psw Posted April 2, 2006 Author Report Share Posted April 2, 2006 Thanks guys... Well...due to a catastrophic crisis that has gone on for over a year now...I have been unable to do any work on the sustainer or anything else really. So, I have to hand the practical work to you guys. I did do some things to try and correct the pot, I even got creditable advice that it could not be fixed...red rag to a bull. Perhaps the best way, would not to turn it of...just disconect the driver!!! Of course remote power would be best to make this happen, but as I have suggested this may be best anyway!!! But there may well be better ways and I have only installed one on a single coil 3 pickup guitar which is probably harder than some, if not most, guitars!!! If you have the will, I'm sure you will find a way. I should stress that although the pop is not good, it only occurs in tuning off, not on and there is no sound made with the harmonic switch operation. I'd love to have a push button momentary harmonic switch to add a little harmonic lift to the end of long notes... By the way, what do all those extra knobs on your guitar do? I assume one is sensitivity for the sustainer... what about the rest? Ok...this guitar was a test bed for all kinds of wiring and construction experiments before the sustainer. There is a master volume and tone. The middle tone is the volume for the middle pickup. The gibson style 3 way operates the bridge and neck pickups and you can add the middle in any amount you like. The only selection you can't get is the middle alone! There are three mini switches, phase switches for the neck and middle and a series/parallel for the stacked bridge humbucker. two switches operate the sustainer and there is a sensitivity control. The other knob is not connected but was/is for a piezo volume. I did various piezo experiments and had a buzzer element in the neck pocket that worked really well. I never got round to installing it, but made allowance when I routed the cavity for the sustainer in the back of the guitar behind the jack. Some of the ideas on this guitar are really good, some not so. The sensitivity control is one I feel. There are other not electronic features that are good too that come up from time to time. The ideas on this guitar I intended to carry over onto the next one, this being just a prototype. The eventual guitar will be far simpler but still have a lot of these functions. I'll have to consider the switch later as I am just too tired now, but thanks again for the compliments and interest and I hope all the experiments forward your own projects and the sustainer project for all as a result!!! see you later... pete Link to comment Share on other sites More sharing options...
Ben Posted April 2, 2006 Report Share Posted April 2, 2006 The ideas on this guitar I intended to carry over onto the next one, this being just a prototype. The eventual guitar will be far simpler but still have a lot of these functions. Exactly my thinking with my guitar! Mine has (or will have) a ridiculous amount of switching options, so that I can test all the settings, keep what I like and ditch what I dont, and make my future guitars have all the best settings. Link to comment Share on other sites More sharing options...
starry_night Posted April 2, 2006 Report Share Posted April 2, 2006 Your pickup would only put out half the power of an HB and less than a single coil so you will have no balance the bridge and neck pickups (you can't compensate by height) and poor tone, but it would work in it's own way I guess. Better yet, would be to set the driver on top of one coil and lift the other...but that would take more construction, particularly with the magnet arrangement I suspect. What I would recomend is that people make a circuit and test driver. A small roll of wire is enough to make probably three drivers anyway at very little expense. This is effectively what I did, mad a 3mm driver...stuck it on top of the pickup, it worked so I replicated it built on the pickup, then set about installing everything into the guitar. It is easier to work out what went wrong this way (though mine worked well straight off) than to modify the guitar and have to keep taking it apart and change things that you have commited yourself too. yes pete youre exactly right and thats what actually happened! it made the pickup perform poor and unbalanced! but dont worry because i havent altered anything on my guitar yet. what i used is my cheap replacement hb pickup and my guitar is still in its original form. well i think im gonna need to forget the 'two-magnet' idea now that i know that it was the cause of the poor tone of my pickup. well, gotta build a taller driver core i guess... thanks very much pete.. Link to comment Share on other sites More sharing options...
fookgub Posted April 4, 2006 Report Share Posted April 4, 2006 I did various piezo experiments and had a buzzer element in the neck pocket that worked really well. Funny, when I did some buzzer experiments, I found that I also preferred the neck pocket to any other position. I tried the piezo buzzer experiment a few times over the years, but could never really get the sound I wanted. It always seemed honky in the mids, even with a high impedance preamp and some filtering. For now I've got a Graphtech system in my main axe, but I'd like to try out some the film stuff available here. Maybe I'd like it better without the metal backing... Ok, now, as promised, some ebow junk: This is one of the coils. As near as I can tell both coils are identical. I was wrong before when I said it's wound with 42 AWG. Now that I've taken a closer look, I think it's more like 32, or maybe a tad smaller. In the image, you're looking at the back of the coil (ie: the part that faces away from the strings... imagine the razor blade is the strings). The magnet on the right fits on top of the coil. If you look closely, you can see the indentation from that curled up piece of wire. I wasn't able to get a resistance reading on the coil. It was probably damaged in the removal process. That white junk was what the entire inside of the sustainer was potted in. It's pretty hard, but brittle, so I was able to chip a lot of it off. I think it's some kind of two-part urethane, as it's similar to some stuff we have at work. Side view: http://www.ece.utexas.edu/~wrobert/ebow2.jpg This is the assembled coil & magnet structure. Not much to say here, as the picture is fairly self-explanatory. The left side goes towards the strings. Front view: http://www.ece.utexas.edu/~wrobert/ebow3.jpg This is what the coil looks like from the string side. Note that it is wrapped around a core of some sort. I'm not sure if it's steel or magnet, but I'm guessing steel. I'll disassemble the coil eventually and find out. Circuit board: http://www.ece.utexas.edu/~wrobert/ebow4.jpg This is the string side of the circuit board with one coil still intact. I've chipped away a substantial amount of potting, but there still isn't much to see. I finally had to give up when I pierced an electrolytic cap and the smell drove me away... d'oh. As you can see, both coils are very similar... I think they're identical. Can you spot the diode I sliced in half? Circuit board, bottom: http://www.ece.utexas.edu/~wrobert/ebow5.jpg Ok, this is the bottom of the circuit board. Not much to see, but you should have a pretty good feel of how the driver/sensing coils are placed. It's hard to be sure, but I think I can make out the footprint of an 8-pin DIP. It would probably be fair to assume there is only one IC on the board, so I'm still wondering how exactly that harmonic switch works. You can see the 3-pin header that I tried to draw above. With all the potting in place, this was the only connection from the circuit to the outside world. Center is ground, other two were +9V depending on whether the switch was in 'normal' or 'harmonic' mode. I looked up the original ebow patent, and there is no mention of the harmonic generation circuitry. To be expected, since that was a later addition. I wasn't able to find a more recent ebow patent, and I didn't feel like sifting through the other sustainer patents for their implementations. There are actually quite a few sustainer patents in the U.S., so I'm surprised there are only three different devices on the market. Ok, shifting gears, here is the current state of my coil: http://www.ece.utexas.edu/~wrobert/sus1.jpg http://www.ece.utexas.edu/~wrobert/sus2.jpg http://www.ece.utexas.edu/~wrobert/sus3.jpg So I haven't made much progress lately. I departed from your design in a couple ways. First, the magnet structure... my bobbin is sitting on top of the magnet, whereas I believe your magnet is actually inside the bobbin. I had to do it this way because there wasn't enough room inside the bobbin to cut a slot for the magnet. Next, my pickup cover is one piece. It's still a work in progress, but it's coming along. I did this because I wanted a cleaner look, and I didn't want to accidentally catch my pick on the edge of the bobbin and pull it up. I still have to make the top part of the bobbin for the coil. I may just use some thin plastic and peel it off after the coil has set... sort of a semi-bobbinless design. The Loctite experiment didn't turn out very well. It just won't cure... I'm not really sure why. It wasn't designed to pot coils in the first place, though, so I guess I'm not surprised. I'm going to try some two-part urethane on my coil. Not the same stuff as used in the ebow... this is about the strength and consistency of that liquid electrical tape stuff, but not nearly as nasty and cures anaerobically. Just for grins, here's a picture of my current attempt next to my original coil from 5 years ago: http://www.ece.utexas.edu/~wrobert/sus4.jpg There is, of course, a cover for the coil, but I thought it would be more interesting to show the insides. Link to comment Share on other sites More sharing options...
psw Posted April 4, 2006 Author Report Share Posted April 4, 2006 Wow, thanks a lot for that post...it is probably the only pics yet of the insides of an actual ebow. I am pretty sure that the drive circuit uses a LM386 and the coils probably optimised for this and so avoiding the need for a preamp. I had not considered the shielding outer "core" nor have I heard it mentioned, but I have tried these types of things and is possibly something more to explore...perhaps it could be refined to make a mid driver like Dizzys without the complexity...that would be cool as you could use neck or bridge pickups with it maybe. I am sure there will be some traffic just to look at those pics...very nice!!! Your driver is not that dissimilar to mine...though my blade is starting to rust...but not as bad as you might expect. Mine is not curved which I kind of regret, so that's neat too. Perhaps try a thin cardboard bobbin top supported while winding and just leave it on there under the cover...it has worked well for me with PVA. The "bobbinless" one I showed pictured on top of an EMG was made by PG member onelastgoodbye/Tim (though I have made others with magnet cores and they may be superior than the pickup/driver idea in some ways) and is solely a driver...easily my fav though! My blade does go all the way through the pickup coil to a ceramic magnet, just like yours. I cut the top off the pickup cover to enable fitting the whole thing into it. as the blade is flush with the bobbin and the cover was not made for a blade so would have looked odd anyway. So, it is much the same...a little wider in the blade and flat on top. Looks like it will be a success...great stuff! Your earlier coil is a lot neater than the one I made that caught on fire!!! That was pretty funny. One thing about it was that it generated so much electromagnetic force it would pull the strings out of tune too...hehehe!!! This whole sustainer thing was kind of accidently started. I actually discovered project guitar while looking into novel pickup designs. I recalled my previous experiments and along the way, realised I was building skills and knowledge that could make the thing work...from there it just got out of hand and I never really got to apply my ideas and time to pickups. I have probably learn't more thought through this project about pickups and all manner of things, than I would have just doing that. I feel like taking this opportunity to thank everyone who has ever contributed to the discussion on the sustainer project as it has become and encouraged me to continue to encourage you to try this out for yourselves. Also, a big thanks to all associated with the wider PG forum for providing such a great site for everyone to share such ideas...just wonderful. I hope everyone else has been as interested in it all as I have...42,000 visits is simply amazing for this or any site on such an obscure subject and is a testiment on the lure of the idea of this device as much as anything. Enjoy... pete Link to comment Share on other sites More sharing options...
fookgub Posted April 4, 2006 Report Share Posted April 4, 2006 (edited) Wow, thanks a lot for that post...it is probably the only pics yet of the insides of an actual ebow. I am pretty sure that the drive circuit uses a LM386 and the coils probably optimised for this and so avoiding the need for a preamp. Could be. The 386 relatively new, though. I couldn't find a press release anywhere, but the copyright on the datasheet says 1994. The latest ebow incarnation came out in 1998, so it might use the 386, but earlier ebow incarnations would have used something else. The ebow patent literature specifies a VCA. This could be done with the LM386 and a couple extra components, or they may have left it out entirely (remember, the patent is 30 years old now). Either way, I'm sure there is no separate preamp. I haven't found any semiconductors yet, but the number and size of the caps looks about right for a 386 circuit. I'm going to hack away at the potting some more and see what I can find. Hopefully I'll be able to get a resistance measurement for the coil that is still intact. EDIT: Ok, I took a closer look at the ebow patent. It doesn't appear to spec a VCA. Instead there is a variable gain amplifier that can be adjusted via a knob. Obviously, they found this unnecessary and left it out of the commercial design. Even if the real ebow doesn't use the 386, I see no reason why a DIY version couldn't. Here's one more interesting quote from the patent document: "In one embodiment an unusual effect is produced where the current through the output coil 28 is reversed. In such cases it has been found that the fundamental frequency of the string is damped, however the overtones or harmonics are driven and become more pronounced. A manual switch may be used to permit selections of this effect." Looks like they're doing the harmonic generation the same way we are. Now if I could just figure out how that darn switch works.... maybe it controls an optocoupler or something. By the way, the (U.S) patent number is 4,075,921, and you can find it here. perhaps it could be refined to make a mid driver like Dizzys without the complexity...that would be cool as you could use neck or bridge pickups with it maybe. Got a link? The one in this thread is broken. I went over to diystompboxes and did a little searching, but I couldn't find it. Funny how many PG'ers have dual-citizenship. Also, it's very cool to see some guys sticking around that helped me out way back in the day when I was first getting into electronics. I built Mark Hammer's modded 'tube sound fuzz' about a million years ago... ahh, memories. Your driver is not that dissimilar to mine...though my blade is starting to rust...but not as bad as you might expect. Mine is not curved which I kind of regret, so that's neat too. Perhaps try a thin cardboard bobbin top supported while winding and just leave it on there under the cover... I'll probably give that a try. I gave my polepiece a little coat of epoxy to help prevent rust. I think the steel I used is rust resistant anyway. The radius wasn't too hard... I roughed it out on the bandsaw then did the final shaping on the belt sander. I cut the slot in my top cover on a 3-axis mill, the rough shaping was done on a belt sander, and the final shaping was done by hand with a file and sandpaper. Took a couple hours, but I'm pretty happy with the result. Now I'm just painting and sanding, painting and sanding, painting and sanding... Your earlier coil is a lot neater than the one I made that caught on fire!!! That was pretty funny. One thing about it was that it generated so much electromagnetic force it would pull the strings out of tune too...hehehe!!! Mine had the opposite problem. It barely worked, and only on the wound strings. It required a substantial amount of power, too, so like you, I had heating problems. Edited April 4, 2006 by fookgub Link to comment Share on other sites More sharing options...
lovekraft Posted April 4, 2006 Report Share Posted April 4, 2006 The 386 relatively new, though.No, the LM386 has been around for over 20 years now - it's almost certainly the power amp pictured in the original Heet patent. It is definitely the chip in Bruce Zinky's original Smokey amp from the early 80s, so it was available even back in the dark ages. Link to comment Share on other sites More sharing options...
fookgub Posted April 4, 2006 Report Share Posted April 4, 2006 The 386 relatively new, though.No, the LM386 has been around for over 20 years now - it's almost certainly the power amp pictured in the original Heet patent. It is definitely the chip in Bruce Zinky's original Smokey amp from the early 80s, so it was available even back in the dark ages. Thanks for the correction... learn something new every day. I guess all the ebows use the 386 then. Link to comment Share on other sites More sharing options...
Ben Posted April 5, 2006 Report Share Posted April 5, 2006 Just one thing I am a little hazy on... Diagram Look at the bit with the "?" Is that all you have to do to split the signal between the output and sustainer stuff? I'd have thought that it would divide the current, making the output signal to the amplifier (big external one) weaker... or that one of the routes to ground through either amplifier (internal or external) could be a significantly lower resistance that the other, meaning that the current was unevenly divided and one amp got all the current from the signal while the other got very little... Or is that irrelevant, since the amp inside the guitar only needs a small current (since its an amplifier, ie turns a small current into a larger one) and its really just the frequency of the voltage oscillation that matters? I'm just kind of guessing, I'm not 100% clear on all this as this is mainly stuff I have been learning myself ahead of my current education. Somebody else on another forum was very kind and checked over the rest of the schematic for me (So I know where the flaws are, like pos. 5 of the pickup selector, I'll get round to sorting that) They sugested that if the signal spiltting was a problem I could use a 1:1 transformer to duplicate the signal, and keep a fixed resistance on the bypass, so it won't matter if the amp is on or not- the circuit'll behave as if it's "on" all the time. (I dont fully understand that, I get the basic idea though) I'm guessing though that since I have never heard anyone else who has made a working sustainer mention 1:1 transformers or anything, that it works fine without one? Has anyone noticed any output drop when the sustainer is on? Link to comment Share on other sites More sharing options...
fookgub Posted April 5, 2006 Report Share Posted April 5, 2006 Just one thing I am a little hazy on... Diagram Please do yourself and all of us a favor by downloading ExpressPCB. Your schematics will be easier to read and easier to create. I have my own questions about what's going on in your schematic, but I think you've got the sustainer connection right. You want to connect it in parallel with the volume and tone pots. I'd have thought that it would divide the current, making the output signal to the amplifier (big external one) weaker... or that one of the routes to ground through either amplifier (internal or external) could be a significantly lower resistance that the other, meaning that the current was unevenly divided and one amp got all the current from the signal while the other got very little... Yes, but the more intuitive way to think about it is in terms of the load impedance seen by the pickups. Pickups have their own frequency-dependent impedance, which is why we want to avoid loading the pickups too much. By connecting the preamp in parallel with the volume and tone pots, you are indeed reducing the impedance seen by the pickups; however, the sustainer amp has a fairly high input impedance, so the overall effect is minimal. Or is that irrelevant, since the amp inside the guitar only needs a small current Right, because of it's high input impedance. (since its an amplifier, ie turns a small current into a larger one) and its really just the frequency of the voltage oscillation that matters? Not as right... this is a voltage amplifier. Depending on the configuration, it could turn a larger current into a smaller one (for instance, if no load was connected). They sugested that if the signal spiltting was a problem I could use a 1:1 transformer to duplicate the signal, and keep a fixed resistance on the bypass, so it won't matter if the amp is on or not- the circuit'll behave as if it's "on" all the time. (I dont fully understand that, I get the basic idea though) I don't fully understand it either. Did they, perhaps, provide a drawing? Transformer design can get complicated quickly, but it will suffice to say that transformers aren't free signal duplication devices. With an ideal 1:1 transformer, the source will "see" the load as if it was connected directly to it. I'm guessing though that since I have never heard anyone else who has made a working sustainer mention 1:1 transformers or anything, that it works fine without one? You won't need the transformer. Has anyone noticed any output drop when the sustainer is on? Yes, people who have changed the input stage of the circuit and lowered the input impedance have noticed a change in the volume and character of their sound. Link to comment Share on other sites More sharing options...
JTech Posted April 6, 2006 Report Share Posted April 6, 2006 I finally bought some of the stuff i need to make the sustainer. Except for the steel blade and the magnets for the driver. where can i buy this? any help??? Another question is what will happen if i use neck pickup thats on my guitar and hook it up to the sustainer circuit? Link to comment Share on other sites More sharing options...
fookgub Posted April 6, 2006 Report Share Posted April 6, 2006 I finally bought some of the stuff i need to make the sustainer. Except for the steel blade and the magnets for the driver. where can i buy this? any help??? The easiest way to get the magnets is to disassemble a cheap pickup. You might check ebay if you don't have one. I found suitable steel in the scrap pile at work. Be creative... the world is built on steel (well, concrete... but there's a crapload of steel, too). If you can't find any scrap, I'm sure the local hardware store will sell you some. Another question is what will happen if i use neck pickup thats on my guitar and hook it up to the sustainer circuit? It will oscillate. You can try if you want... just make double extra sure to turn your amp's volume down first! Link to comment Share on other sites More sharing options...
psw Posted April 6, 2006 Author Report Share Posted April 6, 2006 Hi Jtech the steel blade and the magnets for the driver. where can i buy this? any help??? I used ordinary steel from the hardware cut down. You could use just about anything that is magnetic and cut it down...even a row of screws maybe like poles in a pickup...or the magnet itself...though finding one that's suitable will be hard. Speaking of Magnets...DO NOT try cutting, breakin, grinding, etc them...especially Neodyminium or Rare Earth magnets as they are extremely dangerous. Also, beware whith these super powerfull things...they will have to be extremely small to be suitable. The ideal ones are found in pickups...but you can use several cheap creamic magnets in a row at the bottom of the blade, no worries. These type of magnets are often found in craft shops for making fridge magnets...you may even have some on your fridge. Due to ill health (on the mend) I have had too do a fair bit of walking and as it happens the place where I used to get magnets (aussie magnets) is right near where I am now staying. They had this flexible rubber stuff for labeling that looked like it would make a good magnetic "blade". It was not the common type you see stuck to callenders or for magnetic cards...these have stripes of polarities...this had the poles on the edges and could be cut with a sharp knife...pity they wanted to sell them by the roll for a fortune!!!...doh! If you had access to a lot of dead disk drives, there are usually Neo Mags in them it you have a mind to rip them apart...but dont break the mags...more trouble than it is worth I'd say. Think laterally though and you will find magnets...they are everywhere when you think about it. Another question is what will happen if i use neck pickup thats on my guitar and hook it up to the sustainer circuit? No...don't do this...first it won't work...second it will probably destroy the pickup. A driver and a pickup only superficially seem to be the same but are built to do very different things. The driver is built to a very low impedance with wire thick enough to carry the power put out by the sustainer circuit. Pickup wire is very high impedance and it's wire so thin it will burn out in no time. It can't work because the impedances are wrong for a start and it can't stand up to the power required. One thing also is that it couldn't possibly work "fast" enough! There is a delay between picking up the vibration of the string, amplifying it and then driving it. The speed at which the driver responds is the weak link. In conventional commercial designs there is compensating circuitry and "shunts" on the high strings to address this delay...or phase shift. With my approach here, we are using a simple amplifier and a driver design...the very thin driver...that is so designed to work "fast" enough (minimum phase shift) so as to be simple and efficient. The design that I came up with also has the happy outcome of being so thin as to be easy to fit to a guitar...even to it's pickup or beside it. The dimension and wire guage and things of this nature...although may seem insignificant...is actually very important. Variations may work, but the principle does seem sound and those that have strayed from the concept seem to have less than satisfactory results. I am not completely satisfied with mine yet. My concerns are these... > I still have a pop on turn off. > I would like there to be an option of remote power. > It would be nice to be able to simplify the switching...but it would take some complex circuitry I suspect, making that part more expensive and bigger...the installation wiring will always be fairly complex by its nature though. > I think there is a potential problem (though mine seems to be ok) with my preamp design as far as loading is concerned and in splitting the signal. The Fetzer/Ruby wouldn't suffer from this so should be ok...but is it as good as my design? I don't know! I have some ideas about all these things, but it will be some time before I can return to any practical work on doing anything about them myself and rely on you guys to take it a step further. All I can say is that my guitar seems to work very well and that I believe that these problems can be overcome Good luck with your building. I would go ahead and make up the circuit. Test it with a small speaker to be sure it is working. Be prepared to make a few test drivers if necessary and try the thing out before you worry about installing and such by holding the driver above the strings or removing the neck pickup to provide space while testing. The cost of making a driver is only a few dollars really (perhaps $2) and the magnets can be reused if you like for the next one. The circuit remains the same and with practice it shouldn't take too long to get a driver together by hand...that's how I made all mine even though I have winders, etc! pete Link to comment Share on other sites More sharing options...
Ben Posted April 6, 2006 Report Share Posted April 6, 2006 Thanks fookgub! you answered all my questions. I am downloading expresspcb right now. The transformer thing is probably confusing because of the way I phrased it, its hard to convey something I dont fully understand. As you said, it works fine without it so I wont use it and will save myself the added complications. They didnt provide a drawing, and I don't really want to ask them for one unless you are very interested, because since I'm not using the transformer it would be a bit of a waste of their time. Link to comment Share on other sites More sharing options...
fookgub Posted April 6, 2006 Report Share Posted April 6, 2006 (edited) I am downloading expresspcb right now. Great. If you've never used a schematic capture program before, there will be a bit of a learning curve. ExpressPCB is probably one of the easiest out there, though, and it has a good selection of components. For this type of stuff, you may eventually want to symbolize some components of your own (ie: those 5-way rotary switches, pickups, etc.). Again, it may take a bit of time to learn, but you'll be pretty happy when you can bang out a complete guitar schematic in 5 minutes. Plus you can easily edit old schematics. The transformer thing is probably confusing because of the way I phrased it, its hard to convey something I dont fully understand. As you said, it works fine without it so I wont use it and will save myself the added complications. They didnt provide a drawing, and I don't really want to ask them for one unless you are very interested, because since I'm not using the transformer it would be a bit of a waste of their time. No need for a drawing. The guy's idea may be good or bad, but either way, you shouldn't need a transformer. The Fernandes sustainer uses a big ol' transformer, but I'm not sure what for. It would be interesting to see a schematic of that... JTech, I may have misunderstood your question. If you want to use the neck pickup in conjunction with the sustainer system, it will almost surely oscillate. If you want to use the neck pickup as the driver, it won't work. I'm not sure that I agree with pete's assessment that it will destroy the pickup, but he is the resident sustainer expert here and his advice is worth heeding. I'd estimate that the sustainer amp could put around 1 mA of RMS current into a nominal 4k Ohm pickup. 42 AWG is rated for around 10mA in free air, but you'd have to degrade that slightly in a coil. Bottom line: it may or may not destroy the pickup, but it won't work anyway, so there's no reason to try. Edited April 6, 2006 by fookgub Link to comment Share on other sites More sharing options...
psw Posted April 6, 2006 Author Report Share Posted April 6, 2006 (edited) The transformer thing is probably confusing because of the way I phrased it, its hard to convey something I dont fully understand. As you said, it works fine without it so I wont use it and will save myself the added complications. Don't apologise...the transformer is a worthy contribution...in fact there is a transformer for some unknown purpose on the fernandes system! The idea is to electrically disconnect the circuit...the transformer connects it "magnetically" if you will. It is there to address the loading problem, it has been addressed though by having a very high impedance preamp in the fetzer. I am not sure about the use of transformers myself in this application...it adds yet another coil suseptible to noise and having an impedance itself...hmmm. Concerns will make themselves apparent as and if they occur...just put together the basic elements...circuit, driver and switching and modify as required before installing completely. As for drawing programs...your drawing was not that bad...very colorful...but it is complicated...but then that is the nature of it. PCBexpress and like programs are great for doing schematics and especially PCB boards...but there is a steep learning curve and I'm not really sure that they are so good for all these "off-board" wired components. I have had trouble learning them even for drawing up circuits. I use Serif's DrawPlus program at the moment but have also used TurboDraw. These deal with shapes quite a bit and draw the lines straight rather than freehand. If you look about you may well find better programs than your standard Paint program for free. How I approached wiring my guitar was to get the basic switching right then, add the complications. So for phase switching, the pickup goes to the reversing switch and then it is to the selector. I just added the switch in between these two components. I did the same for each pickup...so although there is a lot of connections (3xdpdt switches) it is just as if it was going from pickup to selector. Likewise...the selector is just between the pickup and the controls. The controls between the pickup and the output. Basically, every component is an interuption to the signal chain and can be worked out one by one, no matter the complexity. The sustainer's wiring is a little different...it runs in parrallel to the guitars signal chain and a little apart from it. In this case, we are turning off all the guitars wiring just before the controls, we are turning on the sustainer's amplifier circuit (power) and connecting the bridge pickup back to the controls from the input of the circuit (it goes from the pickup to the circuit and to the controls). So, the bridge pickup along with all the other wiring up to the controls is disconnected, and the bridge pickup re-connected when the sustainer is turned on. It needs to be this way so that no matter what selection of pickups or other wiring you may have, it will always switch to a single pickup guitar during sustainer operation. To do all these functions I needed a 4pdt switch (above). It is a little complicated but if you consider it as 4 switches and take one at a time it's not so bad. (from right to left) One switch for the power. One for the connection of the bridge pickup to the output of the guitar via the selector or the controls and circuit when on. two switches to isolate the other pickups and wiring. Notice that both the hot and grounds are lifted and the coils shorted through that wire bridge...they no longer are connected to any earth or any other wiring. Anyway...carry on... pete If you want to use the neck pickup in conjunction with the sustainer system, it will almost surely oscillate. very true...or cancell out all output too! If you want to use the neck pickup as the driver, it won't work. correct, the impedance mis-match would be tremendous for a start...some have speculated with transformers or a special circuit or other hocus-pocus...but I don't think so! I'm not sure that I agree with pete's assessment that it will destroy the pickup Well, I have tried it in short bursts to prove that it won't work! I have not destroyed a pickup yet, but I have destroyed my very own carefully wound miniture fine wire coil designs with correct impedances...doh! Although the current may be within tolerances for the wire...once in a coil and subjected to rapid alternating current from the amplifier, it will generate heat...perhaps enough to burn through the wire or melt the insulation in the coil. That is the concern I feel. I am all for experimentation, but I feel a little responsible if I were not to point out the risk. As I say though..it short bursts it did no harm...it doesn't work...but you can try it if you wish! Mainly, I would like people to see pickups and driver's as essentially different animals. It is possible to use a driver as a pickup though with active electronics...but I can't vouch for the sound quality. Thanks fookgub! Edited April 6, 2006 by psw Link to comment Share on other sites More sharing options...
Ben Posted April 6, 2006 Report Share Posted April 6, 2006 (edited) Regarding the transformer idea, since it wasn't my idea and I cant really explain it well, here is a link to the original discussion on the MIMForum where it was suggested: Thread I may be completely barking up the wrong tree, but is there a chance that it could help with the 'pop' on turn off that you mentioned? "The sustainer's wiring is a little different...it runs in parrallel to the guitars signal chain and a little apart from it. In this case, we are turning off all the guitars wiring just before the controls, we are turning on the sustainer's amplifier circuit (power) and connecting the bridge pickup back to the controls from the input of the circuit (it goes from the pickup to the circuit and to the controls). So, the bridge pickup along with all the other wiring up to the controls is disconnected, and the bridge pickup re-connected when the sustainer is turned on. It needs to be this way so that no matter what selection of pickups or other wiring you may have, it will always switch to a single pickup guitar during sustainer operation." With my current wiring set up for the sustainer using the rotary switch the pickup selector has to be in pos 4 (bridge pickup only)... which is a bit of a limitation. Currently the sustainer rotary is wired as: Position 1- power off, sustainer disconnected Position 2-power on, sustainer connected, normal sustain Position 3- power on, sustainer connected, harmonic sustain If I could only get a 3 way rotary with more that 4 poles I could probably get it to turn the neck pup off and bridge on too, which would be ideal Actually looking at my diagram, isnt the bit on the sustainer rotary with the blue wires from the 'in' on the fetzer ruby thing and a red 'hot wire' actually completely pointless... Might have some more scope for modifying the wiring there... I dunno, its late and I'm tired and I'll think clearer if I look at it tomorrow. I'll have a better look at the way your switch is wired too. Many thanks, Ben I'll mess around with those programs and try to refine my drawings too! Edited April 6, 2006 by Ben Link to comment Share on other sites More sharing options...
psw Posted April 7, 2006 Author Report Share Posted April 7, 2006 Gee...the sustainer has made the MIMF...I wonder if they know about this thread? Anyway...found a drawing of the Sustainer-Strats total wiring scheme...so here it is! There is a lot of stuff in there Link to comment Share on other sites More sharing options...
onelastgoodbye Posted April 9, 2006 Report Share Posted April 9, 2006 Hi peeps, I'm still reading up on this thread almost daily, but it's pretty hectic for me right now so I don't have a lot of posting time. There has been some interest in the bobbinless driver it seems, so here's a little quick something that might help you guys...the new and improved way of making temporary bobbins: the steel (or mdf or cardboard or whatever) pieces are there for support, the PE is there because it's about the only thing that epoxy doesn't stick to. If you're wondering where to find PE, things like shampoo bottles and those 5 litre containers for thinner and acetone are usually made out of PE plastic. As for potting with epoxy while winding...it can get pretty messy so you'll have to be careful.Wear gloves if possible because it's actually pretty unhealthy stuff and hard to get off your hands (apparently it can make the tips of your fingers go numb after years of (a)buse). Here's a tip... I usually let the mixed epoxy sit for a few hours before using it. That way, it's less runny and more sticky which makes it a lot easier to work with (obviously it depends on the sort of epoxy you're using: short-long drying time). rock on, Tim Link to comment Share on other sites More sharing options...
fookgub Posted April 10, 2006 Report Share Posted April 10, 2006 Tim, That's great stuff. I had no idea epoxy wouldn't stick to PE. The bobbinless driver really simplifies a few things regarding the construction. Have you actually installed it? Does it work? I'm still fighting my way through the driver thing. I made a new coil on Friday for my combined pickup/driver. This time I potted it in Hardman A-85 urethane. In short, it was a disaster. The urethane sets up very quickly, so it was difficult to apply while winding because it was so "gummy". The final coil oscillated when I applied any significant singal to it. It also vibrated audibly about as badly my first Lace Sensor coil. I tried running the bridge pickup only (hardwired to the output), so I don't think it's the grounding system I'm using (I'll try to get a diagram of that up soon). It looks like I'll be doing yet another coil. I also managed blow up the little Fender amp I was using for testing this weekend. Some sort of grounding issue, I think... it happened when I tried to connect my oscilloscope probes to the speaker output. Luckly it wasn't too badly damaged. The primary on the power transformer is open, but everything else is fine, so I've been using it with my bench supply until I can find a new transformer for it. Anyway, this made my decide to build a dedicated sustainer amp. I built a Ruby-Fetzer, but changed the input stage biasing slightly for a little more gain. I also built another amp that's got an opamp input stage and the power section from a cheapo set of computer speakers. It should develop about 5W into an 8-ohm load. I wasn't able to test the last coil with the new amps... I tore it apart in frustration on Friday night, but I doubt it would have worked anyway. Bad weekend for projects... I'm also getting noise through the ground on my new car stereo... Along with the continuing development on the pickup/driver, I think I'll build several bobbinless coils of various impedances and try them out with the two amps I've got. It's possible that my particular installation just demands a little different design. I still haven't built my coil winder, so the coils may have to wait until then (I'm starting to get sick of staying late at work to do these things). Now that I've gotten used to the winding machine, I don't think I can go back to doing by hand. The coils come out much tighter on the machine, and I like having two free hands while I'm winding. I'm still searching for the perfect potting material, too. Epoxy is the obvious choice for the bobbinless coils, but I don't know where to go with the pickup/driver. PVA will probably be my next choice, but I'd like to look into something that's 2-part or faster drying. Link to comment Share on other sites More sharing options...
onelastgoodbye Posted April 10, 2006 Report Share Posted April 10, 2006 Tim, That's great stuff. I had no idea epoxy wouldn't stick to PE. The bobbinless driver really simplifies a few things regarding the construction. Have you actually installed it? Does it work? I'm still fighting my way through the driver thing. I made a new coil on Friday for my combined pickup/driver. This time I potted it in Hardman A-85 urethane. In short, it was a disaster. The urethane sets up very quickly, so it was difficult to apply while winding because it was so "gummy". The final coil oscillated when I applied any significant singal to it. It also vibrated audibly about as badly my first Lace Sensor coil. I tried running the bridge pickup only (hardwired to the output), so I don't think it's the grounding system I'm using (I'll try to get a diagram of that up soon). It looks like I'll be doing yet another coil. The coil works and does a pretty good job on the high strings, but it has to be positioned in an EXACT spot somewhere between the 24- 25th fret, otherwise it squeals/feeds back like mad. The squealing is a lot less than with my former badly potted drivers though (including a PVA one). In my opinion, a marketable version of this driver would require some form of shielding or shunting, maybe a humbucking configuration, because it puts out massive amounts of EMI. Fact is I experimented with steel pieces (just holding them to the sides of the driver) and that seemed to quiet the beast significantly...also, I recall someone here made a succesful driver with an iron bar sitting next to it in order to emm...inhibit the magnetic field. The sustainiac driver has some small shunts as well, atleast in the patent drawings. I hear 2-part urethane needs to be mixed juuust right to properly harden, but I don't know if that's the stuff you're using. Epoxy is a bit more forgiving, tho' I've mixed some bad batches before; those household scales really aren't that precise. Maybe you could look into 2-part polyester.There's lots of different types (from car body filler stuff to guitar laquer) and some of them can be used like you would use epoxy. It usually dries a lot quicker though. Tim Link to comment Share on other sites More sharing options...
psw Posted April 11, 2006 Author Report Share Posted April 11, 2006 Hi guys...just returned from my employment three day tour of duty...good to see you back Tim (I knew you were out there) and sorry to hear your tales of woe there fookrub... You can understand the amount of work and frustration I was going through to make things like my hex drivers...but with those things behind me, I was able to put together this design with little difficulty and made a few and everyone has worked. All have been about 3mm thick, one was on a small pickup bobbin, another had a cardboard/paper bobbin and the one on my guitar has a very thin plastic (paper thin) top on a pickup. All were potted with PVA woodworking glue and all worked pretty well with a creamic magnet...and even with the tiny neodyminium mags. All were tested with variations on the LM386 running at x200 (though some have a variable gain) and various preamps. I think you may have been testing with too much power...I am probably only putting out 0.5 watt and running off a battery means it has a limited power too. More power would only mean more EMI and also, with the installation, I did have to lift and short both the neck and mid pickup from the guitar circuit...de-selecting it may not be enough...study my bypass switch to see how I did that. Beware of futile experimentation...it may lead to frustration and little more. If one was to look closely at this threads dates, you will see I spent a good year or more pursuing the hex driver ideas only to return to a much simpler platform. The circuit that drove it was the same and the thin driver concept came from this too, but it is possible that I would have arrived at this point a year earlier anyway. All the same, far be it for me to stifle experimentation. The ebow pickup and driver was of interest in the ferrite ring around it...this could easily be used in the larger driver model. I did quite a few experiments with this idea. One used common staples to create a magnetised sheild up the sides of the driver with a polarity the reverse of the core. Theoretically this should have been great, but in practice, it seemed to make little difference...so I didn't mention it much. Many of the Hex drivers were encapsulated in steel impregnated epoxy (post-winding) and some completely which helped significantly. The Hex drivers developed into a radically different driving mode to our current coils and had six balanced magnetic fields (12 magnets) and were also a fair bit smaller than even these thin coils...taking these radical steps, I was able to drive the strings at one point with the driver between the bridge and middle pickups on my strat, and had hoped to have the thing working eventually at the bridge...using the steel bridge itself as a magnetic "sink" also, and to address the alignment issues I was having...however...alas... Anyway...what I am getting at, is there are lots of experimental improvements that one could make...but mine seems to work pretty well in it's simple format. I think that too much speculation and deviation may lead to disappointment and disillusionment with the project. Hopefully, things will turn around for me privately and I may spend a little while developing this a bit to make it clear and simple...but that may take a little while. In the mean time, I hope people can see that it can work with a simple circuit and a coil of wire without the risk of epoxies or anything too fancy really...you may wish to just see if you can get my basic idea to work as it has for me...then set about improvements. Eventually, I may have a "standard" proven circuit and driver formula for people to build and improve upon...that seems to be the way to go... Anyway...always good to see activity in peoples minds and people getting their hands dirty having a go! pete Link to comment Share on other sites More sharing options...
fookgub Posted April 11, 2006 Report Share Posted April 11, 2006 I recall someone here made a succesful driver with an iron bar sitting next to it in order to emm...inhibit the magnetic field. The sustainiac driver has some small shunts as well, atleast in the patent drawings. That's an idea that had occured to me as well. The steel bar would sort of pull the magnetic field towards it and away from the other pickups. I'll probably do another coil towards the end of the week. I'll try out some steel bar experiments if I still have problems with feedback and oscillation. Maybe you could look into 2-part polyester.There's lots of different types (from car body filler stuff to guitar laquer) and some of them can be used like you would use epoxy. It usually dries a lot quicker though. 2-part poly... hmm. Doesn't that stuff dry pretty hard? The problem I have is that I've only got one bobbin for the combined pickup/driver and I don't want to make another one. Since I've already had to rewind it a couple of times I want to make sure that whatever I wind it with is reversable. The reason I keep going after 2-part is that I want to make sure whatever I use is going to cure properly. The idea with "fast drying" would be something that would cure while I was winding it. About the only thing I can think of like that is CA, but it probably wouldn't be reversible. The A-85 urethane I used came in a "job pack" so I know the ratio was right... it's just the wrong material for the job. I've found that epoxy is pretty tolerant of bad mixing... it mostly seems to affect the hardening time. Probably affects the bonding strength, too, but I don't think that's a concern for us. If anything, I think it's better to err on the side of too much hardener. Doing a bunch of different coils is something I may not get to. It really depends on how many more iterations it takes me to get a working driver. I would like to build at least one or two coils in Tim's style, though. I had an idea for a surface mount driver that could be used on a semi-permenant basis with a few different guitars, and I think the bobbinless driver is a natural canidate for that sort of thing. Here is the grounding system I've been talking about: It uses a 2 pole guitar switch. One pole switches the 'hot' leads as normal, while the other side switches ground. When the bridge pickup is selected, its ground is connected directly, while the other two pickups are grounded through 100k resistors. This guards against switching transients by keeping the neck and middle pickups referenced to ground, but prevents any significant current from flowing. The nodes in the schematic are kinda hard to see, but hopefully you can see what I'm trying to do. I tried this with my last coil, and I also tried disconnecting the middle and neck pickups entirely... it didn't seem to make a difference. Anyway, I've got a few other projects on my bench, too, but I've been trying to make as much time for the sustainer as possible. I'm hoping that within about a month I can have the combined pickup/driver working and one or two bobbinless drivers ready for temporary installs. I'd like to get going on rebuilding that ebow, too... but one thing at a time. Link to comment Share on other sites More sharing options...
Ben Posted April 11, 2006 Report Share Posted April 11, 2006 About the only thing I can think of like that is CA, but it probably wouldn't be reversible. The CA I have came with a little tube of 'de-bonder', so maybe it can be reversed. Link to comment Share on other sites More sharing options...
lovekraft Posted April 11, 2006 Report Share Posted April 11, 2006 (edited) Not to hijack the thread or anything, but this might be important. Pete and I have discussed gain control in theoretical terms several times, and rejected it as too complex and fiddly, but this idea (from Brett Robinson, another proud Aussie ) might just make it a lot easier. Brett's come up with an ultra-simple compressor based on the 386: Brett's Aussie Compressor Since it works using a super simple feedback sidechain and a single MOSFET, it should be fairly trivial to integrate into Pete's basic power amp. For more info, see this thread over at Aron's DIY Stompbox forum. Unfortunately, I don't have the time to pursue this right now, but it's too good an idea not to share with the group - it could (theoretically) help even out the response curve over the entire frequency range, and make for much smoother sustain. Now, you maniacs take it and run with it - both BS170 and 2N7000 MOSFETs should be easy to find and fairly cheap, and the rest is stock components. If anybody gets truly superb results, please let us know! Edited April 11, 2006 by lovekraft Link to comment Share on other sites More sharing options...
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