Truth_David Posted July 4, 2007 Report Share Posted July 4, 2007 (edited) I wouldn't ask Juan to help me take on such a task fully anyway -- way too much to ask.... I just wondered if there was someone already doing it, and maybe had a team of helpers, or a schematic that was proven to work.... oh well. I think you'll find that most projects for guitar amps are based upon fairly simple valve amps for which there are hundreds of freely available schematics - but I only know of a couple of amps that are capable of what you are looking to do, the Hartley Thompsons that AH apparently still uses for comparison, the Pearse amps and the new Yamahas that AH now uses, and also some of the latest Carvins, whose design AH had a hand in too. It just might be that you might be able to obtain the schematics for one or other of these, and if you should come up with anything on the Hartleys, I would be really grateful if you would share with me, as I have one in need of repair (rebuild), and as I no longer have access to my contacts in the UK, I have drawn a blank. Pete Hartley would have been a very good starting point for you, especially if you are determined to go the solid state route, but I don't think he is trading any longer. He is the guy who started making solid state amps with valve amp characteristics, then guys like Pearse picked up form there. But I would have to say that compared to typical valve amps, the technology required to get an amp to sound like a valve amp with even order harmonic distortion and really good sustain requires far more knowledge of in depth electronics, and these amps are vastly more complex......good luck. But there is a positive side to your choice, it is far less likely that you are going to fry yourself than in the case of working with the very high voltages that valve amps produce !. That is what put me off such an endeavour with a valve amp project. If you are interested in photos of the HT circuit boards PM me and I'll send you the Photobucket links. David Edited July 4, 2007 by Truth_David Link to comment Share on other sites More sharing options...
psw Posted July 5, 2007 Author Report Share Posted July 5, 2007 Got a half hour to test the mid-driver stuff again...developing these things can be very frustrating... Anyway...the LM386 circuit works perfectly so that layout will be good to go in the near future... The mid-driver is working, kind of! Still a lot of fizzy emi and hard to control...when it does work I am getting lovely sustain on the g string but there is a bit of background noise in there...still a bit of troubleshooting to go there... Also, the different pickup selections are disappointing...could be that the circuit needs to be wired in a little better (never trust croc clips) and directly from the Bridge HB regardless of pickup selection... I am even unsure as to whether the amp under the driver is such a good idea...seems to be effected by the EMI...or perhaps there is something else going on here... Next step will be to build the preamp and perhaps do some more conclusive testing with all the circuitry outside of the guitar. Other than that, if this mid-driver is going to be too hard or ultimately unrewarding (I am aware that sustainiac never released their patented version) I have plans for several other implementations of the neck driver...so we will see... So...circuitry should be finalised soon regardless of the direction this should take which should relieve many I am sure... pete Link to comment Share on other sites More sharing options...
psw Posted July 5, 2007 Author Report Share Posted July 5, 2007 Got anther little while to build the preamp...looking good so far. I have 3 trim pots...one is for the LM386 gain (20-200x amplication) bridging pins 1 and 8. I also have a trim pot on the preamp so it can go from buffer to about 100x amplification. The third is attached to the harmonic mode/phase reverse switch that is connected between these two little circuits...this works like a volume control that adjusts from 0 to full and could be replaced by a "sensitivity" control if that is required...I am not sure of the benefit of this control anymore, I don't use it on my strat. I have built in a little overkill and once this first one is tested I will build another stripped down to it's essentials...for instance I have built power protection and powersmoothing into both circuits so some of this is redundant. One neat little coincidence is the possibility of gluing the harmonic switch to the side of the preamp circuit solving mounting and the switch nestles in nicely between the capacitors making fitting it in tight spaces easy... The combined circuitry though is bigger than the fetzer ruby but is fairly easy and cheap to make with very common components and the layout would be unlikely to get any smaller with a circuitboard as the veroboard is ideal for the design. The circuit is smaller than my present design and should work well...a little more testing required. pete Link to comment Share on other sites More sharing options...
mrjstudios Posted July 5, 2007 Report Share Posted July 5, 2007 (edited) Truth_David Well, after a very fine and extensive search of the internet, I found that there is NO way to aquire a schematic for a HT amp.... Pearce amps seem to be the same way, unless you buy a $20 service manual, but even that may not have a full schematic. Hmmm. Basically my idea, (which by the way I got from not wanting the effect in my sustainer circut) would be to use the same basic layout of a tube amp, but insert some sort of small circut (such as the THUNDERCHIEF pedal) into the place of each tube. Pedals like that one from runoffgrove seem to emulate a tube sound very simply and very well, all in a small 9v scale, so I thought perhaps if you used bigger parts that could handle the full 120v, you could use that kind of circut design repeated as a 'tube unit' in as many places as you would normally put a tube. Maybe I am oversimplifying this past where it could realistically be implemented, but oh well. Another thought I had was to build 'tube-sounding conversions' for old solid state amps. Like in most 80's amps, my solid state Peavey's effects chain is inbetween the preamp and poweramp stages. Wouldn't that let you have 'access' to what type of gain/overdrive is going into the poweramp?! Like Eddie Van Halen says, his tone is all in the preamp stage, and having enough headroom to force a ton of tube power into the poweramp, creating his signature sound. Soooo... if you could simply place a tube emulating circut in between the preamp and poweramp, shouldn't the amp itself distort much more like a tube amp? I (thought) I understood that the great tube tone comes from the preamp tubes 'rounding off' the soundwaves (instead of clipping them like a solid state amp would) when they distort them, so why couldn't a tube emulator, or even a real tube box be used in these solid-states to make them sound like tube amps?! Well, anyway.... looks like some good progress on the new circut. Hey PSW, given any thought as to what its name will be?! -MRJ Edited July 5, 2007 by mrjstudios Link to comment Share on other sites More sharing options...
Truth_David Posted July 6, 2007 Report Share Posted July 6, 2007 Truth_David Well, after a very fine and extensive search of the internet, I found that there is NO way to aquire a schematic for a HT amp.... Yes, I know.....well there is a way, because they are patented, but I couldn't make use of the schematics anyway myself, although Juán was quite interested in working on mine at some point. Pearce amps seem to be the same way, unless you buy a $20 service manual, but even that may not have a full schematic. Hmmm. Basically my idea, (which by the way I got from not wanting the effect in my sustainer circut) would be to use the same basic layout of a tube amp, but insert some sort of small circut (such as the THUNDERCHIEF pedal) into the place of each tube. Pedals like that one from runoffgrove seem to emulate a tube sound very simply and very well, all in a small 9v scale, so I thought perhaps if you used bigger parts that could handle the full 120v, you could use that kind of circut design repeated as a 'tube unit' in as many places as you would normally put a tube. Maybe I am oversimplifying this past where it could realistically be implemented, but oh well. Another thought I had was to build 'tube-sounding conversions' for old solid state amps. Like in most 80's amps, my solid state Peavey's effects chain is inbetween the preamp and poweramp stages. Wouldn't that let you have 'access' to what type of gain/overdrive is going into the poweramp?! Like Eddie Van Halen says, his tone is all in the preamp stage, and having enough headroom to force a ton of tube power into the poweramp, creating his signature sound. Soooo... if you could simply place a tube emulating circut in between the preamp and poweramp, shouldn't the amp itself distort much more like a tube amp? I (thought) I understood that the great tube tone comes from the preamp tubes 'rounding off' the soundwaves (instead of clipping them like a solid state amp would) when they distort them, so why couldn't a tube emulator, or even a real tube box be used in these solid-states to make them sound like tube amps?! Sorry, I disagree, many people have tried using valve pre-amps in rack systems over the years then found that they just didn't cut it....the brown tone comes from overdriving the power amp section, not just the pre-amp, as many will attest, if you check out any of the tube amp sites, you can read up on this. EVH not only used to push the power amp to the limits, but he used a Variac to vary the voltage, which effectively burns out the transformer in many cases. In addition to that, it is also down to the combination of the entire amp, in other words pre-amp, power amp and speaker cabs. The speakers are critical to the sound as well, because you need to be able to drive the speakers sufficiently hard to produce the tone you want, and that means a great deal of volume, if you have a 100w amp with a pair of 4x12 cabs - unless you use a power soak of some sort, but those tend to affect the tone. So choice of cab is also very much a part of the whole picture, and so of course is the miking up of the cab...... The other thing is that when compared to a valve amp, a solid state amp has a very different attack and response, and is far too clean sounding and unmusical in terms of the way it distorts, because it just clips, as you mentioned, which produces mostly odd harmonic distortion, rather than even order harmonics as in the case of a valve amp. So Pete Hartley and all those guys were dedicated to the task of getting those parameters out of mos-FET amps for the most part, and actually getting the transistors to behave like valves. These amps tend to be very complicated, both in the pre-amp EQ section and the distortion/compression circuits, as you will see from the photos.... And these amps were also very expensive. I don't pretend to have sufficient understanding of electronics to know whether or not your ideas are likely to work, but perhaps someone else here will be able to give you some feedback on that. One thing to consider is that in the case of a valve amp, unless you are talking about a 1watt amp (which is all you really need, if it is a class A valve amp), or say an 18watt combo, the cost of building the amp yourself combined with the time involved apparently means that you could well be spending more than you would if you just bought a factory produced model, even a boutique amp....it might well be the case also for a solid state amp, I would ask myself 'is it really worth all that time and trouble?', especially when there are the new Yamaha amps for example, which sound amazing.... But what I would recommend would be using a small valve or simulated valve amp, such as the Lovepedal 1/2 watt amp, to power a valve power amp or a solid state one if you prefer, for example a PA amp, then have a second clean amp setup and switch between them. Do a search on Youtube and check out the Lovepedal, to my ears it sounded amazing, and it will power a 4x12 cab. I tried to get my hands on one, but although the guy is still around, he hasn't produced any of these little amps in some time. Another similar amp is the Cricket. Both of these were selling for around $199 originally. David Link to comment Share on other sites More sharing options...
mrjstudios Posted July 6, 2007 Report Share Posted July 6, 2007 (edited) Sorry, I disagree, many people have tried using valve pre-amps in rack systems over the years then found that they just didn't cut it....the brown tone comes from overdriving the power amp section, not just the pre-amp, as many will attest, if you check out any of the tube amp sites, you can read up on this. EVH not only used to push the power amp to the limits, but he used a Variac to vary the voltage, which effectively burns out the transformer in many cases. In addition to that, it is also down to the combination of the entire amp, in other words pre-amp, power amp and speaker cabs. The speakers are critical to the sound as well, because you need to be able to drive the speakers sufficiently hard to produce the tone you want, and that means a great deal of volume, if you have a 100w amp with a pair of 4x12 cabs - unless you use a power soak of some sort, but those tend to affect the tone. So choice of cab is also very much a part of the whole picture, and so of course is the miking up of the cab...... Oh, ok -- but how do you overdrive the poweramp? I am very familiar in the EVH techniques at all stages of his setup, and I know he used a variac, etc., but how did he overdrive the poweramp? In otherwords, how do you get the poweramp to distort at all if no preamp distortion/overdrive in used (a.k.a. a clean sound)? Because theoretically for a poweramp to contibute to the sound quality (like you mentioned) and not just volume, it would have to distort a little and effect the tone by itself. I will be doing more research ..... One thing to consider is that in the case of a valve amp, unless you are talking about a 1watt amp (which is all you really need, if it is a class A valve amp), or say an 18watt combo, the cost of building the amp yourself combined with the time involved apparently means that you could well be spending more than you would if you just bought a factory produced model, even a boutique amp....it might well be the case also for a solid state amp, I would ask myself 'is it really worth all that time and trouble?', especially when there are the new Yamaha amps for example, which sound amazing.... Correct! I know it would be a waste of time and $$$ for me, but I still would like to scheme and work out in my mind how I would build one -- or at least understand better how they work. Either way, I would rather just buy a 5150, a 5150II or better yet, a 5150III!!!!! Perhaps someday.... As for the sustainer: I'd like some ideas as to how I should fill the ~2mm total gap between my cores and my magnet. Would metal strips do just fine, or should I magnetize some metal strips and then match the poles to the magnet? And the final count is: Dual-Coil Driver = 7.79ohms Total (15.8ohms x 15.4ohms in parallel) -MRJ Edited July 6, 2007 by mrjstudios Link to comment Share on other sites More sharing options...
teddybear Posted July 7, 2007 Report Share Posted July 7, 2007 spdt connect to? spst connect to? Link to comment Share on other sites More sharing options...
psw Posted July 7, 2007 Author Report Share Posted July 7, 2007 spdt connect to? spst connect to? I don't know what you mean...single pole single or double throw switches are not used in the sustainer I'd like some ideas as to how I should fill the ~2mm total gap between my cores and my magnet. Use metal strips...2mm gap is substanial, the blades need to touch the magnets...I built mine to the specifications of the magnet... Having trouble finding the time, but I reinstalled the mid-driver and have connected up the circuit...connecting a speaker I can tell the LM386 section is working (see it is easier to troubleshoot with modules) but am getting nothing from my new preamp design. It could be a problem with the design or in the construction...It all looks ok, so I have no idea. I bought enough parts to build a couple of preamps, so may have to do it again...next week! Otherwise, I am getting a little disillusioned with the mid-driver...I kind of see why sustainiac and co did not pursue it. Unless something really special comes from it, a neck driver design is better in many ways. The complicated bypassing would be nice to overcome but given the total rewire the guitar required and the loss of the middle pickup, is it worth it? I'll give it a bit more of a go and get this circuitry worked out...then perhaps it is time to try a completely different driver design... pete Link to comment Share on other sites More sharing options...
teddybear Posted July 7, 2007 Report Share Posted July 7, 2007 so, which switch are use? trim pot for gain or volume? Link to comment Share on other sites More sharing options...
psw Posted July 7, 2007 Author Report Share Posted July 7, 2007 You are going to have to give more detail about what you are trying to do there Teddybear... On a single pickup guitar you can use a SPDT switch to turn on the power and the sustainer. For guitars with more than one pickup you will probably need a 4PDT switch to enable bypass, auto select the bridge pickup and turn on the power. The harmonic switch is a DPDT switch to reverse the driver leads...this is wired like a phase switch...I think the details are on the tutorial of how I wired up my strat... On my new circuit I am trying to wire the harmonic switch between the preamp and LM386 amp by switching the inputs from inverting to non-inverting mode...same kind of thing really.... There is the possiblilty that I could make a few layouts of the same basic circuit...we'll see when I get the thing working. I am very keen to try the bi-lateral side driver idea that I have...in some ways it is similar to Juan's multi-coil (seemed to have three, with cores made from saw blades) but I got very little detail other than the pics from that. Juan certainly had some good ideas but the translation seems to be difficult. Also, people are having trouble replicating his circuit and other procedures which is a pity... Oh well...the kids have gone now for a while so after a few days back at work, I'll nut out some more on this...perhaps then I'll have a suitable circuit design and layout to present. I am happy that the designs I am making are very compact, that is an achievement, I don't think it would get any smaller with a purpose built printed circuit board. Anyway...lots to do and think about, but this project does take the mind of some things best forgotten... pete Link to comment Share on other sites More sharing options...
psw Posted July 7, 2007 Author Report Share Posted July 7, 2007 OK...so have done a few quick and dirty tests of the mid-driver with some success... Running the bridge Hb pickup into the LM386 stage alone on minimum gain in the fundumental mode you get a very strong sustain, particularly on the lower strings and, like with my sustainer strat but more so, a morphing into harmonics with the lower strings quite quickly. Perhaps too much. I am getting a bit of fizz and distortion and even lowering the driver on the bass side quite a bit, I am still getting a very strong drive on these strings. The high strings are a little less responsive but only the high e doesn't work at all, but given the light guage strings (09's) this is to be expected... Given these results, I should get the same or similar using just a buffer to prevent loading of the pickups... However...switching the driver leads to harmonic mode results in an uncontrolable squeel...as if the driver is too close to the source pickup (which it probably is for this mode)...hmmm So...given the lower gains and such, is the rail driver more efficient? Is the position a factor in this strong drive? The fizz and distrtions are only evident when the string reaches it's maximum vibration potential (which is pretty quick) so would a circuit like col's with AGC keep the drive down to a respectable level, prevent this and even further extend battery life? So...some interesting results and a further test of the LM386 stage and layout...now about that preamp...hmmm...I haven't found any faults with the design or the layout and modifying it results in various forms of "motorboating" or other undesirable effects. Possibly rebuilding it, or a simpler version is the way to go...thinking, thinking... pete Link to comment Share on other sites More sharing options...
mrjstudios Posted July 7, 2007 Report Share Posted July 7, 2007 (edited) However...switching the driver leads to harmonic mode results in an uncontrolable squeel...as if the driver is too close to the source pickup (which it probably is for this mode)...hmmm Hmmm.... is right. That is the exact same results I got with my driver in harmonic mode (in the limited testing that I got done with the crappy F/R), and my driver was about 10cm away from the bridge pickup -- and might I add not a mid driver or a dual coil driver. It was my single coil driver being used with our more 'modern' techniques of placement and arrangement. I would lean toward that being a circut error on both of our parts -- don't give up on dual coil just yet Hmmmm...... But good progress anyway -- any tests at all are useful tests. I do still believe that the rail driver is the way to go though, mostly because of the string-bending principals alone, and because of there simple, clean, and good easy to build design. Poles would just focus the energy more and perhaps make a more intense drive, while also not performing while bending strings, so the rail just seems to be a good medium. As for the over-driving of the strings.... wouldn't you rather have more power/ headroom and be able to just turn the thing down? I sure would, given my largely inefficient and underpowered single coil driver thus far. And just like the pricipal of amps, more headroom would also mean a cleaner sound at the lower to mid levels of operation!! You may have stumbled on a partial cure for our distortion!! If we build circuts designed to run off the same wattage, ohmage, etc., as before, but given their different designs / preamp combinations they are more powerful, then just turning them down to normal sustainer operation levels would give us a cleaner signal (via more headroom) and also conserve the battery life too, or at least make them as efficient as the previous sustainers. To test this theory, I'm gonna hook up my 4watt, 8ohm guitar practice amp (shown previously) to my single coil driver. I will just keep it turned WAY DOWN, since this thing has about 60-80% headroom for sustainer purposes. Might make a demo vid if it works well.... but given the light guage strings (09's) this is to be expected... You mean my beloved Guitar Research 850's (with a .09 guage high E string) will never work with the sustainer?! Darn. -MRJ Edited July 7, 2007 by mrjstudios Link to comment Share on other sites More sharing options...
psw Posted July 8, 2007 Author Report Share Posted July 8, 2007 Hmmm.... is right. That is the exact same results I got with my driver in harmonic mode (in the limited testing that I got done with the crappy F/R), and my driver was about 10cm away from the bridge pickup Yes...this is a common problem of EMI and really needs a bit of perserverance to overcome. For instance, with my sustainer strat, it was not enough to turn the thing on and select the bridge pickup, both other pickups needed to be disconnected on both ends of the coils to avoid noise...a 4PDT switch was required to do this...it was not enough to disconnect one end of the coil or short it out in the manner of a selector switch, they needed completely to be taken out of the circuit. Similarly, the driving leads need special treatment. I would lean toward that being a circut error on both of our parts mad.gif help.gif -- don't give up on dual coil just yet blink.gif Hmmmm...... No...not a circuit "error"...I have several circuits and this LM386 stage is fully tested. The HB that is driving the sustainer is completely removed from the circuitry of the guitar...the effect is completly as a result of the EMI coming out of the driver and the action of the strings... I do still believe that the rail driver is the way to go though Well...I think you mean a bladed driver...a rail driver tends to be a single coil sized dual rail...or larger as col and avalon have made. This design has two oposite magnetic polarities close together and so are attracted from rail to rail...there is less "throw" than the single coil driver. Less throw means better control of the EMI field perhaps, but perhaps less power...the jury is out a little. My dual rail parallel driver does seem to work pretty effectively, perhaps more efficiently. I have had a fair amount of experience and perserverance making these things...this driver is rock solid and has had quite a deal of care taken in it's construction and avoiding the common pitfalls that effect driver efficiency. As for the over-driving of the strings.... wouldn't you rather have more power/ headroom and be able to just turn the thing down? biggrin.gif I sure would, given my largely inefficient and underpowered single coil driver thus far. Ah...now here's the thing...the sustainer picks up the vibration of the string and excites the string, this energised string is then picked up again and energised still more. Turning it down does not necessary decrease the effect to a controlable level, it might extend the time it takes, but eventually the string will reach it's maximum available vibrational capacity. Does that make sense? Consider Col's preamp design with automatic gain control. This automatically adjusts the gain so that it cuts back the gain before the string goes completely beserk and generates so much energy through physical vibration and associated EMI from the driver and overdriving the signal chain. You need the power to get the effect going but then you want to "turn it down" to control it...hmmm. Cols circuit is clever and fairly unique in that it senses the incoming signal of the amp and responds to that, not the signal coming out of the amp (which does not necessarily respond to what the signal coming in is doing)... The sustainer circuit will work without this AGC but it is a little more brutal. This has some of it's own charm if you are good enough to control it and it is set up right...it is a lot more like traditional amp feedback but with predictability and control. Getting EMI control is a matter of setting the gain to be just enough and no more with the sustainer. It really shouldn't take much power at all to keep a string vibrating. You mean my beloved Guitar Research 850's (with a .09 guage high E string) will never work with the sustainer?! Well...not the high string anyway...it really does need the metal to work with...sorry. Now...I have thought that there are other ways of controling the EMI problem and explored quite a few of them. One thing that we have rarely considered is the orientation of the coil. By having the coil oriented different from the pickups coils, it substantially addresses EM coupling between the two devices. One way for instance is to tip the coil on it's side and direct the energy from the coil through fins towards the strings. Another approach is the bi-lateral driver (sustainiac for instance) which has different polarities between the top and bottom 3 string sets of strings. I have an idea of combining these two ideas and making it more compact to boot...may help, maybe overkill... OK..so the dual rail driver of mine works...it could work with less power but I am not sure taht this will entirely fix the problem, especially with the harmonic squeel. It is possible that you could achiewve a very similar harmonic effect by other means which may well suggest that if it will run in fundumental mode, that may well be enough...already I get a wide range of harmonics by treble bias. Anyway...better run...will try a buffer and some gain reduction to see how low a power I can run it with later in the week. till then... pete Link to comment Share on other sites More sharing options...
psw Posted July 8, 2007 Author Report Share Posted July 8, 2007 Ok...that wasn't very clear at all...a bit tired, long day at work... Did a bit of a picture of the type of device I'm interested in trying...comments welcome... Each coil stradles 3 string each and are wound around 30mmx5mmx5mm magnets...or smaller neodyminiums...making a slim design. Blades protrude above the coils attached to the internal magnets and forming a partial bobbin. Each blade is therefore an alternate polarity. The strategies at work are dual opposing coils as in the dual blade driver, 90 degree angle of the driving coil in relation to the pickup coils and magnetic forces that work in part across the strings rather than along them...well that's the idea. Construction seems pretty simple (if you can find approapriate magnets) as no bobbins as such are required (the outer blades hold the coils in place...and very compact. This is an experimental proposition and I have no idea if this would be an effective design. It shares some similarities with Fernandes' old side wound driver (no longer in production)... and the sustainer bi-lateral design (similar to Fender's P-bass pickups and Z-coil designs)... One attraction of this is that I believe that it may be possible to make the drivers as compact as my Hex designs were...yet another strategy for containing EMI...miniturization! This would possibly allow surface mounting on a strat type guitar between the neck pickup and the neck (even on my 22 fret strat) or, perhaps even next to the middle pickup if a mid-driver is effective by this design. Of course, appropriate bypassing would still be required with this type of installation. Anyway...it is an avenue yet to fully explore. I actually enjoy finding out if this stuff works and discussing it with you guys believe it or not! Still...will need to fully test what I have got to so far and to develop that amp design a little further...will post the layout for the LM386 stage that is tested soon along with some pics... pete Link to comment Share on other sites More sharing options...
mrjstudios Posted July 8, 2007 Report Share Posted July 8, 2007 The HB that is driving the sustainer is completely removed from the circuitry of the guitar...the effect is completly as a result of the EMI coming out of the driver and the action of the strings... Yes, I know -- I removed the other pickups from my guitar period. Right now it just has a single coil strat pickup, and the sustainer.... that's why I thought it might be a circut error.... Turning it down does not necessary decrease the effect to a controlable level, it might extend the time it takes, but eventually the string will reach it's maximum available vibrational capacity. Does that make sense? Uh, sorry... no. I must not quite understand the concept of pot's or something.... I thought that if you had a signal lowered down enough that you could make the sustainer not even work at all. Like you said - you could extend the time it takes to overdrive... so then couldn't you find a sweetspot where it either took too long to get to that point to ever notice while playing, or just didn't ever overdrive at all?? I don't know. As for your Bi-Lateral design.... how many coils are in either driver section, and to what ohmage would you wind it, and with what guage wire?! Once you finish the full sustainer circut, and I have built it and have it working solidly, I might be up to this new driver challenge. By the way.... I tested both my single coil driver (9.3ohms) and my new dual coil driver with that 4watt practice amp. The single coil did almost nothing in regular mode; it only sustained a few open strings. The dual coil driver didn't really do any better, but in regular mode I was able to turn the amp up to full volume, which should be way overkill, and it did not squeel!!! So the dual coil parallel driver definitely has a much improved EMI response. I am excited to see what it will do with the new circut, and maybe it will turn out that our 'mid-driver' concept works perfectly in the neck position. Will test more later..... -MRJ Link to comment Share on other sites More sharing options...
mrjstudios Posted July 8, 2007 Report Share Posted July 8, 2007 Here is another thought. -MRJ Link to comment Share on other sites More sharing options...
psw Posted July 8, 2007 Author Report Share Posted July 8, 2007 Yes...I thought of that idea of encapsulating the whole thing but you have to understand that the gaps between magnetic things are imporatnt...mechanically it seems like a good idea but magnetically not so much (could be tricky getting the magnets and coils in there too!). To understand this a little more it is worth modeling it with the FEMM analysis program to see what the magnetic fields are doing. My concern is that, the metal fins direct the magnetic fields and favour magnetic materials over non-magnetic materials like air. With your blades joined the lines of magnetisim will substantially move through the metal from one magnet to another both sideways and from one pole to another underneath. The result is little if any magnetic forces working above the device and on the strings...good for EMI, not for string driving. The other problem is that metal blades like this can cause eddy currents that effect the working of the coil and it's magnetic properties. In my design I purposely made the blades as small as possible and only directed towards the strings. I might even make more gaps between the two coil units as the join would be between the d and g strings... As for the coils...I am not sure. 2.5mm seems a little thick from my experience. Two 4's in series or 16's in parallel perhaps...maybe a stronger coil under the high strings to get them going a little easier. There are some drawbacks to such designs and it should be noted that side coiled drivers (and pickups) are substantially out of production. With bi-lateral designs, there is a potential problem with being mounted close to pickups, particularly single coils. The different magnetic poles on each of the 3 string sets may/will distort the shape of the pickups magnetic field...whether in an unpleasant way is yet to be discovered...hmmm Also, the core of the device is now in the middle of the windings forcing it deeper below the strings. There may even be some phase problems with a coil mounted 45% to the source pickup coil...so the whole idea could be problematic. Still...there are elements of it that interest me as a concept...plus I have found magnets now that perfectly fit such a design (30x5x5mm with the poles along the width, not the ends) pete Link to comment Share on other sites More sharing options...
psw Posted July 8, 2007 Author Report Share Posted July 8, 2007 The HB that is driving the sustainer is completely removed from the circuitry of the guitar...the effect is completly as a result of the EMI coming out of the driver and the action of the strings... Yes, I know -- I removed the other pickups from my guitar period. Right now it just has a single coil strat pickup, and the sustainer.... that's why I thought it might be a circut error.... No...I have the source pickup (the bridge HB driving the circuit completely removed from the signal cain and the neck single coil to a guitar amp) the source pickup is out of the signal chain, both pickups are still in the guitar but are doing separate functions. Kind of like an ebow where the pickup coil is not connected to the signal chain. Turning it down does not necessary decrease the effect to a controlable level, it might extend the time it takes, but eventually the string will reach it's maximum available vibrational capacity. Does that make sense? Uh, sorry... no. I must not quite understand the concept of pot's or something.... I thought that if you had a signal lowered down enough that you could make the sustainer not even work at all. Like you said - you could extend the time it takes to overdrive... so then couldn't you find a sweetspot where it either took too long to get to that point to ever notice while playing, or just didn't ever overdrive at all?? I don't know. No...the sustainer is different from an amplifier. Sure the circuit is an amplifier but consider what the device is trying to do with an ordinary amplifier circuit. The volume builds. A low level string vibration is sensed, amplified and played back into the strings which causes them to vibrate more and increase the level of the signal. This signal is then sensed and further amplified and the string excited even more...pretty soon the string will be vibrating so much and the level of the signal it creates so great, that it simply can't vibrate any more...it will start banging into frets or pickups or simply not physically be able to stretch any more in response to the driver's ever increasing signal. An ever increasing amount of EMI is also produced as the driver puts out more and more magnetic force. This exponential response means that the device either has enough drive to create sustain and therefore continue to build...or it doesn't, in which case it doesn't work at all. Turning it down may slow the response down a little, but not by much as the effect is not linear. Also, the response is vastly different with different frets and string guages...as well as frequencies...lots of variables there, so a sweetspot would be impossible to find if there was one othere than for a single note fretted in a specific location on an particular guitar. I don't think such a "sweetspot" will exist in the way you are thinking... What is clever about Col's preamp circuit is that it responds to the incoming signal raising low level signals and cutting back amplification before the strings get overdriven, controlling this exponential build up of gain and EMI production. By the way.... I tested both my single coil driver (9.3ohms) and my new dual coil driver with that 4watt practice amp. The single coil did almost nothing in regular mode; it only sustained a few open strings. The dual coil driver didn't really do any better, but in regular mode I was able to turn the amp up to full volume, which should be way overkill, and it did not squeel!!! So the dual coil parallel driver definitely has a much improved EMI response. I am excited to see what it will do with the new circut, and maybe it will turn out that our 'mid-driver' concept works perfectly in the neck position. Will test more later..... The dual coil design should work well in the neck position...mine would work perfectly like this...so if the mid-position should be not of much use...at least I have a very good neck position driver! I fail to usnderstand though why the harmonic mode sheiks like this but the fundumental doesn't...it is not as if more power is produced because the leads are reversed...it is a symptom of all drivers I have built but distance from the pickups generally cures it...in this case I dont have that luxury and am considering Col's design as an approach that could help address it a little... -MRJ Link to comment Share on other sites More sharing options...
psw Posted July 9, 2007 Author Report Share Posted July 9, 2007 (edited) OK...a few quick and dirty FEMM models to illustrate and to think about some of these ideas... Here is a side elevation of the magnetic field in the driver idea as I proposed... By contrast MRJ's alterations while mechanically sound...look like this...(nothing escapes...no EMI but no drive at all ) On the other hand...from a top elevation, things do look a little strange... Hmmm...and in a kind of simulation as to the effect of a coil through a cycle...check this out... A weird twisting motion of the field...similar to the wave drive I was hinting at a while back... So...a little strange and I am not sure if there is any benefit to such a design... I hope though that it will open up your thoughts on driver design, or at least be of interest...magnets are fascinating things, a program like this can make the invisible, visible to an extent but it is an approximationa dn only in 2D and static...it has limitations... You may want to consider these drawings in relation to the dual coil rail driver designs also...notice that in the first diagram, the fins extending only from the magnet up extends the field up above the driver (towards the strings) more than if it were symetrical (above and below the strings). Extended blades below the coils as MRJ had in his previous design may be of a little concern, not enough to stop it working, but perhaps lowering efficiency. Mounting can be achieved by any non-magnetic means really but anything magnetic, or even conductive (like my aluminium pieces) should give some reservations (for instance my aluminium top strip that is purely decorative and protective yet could also harness eddy currents in a detrimental way to the operation of the coils...hmmm) So...still another work day (BTW...I do a long work day, eat, sleep work routine for a few days then stop completely...all a bit odd lifestyle wise...but allows me to play with things like this later in the week). Will look into the amp situation and post at least the LM386 part soon... pete Edited July 9, 2007 by psw Link to comment Share on other sites More sharing options...
mrjstudios Posted July 9, 2007 Report Share Posted July 9, 2007 I didn't think my bi-lateral driver would trap that much magnetic field.... oh well. The concept sounds cool and all, but do you think perhaps there is a reason why none of these are in production any more? Anyway, if I can get magnets, I just may want to try building this. By the way, listen to the Eddie Van Halen songs "Rise" and "Catherine," and the Van Halen song "Learning to See." Those songs were made with the extensive use of the sustainer, and really show what a true artist can accomplish with the device. They were basically the reason I got into this stuff in the first place, because when watching one of them on Youtube, I saw a comment that said "check out that sustainer pickup," and of course I Googled it. That led me here..... -MRJ Link to comment Share on other sites More sharing options...
Mikysk8 Posted July 10, 2007 Report Share Posted July 10, 2007 (edited) Hi guys, i have build a sustainer time ago (a simple coil driver, like one in the tutorial, and the Ruby) and it works but not so good expecially on the 2 thin strings (B e E) and on the others works, but not with a clean sound, there are a lot of harmonics so what is the best configuration to make? wich driver, wich electronic use for amplificate the signal? i haven't got the time for read all the 200 pages of this topic so if you could answer to my questions i'll be very happy tnx Michael Edited July 10, 2007 by Mikysk8 Link to comment Share on other sites More sharing options...
psw Posted July 11, 2007 Author Report Share Posted July 11, 2007 Welcome Mikysk8... The distortions are some of the problems I am trying to deal with at the moment with my new mid-driver. It is caused by the signal of the amplifier being "picked up" by the pickup and sent to the amp through the magnetic field. To address this problem, many people are building two coil designs similar to Humbucking pickups... These dimensions are possibly a little big, thin coils (say 3-4mm) and 0.2mm wire is recomended. This picture illustrates my version... You could use two 4 ohm coils in series or two 16 ohm coils in parallel to make a total of around 8 ohms...or aim a little lower. The EMI from one coil will tend to cancel out the other. Otherwise, it could be a little close to the other pickups or even picking up the signal from the wiring...I'd need a little more detail and some pics to have an opinion. As for the high strings, you could try a 100uF capacitor in place of the 220uF to allow more treble bias and get them moving. Also, you will need to have at least 10's for the high e to get a response, some string guages are just too thin for the magnets to get a good hold on to them. I would try to make a new driver with two coils and use the circuitry and everything you have already, that may well be enough to improve things... Meanwhile... I have played a little with the mid driver but it is very frustrating and am thinking of abandoning it for a more conventional neck positioned driver that could perhaps work beside the neck pickup (with bypassing, etc). The dual rail design works very well though and would make an excellent neck positioned driver as with avalon's and Col's versions...probably more efficient (could be the parallel 16 ohm coils) and works with less power which is a good thing for cutting back on EMI in addition to the design itself. The loss of the middle pickup and the extensive rewiring is probably not worth the added benefits obtained by the mid driver though...ease of installation and pickup selection...at least not unless it can run perfectly quietly. I think it could work adequately with a preamp design such as col's to limit the power a little more, at low levels it is pretty quiet...but the harmonic mode does not work at all (squeel)...so that is another potential down side. In other related news... I found the original single string coil that I made at the start of this thread and hooked it up to a lm386 circuit (no preamp) and my "relay pickup"....have I mentioned this?... This A$4 relay is easily taken apart to salvage the coil wich makes quite a good pickup with a magnet stuck to the back of it. Wire this to the input and a similar coil wound as a driver, and you get an instant ebow!!! I will be exploring this a little more as it offers some valuable insights into the sustainer stuff, but may be a cool project or introduction to the more complex sustainer devices we attempt...a lot simpler and cheaper and without any guitar modifications. It may even suit my purposes better than the full on sustainer and I'll be hooked on this thing... Still looking for suggestions as to how an ebow could be "improved" or redesigned in some cool way... I am still interested in trying a side coil design of some sort. I am looking around for very small powerful magnets to make a very thin driver (3mm) on it's side to be mounted at the end of the neck. Part of the attraction of this is my sense of a "wave drive effect"...that is that the two blades (in this design) are alternating on different parts of the string, not so much bouncing the string up and down but stimulating it along it's length. There are EMI advantages to laying a coil on it's side, or any direction different from the pickup coils orientation, but there are inefficiencies too that may require more power that could overcome those savings...I'm just curious I guess about the possibilities. Both the side coil design and bi-lateral designs (such as sustainiac use) have not really been explored. I wonder if anyone has any idea of what kind of coil/s Fernandes now uses in thier drivers? As for the circuit design... I am not sure how much gain is really required...it could be that the buffer design I posted earlier will be adequate with the tried and tested modified champ circuit that I use. My new layout for that works pretty well and is very small...will tidy that up and post it soon. A stock ruby or fetzer ruby design is probably perfectly adequate if the driver is efficient enough. Anyway...better get moving... pete Link to comment Share on other sites More sharing options...
mrjstudios Posted July 13, 2007 Report Share Posted July 13, 2007 A stock ruby or fetzer ruby design is probably perfectly adequate if the driver is efficient enough. Ehhhh...... I wouldn't say that just yet..... You have seen how my newest dual coil design was built -- almost to the exact same specs as yours was, just a little less squeezed together -- and that stupid F/R will not drive it at all. Even that little 4watt practice amp works much, much better than the F/R without even being modified (I just swapped the speaker leads onto the sustainer) and at FULL gain AND volume that dual coil sustainer didn't even distort or squeel at all in regular (not harmonic) mode. So, although a lot of people have used the F/R to success with single coil drivers, I think for some unknown reason that the F/R circut will not work specifically with a dual rail design. Perhaps it is the 16ohm coils wired in parallel or something, but there is a huge difference in performance between my single and dual coil drivers when hooked up to the F/R. That huge performance difference was not evident between the 2 different driver designs with the mini-amp circut (and was actually reversed, with the dual coil driver working much better, instead of much worse than the single coil.) Very weird stuff. Excited to see your new circut PSW, and hopefully it will make my testing much more productive/consistant. -MRJ Link to comment Share on other sites More sharing options...
psw Posted July 13, 2007 Author Report Share Posted July 13, 2007 OK...so a little more doings down here... I made an ebow from the LM386 amp and two relay coils...one I rewound with 0.2mm wire to about 6 ohms the other as is works as a pickup without preamp...seems to work reasonably well, needs a little tweaking... Been working on a new driver design combining the side driver ideas I posted earlier with my thin coil designs and the original fernandes concept of three fins... This driver is 55mm long and 6mm wide so pretty small and features 12 tiny (2mm) neodyminium "rare earth" magnets all with their like poles facing the centre blade. So far I have made the blades, fitted the magnets and used epoxy putty to fill the spaces in the core. I am intending to use two coils of 0.2mm wound to 4 ohms each in series (8 ohms) as this thing is pretty small and I want the cores to be as close to the strings as possible. The blades extend only from the magnets up, so is a departure from the fernandes design in that respect... My FEMM model shoed that very little magnetic field extends to the side of the device. These neodyminum magnets are pretty strong but are also strongly attracted to themselves so the lines of magnetisim turn back upon themselves pretty strongly. I am hoping that the presence of two blades of one polarity and the stronger centre blade of the other will provide a balance to the strength of these fields. The two coils are wired in reverse so there is some HB EMI like reduction effects as with the rail driver idea...additionally, the coils and cores on their side means that the action of the driver coils on the pickups (which have coils at 45 degrees to the driver coils) should also be greatly reduced... These are some of the resons I am attracted to this kind of design, but mainly it makes for a very compact driver and I believe that the compactness of my designs have a lot to do with their success. Mounted between the neck pickup and the neck, this thing should be hardly noticable... Of course, I have to get it to work... Have done a little more on circuit designs...haven't built the preamp or found time to clean up the LM386 circuit layout yet for posting. I really want the two to be matched (lining up inputs and power rails) so am leaning towards making them both an testing them anyway...have been out and got the parts so on the way with that... I'm far more at home designing and building drivers than designing stuff that may or may not work, way too frustrating... pete Link to comment Share on other sites More sharing options...
psw Posted July 13, 2007 Author Report Share Posted July 13, 2007 Well...watching TV and making drivers is a good mix...my sidewinder driver looks really interesting...the 4 ohm coils of 0.2mm wire fitted on the little 3 blade bobbin perfectly and now it is setting in epoxy to hold it all together. Hope I can work out how it needs to be wired up and...of course...that the thing works! Here's a pic to give you guys an idea of what it is about... The green curves indicate the magnetic flow...the magnets pointing towards the middle blade make it twice as strong as the outer blades so the outer blades are attracted back into itself. The difference between my design and other side wound drivers is that the small size of the thing, the strong magnets and the blades extending only above the core. It was a little tricky to wind but not as hard as the dual rail was...perhaps I'm learning. The blades form half bobbins and with a supporting jig and plenty of glue in winding the exposed coils below have held their shape well. Anyway...the side coil driver idea has always intrigued me...so now I have one. This time I will do further tests outsid of the guitar (as I advise everyone)...even though I did test the mid-driver, this one is small enough to surface mount in position. There is even a chance that it would work as a mid driver should I choose to, but as I explained previously, I am getting a little disillusioned with it due to the extensive rewiring required anyway to free up the mid position for it. I am not prepared to give up the neck position pickup, so with this design I have been able to make it small enough that it is inconspicuous, requires no routing and no loss of pickup function or modification to the neck pickup required. If all goes well, I may even be able to use the superswitch to select the sustainer as if it were a simple pickup selection...if not, I have these neat push button switches that should be able to do the job... Anyway...time to sleep it off now... pete Link to comment Share on other sites More sharing options...
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