psw Posted November 4, 2006 Author Report Share Posted November 4, 2006 Nice analogy about the playground swing... Watching my young son learning to operate a swing is instructive and makes you wonder about the phase discrepency factors inherent in the fixed sustainer...hmmm Hmm, I still get crosstalk fizz with the driver in the neck position - trying to put it in the middle position makes that issue much worse = totally unacceptable. It is probably related to the high power pickup i have in the bridge position, but that is how I (and MANY others) get the sound I like best. I never said it would be easy...though finally I would hope that the solution be simple... Certainly I have reason to believe that it could be done! Dizzy's mid driver and my own Hex experiments... I do know that my present design does not work due to EMI issues in the mid position and that even in the neck there is some "fizz" in very clean harmonic modes in particular... There are some who would suggest (sustainiac) that single coils by their nature could be even more suseptable to EMI and the fizz effect than your high powered humbucker... There are reasons to be encouraged however...tim's successful coil making jig produces extremely compact and solid coils that can be configured in numerous ways and promises the opportunity for innovative driver variations that could hold the key to this... I do know that the "fizz effect" can be generated by the driver leads also. My desire to move all the poweramp functions to the driver is aimed at least in part at eliminating these EMI inducing signals from the control cavities and pickups... I can not say however if there won't be interferance from the driver on the signal leads or the operation of the amplifier if situated in this environment... There may well be improvements to be gained with a different kind of amplifier (eg BTL) than the LM386 configuration we have been using. This too could have some impact on the fizz effect. I should point out however...that a mid driver is not a total solution. I was actually a little disappointed in measuring the changes in distance between the fretted notes over the driver and the middle pickup...there will still be a discrepancy and obviously very small distances make a huge difference to response... Your endeavours on the electronic front is the only way that seeks to fully address them at present...I don't see any feed-forward AGC control in the patents BTW ...and is likely to be important even with a mid driver...and may well have implications for power consumption as you have discussed... As far as the patents, I've purposly avoided looking at them closely - don't want to get too heavily influenced until we have exhausted all our own ideas. Well...we aren't adverse to "drawing inspiration" from other sources of circuit design, I don't see a reason not to analyse these...except... I have looked at all the patents but have found them at best misleading. I absolutely agonised over the phase compensation issues (as can be read in early parts of the thread) and they seemed to be crucial...and they are...to an extent. My inability to address things with circuitry lead me to look at it in other ways. Obviously the thing will work without all the bells and whistles described and my design does work across all frequencies. The effect of action, at least in the thin coil/thin core device is far more of an influence it would seem than these phase discrepancies... If anyone had found a total solution, I doubt we would be having this conversation...perhaps such a solution will always be evasive, but improvements can and have been made and where there is a will there is a way, if you desire it. It might not be the way that you suspect but sufficient perserverance will provide an answer... Now...in addition, there is the posibility of a closed system that draws the signal not from the guitar but it's own pickup...a giant fixed ebow in effect! This has yet to be fully explored but the size of tim's new coils should give pause to think about the possibilities in this regard also... Even if a mid driver is not practical...the research into a driver design that almost works in this position can only be an improvement to a neck driver...so there is no loss, just a reaching a little further... keep plugging at it, it is appreciated and I certainly don't have the skills to do it... pete Link to comment Share on other sites More sharing options...
da_free_runner Posted November 5, 2006 Report Share Posted November 5, 2006 *Note: I wrote this reply just after the Da_free_runner posted, unfortunately, there has been a problem with my forum account, so I couldn't post until now. I'm not trying to 'shoot you down' DFR, just want to help point out possible issues thay you may not have considered, and also to discover if I am misunderstanding the intention of your design. haha no problem i wil take any advice i can get, i have only been inverstigating this field of study for a short period of time, and electronics itself for a couple of years, so the more information i can get the better all the circuit is basically doing is sending a variable pulse to the driver coil so that the guitar strings vibrate. But it's a manually variable pulse that is independant of the frequency that the guitar is producing? it will also work better on strings already vibrating so that will maybe cut down on likelyhood of strings starting to vibrate when you dont want them to Are you sure? Assuming that each pulse is of the same polarity, it will push/pull the string the same way each time... with the string at rest, this will always exite it. with the string already vibrating at some arbitrary frequency, your circuit is as likely to damp the string as exite it further ! To help see this a good analogy is a swing in a playground... when you puch a child on a swing, you only need to give small pushes, the important thing is that the pushes are exactly synchronised with the natural frequency of the swing... What you are doing would be like sometimes pushing with the existing motion and sometimes against. i had actually thought about that, i am very hyperactive when workin on this kind of stuff though so i had not looked closely enough at it, thank you for the reminder, i am thinking maybe to design the circuit so it detects the frequency of the string vibrating and adjusts the frequency of the driver pulses to suit, but then there might be a problem where, as the string begins to slow down the circuit would notice and adjust the signal to the driver so the pulses dropped i can see i am going to have fun with this on another point, has anyone thought of using a digital latch type circuit that picks up the output of the pickups and then effectively "latches" the signal to sustain it infinitely (im not sure if it would work, but there is a possibility it would) i am good at digital electronics so i am trying to create a small digital circuit that works, thats all. the way i see it, all you need to do for sustain is to keep the strings vibrating, if keep them vibrating then you keep the sound going and therfore get sustain, Thats kind of a simplistic description, you missed a key point - yes it is about keeping the strings vibrating.... but the need to be kept vibrating at their existing frequency. Unfortunately, for your circuit to do this, you would need to manually adjust the frequency to somehow match the frequency of the guitars note. e.g. if your circuit was set to 200hz, and the string was vibrating at 300hz, then the drive circuit will only be in phase (helping) the string every 3rd cycle - so it will spend 2 thirds of the time either interfering with or completely opposing the desired vibration of the string. I suppose one thing would be to have the driver output short pulses at a much lower frequency - like tremelo picking.... This could work theoretically, although intuition suggests that it would have audible side-effects, and would require a _lot_ of energy behind each pulse... yet again another point i have found to be true, kind of along the lines of the swing..... as i said above thought, i would be possible to create a circuit that detects the signal frequency and outputs the correct frequency to the driver........ although you cannot get some of the tricks like sustain that automatically gives you the harmonic of the note fretted (like fernandes sustainers) bookread.gif the circuit i have designed gives a few fresh ideas like being able to change the speed and strength of the pulses, effectively giving you a weird kind of volume/decay control have you tested your system on a guitar ? I would be very interested to hear it working - say, sustaining natural guitar tones on a scale. I would also be interested to see what you could do with the approach we are trying to develop. You say that you are good at digital electronics... would you be able to develop a simple circuit that could digitise the driver signal and apply more controllable conditioning and AGC in the digital realm before using a class-T amp (or similar) to feed the driver ? What would be the minimum processing requirements to provide DSP for a usable mono signal? microcontroller? PIC? what would the current drain be like? how big would the circuit be? If you can get a circuit designed, I'd be happy to do the coding - I have plenty assembly language experience, some embedded (kind of) and some audio dsp knowledge. maybe there are existing off the shelf boards that would make this easy? just load in our custom dsp code and plug it in ? Col firstly, no i have not tried it on a guitar yet, simply because i have alot of bugs to work out before i even prepare the pcb for the prototype, and fortunately you have pointed out some finerpoints i had not giving enough thought due to me being an impulsive little bugger and not thinkin enough about side effects secondly, yes i am good with digital electronics, i have passed my digital electronics at college with merit, although a lot of that was digital logic but i must say that i would NEVER even pretend to be an expert at it!!! i have done some P.I.C. programming as well though, i just need to do a bit more research on this precise field of design and i should be able come up with something that fits the specs req. the processing power you will need depends on what you want exactly you want to do, i would check into that field yourself and research it to decide on to use. thirdly, you can buy off the shelf boards at relitively cheap prices, just go on google, at my college we imported P.I.C. program/test kits from america although i doubt you would need to go to such extremes to get a decent board. thank you for your input to my attempts it is much appreciated, and it has been a lot of use in giving me more ideas on a appropriate circuit. will Link to comment Share on other sites More sharing options...
bancika Posted November 6, 2006 Report Share Posted November 6, 2006 Hi, I just wanted to pop in and say that my driver is mostly completed. I just finished winding. I potted coil with glue, soldered leads and glued them to bobbin. It looks decent, considering it's my very first attempt. Also I'd like to thank Pete for sending me a spool of winding wire As soon as I find a camera to borrow I'll take a few photos. I'm making a photo essay for those even more noob than me Will keep you posted... Cheers! Link to comment Share on other sites More sharing options...
psw Posted November 6, 2006 Author Report Share Posted November 6, 2006 Also I'd like to thank Pete for sending me a spool of winding wire No problem...it got there amazingly fast!!! It wasn't so hard to do was it and I am sure it will work well enogh to set other ideas in motion... secondly, yes i am good with digital electronics, i have passed my digital electronics at college with merit, although a lot of that was digital logic but i must say that i would NEVER even pretend to be an expert at it!!! Don't sweat it Will, even if you find the analogue way to be the most effective (the string's vibrations which are a part of the feedback loop are intrinsically analogue remember) and simplest approach to this device, there are a lot of ideas being floated about digital logic for switching, and possibly other applications so your input will be appreciated... People should note that I effectively taught myself "electronics" for this project and so understand concepts and can solder pretty well...the details soon get beyond me as far as design goes...I am more of an ideas guy with the tenacity to stick at it till I get it to work, the curiosity to understand why it does (or doesn't) and the generosity to share it with others... It seems by this thread that I am not alone in these attributes ! I did try at an early stage to drive a single string "guitar" (string on a piece of wood) by various means...one of which was to use a driver driven by a tone generator from the computer's headphone socket. Part of this was to see effects of resonance and phase differences but mostly to crudely see the results of driving a string with various wave forms...including a square wave pulse. It was essential that the tone generator and the string were tuned to one another. You could get sustain by many means if you hit the resonance just right...One novel way was to make a coil around a steel rivet at the bridge through which the string passed...the string threfore became the core of the coil and just ahead of the bridge were little Neo mags N&S of each string...the string was thus pulled from side to side... This kind of thing sounds exciting but...it would only work if the resonance was right and effectively passed a magnetic pulse down the string and right into the bridge pickup...hmmm Now...perhaps this idea could be used as some kind of hex pickup, and possibly why I didn't document it, along with many other failures... I am pretty sure though that a simple digital pulse approach is not the way to go...an amplifier will automatically follow the pulse of the string...but there are other parts of the project that do require attention and may well benifit from digital intervention of some type. Switching is an obvious thought, signal conditioning like col is looking into, maybe...and phase correction may also be able to be addressed with logic circuits.... There may well be something to do with effects too down the track...I could see pitch shifter being used to create consistant harmonics rather than the cancellation, pahse reversal switch currently being used to generate them (the harmonics that result depend on the length of the string relative to the position of the driver so could be anything from an octave, fifth, third two octaves above a given note) One of the biggest hurdles is the effective transferance of the signal into a magnetic energy to activate the string...in other words, the driver...no matter how that signal is derived. There are many ways to do this but finding a practical one is the problem and I abandoned the purely experimental stuff described in favour of working with real instruments for practical applications... There are other variations on the sustainer theme too that could be explored...I am thinking of building an ebow...perhaps in miniture! on another point, has anyone thought of using a digital latch type circuit that picks up the output of the pickups and then effectively "latches" the signal to sustain it infinitely (im not sure if it would work, but there is a possibility it would) Ok...now this is another form of sustain...I have a Boss DD3 that has a hold mode that effectively holds what ever you are/were playing while the pedal is depressed...so you can hold a note indefinitely in a sampled loop in this way... Another way was done in a Boss distortion/feedbacker pedal (quite rare I believe) that also sampled and held notes I believe...I think it used continuous short sampling... Similar things are available once you get into synthisis and I wonder if a modelling guitar like line 6's couldn't perhaps do this digitally if they wished to develop it... These do not however actually sustain a string's vibration as we are attemptinjg to do. The absolute ultimate goal for me would be to produce a device analogous to the violin bow but that allowed all the same technique and sounds of the guitar yet seemlessly can be incorportaed and expand the guitar's expressive capabilities...I do not consider the sustainer to be an effect but an extention of the instrument... To achieve such a lofty goal you will need to be able to provide a consistant response (as col is seeking to do), expand the tonal variation (as I am trying to do by regaining pickup selection) and to provide an effective control and installation system. I'd like it to be as easy to use or ignore as a tremolo arm...at this point miniture digital or other push button switches really appeal to me. I know you could hide controls in a push pull knob and such, but I would really like to be able to simply touch a tiny switch on the guitar to produce sustain or harmonic effects to any particular note or passage of notes...just as a tremolo can be used to provide pitch bends as required... These types of things though are becoming closer...if I could make a mid driver that didn't require bypassing a simple SMD switch could be used to switch the device on, perhaps located on the driver itself... Anyway...it's good to aim high as you are likely to hit something...spending time on a mid driver, even if it fails, will only improve neck driver technology and the device as a whole... pete Oh...I have been meaning to ask...col, didn't you mention trying a pickup as a source for the driver so that the guitar's signla was not a part of the chain...if I remember, you suggested that you got microphonic feedback. I am intrigued that I didn't get a similar effect (though I did get distortion and other weird things happening) with my pickup over a sustainerized guitar... Link to comment Share on other sites More sharing options...
pillowhead Posted November 6, 2006 Report Share Posted November 6, 2006 Hey, all. This thread never ceases to amaze me. Speaking as a lurker who is responsible for a decent hunk of the near 70,000 visits, i've loved every minute of it. Anyway: Another way was done in a Boss distortion/feedbacker pedal (quite rare I believe) that also sampled and held notes I believe...I think it used continuous short sampling... Similar things are available once you get into synthisis and I wonder if a modelling guitar like line 6's couldn't perhaps do this digitally if they wished to develop it... These do not however actually sustain a string's vibration as we are attemptinjg to do. PSW, the dist/feedbacker works on a type of logic chip called a 'phase locked loop'. Basically it samples the incoming frequency and outputs a related frequency, be it unison, or pitchshifted through clocking the chip differently. The outgoing waveform is a pulse wave, and on the Boss it is filtered to make it sound like guitar feedback. For those interested, I think I got the schematic from www.freeinfosociety.org So, maybe it could be adapted for a sustainer, but it seems to me a complex and counter-intuitive method. The Ruby/Fetzer seems like a much more simple method. The PLL may or may not introduce phase problems, I'm not too certain, but it *is* a *phase locked* loop... Anyway, peace out. Simon. Link to comment Share on other sites More sharing options...
col Posted November 6, 2006 Report Share Posted November 6, 2006 Oh...I have been meaning to ask...col, didn't you mention trying a pickup as a source for the driver so that the guitar's signla was not a part of the chain...if I remember, you suggested that you got microphonic feedback. I am intrigued that I didn't get a similar effect (though I did get distortion and other weird things happening) with my pickup over a sustainerized guitar... There was no microphonic feedback, but the fizz was just the same, so for my purposes at the time, it was a failure. Of course, it's possible that the fizz was caused by other problems.... I'm guessing that the fizz has multiple causes anyway . But if you think it through, if the fizz is caused by transformer style magnetic feild coupling between driver and pickup, then having a seperate electrically isolated pickup for the sustainer isn't going to help - it only helps if the fizz is coming through electrical connections e.g. earth/power wires. Col Link to comment Share on other sites More sharing options...
col Posted November 6, 2006 Report Share Posted November 6, 2006 I am thinking maybe to design the circuit so it detects the frequency of the string vibrating and adjusts the frequency of the driver pulses to suit, but then there might be a problem where, as the string begins to slow down the circuit would notice and adjust the signal to the driver so the pulses dropped i can see i am going to have fun with this on another point, has anyone thought of using a digital latch type circuit that picks up the output of the pickups and then effectively "latches" the signal to sustain it infinitely (im not sure if it would work, but there is a possibility it would) I'm not sure why you would want to adjust the frequency of the driver pulses ? If you want to get harmonics, surely the easiest and most effective way is to use filtering to encourage resonance rather than some artificial signal generation..... As far as 'latching' the signal - assuming that I understand what you mean - that is something I have suggested as a possibility - using a comparator (or schmitt trigger) to generate a square wave from the guitar signal. Then using some sort of window detector to limit the amplitude above and below two user variable thresholds. There are a few potential issues here: #1 complexity of the circuit #2 it may be that using a square wave will have a negative impact on how the unit functions when chords are played #3 the window detector needs 'soft' corners... particularly for the upper level, it is importand that the threshold is not an abrupt on/off, because the systems will reach an equilibrium somewhere between the on and off points of this threshold. I have been considering a setup that involves using standard feedback compressor to generate a even amplitude signal, then applying a 'squelch' gate to didtch the low level signals, and a feedforward limiter to provide a 'soft' upper threshold. This looks like it should provide everything in terms of functionality. Unfortunately, the circuit is way too complex - too many op-amp stages and FETS - too much power to drive them etc. So I'm going to leave it for a while and then have another go using vactrol style resistive opto-couplers. yet again another point i have found to be true, kind of along the lines of the swing..... as i said above thought, i would be possible to create a circuit that detects the signal frequency and outputs the correct frequency to the driver........ Or, just use the input signal via an automatic gain control to feed the driver... hey wait a minute... firstly, no i have not tried it on a guitar yet, simply because i have alot of bugs to work out before i even prepare the pcb for the prototype, and fortunately you have pointed out some finerpoints i had not giving enough thought due to me being an impulsive little bugger and not thinkin enough about side effects I would suggest that you try it on a real guitar _before_ you start making pcbs... just use a plugboard, or stripboard... Remember, this is a deceptive project - it seems really simple, but in reality its tricky to get your head around all the variables and truly understand what is going on.... The best thing to do is make a driver coil and a simple fetzer/ruby type amp and try to get that working on a guitar... get your base camp set up before you try to tackle the north face secondly, yes i am good with digital electronics, i have passed my digital electronics at college with merit, although a lot of that was digital logic but i must say that i would NEVER even pretend to be an expert at it!!! i have done some P.I.C. programming as well though, i just need to do a bit more research on this precise field of design and i should be able come up with something that fits the specs req. the processing power you will need depends on what you want exactly you want to do, i would check into that field yourself and research it to decide on to use. I would guess that a minimum spec would be mono 8bit 22kHz. (better to use a higher sample rate than try to use 11khz then have to use bandlimited algorithms to deal with aliasing issues.). I'm not sure how much ram would be needed. Possibly very little - just enough for audio buffer, variables and a small stack. If we use a simple IIR averaging filter for the limiter control and don't try to introduce and fancy filters, it should be doable (depending on the instruction set) with somthing running a very low clock speed < 1Mhz... how fast are pics ? thirdly, you can buy off the shelf boards at relitively cheap prices, just go on google, at my college we imported P.I.C. program/test kits from america although i doubt you would need to go to such extremes to get a decent board. I had a quick google for ready to use dsp modules, but didn't find anything useful - mostly they seem geared for mobile phone handsets - no surprise there... cheers Col Link to comment Share on other sites More sharing options...
col Posted November 6, 2006 Report Share Posted November 6, 2006 thirdly, you can buy off the shelf boards at relitively cheap prices, just go on google, at my college we imported P.I.C. program/test kits from america although i doubt you would need to go to such extremes to get a decent board. Just been looking at some PIC datasheets - wow. I didn't realise that these chips had so many features - built in rom, ram, comparators, ADC.. most of what we would need. One thing I couldn't find out is what power drain to expect... also, do they need an external clock pulse, or other external support circuitry ? If not, we could just use a suitable pic and a suitable digital input class-d power amp, and that would be it apart from a few caps and resistors ? Col Link to comment Share on other sites More sharing options...
psw Posted November 6, 2006 Author Report Share Posted November 6, 2006 Welcome pillowhead...so you are one of the 70,000 club!!! That's right...the PLL...the name alone made me look into it and then found it used in this 'box. When I thought phase issues would be paramount (led on by the patents) I thought this thing would have an application (maybe it does) and it was discussed a little early on in the thread somewhere... This type of "effect" of course, is an imitation of actual feedback, but on this thread would still be looked at as a sustainer of sorts. Ansil posted some other ideas he was working on as far as "synthetic" sustain goes in a stompbox format, but I am not sure how far he went with it... Typically we are talking here about magntic sustainers that include the string in a feedback loop to physically move the string. I'd really like to change the name, the sustainer is a little deceptive as to what it can do BTW (and is trademarked)...but if we don't call it that people will be confused and other's will think we haven't heard of the "sustainer" and point it out... col... Remember, this is a deceptive project - it seems really simple, but in reality its tricky to get your head around all the variables and truly understand what is going on.... The best thing to do is make a driver coil and a simple fetzer/ruby type amp and try to get that working on a guitar... get your base camp set up before you try to tackle the north Excactly...we have all at one point in our enthusiasim jumped right in on this thing... It is deceptively simple yet deceptively tricky...and that is what is so appealing and beguiling.... Just been looking at some PIC datasheets - wow. I didn't realise that these chips had so many features - built in rom, ram, comparators, ADC.. most of what we would need. I was going to get into this myself, but there would be a very steep learning curve of course. A great little device. I think the power is pretty low and I was aware it had a lot of programmable functions, I think it is all there in the chip BTW waiting to be unlocked by software. As digital chips seemed to be bulky for switching, I had thought such a device could handle this kind of complex switching and may well have application for signal conditioning...I do know one guy down here who has used them for a stompbox of some kind, but they are rarely used...perhaps because of the steep learning curve... here was no microphonic feedback, but the fizz was just the same, so for my purposes at the time, it was a failure. Of course, it's possible that the fizz was caused by other problems.... I'm guessing that the fizz has multiple causes anyway You really don't like the fizz do you?! OK...I think that the fizz may well have other aspects, possibly phase or frequency related (given that it is worse in harmonic mode) and certainly I did find that the driver leads could induce it...hence my call to have the whole amp relocated away from other pickups and controls (near or in the driver) in an attempt to eliminate this aspect. But it is not the whole story... I found it interesting that the thing didn't squeel...but then the sustainer was separated from the signal chain so that for all I know it could have been squeeling...but why that didn't enter the signal chain is a little bit of a mystery, perhaps it did as this weird distortion.... One thing I didn't do with the hex devices is disconnect the pickups (we were aiming essentially for a virtually no-mod, stick on approach to installation)...Now I did get one working between the mid and bridge pickups on a cheap strat with real single coil pickups...driving one string... I had other's that sat on top of the middle pickup... Now of course I know that such a device on a pickup that isn't completely isolated from the rest of the instrument (even if not selected) was never going to work distortion free, even though it did provide sustain... It seems ludicrous now to think that you could put such a device on a coil and expect it to work effectively...but the isolation thing really didn't become apparent till I actually finally installed my current set up with the thin driver/pickup (you can see it's heritage here, right!)...as curtis has just found too... Now...what would have happened if that pickup had had it's wires cut...hmmm...it may well have worked as a mid-driver afterall! Deceptive little buggers...I hope I get that one back! So you see...an idea may well be very close, inpractical ideas may well spur practical solutions in another area of inquiry, and somewhere along the way something will likely emerge... ...we could just use a suitable pic and a suitable digital input class-d power amp, and that would be it apart from a few caps and resistors... And such a solution will look so simple and obvious...yet to get there we have to go through all this... I am hoping my real life will turn in such ways if I just keep plugging away at it...here's hopeing...meanwhile...it's back to work, it's 4am... pete Link to comment Share on other sites More sharing options...
curtisa Posted November 6, 2006 Report Share Posted November 6, 2006 Just a couple of quick replies, not much time today Just been looking at some PIC datasheets - wow. I didn't realise that these chips had so many features - built in rom, ram, comparators, ADC.. most of what we would need. One thing I couldn't find out is what power drain to expect... also, do they need an external clock pulse, or other external support circuitry ? If not, we could just use a suitable pic and a suitable digital input class-d power amp, and that would be it Been a while since I've done any PIC work. From memory, the bare minimum to get a PIC going is a crystal, two 100pF caps (all for the self generating CPU clock) and a 5V supply. The A/D converters aren't fantastic, and they need a fair bit of support code to get them going, especially if you're also aiming to do D/A as most of the PIC's I remember don't have integrated D/A converters. But some of them do have PWM which can be cobbled together to form a crude D/A section. Power drain is pretty good from what I remember - a couple of mA when running from a crystal clock. The biggest prob will be spending time coming up with the coding and then burning the code onto the chip. I have the software and chip burner at home, but it's been a while since I've done anything with it. You can probably find PIC burning companies that will mass-burn chips for our purposes (assuming no-one can burn the chip themselves). Oh, I spoke too soon about the DPDT sustainer on/off switch - the absolute minimum switch I can do it with is a 3PDT switch. At the moment I have noiseless sustainer ON, but when switching OFF the sustainer makes a farting noise, for want of a better term Current drain in my sustainer is 7mA when switched on and no signal passing through. Wasn't able to take a measurement when playing. I used the guitar in the weekend at rehearsal. I've made a recording of it, and will post a clip of it soon to illustrate how it works in practice. I too get fizz in clean mode, but I'm actually not that bothered by it - I kinda like the sustainer more when it's working as an effect with a high-gain amp Cheers, Curtis. Link to comment Share on other sites More sharing options...
spazzyone Posted November 7, 2006 Report Share Posted November 7, 2006 i would just like to say this thread has been amazing just the fact that nobody seems to be holding back on their discoveries and the sharing that has taken place is something to take pride in from sharing ideas to materials just blows me away. this is truly a "collective" experiment i just want to say thanks to all those nonselfish members that contribute to this thread as this would not take place in many other forums. im sure fernandes and sustainiac are biteing their nails about now. Pete what did you do spazzy Link to comment Share on other sites More sharing options...
GregP Posted November 7, 2006 Report Share Posted November 7, 2006 A big thanks from the lurker contingent, too. ;-) We might not have much to offer but support, but it's something! Go, guys, Go! Link to comment Share on other sites More sharing options...
psw Posted November 7, 2006 Author Report Share Posted November 7, 2006 Warning...long and far rangeing post alert... i would just like to say this thread has been amazing A big thanks from the lurker contingent, too. Thanks shawn, and gregP...a long time lurker of this thread and your encouragement is always a welcome treat... Yeah...I know a lot of people are following this thread with amazement...I certainly am and I think, if nothing else, it is entertaining to see a global collective at work...if this is the future of this kind of thing, bring it on! Oh, I spoke too soon about the DPDT sustainer on/off switch - the absolute minimum switch I can do it with is a 3PDT switch. At the moment I have noiseless sustainer ON, but when switching OFF the sustainer makes a farting noise, for want of a better term The prognosis I have had is that the driver coil stores some current and that there is a "backlash" of energy from the coil when the sustainer is switched off. In performance, you can turn it "off" by turning the sensitivity down to zero...but you will still have your other pickups bypassed. One solution would be to disconnect the driver and leave the amp in idle. One interesting feature of some of these alternate amps is a mute function. The BTL amps also are not connected to the guitars ground so the driver may be isolated. A dual coil HB like design may cancel out the pop as the backlash would be in equal and opposite directions... As both curtis and I both use a similar single coil driver, it is not surprising that it suffers the same symptoms... Another approach may be to disconnect the driver on switch off...but then you are looking at even more switching (hence a possible application for digital switching and perhaps a PIC could serve some purpose there, I don't know). I did try a few suggestions that are typically used in stompbox design, but the problem is a different one I beleive and these remedies didn't work for me... It is interesting that the fizz is effectively masked by even mild distortion, but an ultra clean potential (ie no fizz) is the ultimate aim. Clean controlled feedback is one of the potential unique sounds available with this device and is ultimately what should be strived for...exactly where this fizz originates is still not conclusive either and another of the enigmas of the project and so must be addressed if only by the curious. As curtis and I have found, it is still a worth while device even with this fizz and the true nature of this can be found in some of the sound clips for those concerned... I use a 4PDT switch because I have three pickups to contend with so you may well have a very similar switching to me...here's mine again... I am not even sure if this is adequate for a conventional strats wiring and I did have to comprimise my custom wiring to keep it to 4 poles. Such a switch is a little bulky (though it looks the same outside the guitar) and expensive and possibly tricky to find...I think mine was about $8. A single pickup guitar need only switch power SPDT and so is very easy...a mid driver as I am aiming for, with no mid pickup option, would be the same, as bypassing would not be required...yet another reason to strive in this direction. So...let's see...reasons for my seeking a mid driver option... Choice of pickups Some alleviation of the "action" effect on response Easier installation Lower cost Problems to overcome... There has been no conventional driver design yet able to operate that close to the source pickups Unknown effects of running a driver at this point in the string's length Reasons to think it is possible... Dizzy made a bi-lateral driver that worked in this manner (though with secret circuitry) Some of my Hex designs got close enough to work though suffered other unrelated problems Sustainiac have a patent that suggests that it did work at least in prototype form What is required... A better driver design to reduce EMI... A better understanding of what causes the fizz Some experimentation with different amps than the old LM386... ----- Dizzy was a little elusive about the guitar and the pics have gone but the track is an outstanding production and an ideal show piece for the device...I'll post it here and would encourage everyone to have a listen... Diablo Theme(1.44 Mb) Here is what he wrote about it... The driver is a much like Sustainiac bilateral driver. Signal from pickups goes to buffer with a very high impedance, then to a complicated phase and amplitude correction scheme, to a AGC circuit and finally to the power amp (lm386, heh). No a fundamental/harnonic mode because of placement of driver. Just a some mixed mode - harmonics on most bass strings and fund. on high strings. Varying picking style and switching to different pickup combintation, i got a different harmnonics. Almost all notes of the lead were picked with left hand only. Although Dizzy's circuitry is original, it clearly owes a lot to the ideas of the osborne/hoover sustainiac patent. ----- Now I know there are some tricks up our sleeves and a few areas to explore... Tim's making of compact coils will prove invaluable and things like stacked coils and compact bilateral designs have not yet been made. My thin driver may not be the last word either in coil design, though I am convinced of it's merits... Radical designs like side wound coils could be explored. ----- I may even reserect some of my Hex ideas to see if they could in fact be used... just the fact that nobody seems to be holding back on their discoveries and the sharing that has taken place is something to take pride in from sharing ideas to materials just blows me away. this is truly a "collective" experiment This is a guitly sore point with me however. The "technology" of the Hex Drivers (which involved no coil winding) has been a closely guarded and critisized secret...precisely because I havn't shared... I spent a whole year on these in various forms and perhaps there development and potential were hampered by that secrecy. Certainly I was under a little pressure to reveal what I was doing and a lot of suspition was cast on them... In the end, I gave up... I think people can "get" the idea of my wave driver...though I have done nothing to prove it's worth and it may come to nothing. The main aspect of the hex designs success was carried over...compactness...but others weren't...high speed, dual magnetic polarity high powered but "balanced" fields, composite sheilding, very fast ferrite materials, core direction, multiple cancelling coil like elements... The problem of course is that we are now getting into complex jigs hard to get materials...not at all DIY friendly... So, what do you do with an idea with some potential, a unique approach but that would lead people away from participation in the project and would ultimately end up with the disclosure without protection and potential exploitation...or a single working prototype that would still seem a mystery... If people couldn't follow what I am doing the life of this thread would die, surely... And, in the end, the hex experiments really didn't amount to anything and I can't help but feel I wasted a lot of time following the exotic...or aiming too high. Although it will be next year at least till I could resume any real work on these things, it would be an interesting discussion... im sure fernandes and sustainiac are biteing their nails about now. I think that they should/would be happy that we are doing so much to effectively promote their "product"...I am sure that we generate a fair amount of interest that translates to sales for them, so I don't think they would be too concerned, certainly they have never contacted me...though they might if I started selling anything. I really do give all these guys credit for all the work they have done and do actively endorse their products for anyone wishing an easy off the shelf product... but this is "project guitar" and this is a guitar project. Also...there are unique approaches that I have put forward...the thin driver, the pickup driver, simplification of the circuitry, etc...that are quite different. I trust that by disclosing my ideas so publically that I can claim prior ownership of these ideas and that they would therefore be effectively "public domain" and thus unpatentable... Perhaps we are entering an age where patents and copyrights are becoming blured and true ownership is a little hard to detirmine... It is interesting to see how internet technology can bring people together from all over the world to work collectively on something in this way and how people's ideas feed off one another and spur development of ideas to the point that "ownership" is very hard to detirmine. For instance...I did propose an idea for coil making, tim took it up and in his characteristic way, made it happen...was it my idea, his idea...or perhaps our idea... If not for this thread and the encoragement to do these things, would they ever be done at all...probably not... Philisophically, I find these things intiguing. The power of an audience is significant also. Anyone who has played guitar in front of an audience will know that an audience brings out something in your playing and rewards that can't be matched...so too, the lurkers who make a proportion of the nearly 70,000 visits also can claim credit for this thread and all that comes from it, not just the authors of the over 2,000 posts to date.... so endith another classically long post by yours truely... pete Link to comment Share on other sites More sharing options...
curtisa Posted November 7, 2006 Report Share Posted November 7, 2006 The prognosis I have had is that the driver coil stores some current and that there is a "backlash" of energy from the coil when the sustainer is switched off. In performance, you can turn it "off" by turning the sensitivity down to zero...but you will still have your other pickups bypassed. One solution would be to disconnect the driver and leave the amp in idle. One interesting feature of some of these alternate amps is a mute function. The BTL amps also are not connected to the guitars ground so the driver may be isolated. A dual coil HB like design may cancel out the pop as the backlash would be in equal and opposite directions... As both curtis and I both use a similar single coil driver, it is not surprising that it suffers the same symptoms... Welllllll, I wouldn't call it the same symptoms. You say you have an annoying "pop" whereas I have a mildly amusing "thbpbpbpbpbp" What's interesting to note is that I have a volume control (sits in the position in which the guitars' tone control used to be) between the JFET buffer and the LM386, so I can dial in the amount of drive being passed through to the sustainer. Even with this all the way to zero, ie no signal being passed to the sustainer, input shorted to ground, I still get the "thbpbpbpbp" when I turn off the sustainer. I'm starting to think that the noise I'm hearing is the LM386 in it's death throes as the battery supply disappears, not a backlash pop from the inductive load of the sustainer. If you think about it, it's very unusual to get a pop from most hifi amps when turning them off (at least in my experience), and they're connected full time to an inductive load too, ie the speaker. When I was testing the LM386 circuit in the bench before connecting it to the guitar, I had it driving a little 2" speaker just to confirm it was working. It never made much noise when I turned it on and off. At the moment my switching arrangement is toggling the battery +ve and -ve, whereas yours toggles the +ve only. Could be a clue there? You're also using a multi-stage transistor preamp in front of your LM386. I've only got a single JFET buffer connected as a source-follower, ie no extra gain. I'm also curious about some of these class-D chips I've seen mentioned here. Some of them have a standby mode which is claimed to be completely pop-free. All it does is place the driver chip to "sleep", but still powered up, with a current drain of a few nA (yes, nano not milli, that's not meant to be a typo). Cheers, Curtis. Link to comment Share on other sites More sharing options...
psw Posted November 7, 2006 Author Report Share Posted November 7, 2006 Well...I don't know... One man's "pop" may be another man's "thbpbpbpbpbp"...you may find it mildly amusing, I may find it annoying... D class would certainly be great...but no one has come up with something we could even experiment with...and even if we did, is there really a market for some kind of production to justify going that way into SMD technology.... Certainly, the LM386 is the most basic and approachable...but there maybe others and I for one want to check out BTL to see if that might work... When I was testing the LM386 circuit in the bench before connecting it to the guitar, I had it driving a little 2" speaker just to confirm it was working. It never made much noise when I turned it on and off. Exactly...so where is the noise coming from, why only on switch off...!!! How about simply disconecting the driver leads...wouldn't that turn it off without a pop...or not! If you think about it, it's very unusual to get a pop from most hifi amps when turning them off (at least in my experience), and they're connected full time to an inductive load too, ie the speaker. Well, my old Hi-Fi thumps...and my guitar amp...isn't there a de-thump circuit somewhere to eliminate this... While the fizz is not ideal...I don't think the "thump" or whatever it is, is acceptable....it is the main reason for not making my present circuit available in a kit form at this stage... perhaps there is some residual in the output capacitor that drains away... Anyway...it is a mystery to me...I would like to see it solved but it is probably secondary in the bigger scheme of things next to my mid-driver asperations...I expect someone will solve it in time, or a dual coil or other change may result in some solution.... Interestingly, Primal who also made a similar setup (F/R with single coil driver) but with no pickup didn't report having such a problem as I recall...could it be something transfered from the amp or the driver into this coil, or voltage inducted into the pickups coil that is released when it is switched off? I really don't know, but I'd like someone to do something about it, or at least put some thought into it...my only other idea is a separate system that uses a small pickup coil matched to the amp that makes the whole device separate from the guitar's signal chain...how big a pickup would be required I am not sure...but in effect we would have a giant fixed ebow... pete Oh yeah...I realised I mentioned this once before, but not posted it on this thread...a sustainer from 1892...no this is not a joke... nothing new under the sun... pete Link to comment Share on other sites More sharing options...
col Posted November 7, 2006 Report Share Posted November 7, 2006 Been a while since I've done any PIC work. From memory, the bare minimum to get a PIC going is a crystal, two 100pF caps (all for the self generating CPU clock) and a 5V supply. The A/D converters aren't fantastic, and they need a fair bit of support code to get them going, especially if you're also aiming to do D/A as most of the PIC's I remember don't have integrated D/A converters. But some of them do have PWM which can be cobbled together to form a crude D/A section. I've never done any PIC work. Only messing with ancient simple stomp box circuits. Seems that it would be fairly simple then as far as support circuitry - thats good. I'm not sure that a D/A section would be necessary, there are a number of low power class-D 'solutions' that have digital inputs - i guess for all the tiny media players that abound these days. Power drain is pretty good from what I remember - a couple of mA when running from a crystal clock. Excellent The biggest prob will be spending time coming up with the coding and then burning the code onto the chip. I have the software and chip burner at home, but it's been a while since I've done anything with it. You can probably find PIC burning companies that will mass-burn chips for our purposes (assuming no-one can burn the chip themselves). Programming is something I CAN do. My first assembly coding was on a ZX Spectrum in the early 80s ! More recently I've done some game boy advance stuff (ARM asm and C/C++). I've also done a little simple dsp stuff, using the VST kit from steiberg, and also building gadgets with sync modular and Reaktor(the new low-level 'core' tech). The PICs seem to have a lot in common with the ARM chips... risc instruction set... there are emulators for development.... anyhow, the coding wouldn't be a problem I think... Unfortunately, I don't have a pic programmer, and although some of them are really cheap(£20), I cannot justify spending money on that right now. Maybe at christmas I am very interested in this avenue though, it goes under vactrols on the 'try this next' list. I would also like to see just how easy it would be to set up a simple programmable dsp processor in stomp box format. I'd never considered it before, but now it looks possible. It would be good fun doing lo-fi diy digital fx hehe - nice departure from all that quasi religious germanium and tube based stuff. Imagine a DSP stomp box with a usb cable that you could plug into your pc and download homebrew fx from the internet - that would be mucho fun... like a lo-fi cheap POD with no pretentions and no restrictions. Current drain in my sustainer is 7mA when switched on and no signal passing through. Wasn't able to take a measurement when playing. Thats a nice low quiescent drain... will be somewhat different when sustaining I would imagine I used the guitar in the weekend at rehearsal. I've made a recording of it, and will post a clip of it soon to illustrate how it works in practice. I too get fizz in clean mode, but I'm actually not that bothered by it - I kinda like the sustainer more when it's working as an effect with a high-gain amp Looking forward to hearing that As far as the fizz, it one of those annoying 'matter of principle' things... I agree that the best use is with a nice overdrivven sound, however, I also want to play around with other possibilities, and that fizz just wipes out a whole area of 'tonal research' for me. cheers Col Link to comment Share on other sites More sharing options...
zfrittz6 Posted November 7, 2006 Report Share Posted November 7, 2006 For the subject of the commutation we have the 4017 which I have used in other projects along with the 4066 and goes very or without noise in the commutation and with possibility of exchanging many circuits that if sequentially, it comment by the subject of the programming of pics, that many do not tendran whereupon to program them or can be them complicated, for that reason I propose east circuit that is very simple and all the circuits can be exchanged that we wish. Salu2. Link to comment Share on other sites More sharing options...
psw Posted November 7, 2006 Author Report Share Posted November 7, 2006 zfrittz6 I am aware of this circuit...it is a members here father ...but each switch is a SPST so you would need a 14pin DIL 4066 at least just to do the bypass stuff just to trigger what I have with my 4PDT switch, it would be bigger and the circuit bigger than the entire sustainer circuit as it now stands so I couldn't justify something like this inside a guitar.... This kind of thing is as far as I understand in terms of digital stuff on a practical level. There must be an easier more compact solution but I don't know what it is, and perhaps there isn't without going to SMD type stuff... This is a neat circuit for sequential stompbox switching though, which is what it is designed for, worth checking out that site for that type of thing. As far as the fizz, it one of those annoying 'matter of principle' things... I agree that the best use is with a nice overdrivven sound, however, I also want to play around with other possibilities, and that fizz just wipes out a whole area of 'tonal research' for me. Yes...and that switch noise does the same for me...it also would mean that it is an all on, or off kind of device...ideally i'd like to be able to switch the "effect" on and off for the odd note or harmonic in a solo or for short phrases...the "pop" won't let me do that... Do you have switch noise with your dual coil driver guitar, col? It is frustrating to see all the tiny electronic products around these days and know how small this thing could be, but not be able to even approach the technology with experimentation on our level of expertise... pete Link to comment Share on other sites More sharing options...
col Posted November 7, 2006 Report Share Posted November 7, 2006 Yes...and that switch noise does the same for me...it also would mean that it is an all on, or off kind of device...ideally i'd like to be able to switch the "effect" on and off for the odd note or harmonic in a solo or for short phrases...the "pop" won't let me do that... If it came down to it, you could turn the gain right down, this would cause the sustain to be 'switched off' (effectively), and would reduce the power drain to something reasonable - 7mA for curtis' buffer/LM386, 11mA for my old LM13700 circuit... Do you have switch noise with your dual coil driver guitar, col? Still not done any conclusive tests, however, I've not noticed a pop or ffdphhhfffddddp sound, and I normally notice those kindsa things. Mind you, I'm just running a bridge humbucker and a dual rail driver. It is frustrating to see all the tiny electronic products around these days and know how small this thing could be, but not be able to even approach the technology with experimentation on our level of expertise... I think we can experiment with some smd stuff without too much hassle, I havn't yet because money is tight and I don't have any smd chips to play with I would be tempted to wire them 'dead bug' style to a SIP adapter.... or use the technique explained here. Then, once a circuit is finalised, find a company who will manufacture a small number of boards at reasonable cost - they do exist !!... the folks that make ExpressPCB might be a good place to start looking. Col Link to comment Share on other sites More sharing options...
curtisa Posted November 8, 2006 Report Share Posted November 8, 2006 One man's "pop" may be another man's "thbpbpbpbpbp"...you may find it mildly amusing, I may find it annoying... Well, it is annoying, yes. But it does sound funny Either way, yes, it'd be better if it didn't exist. The PICs seem to have a lot in common with the ARM chips... risc instruction set... there are emulators for development.... anyhow, the coding wouldn't be a problem I think... The software is free from the manufacturers website - http://www.microchip.com It's called (or at least used to be - haven't used it for some time) MPLAB. Looking forward to hearing that Here you go then : Linky Please 'scuse the quality - it's just a pair of mikes in the room. Just after the fade-in, you can hear me switch the sustainer in on fundamental mode, and then at about the 15sec mark I switch to harmonic mode for the rest of the recording. Cheers, Curtis. Link to comment Share on other sites More sharing options...
psw Posted November 8, 2006 Author Report Share Posted November 8, 2006 Looking forward to hearing that Here you go then : Linky Please 'scuse the quality - it's just a pair of mikes in the room. Just after the fade-in, you can hear me switch the sustainer in on fundamental mode, and then at about the 15sec mark I switch to harmonic mode for the rest of the recording. Excellent... Now that is a great example of how this device is not just about "infinite sustain"...those harmonic sounds are something that would be virtually impossible to achieve without the "sustainer" ...got to watch the ears on that high harmonic around 32secs ... Good to hear it in a band context too. It is nice that you haven't allowed the sustain ability to overwhelm your style showing that even with the device on you don't have to loose speed, it just provides more options in what you can do... I am sure you could see how it might be nice to add sustain or harmonics with a simple momentary switch so as to add these effects to a note or a chord...that might take a while...or to allow for pickup selection...but as it is, it allows for a broad range of extra expressive tones and techniques... Nice playing too, a mix of blues, fusion and rock without being too heavy on the shred...I'll be looking forward to hearing what you do with it once you have been playing with it a while...top notch... pete Link to comment Share on other sites More sharing options...
spazzyone Posted November 9, 2006 Report Share Posted November 9, 2006 (edited) great sound clip now i said this about col. but your a David Gilmour fan? but anyway it was very tastey sounding now when this http://i32.photobucket.com/albums/d38/femf...fan/ouch008.jpg heals i'll finnish a song i started that was written around the sustainer Edited November 9, 2006 by spazzyone Link to comment Share on other sites More sharing options...
psw Posted November 9, 2006 Author Report Share Posted November 9, 2006 70 thousand visits! Link to comment Share on other sites More sharing options...
curtisa Posted November 9, 2006 Report Share Posted November 9, 2006 great sound clip now i said this about col. but your a David Gilmour fan? but anyway it was very tastey sounding Thanks Pete and Spazzy. Yeah, I'm a bit of a Dave Gilmour fan, although as the saying goes, I like his old stuff more than his new stuff Cheers, Curtis. Link to comment Share on other sites More sharing options...
Roobin Posted November 9, 2006 Report Share Posted November 9, 2006 (edited) Hey guys, long time (and about double the amount of posts there were last time I looked!). psw, i liked this summary: So...let's see...reasons for my seeking a mid driver option... Choice of pickups Some alleviation of the "action" effect on response Easier installation Lower cost Problems to overcome... There has been no conventional driver design yet able to operate that close to the source pickups Unknown effects of running a driver at this point in the string's length Reasons to think it is possible... Dizzy made a bi-lateral driver that worked in this manner (though with secret circuitry) Some of my Hex designs got close enough to work though suffered other unrelated problems Sustainiac have a patent that suggests that it did work at least in prototype form What is required... A better driver design to reduce EMI... A better understanding of what causes the fizz Some experimentation with different amps than the old LM386... Could you possibly do a lowdown on the current state of neck sustainers? It would be handy to see where they stand. btw spazzy, nasty! Edited November 9, 2006 by Roobin Link to comment Share on other sites More sharing options...
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