than my anecdotes, may I suggest you also have a look into this thread about starting a sim subforum at Diystompboxes : http://www.diystompboxes.com/smfforum/inde...p?topic=75038.0 . Aron has proposed to agree on a "default" sim application, and if (I hope that's a "when") the sim subforum comes alive, I know that's the one I'm gonna use from then on. (Sorry for topic digression.) Edited March 26, 2009 by lvs Link to comment Share on other sites More sharing options...
col Posted March 26, 2009 Report Share Posted March 26, 2009 They use a bit of 'threshold' circuitry, both to conserve power & stop EMI when the bridge pickup input signal falls below a preset level (makes complete sense & I've not seen much reference to that aspect on here) 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. Well, after a further night's experimentation, I'm starting to really hate that LM386...it truly is a pig of a little chip. It distorts the signal terribly (which I reckon accounts for the 'fizz' many speak of on here). I've revisted & edited my test results from two nights ago (specifically about disregarding distortion - bad info is worse than no info!). I did use a TDA7053A power amp chip to drive the coil ...the output was *much*, much better as observed on a scope...but ran out of time. You are right about the LM386 for sure - I've heard the same things said in other forums related to various applications. However () Its cheap, its small and its very easy to get hold of. I have managed to get very clean results using it, you just have to stop it from clipping and keep a resonable distance between driver and pickup. I think that its the gain it forces on us that is the bigger problem, but anyhow, lets find a better alternative that is readily available (and has access to the feedback resistor)... By the way, it'd be nice to have us all the same language, so here's my take (& once agreed it should be in a FAQ) .... I think it's important we all talk the same language & make sure we can account for every one of the above (else how can we elimante them) I agree, however, I don't think its ever going to happen here - what ever language you use, if it's technically specific, it WILL be misinterpreted, then drowned in a sea of techno babble RE the Fizz... well, using an LM386, I noticed that when I had fizz, if I took the VCC down from 9-12V to about 5.5V it disappeared....below 5V, the fizz changed timbre. I reckon the fizz may be down to high frequency distortion as produced by that nasty LM386. That sounds like a reasonable theory, but how do you account for the fact that I can run an LM386 based system at 9.3V with good sustain and NO fizz whatsoever - none ? What I would be interested in finding out is that if you have a power stage that doesn't have such nasty distortion characteristics, can you then use a square wave or similar as drive signal with less fizz ? ... btw, have you tried other drive frequencies yet? if so, how did you get on? how do they compare to the 330Hz? cheers Col Link to comment Share on other sites More sharing options...
Truth_David Posted March 26, 2009 Report Share Posted March 26, 2009 http://www.vibesware.com/ Interesting...like an ebow on a stick! There is a lot that's not being said I suspect....what happens if you wanted to play high up the neck with a standard guitar with a neck pickup...the device would need to be forward of the fretting and so essentially over the pickup...hmmm Well it might be described like that, except that as Hank noted, it does not include a magnetic p/up, so it will only work via the guitar's electronics. I think that is a shame - a version of this technology affecting all the strings, but using an integrated p/up and with it's own psp, sold at a similar price to the e-Bow would be likely to find a good number of players willing to shell out for one. If the e-Bow affected all the strings at once, I might even be willing to sacrifice my right hand picking in order to use it from time to time..... Regarding your suspicions that the Resonator will be problematic when used high up the neck, perhaps it might be worth asking their technical support about that. Here is their e-mail address: info@vibesware.com I don't follow this...Uli is sustaining harmonics it would seem...but all the sustainers including mine create harmonics "on demand"...the only caveat is that the harmonics generated, while completely predictable, are not selectable...the "mix" control comes a little closer perhaps. Maybe like ebow and us, they are going to offer the opportunity to reverse the signal to create harmonics (more likely) or a variable filter (so effectively a wha as in the "mix" control...but their advantage is that they can move the driver along the string. I think it is most likely just a footswitch based harmonic switch, judging from the photos.... David L Link to comment Share on other sites More sharing options...
chops1983 Posted March 26, 2009 Report Share Posted March 26, 2009 I just thought I would add another link in which the Vibesware Guitar Resonator appears. I don't know whether you remember a few posts back, when I was postulating the idea of somehow having the driver above the strings? I seem to remember someone shooting me down in flames pretty rapidly....well I had actually forgotten that it has already been done by this company Vibesware, and it seems to work. In my opinion it is vastly overpriced, but it seems well constructed. Anyway, for those interested in a hexaphonic system, it might be that such a system might be somehow made to work with individual strings, by sensing which strings are being struck by the plectrum, then using the hexaphonic system to send the message to the controller as to which strings to excite into sustain. It is only an idea, and I have little idea how it might be possible to implement, perhaps as silly as any of my previous ideas, but perhaps it will serve as a catalyst towards a different approach? Another interesting fact is that Vibesware state that their product should only be used on the fretboard itself, as when brought into proximity with the p/ups it will produce squealing and howling. Given that this is precisely the most difficult of the issues this project seems to be dealing with, perhaps this might offer a different approach, by literally avoiding the issue? I look forward to hearing your feedback (pun intended )..... David L Hey guys! I have been interested in a sustainer for awhile but alot of the stuff you guys are talking about flys way past me. But in Davids quote here he says that vibesware say to move the driver up the fretboard to reduce squealing and howling. Now this may have already been said as i have not read every page here, but is it possible to make a driver that is relatively flat and inlay between your last frets? Say in between the 21-22 etc. This is just from an outside looking in. You can tell me im a fool if you like and that it will not work its just a thought really. Chad. Link to comment Share on other sites More sharing options...
col Posted March 26, 2009 Report Share Posted March 26, 2009 This occurs when there is excessive drive signals (so my circuits and the F/R can display this at the higher gains quite easily...cols heavily AGC things far less if at all I suspect). but that wouldn't be the case when the battery is dying (when youve said fizz is especially prevelant) You get fizz when there's hard clipping. This occurs with too much gain. It also occurs when the battery is very low - As the battery drains, the voltage drops and the headroom is reduced so clipping occurs with lower voltage signals than when the battery is fresh. cheers Col Link to comment Share on other sites More sharing options...
psw Posted March 26, 2009 Author Report Share Posted March 26, 2009 Hi Chad and fellow aussie You are not likely to be able to inlay it on a fretboard...have a look at my recent tele driver (see blue link in sig). On such a coil the blade is just wider than the width of the string spread...but the coil needs to go around that...much like and for the same reasons that a pickup is wider than a neck. There would be other problems implimenting it as well if you think through how you would go about this... pete yes...completely agree col... Link to comment Share on other sites More sharing options...
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