col Posted September 10, 2006 Report Share Posted September 10, 2006 (edited) Hi again... A quick explanation of how i discovered this gargantuan thread: I've been playing guitar on and off for about 20 years, however for the last 5 years, after starting a family, it's been mostly acoustic - babies and loud noise don't get on I have tried numerous ways of getting my Rock'n'roll fix without the extreme volume, but nothing seems to work - without the volume, the guitar isn't alive. My most recent bout of stomp box building was a combo of Runoffgroove thunderchief & condor cabsim. These boxes are superb - they sound very convincing, however i was still left with the same feeling of something missing... then a thought came into my head. Back in the 80s I remember reading about the sustainer system U2s the Edge was using. I followed the releases of the sustaniac and fernandes systems and even had sustainer lust for a short time but empty pockets and a move into a more hendrixy style put it to the back of my mind.... Anyhow all this sustainer stuff came back to my mind - I started to wonder if an electro magnetic sustainer could replace that missing something that you get with loud volume. So I googled "DIY guitar sustainer" and here I am hehe. After one abortive attempt, I have constructed a working driver - its not perfect, but good enough to experiment with. I used some 6mmx2mm iron bar that i got from B&Q. The coil is 2mm deep with about 135 turns of .23 wire for about 7.5ohms. I made the driver core too long, it overlaps the strings a bit too far... also the bobbin wasn't quite wide enough so even getting it up to 7.5 ohm was a struggle - epoxy all over the place :-| fortunately i bought a pack of disposable latex gloves for protection. My next one will be better The main thing I've been working on is some circuit ideas. After breadboarding it, I figured that the Fetzer/Ruby isn't quite right - I couldn't get the fet to bias correctly. Not sure if this is because its a cludge of two circuits that were not designed to go together... or if I just messed it up. Anyhow, after some messing about with different input stages, i've settled on an op-amp based pair of unity gain buffers - one feeds the sustainer amp, the other is the guitar output - I Hope this setup will prevent any 'loading' that often happens when a guitar signal is divided between 2 amps without buffering. I'm having the usual issues with the top E string - it struggles on the first 6 or so frets, but improves higher up the neck. To get the high E going I had to turn up the gain so much that the A and G strings were much too 'lively'. Tweaking the output cap can help fix this, but it messes up the response of the low E and A... So I figured some sort of compression/Auto gain control(AGC) might help. After lots of web research, I have tried two approaches, a preamp with loads of gain that clips all input to about the same level, and a non-clipping AGC based on an LM13700 chip. So far, the Auto gain control approach seems much better. The guitar responds in a more natural way - more the effect I was hoping for, similar to being in a room with an amp turned up loud . The balance accross the strings is much better, so the LM386 doesn't have to be dimed ( i disconnected pins 1 and 8 and use an attenuator on the input to set the level ! What this means is that the thing draws much less current so the battery should last longer. My initial measurements are between 30 and 70 mA, so a 9v alkaline should last in the region of 10 hours (I'd be happy with that, so I hope its correct ). The downside of the LM13700 is that its fairly chunky, and with that, the buffer op-amp and the LM386, along with ~30 smaller bits and pieces, the circuit won't be so compact. Theres enough room in my axe, but maybe not some others. I still want to mess about with some combinations of filters to tweak the Phase and frequency response to control the Harmonic effects - I find the 180º phase trick to be a bit extreme, but some level of harmonic bloom is very nice - it would be good to have control over that with a knob on the front of the guitar - maybe a push pull job that doubles as an on/off switch. Fwiw I'll post a schematic when i'm happy with it. Hopefully, someone with better electronics skills than me can then take it and iron out all the noobie errors I've noticed some potential alternatives out there - lots of different multi-function ICs exist, the most promising I have found so far is the LA4160 which is a combined pre-amp, AGC, poweramp that has phase compensation and on/off click protection... it seems to be available in a traditional DIP package (i've not tried tackling surface mount components yet so DIP is good ). and it's "cheap as chips". If someone can hack together a circuit with it, it could be very promising. here's the datasheet for it Anyway thats enough from me... cheers, Col Edited September 10, 2006 by col Link to comment Share on other sites More sharing options...
axe_2_grind Posted September 10, 2006 Report Share Posted September 10, 2006 Alrighty, so I got my ruby circuit all wired (total noob job, pics coming soon ). Anyone know how to hook up a power LED? Anyway I'm trying the fetzer/ruby circuit first, but couldn't I built a preamp out of JFETs? Link to comment Share on other sites More sharing options...
psw Posted September 10, 2006 Author Report Share Posted September 10, 2006 Anyone know how to hook up a power LED? Just use a resistor to pull down the voltage for the LED to suit the powersupply (sorry, I don't have my book to give you the value) and connect it to the led then connect this pair to the + and - on the circuit. When the circuit is powered up, the LED will light also. After one abortive attempt, I have constructed a working driver - its not perfect, but good enough to experiment with. Most people find that they could make a better driver the second time around... After breadboarding it, I figured that the Fetzer/Ruby isn't quite right I have some reservations about it...but it does seem to work...so hey! Anyhow, after some messing about with different input stages, i've settled on an op-amp based pair of unity gain buffers - one feeds the sustainer amp, the other is the guitar output - I Hope this setup will prevent any 'loading' that often happens when a guitar signal is divided between 2 amps without buffering. I liked this idea...but now you have an active guitar. Just the one preamp can prevent loading and leave the guitar totaly passive and without any change in tone. A buffer though will counteract the loading caused by the guitar leads (like EMG's do) and give a "better", more HiFi sound. This isn't always what people want though, my initial aim was to keep it simple and to retain all of the instruments inherient characteristics (in my guitar these largely flaws and a little buffering would be a good thing I think). I'd like to see a circuit with an option of running the guitar signal through a part of the preamp if you wanted to, or ignore it if not, or even have it switchable between active and passive mode. So this is a good area to explore. The downside of the LM13700 is that its fairly chunky, and with that, the buffer op-amp and the LM386, along with ~30 smaller bits and pieces, the circuit won't be so compact. Theres enough room in my axe, but maybe not some others. Yes, and it is getting a little complicated for most. I made a compressor/limiter and built a LM3867 stage into it to test the Hex designs at one point and it worked well....with a bit of tweaking...but it wasn't really that practical. My preamp has so much gain, it kind of has it's own AGC because it drives it to saturation like an overdrive. It could be that my preamp's large gain helps via AGC and more square/fuzz type signal to drive the strings. If you look back, or on the net, you will find something called an "Aussie Compressor" that uses a feedback loop (as I recall) on a LM386 for AGC that was put forward as another circuit to experiment with for this project (certainly a lot smaller and cheaper approach). I still want to mess about with some combinations of filters to tweak the Phase and frequency response to control the Harmonic effects - I find the 180º phase trick to be a bit extreme, but some level of harmonic bloom is very nice - it would be good to have control over that with a knob on the front of the guitar - maybe a push pull job that doubles as an on/off switch. Well...you can kind of do that with the sensitivity control and/or technique. The harmonics do bloom if you pick very softly. I think you could do something with switchable output caps. I didn't get a chance to try out much but I have to wonder the effect of an even smaller output cap on harmonic response. I get this "bloom" on the lower strings with the 100uF and a reasonable high string response, larger (220uF) gives good solid fundumental bass notes but the high strings really struggle...but what of even smaller...would you get the bloom on the middle and higher strings, what would the bass notes do? A simple enough experiment, but alas, not one I can do at this time (sans soldering iron...if you have followed the sad events in my life the past year). Fwiw I'll post a schematic when i'm happy with it. Hopefully, someone with better electronics skills than me can then take it and iron out all the noobie errors I'll look forward to it, perhaps between us we could develop something especially for this project...this has been a bit of a frustration for too long! I've noticed some potential alternatives out there - lots of different multi-function ICs exist, the most promising I have found so far is the LA4160 which is a combined pre-amp, AGC, poweramp that has phase compensation and on/off click protection... it seems to be available in a traditional DIP package (i've not tried tackling surface mount components yet so DIP is good ). and it's "cheap as chips". If someone can hack together a circuit with it, it could be very promising. I'll have a look at it when I get some time...haven't seen that one, but I have seen stuff like it, but it is always in SMD. Not something that comes off the shelf I suspect, but worth a look-see. Thanks for the tip... Anyway thats enough from me... me too, cheers to you... pete Link to comment Share on other sites More sharing options...
axe_2_grind Posted September 10, 2006 Report Share Posted September 10, 2006 (edited) Ok. finally some photos... Here's my ruby sans LED ...and the total noob job wiring... I used a 16pin socket because I had them sitting around from my failed Tube Sound Fuzz project. (OK different project altogether, but I discovered I was using the wrong type of 4049 chips, schematic called for a CD4049, the ones I bought were MC14049BCP. When I switch it on, all I get is a hum, and that's mainly from the wall-wart I was using to test it out.) Anyway... So pins 5-8 on the IC take up holes 13-16 on the socket, and the MPF102 JFET fits into 6, 7, & 8 (gate side on 8) The layout may not be the best, but hey, it's my first build. Next one 'll be better (i hope) I've since attached a power LED from a SPDT switch with a 100ohm resistor and to ground. The switch is wired from the positive battery lead to the coupled Resistor/LED connection and to the board. Thus I have my On/Off switching done. Next will be the phase switch and the driver build. I still need to get the wire and bar magnet or steel bar for the driver. So now the fun stuff begins!! For the phase switch I assume you just use a DPDT switch with wires crossing in an X shaped pattern on the outside lugs? (Y/N)??? Edit: just for the hell of it I decided to solder on output & input jacks and it seems to work ok. I get a little bit of squeal though when I switch it out of phase. I'm just having fun right now messing with the controls. It does seem, hoever, that the "trim" control is crucial to getting this thing to even work. There also seems to be a balance between the gain and volume settings that seems to be optimal. I guess it just takes some playing around with. Edited September 11, 2006 by axe_2_grind Link to comment Share on other sites More sharing options...
psw Posted September 11, 2006 Author Report Share Posted September 11, 2006 Haha...I like the shopping lists in the background!!!! It's a fine start, and I am sure you could make it smaller and neater the next time around if required. For the phase switch I assume you just use a DPDT switch with wires crossing in an X shaped pattern on the outside lugs? (Y/N)??? Y Edit: just for the hell of it I decided to solder on output & input jacks and it seems to work ok. Good idea...I always recomend that people try out the circuit with a little speaker (the kind from an old radio or computer is fine) just to see that it does in fact work...it is afterall, simply a practice amplifier. good start... pete Link to comment Share on other sites More sharing options...
TeiscosRock Posted September 12, 2006 Report Share Posted September 12, 2006 (edited) More questions, this time having to do with switching. . . THe thing is, I'm operating on a tight budget here, and am also wanting to build a Bassman Ruby to use as a practice amp. Sooooo Does the on/off switch for the sustainer circuit need to be DPDT (is true bypass necesary in an onboard circuit)?, or can I use a simpler, cheaper SPDT? Also, I'm thinking of taking the push-pull pot out of my Tele to use as the phase switch/volume control for guitar - there shouldn't be a problem with this, correct? I believe push-pulls are DPDT. . . Edited September 12, 2006 by TeiscosRock Link to comment Share on other sites More sharing options...
psw Posted September 12, 2006 Author Report Share Posted September 12, 2006 More questions No problem... I'm operating on a tight budget here I understand!! Does the on/off switch for the sustainer circuit need to be DPDT (is true bypass necesary in an onboard circuit)?, or can I use a simpler, cheaper SPDT? Well...I've forgotten, is this a single bridge pickup guitar we are talking about here? If so, probably a SPDT switch would be fine...just turn off the power. If there are other pickups, that becomes a little more complex...that is where you need to bypass other pickups and engage the bridge pickup no matter the location of the selector. On my three pickup Strat, I needed a 4PDT switch. Also, I'm thinking of taking the push-pull pot out of my Tele to use as the phase switch/volume control for guitar - there shouldn't be a problem with this, correct? I believe push-pulls are DPDT. . . Generally they are...a DPDT switch has six lugs/connection points. The wiring of this is illustrated somewhere here, but you are right that it is a simple X style phase switch on the driver. Hope that helps... pete PS...for experiments sake, you could just pull the battery off it's connector for the on/off switch and manually switch the wires over for the phase of the driver so that you know everthing is working as you hoped before committing to the $$ for the switches. Link to comment Share on other sites More sharing options...
Primal Posted September 12, 2006 Report Share Posted September 12, 2006 So, I've run into a problem with my circuit: it magically just stopped working. I think the transistor blew, because there is some white power between it and a resistor (maybe the resistor heating up overheated the transistor?). Anyway, since I've got this all out of my guitar, if anyone is interested I can post some pictures of my actual circuit board so you all can see just how small you can get it (and it could be made even smaller if you work at it). Col, if you could post your circuit, it would be great. I'm using the Fetzer/Ruby amp, and I don't think that its powerful enough because it distorts too easily (my gain is at about 1/2 just to keep it from distorting, which was coming through the amp and making a horrible sound). Link to comment Share on other sites More sharing options...
col Posted September 12, 2006 Report Share Posted September 12, 2006 (edited) So, I've run into a problem with my circuit: it magically just stopped working. I think the transistor blew, because there is some white power between it and a resistor (maybe the resistor heating up overheated the transistor?). Anyway, since I've got this all out of my guitar, if anyone is interested I can post some pictures of my actual circuit board so you all can see just how small you can get it (and it could be made even smaller if you work at it). Bummer. what does the white powder look like ? is it on the transistor, or on the solder joint ? do you have a multi-meter? If so, when you replace the blown bits (assuming they're blown), you should check the voltage on the transistor pins, and measure the current going through it to make sure they are within the limits on the datasheet for that transistor. If I remember correctly, you are using a supply greater than 9v ? Maybe some of the other component values need tweaking ? fwiw, I always use sockets for transistors - i get stuff called SIL socket strip, and break off 3 hole chunks Col, if you could post your circuit, it would be great. I'm using the Fetzer/Ruby amp, and I don't think that its powerful enough because it distorts too easily (my gain is at about 1/2 just to keep it from distorting, which was coming through the amp and making a horrible sound). It distorts because its designed to . It is a guitar amp after all. A hot passive humbucker can pump out as much as 2.5 volts when you play hard, it won't be that much when the note is decaying. With the sustainer constantly exciting the strings who knows... (just checked, mine is steady at about 100mV The Ruby is based on an LM386 which has a gain from 20 to 200, even at minimum setting, it will probably start clipping at about 400mV (guessing). As you can guess, you don't need much more than minimum gain to get clipping with this setup A few more measurements from my circuit... When the thing is sustaining, the voltage after the gain control is at about 120 - 140 mV. I reduce to 60 - 80mV with a pot before the lm386 input and still get a good sustain - (this is a good thing - the less you put into the lm386, the better the battery life). Of course, how much juice you need to feed the lm386 depends on how efficient your driver is, and possibly even on which kind of lm386 chip you are using !? (not sure - enyone?) So, I set my LM386 up with minimum gain (no cap or pot between pins 1 and 8) and put an attenuator on the input. (My bridge pickup is a duncan JB, it has loads of power, possibly a more subtle single coil pickup would need some power amp gain or a preamp instead of just a buffer - not sure.) As far as posting my circuit, I will do that after some more tweaking and testing. I'm no electronics Whiz, and I don't want to 'publish' some junk circuit that doesn't work properly and breaks down after a few weeks . Its also very complicated, and not finished..... It's not even soldered up yet - still on a bread board. cheers col. Edited September 12, 2006 by col Link to comment Share on other sites More sharing options...
psw Posted September 12, 2006 Author Report Share Posted September 12, 2006 So, I've run into a problem with my circuit: it magically just stopped working. I think the transistor blew, because there is some white power between it and a resistor (maybe the resistor heating up overheated the transistor?). Sorry to hear that Primal...hmmm...I have never had this problem but then I haven't used this circuit. Nothing in mine gets that hot. I have made several of my versions and all still work/ed fine and there was no overheating of the circuit itself. I used to use a powersupply at one stage with a variable voltage so have run mine at 12volts. I can only assume that your voltage current difference (12volt battery pack) is the problem but I can't imagine why. Great reply Col... fwiw, I always use sockets for transistors - i get stuff called SIL socket strip, and break off 3 hole chunks sockets are cheap and a great idea. Makes troubleshooting something like this a lot easier, but also prevents ever burning out a component through over heating with the iron and for doing tweaks and such. Of course, how much juice you need to feed the lm386 depends on how efficient your driver is, and possibly even on which kind of lm386 chip you are using !? (not sure - enyone?) True...the driver is crucial. There is talk that not all lm386's are equal (though their specs are the same) but mine have not been anything special and all have worked. It distorts because its designed to . It is a guitar amp after all. Well...there's distortion and distortion. It is certainly not a clean amp and it is running at some power. It is used in radios and such though, so it is not necessarily "designed for distortion". Perhaps there is a clue or symptom in the distortion that is coming out of the thing...another reason to test it with a speaker. So, I set my LM386 up with minimum gain (no cap or pot between pins 1 and 8) and put an attenuator on the input. (My bridge pickup is a duncan JB, it has loads of power, possibly a more subtle single coil pickup would need some power amp gain or a preamp instead of just a buffer - not sure.) The "Ruby" uses a simple buffer but the "fetzer" is a low powered preamp. The preamp is there to raise the gain a little and to prevent loading. Without it, the "sensitivity control would act as a volume for the whole guitar if you think about it! The idea of the buffer/preamp stage is to help match impedances so as to allow the lm386 to work efficiently also. I do have fairly wimpy single coils (actually a cheap stacked humbucker at the bridge) in the strat and extra gain is a good thing in the preamp. But, I run enormous gain to saturate the signal and thus achieve an overdrive effect that gives a more distorted square wave effect and perhaps more importantly, Automatic Gain Control (AGC) or compression. That is, like a fuzz, all the played notes sound at pretty much maximum volume. (well, that's the idea). I am amazed if you can get the thing to work with such little gain from a battery! My lm386 is pumping out at 10x yours and you have the preamp/AGC effect too. Perhapos there is some mojo in your driver there, or perhaps you have another effect that can occur with interactions between the driver and the pickup. I forget what I called it, but you can get an effect where there is what appears to be magnetic sustain but is really a very heavy compression and the notes will not be infinite. This is usually accompanied by enormous distortion and squealing when ever a note is not played so it is pretty easy to spot. I was wondering if this was what spazzy was experiencing at first, but apparently this is not the case. Anyway...must run...a busy time...back later! pete Link to comment Share on other sites More sharing options...
col Posted September 12, 2006 Report Share Posted September 12, 2006 Hehe, this is probably premature - but I'm excited so I'll post it anyhow I've been messing about trying to get the lower few frets and open note on my high E string to work, and I think I may have found a partial solution. The thing is that it also evens out the overall response more, and best of all, reduces the current draw on my setup to between 12 and 35 mA !!! thats getting really good for battery consumption. OK, so I'm excited, and I've probably missed some big gotcha, I will keep testing it, and fingers crossed it will work out just fine. The basic solution is the result of some circuit 'bending' I was doing. I have built what might be called a 'Volume Inverter'. Maybe someone here with a background in electronics may be able to shead some light on this? any 'correct' way of achieving similar results? What happens is, you feed it a really low signal, you get back a big one, you feed it a big signal, you get back a small one... e.g. 2V in => 250mV out 600mV in => 300mV out 40mV in => 600mV out (The response starts to drop back down again at 20mV, at 14mV output is back down to 300mV) for a sustainer, this is cool. It means the amp works hard to bring a small signal up to a level where it can get the strings moving, then it eases off using just enough juice to keep them going. Ideally, this effect could be even more exaggerated - if 2V in gave 5mV out and 20 mV in gave 800 mV out, we really would be cookin' on gas. The less the sustainer interferes with the natural vibration of the strings the better, so if the thing only worked when it was absolutely required it would be great - much more natural sound - much less battery usage == less of a novelty/effect, more a very useful tool. (of course, there could be a knob to tweak the response so we can have extreme sustainer if required ) Right now, the thing I'm most worried about is that I may be abusing the chip... I've checked the datasheet, and everything is well within the absolute max ratings, but I'm not sure if long term use might still cause problems - I guess I'll have to wait and see. Another likely issue is that amplification of small signals might make the system more sensitive to EMI. If this is a big problem, possibly some sort of 'squelch' may be necessary - don't want to have even more circuitry though Col. Link to comment Share on other sites More sharing options...
col Posted September 13, 2006 Report Share Posted September 13, 2006 Of course, how much juice you need to feed the lm386 depends on how efficient your driver is, and possibly even on which kind of lm386 chip you are using !? (not sure - enyone?) True...the driver is crucial. There is talk that not all lm386's are equal (though their specs are the same) but mine have not been anything special and all have worked. Yes, there are a bunch of different specced lm386 versions. They are tuned to work best in different contexts - smaller and larger voltage supplies etc. They have different max ratings etc. Other than the min/max supply requirements, I'm not sure that the differences would matter much to us. Best to avoid the M and MM versions - those seem to be surface mount, and lower overall power rating. The N-1,N-3 & N-4 seem to be similar but do have different max and min power and dissipation specs. My chip is an LM386N-1 So, I set my LM386 up with minimum gain (no cap or pot between pins 1 and 8) and put an attenuator on the input. (My bridge pickup is a duncan JB, it has loads of power, possibly a more subtle single coil pickup would need some power amp gain or a preamp instead of just a buffer - not sure.) The "Ruby" uses a simple buffer but the "fetzer" is a low powered preamp. The preamp is there to raise the gain a little and to prevent loading. Without it, the "sensitivity control would act as a volume for the whole guitar if you think about it! The idea of the buffer/preamp stage is to help match impedances so as to allow the lm386 to work efficiently also. Yeah, I should have been clearer on that ... in my circuit, the attenuator is between the AGC and the input of the LM386 - there are buffers on the main circuit input I am amazed if you can get the thing to work with such little gain from a battery! My lm386 is pumping out at 10x yours and you have the preamp/AGC effect too. Perhapos there is some mojo in your driver there, The thing about the power consumption is that the LM386 - when its driving an 8ohm load - draws a LOT more current than normal stomp box circuitry. So adding in a few op-amps really doesn't make much of an impact... So if you can get them to 'condition' the signal to allow the LM386/driver combo to work only just as hard as it needs to and no harder, it's like buying a dollar for a cent - you spend a few milliamps to save a few tens of milliamps (or more as it turns out (I hope)). ...or perhaps you have another effect that can occur with interactions between the driver and the pickup. I forget what I called it, but you can get an effect where there is what appears to be magnetic sustain but is really a very heavy compression and the notes will not be infinite. This is usually accompanied by enormous distortion and squealing when ever a note is not played so it is pretty easy to spot. I was wondering if this was what spazzy was experiencing at first, but apparently this is not the case. Nah, it's not that kind of thing - this is proper sustain - lovely stuff. All my testing has been with headphones - or just the guitar/sustainer with no powered output. My 'Volume Inverter' is causing some EMI feedback when there are no notes being played and the strings aren't muted - I suspected i might. This quickly excites the strings and turns into normal sustain, but it's still unacceptable. Shouldn't be too hard to fix though (famous last words ). I thought that spazzy might be getting sustainer feedback supported by traditional 'loud guitar in a small room' feedback, but hey, I havn't posted ANY evidence that my setup even exists so who am I to say. What I am truly concerned about is the idea of feeding a normal pickup with the output of a full-on guitar poweramp though (I wonder when this thread will run out of batteries) cheers col Link to comment Share on other sites More sharing options...
psw Posted September 13, 2006 Author Report Share Posted September 13, 2006 (I wonder when this thread will run out of batteries) Not if we keep inspiring great posts like these and people keep attempting to build and develop the thing...it is truely astonising how long and how big this thread has run The thing about the power consumption is that the LM386 - when its driving an 8ohm load - draws a LOT more current than normal stomp box circuitry. Absolutely...you are going to have to have access to the battery. This thing is an amplifier, a small one, but a power consuming device running an "unsusal" load. The lm386 is the simplest, widest available, foolproof solution to the driving of this device. But that is only the start of the story. I am keen to explore alternatives. Ideally, this effect could be even more exaggerated - if 2V in gave 5mV out and 20 mV in gave 800 mV out, we really would be cookin' on gas. The less the sustainer interferes with the natural vibration of the strings the better, so if the thing only worked when it was absolutely required it would be great - much more natural sound - much less battery usage == less of a novelty/effect, more a very useful tool. (of course, there could be a knob to tweak the response so we can have extreme sustainer if required ) I have the general idea about "voltage inverters" but it will draw what is required to power it, no power is free and the current is the real draw that flattens the batteries. I am amazed at the little power that you are apparently using and would love to see some detail (either here or email me). I can see that the lm386 can draw very little power if run at a low gain (pins 1&8 open) but I really do need that power to get the full effect. My preamp is giving plenty of juice to the lm386 and is based on a tested design that was built to interface with it. That said, battery consumption isn't that bad, but for on board electronics, something that lasts a few days or weeks of intermitent use, will still require easy access and replacement. The second half of this quote is interesting. This is not a novelty effect (as I see it), it holds some promise to fundumentally change the character of the instrument === in the right hands I agree though that a more "natural" responsive sustain is desirable and may address some of the power issues. One problem with the approach of the power inverter is going to be at a point where the instrument is "silent" (nothing truely is of course) and the circuit is trying to drive this silence at full power and causing the EMI problem. Some kind of limiter is also in order. I does concern me that this circuit is getting a little complicated and moving more and more towards the kind of sophistication described of the commercial units. In my work, I have sought to address this with a fast driver design...and more development could be made with the physical driver design and construction yet, without resorting to excessive circuitry...just a thought. The resulting runaway effect of amplifying "silence" is very similar to the effect I was trying to describe of an "inductive feedback loop" (as I think I called it) where the coil of the driver and the pickup, acts like a transformer. The sensitive pickup, senses the signal of itself eminating from the driver heavily amplified then plays it back through both the circuit and the amplifier quickly reaching saturation and loudest possible signal (hence massive distortion), but it is not actually driving the strings but the pickup itself. There is an old thread called ansil's sustainer mod which a speaker is attached to the pickup, hence driving it in the above way, not really creating infinite sustain as we are seeking here...more of a compression/feedback device. Interesting in it's own way. I thought that spazzy might be getting sustainer feedback supported by traditional 'loud guitar in a small room' feedback, but hey, I havn't posted ANY evidence that my setup even exists so who am I to say. What I am truly concerned about is the idea of feeding a normal pickup with the output of a full-on guitar poweramp though I am not sure what is happening with Spazzy's experiment as the impedances are all over the place, but it does seem he is getting infinite sustain as it works with headphones and doesn't squeal when he stops playing. There video evidence to prove the point too, so it is hard to deny. But I share your concerns there and the results don't quite have the finesse of the more developed forms. That said, I have to admit to trying similar experiments and did get some kind of sustain many, many years ago, as described in my first post here. (not really advisable). You are on the right track though and keep up the thoughts and posts. I don't recall if you described your driver, perhaps some more on that and some pics or illustrations to show how you are doing the experiments might help. pete Oh, yes...and I have recently recieved PM's from a member in contact with Sustainiac who have raised some interesting reservations about a proposed installation. In particular is the distance of the driver from the strings, the inability to cope with a nonmagnetic cover and especially the effect the driver would have on a single coil mounted in the mid position. This last reservation is interesting and may show up some faults in the "bi-lateral" z-coil type design they use...lends more credance to a rail style solution as spazzy was working with. Stay tuned for more... Link to comment Share on other sites More sharing options...
axe_2_grind Posted September 13, 2006 Report Share Posted September 13, 2006 (edited) (I wonder when this thread will run out of batteries) Not if we keep inspiring great posts like these and people keep attempting to build and develop the thing...it is truely astonising how long and how big this thread has run As I said a couple of pages ago, this thread itself seems to have infinite sustain. Seriously. I think a lot of guitarists are intrigued by this idea (I wanted a sustainer ever since I watched Steve Vai using one), and the input that everyone has contributed to this thread speaks volumes. You've seriously struck a chord with a lot of people who would like to try this for themselves. Myself included. It was someone over on UG (ultimate guitar) that referred me here, and after looking at Ansil's Project, and subsequent thread, I found this one. I jumped around a bit (not wanting to have to read the WHOLE thing of course) and I knew I had to try it!! Col, I am intrigued by your circuit now. What you describe as a "more natural" kind of sustain, and the idea of longer battery life. Actually what you describe sounds very much like the way a compressor acts. You set a "threshold' and the signal is supposed to be amplified to that point, no further. It more or less balances itself out. I agree with PSW, seems like a Limiter, or perhaps a gate, is all that's missing now. I look forward to seeing a schematic when you get around to it. And maybe some sound clips too? Edited September 13, 2006 by axe_2_grind Link to comment Share on other sites More sharing options...
psw Posted September 13, 2006 Author Report Share Posted September 13, 2006 Seriously. I think a lot of guitarists are intrigued by this idea (I wanted a sustainer ever since I watched Steve Vai using one), and the input that everyone has contributed to this thread speaks volumes. Yes, well I was inspired by the idea, so simple, yet... Oh...and bowed instruments...my daughter plays violin, maybe there is something in the genes that longs for long notes! Now she is going to take up the flute. I tell her to play the guitar, she just says, well I can learn that myself like the keyboard, I do play it a little most weeks, you know you can learn it yourself, dad! I'm missing her a lot right now Anyway...Hendrix was another that I could site as someone who really was exploring the use of feedback and such... Col, I am intrigued by your circuit now. What you describe as a "more natural" kind of sustain, and the idea of longer battery life. Actually what you describe sounds very much like the way a compressor acts. You set a "threshold' and the signal is supposed to be amplified to that point, no further. It more or less balances itself out. I agree with PSW, seems like a Limiter, or perhaps a gate, is all that's missing now. Yeah, possibly...but it could get complicated. Beware...just look at the year of development in my Hex designs... Speaking of which...I built such a thing during those times (a compressor/limiter) as a preamp with a lm386 module tacked on to do such experiments...here's a bad picture... The box with the 4 green knobs is the device. A little big to fit inside the guitar... This and more is now in the custody of my ex-wife...grrr Anyway...it is interesting to see how close and small I was getting these little sustainer thingies...this one was a single string version and you can see that I was able to get it working midway between the mid and bridge pickups on this strat. The idea worked, at the time I was thinking clean amplification was the way to go...maybe it is...so I needed more headroom and better preamplification. This worked well, but you had to do a fair amount of tweaking. After all that, as I recall, I plugged the device into the smaller black box which contained an early version of my present circuit and it worked just as well...without tweaking it....hmmm So...I do hope that in the near future I too can do some more work on this, you guys keep me interested, even after having achieved a result with a working guitar. Perhaps I could put some more sounds together or something...take my mind off the trials and such! You can't have this many pages and words without a little of the personal life coming out nownagain... thanks for the distraction... pete Link to comment Share on other sites More sharing options...
col Posted September 13, 2006 Report Share Posted September 13, 2006 ...I think a lot of guitarists are intrigued by this idea (I wanted a sustainer ever since I watched Steve Vai using one), and the input that everyone has contributed to this thread speaks volumes. You've seriously struck a chord with a lot of people who would like to try this for themselves. Myself included. It was someone over on UG (ultimate guitar) that referred me here, and after looking at Ansil's Project, and subsequent thread, I found this one. I jumped around a bit (not wanting to have to read the WHOLE thing of course) and I knew I had to try it!! Yeah, I've been aware of sustainers since the Edge started using the 'Infinite Guitar' Col, I am intrigued by your circuit now. What you describe as a "more natural" kind of sustain, and the idea of longer battery life. As I've explained, my motivation for building and helping to develop this app is to try and get the same response from an amp sim/headphones/pc recorder setup as I can get from a LOUD amp in a room. So from my point of view, the more natural it sounds the better. In addition, I know that if the batteries only last 2 or 3 hours, it will be impractical. (Personally, I'm willing to sacrifice having a neck pickup in order to achieve the other goals.) Actually what you describe sounds very much like the way a compressor acts. You set a "threshold' and the signal is supposed to be amplified to that point, no further. It more or less balances itself out. I agree with PSW, seems like a Limiter, or perhaps a gate, is all that's missing now. Its kind of like a compressor on pcp... with a compressor, even with extreme settings, it doesn't invert the dynamic range, it just reduces it. I tried that first, and although it does help, it's never going to be a total solution. The problem is that some of the strings and notes on the guitar will vibrate more readily with the same driver input - while others (high E string) need much stronger input to come through... so even if you compress the signal so all input levels give an equal signal level to the driver, some strings will sing loud and rattle the frets while others will struggle to sustain at all. A limiter is of even less use - it just reduces the volume of the loud bits... Using a 'Dynamic Range Inverter' (DRI) goes some way towards improving things. A simple threshold noise gate (squelch) may be necessary to bring my DRI into line and kill the EMI feedback. It is set up so that the amplification drops back off below the amplitude that my high E string produces, however it does still make the thing more prone to EMI feedback I look forward to seeing a schematic when you get around to it. And maybe some sound clips too? Sound clips soon, scheme when it's finished, tested, debugged etc. cheers, Col Link to comment Share on other sites More sharing options...
col Posted September 13, 2006 Report Share Posted September 13, 2006 Ideally, this effect could be even more exaggerated - if 2V in gave 5mV out and 20 mV in gave 800 mV out, we really would be cookin' on gas. The less the sustainer interferes with the natural vibration of the strings the better, so if the thing only worked when it was absolutely required it would be great - much more natural sound - much less battery usage == less of a novelty/effect, more a very useful tool. (of course, there could be a knob to tweak the response so we can have extreme sustainer if required ) I have the general idea about "voltage inverters" but it will draw what is required to power it, no power is free and the current is the real draw that flattens the batteries. I am amazed at the little power that you are apparently using and would love to see some detail (either here or email me). I can see that the lm386 can draw very little power if run at a low gain (pins 1&8 open) but I really do need that power to get the full effect. My preamp is giving plenty of juice to the lm386 and is based on a tested design that was built to interface with it. That said, battery consumption isn't that bad, but for on board electronics, something that lasts a few days or weeks of intermitent use, will still require easy access and replacement. Assuming that I've not made some critical mistake in my measurements etc. (big assumption), you should be able to get a similar battery life using a similar circuit. The trick is in conditioning the signal prior to feeding it into the LM386. Unless you have some hardware on your axe that dampens the strings, or some other impediment, or your drive is very different, it should work. Of course, its possible that you are going for a different end result, and that you would prefer the sound of my setup 'juiced' to the max The second half of this quote is interesting. This is not a novelty effect (as I see it), it holds some promise to fundumentally change the character of the instrument === in the right hands I agree though that a more "natural" responsive sustain is desirable and may address some of the power issues. My reference to a novelty is related to the practical implications of battery life, not the quality of the effect. e.g. IMO a sustainer with a 3 hour battery life is a novelty no matter how good the effect - no-one who is serious about guitar playing is going to incorporate something that expensive and hasslemungous into their playing style - it would just be used as an occasional trick. On the other hand, a 20 hour battery life would move it into the realms of 'useful tool' - it starts looking more like a candidate for permanent installation. If you can have the thing switched on all the time you're playing without having to change batteries every few hours, then you can really start exploring its capabilities, and you have a better chance of developing a unique sustainer dependent playing style - of course, if you have it switched on all the time, it must not have a detrimental impact on your normal sound/style... One problem with the approach of the power inverter is going to be at a point where the instrument is "silent" (nothing truely is of course) and the circuit is trying to drive this silence at full power and causing the EMI problem. Some kind of limiter is also in order. I does concern me that this circuit is getting a little complicated and moving more and more towards the kind of sophistication described of the commercial units. In my work, I have sought to address this with a fast driver design...and more development could be made with the physical driver design and construction yet, without resorting to excessive circuitry...just a thought. when the instrument is silent, it won't amplify - the Dynamic Range Inverter amplification tails off below about 20mV. Its still an issue though - low level EMI feedback that would not have caused problems in a simpler system can still be amplified. So the EMI badness threshold is more sensitive. As far as complexity, right now its about 35 components chips and all - not a huge circuit . I have one half of a dual op amp spare in there, so I'm hoping to use that for some kind of squelch without making much inpact on the component count or board size - fingers crossed. The resulting runaway effect of amplifying "silence" is very similar to the effect I was trying to describe of an "inductive feedback loop" (as I think I called it) where the coil of the driver and the pickup, acts like a transformer. The sensitive pickup, senses the signal of itself eminating from the driver heavily amplified then plays it back through both the circuit and the amplifier quickly reaching saturation and loudest possible signal (hence massive distortion), but it is not actually driving the strings but the pickup itself. There is no runaway effect - as soon as the EMI feedback gets up to sustainer level, the amplification is reduced, and the strings start to take over with normal sustain - you can still hear it squeal a little though which is not acceptable I don't recall if you described your driver, perhaps some more on that and some pics or illustrations to show how you are doing the experiments might help. I did, although only briefly. The core is 60mm x 6mm x 2mm iron bar. the bobbin top and bottom are black cd case plastic. there is about 1mm of core at the top and bottom. The coil is 2mm thick - about 140 turns of .23mm guage wire, potted in epoxy. It is somewhat microphonic - it was my second attempt, and I made a few mistakes that I should be able to rectify when I get around do making another. The way I see it, if I can get the circuit to work well with this driver, I can then make a fab and spiffy one for my final installation. I hope to get around to pics and sound samples soon. Oh, yes...and I have recently recieved PM's from a member in contact with Sustainiac who have raised some interesting reservations about a proposed installation. In particular is the distance of the driver from the strings, the inability to cope with a nonmagnetic cover and especially the effect the driver would have on a single coil mounted in the mid position. This last reservation is interesting and may show up some faults in the "bi-lateral" z-coil type design they use...lends more credance to a rail style solution as spazzy was working with. Stay tuned for more... sounds very interesting - I look forward to hearing more about that. cheers Col Link to comment Share on other sites More sharing options...
psw Posted September 13, 2006 Author Report Share Posted September 13, 2006 hasslemungous I'm using that.... Yeah, I've been aware of sustainers since the Edge started using the 'Infinite Guitar' "I still haven't found what I'm looking for..." a lovely use of this device. Michael Brooks was a pioneer of this device, I must have a listen to him some time... Thinking of that, I was at a school concert of my daughter's the other night, and they played some amazing music from china...some of those ethnic bowed instruments are just amazing, and the articulation possible for expression, just beautiful! I'd love to approximate this type of effect with this device... The trick is in conditioning the signal prior to feeding it into the LM386. I'm not sure quite by what you mean by "conditioning" My reference to a novelty is related to the practical implications of battery life, not the quality of the effect. Ah yes...there are many guitarists that would say that any onboard power or effect is a gimmick...(don't mind racks of effects though)...I still like the concept of an offboard implimentation of this device...any thoughts on this? If you can have the thing switched on all the time you're playing without having to change batteries every few hours, then you can really start exploring its capabilities, and you have a better chance of developing a unique sustainer dependent playing style - of course, if you have it switched on all the time, it must not have a detrimental impact on your normal sound/style... Another reason for off board implimentation as power and circuit size would not be an issue. Now that we have a converted pickup/driver option, perhaps this could be used with some simple rewiring mods to the instrument. Problems with the bypass circuitry for multi pickup guitars of course. A sustainer dependant style could best be perfected on a single pickup guitar or the development of better drivers to allow for a mid location to allow the use of both pickups... when the instrument is silent, it won't amplify - the Dynamic Range Inverter amplification tails off below about 20mV. Its still an issue though - low level EMI feedback that would not have caused problems in a simpler system can still be amplified. So the EMI badness threshold is more sensitive. I understand...got to think/hear what this approach will do... As I've explained, my motivation for building and helping to develop this app is to try and get the same response from an amp sim/headphones/pc recorder setup as I can get from a LOUD amp in a room. So from my point of view, the more natural it sounds the better. Well mine does sound LOUD, even in headphones! Part of the reason is that the device will continue to drive the strings to the limit of their physical ability to vibrate, no matter how quietly you pick (or not!) This is the classic feedback effect (but with far better control and predictability) that makes a loud guitar so "alive". Of course, its possible that you are going for a different end result, and that you would prefer the sound of my setup 'juiced' to the max Well...that is how you get the classic feedback effect and these swells that bloom from nothing...the effect builds and builds. I am wondering if the voltage inverter approach will create "effect". I am sure it could be addresed, perhaps with a pot to control it. I am quite attracted to the possible difference this approach could produce...perhaps more control and nuance. To get such control at present requires a fair bit of technique to dampen and picking strength. (picking softly makes for a great effect). sounds very interesting - I look forward to hearing more about that. The "z-coil" bilateral driver magnetizes the low strings one polarity, the other three the other. A near by single coil will have it's magnetic field reinforced on three strings, and reduced on the other. A humbucker should not be so effected as the opposite will occur on it's alternate coil. Perhaps they have another reason for the preferance for humbuckers for the bridge pickup also. I'd really like to try my driver/pickup combo design on a humbucking pickup...some interesting questions to be resolved. The coil is 2mm thick interesting, a third thinner than even my thin coil design...hmmm Perhaps you are getting a little more efficiency...hmmm It is somewhat microphonic This could be the source of some squealing...this microphic-ness can create it's own signals, regardless of EMI... You are doing some interesting things here and am enjoying the developments...sometimes even good ideas can lead up a bit of a backwater...hence... Yeah, possibly...but it could get complicated. Beware...just look at the year of development in my Hex designs... Looking at this so much reminds me of this work...and I still get an itch to look into it again. If you are not familiar with this episode of the thread (it went for about a year!) I developed a very novel approach...very small, no coil winding and elaborate magnetic fields...a lot of EMI reduction techniques...and the thing worked and fed the development of the simpler thin driver appraoch. But...there were problems and the whole thing soon got out of the DIY approach. Still, though it was the long way around, I did get somewhere with it...still frustrating...grrr Anyway...great posts...heading for 60,000 visits and they are ticking over quicker. I always like to visit the last click on the members list to see what people are looking at...always see a bunch of "guests" viewing the thread and lately, a few more at the sound thread too...obviously still a lot of interest...thanks to everyone who contributes and keeps this thread alive, and it's nice to have an audience... pete quote probs...ecuse me...fix it later...p Link to comment Share on other sites More sharing options...
onelastgoodbye Posted September 14, 2006 Report Share Posted September 14, 2006 As a page 30 vet, it's great to see how far this thing has come. 107 pages without any real flame war, has to be a record . People (including me)seem to be having trouble with coil potting, so here's some further explanation on what I think might solve the problem: the Jiggamathingy® It basically consists of the driver coil core, two temporary removable bobbins (the top bobbin is removed, lying to the right) and two biger L-profiles that form the sides of the coils. The bobbins are made up of two smaller L-profiles, bolted together with a layer of plastic in between. the plastic has the same width as the driver core and a cutout for it, so it sort of clamps onto the core. The idea is to clamp the bobbins to the core, then wind the coil while applying your potting fluid of choice, then the whole assembly gets pushed into a wooden block (the yellowish bit in the picture), and finally the two big profiles get screwed to the wooden block, sliding in between the bobbins an compressing the windings. It's made in aluminium so epoxy won't stick to it, and it has a certain degree of modularity to it, e.g. varying core size. Probably overkill for a one-off, but it's not that hard to build (i'd certainly suspect anybody with guitar building experience to pull it off). The block is the crucial part, because it has to make everything fit snuggly together. In it's current state it's ment for one coil of a humbucking driver, as small as I think I can physically make it; the coil itself is 6 x 56 x 3 mm, the whole 'bucker driver is gonna be 12x 56 x 8. Now if I could find smaller magnets... Tim Link to comment Share on other sites More sharing options...
psw Posted September 14, 2006 Author Report Share Posted September 14, 2006 Hey Tim...I been waiting to se more details on this, surprised you have time with that guitar you are building over in the other thread...if people haven't seen it, check it out now...right here In it's current state it's ment for one coil of a humbucking driver, as small as I think I can physically make it; the coil itself is 6 x 56 x 3 mm, the whole 'bucker driver is gonna be 12x 56 x 8. So, we are talking a rail driver then? I'm thinking this is the preferred design now for future development after spazzy's clip. I don't think he is going about it quite right (high amplification and a standard pickup) but the experiment did seem to show that very close, thin blades could work. I'd love to make a pickup/driver combo out of a rail now...maybe it could go in the middle slot of a strat and solve some other headaches...something for me to work towards... Meanwhile...love the thingamjigie! So is the wooden block a kind of mold? Are you looking to put internal magnets in there, cause that will be ultra-difficult to source. If not, blades of sheet steel, perhaps a few layers to make 1-1.5mm magnetised from below with rare earth magnets would do the job. The two blades even heavily magnetised with such magnets should cancel eachother out and probably not effect the string vibration as much as a single coil, single polarity design would... As always tim, great work...and good to see you back over here... pete Oh, and for you "new guys"...Tim contributed these great realizations for a surface mounted "sustain box" to compliment my hex designs......happy memories...p (makes a fine toaster too!!!) Link to comment Share on other sites More sharing options...
psw Posted September 14, 2006 Author Report Share Posted September 14, 2006 Dodging the one pic per post here... Here is some history... While looking for a pic of some of Tims work (that one from page 39) I found some back there of my circuit... I still use basically the same circuit, this one was being designed to be low profile and fit, battery and all, into some kind of box, like Tim designed. It is built on two circuit boards which I superglued together in this incarnation. The one in my guitar is tha same but the boards go back to back so are half the size (a little bigger than the battery itself. There are a whole range of features in this pic that we were working on at the time. The knob was to be a momentary push switch affair so that you push back with your palm to engage the sustainer, and to work the sensitivity control...you can see I was using trimers for some components for tweaking, and I disguised some of the circuit with a screwdriver for secrecy (there are other pics back there if you want though, so I'm not sure exactly what I was hiding...(strange times). Of particular note is the driver. This is what I was working towards...a bridge mounted unit that was very discrete. One reason for the bridge mount was to use the bridge itself as a magnetic sink (did I ever explain that...well now you know!), another was the need for alignment and "strange effects" if the strings were bent out of the alignment of the six driver "elements" and twelve high powered magnets in that little aluminium case... Came close but no cigar I'm afraid...but exciting times. I am almost of a mind to try again, but I fear the work is folly...I just tried to run much faster than I could crawl, and got better and immediate results transfering the lessons learnt into the simpler "thin driver" theory. In the end, the driver/pickup combo is an excellent solution to a successful implementation of such a device for most and making such miniture drivers with exotic materials (pure iron impregnated epoxy, anyone) was way out of reach to the DIY'er. Secretly, I was hoping someone would pay me for the design when it proved successful. The Hex driver does work BTW and I made quite a few...didn't even have to wind coils in the end...lots of thingamagigies to align the magnets and all the solder joins and alloy molding...but even with dramatically reduced EMI, it just wasn't going to be able to sit that close to a single coil pickup without problems... Heady days though...saves you guys reading the thread to find out what it was all about... pete Oh, and did you know if you push the little box with 107 pages written on it at the top of the page here...you can jump to any page in the thread...neato! Oh, and also, in the background of the pic is my pickup winder (still undergoing some development, and in the hands of my ex-wife for now...grrr)... Originally I was going to make innovative pickup designs...but I got destracted and made sustainers instead. Just think, if I had have, we'd have a 107 page thread of innovative pickup debate...maybe one day we will!!! Link to comment Share on other sites More sharing options...
col Posted September 15, 2006 Report Share Posted September 15, 2006 I've been doing some more tweaking and experimenting. It seems that I'm getting a good sustain, low battery usage, and as it turns out, no real problems with EMI screaming feedback - there is a reasonable window between the good stuff starting to work, and the squealing EMI feedback kicking in. There is one problem I'm having though thats annoying me. Its fairly subtle, so I've not noticed it before, It's only really obvious when playing amplified with a clean amp tone(headphones). I'm not sure that this is related to my driver circuit, my particular driver, or just the general setup... I can hear the signal that feeds the driver faintly in the headphones. Its not terrible - it's a soft mildly fuzzy distortion, but it's very annoying when going for a crystal clear clean tone. some possible causes: The nest of un-shielded wires criss-crossing my bread board that make up the circuit adding the interference to the output buffer/cable. (I hope it's this one) Low level EMI feedback generated by my driver circuit to a level where its interfering with the pickup. Plain simple 'pickup hears the driver' interferance. some other cause I've not yet considered .... Has anyone else noticed similar subtle background distortion when playing a clean tone through their sustainer? cheers Col Link to comment Share on other sites More sharing options...
onelastgoodbye Posted September 15, 2006 Report Share Posted September 15, 2006 Has anyone else noticed similar subtle background distortion when playing a clean tone through their sustainer? Yes. Really annoying and not even that subtle in my case. I always attributed it to the fact I didn't use a preamp (just the emg directly to the little gem) but I see you get it too. I do hope it's not the driver feeding back to the pickup via the strings, cause that would be pretty hard to inhibit. Link to comment Share on other sites More sharing options...
col Posted September 15, 2006 Report Share Posted September 15, 2006 Has anyone else noticed similar subtle background distortion when playing a clean tone through their sustainer? Yes. Really annoying and not even that subtle in my case. I always attributed it to the fact I didn't use a preamp (just the emg directly to the little gem) but I see you get it too. I do hope it's not the driver feeding back to the pickup via the strings, cause that would be pretty hard to inhibit. I have a sneaking suspicion thats exactly what it is :-| I took my driver and used it handheld above the stings. Its difficult to keep it steady so my results are not conclusive, but is seemed like the problem dissapeared as I went further away from the bridge, and worse towards it. I'm putting my hopes in a humbucking driver, maybe that will tame the EMI just enough. What about everyone else ? have you even tried it amplified with a clean tone cheers, Col Link to comment Share on other sites More sharing options...
col Posted September 15, 2006 Report Share Posted September 15, 2006 Does anyone have diagrams of the magnetic flux interaction between two humbuckers - I saw some on the web a while back, but can't find them now... They showed that (iirc) NS-SN keep their flux to themselves, while NS-NS have an interaction between the two inner coils. A couple of other things that may be of interest: A groovy pickup winding calculator - equally good for drivers, but bear in mind that the size of the finished coil in reality will be somewhat wider due to hand winding, sagging coils, potting nuicance etc. kinman pickups look about half way down this page, there are cool pics of his stacked humbuckers. The coil that cancels the hum/noise is completely different from the pickup coil... I wonder if we could have a driver coil and an EMI cancelling coil ? @onelastgoodbye: Is your setup turned up so the LM386 is clipping? My driver circuit produces some distortion in the AGC, but its not hard clipping, just some asymetry - so the background noise I get is quiet, and not totally unpleasant - hard clipping caused by an overdriven LM386 would probably be much more noticable. If we could get the same result as I'm achieving in terms of gain control, but without the asymetrical distortion, it's possible that the low level EMI pickup would not be a problem because it would be the same as the guitar signal therefor completely masked ! Cheers Col Link to comment Share on other sites More sharing options...
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