FlashBandit

What are the drawbacks to using BTL amps? I'm just considering using one, and I want to know what problems I'll face.

I just came across this site: maxim-ic.com and they have free samples of some of there electronics. What's the catch? Has anyone ordered succesfully from them? I know that BTL amplifiers are apparently expensive, and people in the sustainer thread are interested in their use, they have some samples at maxim-ic! I just want to know of any risks in doing business with them for personal use. (By business I mean mooching )

I got the generic definition online, I was just curious about these amps. It sounds like you get 4x the power for the price of 1, and I can't help but think there need to be draw backs/down sides, or else all audio amps would be BTLs. Is there more current draw? drain the batteries faster? is there a problem with halving the impedance?

erikbojerik, that's a pretty sweet looking picture, good job! Where's the rest of it though? Can you apply tru-oil and then use a poly coat after to protect it? If you did that, how rugged would the finish be? Also, any ideas on how to finish cocobolo?

I have an original guitar design that I'm in the process of constructing. I want to be able to post stuff online without fear of theft, what do I need to legally be able to protect myself should I ever try to market these instruments?

Does anyone have any good pictures of the Tru-Oil? Does the Tru-Oil act as a protective coat? Would you use any other chemicals than the Tru-Oil to maybe seal it or whatever? What finish method/chemicals would give me a good high gloss finish? I'm considering giving the edge a thin black burst effect, any thoughts?

Here's some walnut I'm gonna use for a carved top electric, any finishing suggestions/pics? This is one piece, front and back.

OK, I've searched for hours to find a decent source of les paul dimensions, or a simple CAD file, but haven't found a thing. Now I know this has been asked before and similar threads are locked or bashed etc. please dont. I'm sorry I'm cheap, but I don't want to fork out any money for a template. Does anyone have a CAD file they could send me? Or a comprehensive list of dimensions? Please help me out, I've got all the wood I need for this project but can't start yet. Thanks in advance!

Are you saying that this needs to be connected to earth, like in an outlet? Right now I'm testing my guitar without it being plugged into any amp (just the F/R), and therefore it isn't grounded to my house's ground. Is that causing my problems?

Tons of experimenting has yielded no answers. Plugged into an 8 ohm speaker, the amp produces a constant high pitched whine whether notes are playing or not. This seems to go away after a minute until I touch the strings, bridge, ground etc. and the whine returns. I have a trim pot between pins 1 and 8, should I also have a cap? What would the cap do? Also, I checked out this Ebow Tut and the guy seems to succesfully recreate the ebow using much thinner wire for the driver, 38 gauge. Why does our experimentation revolve around 32 gauge wire? Does anyone know the gauge and impedance of a commercial sustainer?

Trouble shooting question: I've built many drivers and they all are microphonic in that when an amplified sound goes through the coil, it reproduces that signal audibly, like a speaker. This seems to kill the efficiency of it. Specs: the driver is a 3mm thick core, 33 AWG wrapped to 8 ohms, and its about 3mm tall. I get the best response on the high E and B, and I didn't understand why that was until recently and correct me if I'm wrong. I think the reason why I only get response on the two highest strings is because since they're higher in pitch, the amplified signal is less likely to create microphonic problems in the driver, where as when the pitch is lower, it more easily vibrates the coil of the driver, and kills the efficiency so it doesn't vibrate the string. Any thoughts?

With all of our hard endeavors to make EMI cancel out, wouldn't it just be easier to shunt it to ground by wrapping the driver or each pickup with a foil thats connected to ground?

I was planning on using regular candle wax, but then I realized that may melt on a hot day. Is there anything cheap, or common to add to the wax to raise its melting point? Have you ever gotten microphonics with wax potting? Also, I had a new core idea. Basically, you have a hole bunch of adjustable "pole" pieces that essentially act together as a bar style core. That way you can mechanically adjust the response of each of the strings instead of electronically. Here's a pic, tell me what you think. Also, any ideas for where to get the small rectangular pieces? I was thinking if they had squared nails like in the olden days... but any small rectangular piece of ferromagnetic metal should work.

Sorry, I've been out of the loop a while. I just had an idea for potting, Why don't we wind the coils dry and then pot them in wax? It works for pickups, basically you just take an un-potted coil, and soak it in hot candle wax for like 10-20 minutes and the wax fills all the pores. You melt the wax by making a double boiler on the stove and the inner pot has your wax. Just afix the driver so it is covered by the wax, but not touching the metal sides. Take it out, let it dry, Any problems with that? Also, where do you get your magnets from? Can you magnetize any bar of steel? How much is a magnetizer?

Mounting Question: PSW, you told mrjstudios to mount it and allow it to have an adjustable height and such. I made all my bobbins myself, so how do I mod them to let the height be adjustable? I'm mounting this in a strat in the neck position. Any suggestions for mounting?

PROGRESS!! I built a new driver that works like a charm. I'm having some weird problems though in harmonic mode, and I have a question. Basically, it seems like the sustainer is trying to "force" a high pitched F# no matter what I'm playing. If I'm playing on the upper strings, the low E will start to resonate at an F# which is insane since they're not harmonically related (I don't think). What's up with that and how can I fix it? As a contribution to the ongoing driver development, 33AWG is very effective at driving the three highest strings. My coil has a 3mmx3mmx6cm core and no top bobbin. That way it can get closer to the strings. It's also 8.1-ish ohms. With my driver, it drives the three highest strings stronger than the bass strings. In fact, it does seem to have problems driving the A and D strings, but the E and three treble strings are fine. I'm thinking that it might work well to have two separate coils for the bass and treble strings, bass with 32AWG and treble with 33AWG. About EMI problems, couldn't you wrap the driver in metal tape and ground that? I think that should shield it. Or, you could wrap each driver and ground them. Just a thought.

OK, I'm tracing alot of my problems back to a high pitched sound produced by my Ruby/Fetz circuit. I find that if I touch the ground/common with my hand, this problem mostly goes away. I don't get it because I only touch the ground, nothing else. This problem is NOT related to feedback between the pup and driver because the loud ringing is apparent when the amp outputs to headphones. This high pitch squeal causes microphonics in my driver that wrecks the efficiency of it. How do I fix this problem so that I don't always have to be in contact with the ground? I think there may be a problem with the trim pot (see the main diagram), but could that be causing it? Thanks!

You asked what circuit I was using, I'm using the Fetzer/Ruby diagram from the front page of this thread with a connector between pins 1 and 8 instead of the gain pot. O.K., I'm starting to realize that either I can't pot drivers, or there is only so much you can do to protect them from microphonics. I'm finding out though that there might be a problem with my circuit now, and the driver problem is related to it. The circuit was perfect before, but apparently something's come up and I don't know what. I plugged in to headphones and found that the circuit produces a squeal that goes microphonic in the driver. If I physically touch the ground of the circuit (or anything grounded like the bridge or strings) the high pitch squeal produced by the circuit goes away. I think that the circuit isn't grounded properly, but I don't know what to fix. Any suggestions? Also, the microphonic problem I've been having is actually two things. Number one is listed above, and the second problem is EMI feedback between the pickup and driver. The first problem is constant no matter the driver's proximity to the pickup, but it goes away when I touch the ground. The second problem is related to the driver's proximity AND orientation to the pickup, but I know I can't fix this any time soon since it's the matter of much debate right now. Anyways, any help you can give me with the grounding issue would be greatly appreciated. Oh, also, have any of you read the patent for the sustainiac system? There's some good material in there including diagrams and stuff. For their circuit, they make it a little more complex and efficient. The signal chain goes: Signal > Preamp > Phase Shifter > Automatic Gain Control > Limiter > Current Booster > Driver This might help Col and his ingenious development of the AGC circuit. They also have alot of different Ideas for drivers and stuff. Useful information, especially if you understand it I don't Anyways, here's the link for the text: Sustainiac Patent They also have all the images at a link at the top of the page. If your internet can't show "tiff" images (mine couldn't) download the freeware "AlternaTIFF". It is incredibly useful for viewing the patents here and has all sorts of great features. Let the development continue! I just keep thinking, "The people's sustainer is almost here!!!". Excited? Me too.

I'm truly sorry to be burdensome, but I'm having terrible troubles building my driver. I've built maybe ten now and all of them are severely microphonic. The coil actually whines at a high pitch without the guitar even being plugged into an amp. This problem is coupled by the driver's proximity to the pickup. I've potted in tons of different ways. My latest contraption was to build a coil without potting and not wrapped around anything. I then wrapped the coil with thread and pulled the coil all tight in together. Then, I cut a cast out of a bar of soap to put the coil in and surround it with iron impregnated epoxy. I put iron powder in the cast and mixed an epoxy in that with the iron. I then stuck the small coil inside and let it dry. The dang thing is till microphonic and it's driving me crazy. Please help! I'm wrapping the coils as tight as I can without breaking the wire. Should I wrap it a little looser? Am I not potting correctly? Also, I'm not really getting sustain yet. I know the amp works strong, I almost accidentally blew out an ear with it. Will microphonic drivers make the sustain not work? What's going on? How do I diagnose my problems? I'm actually very surprised that more people aren't having these same problems, but please give me a hand. Thanks a million!

When I say microphonic, I'm meaning that the actual coil vibrates. I've been testing this without even plugging my guitar in, and the actual driver coil emits a loud whistle. Someone told me that rubbing alcohol will soften the coating on magnetic wire, so I'm soaking 2 microphonic coils in alcohol. One was potted with elmer's wood glue and the other with gorilla glue. I'm hoping that the alcohol will soften everything up, and then I'll let it dry really slow so that the air bubbles that were released while soaking will fill up with glue. Cross your fingers PSW + col, I've been reading about the recent advances with this project and I must say, I'm highly impressed. I want to help so, here's an idea that may help EMI. I've read that a humbucker-type driver helps eliminate EMI. I was thinking that the efficiency of said EMIBucker may be improved if you wrap the coils together. You'll set two cores close together in the same bobbin and then wrap them with wire making an "infinity" pattern. In other words, wrap one, then cross over to the other and wrap a coil. This will give you an "x" pattern in the center. The two coils should be phased opposite by doing this and the fact that the signal crosses one core then immediately the other, then back, may help localize/focus electromagnetic fields. That's just my 2 cents. I hope to try it when I'm done with finals (my university is ending a little early this year )

Arrgh! I've built 4 or 5 drivers and all of them are horribly microphonic. I've potted with elmer's white glue, wood glue and gorilla glue. None of them seem to work (and gorrila glue gets every where and doesn't wash off ). Here's how I wrap a driver: I lay down a thick layer of glue, smear it around, and just start wrapping. I wrap until the wire is no longer covered by glue and I then I lay down another layer of glue. I over wrap it usually about to 10 ohms, and start unwrapping it until I measure 8ohms. If any part is uncovered from glue, I'll put more in then just let it dry. What am I doing wrong? No changes seem to work!

Yeah that's me. I've recently grown an interest in combining guitars and theremins, and so I decided to check it out! EDIT: Oh, and I hope there aren't multiple flashbandit's, I think it's original.

A crazy thought just came to me out of the blue, and I want to know what you guys think: Imagine a pickup/driver as a collection of individual coils around a bar all connected in series. How do you think a pickup would sound if you had a whole bunch of individual coils around a bar connected in parallel? Or maybe each coil could wrap around a few times and then connect in parallel? I'm sure you'd get some new sounds. This could be done most easily by wrapping a coil around the center bar (or poles) with 540 degrees of rotation and leaving two leads of wire coming out. Do this a whole bunch of times and have a whole bunch of leads coming out, then wind and weld them together. Left side wires would make one lead, say ground, and the right side wires would make the other lead, say positive. This configuration could have several immediately obvious benefits. In general, this coil would last longer since, even if one wrapping got severed, the pickup would still work fine. It would (I think) only have one phase unlike todays pickups that have two. That would mean your pickups could never be out of phase with each other. I'm sure it would produce new sounds and coupled with standardly wrapped pickups, you'd have all sorts of neat possibilities. I'm thinking this configuration might especially help with our sustainer project in curing certain ailments that EMI produces. I dunno, maybe it's worth something, maybe not. But with our driver only having 100-200 windings, it may be easy enough to test. Pickups have thousands of windings and may be more difficult. Let me know what you think!

Hey, I just want to say thanks alot to all of you helping so much, namely PSW, zfrittz, David, and col, you guys are awesome. I disassembled my guitar and I've gone back to the basics. It's starting to work real well. I'm redoing a couple coils and I hope it works even better. This is again all thanks to you guys, I can't thank you enough, I'm so excited to get this working. Quick question: First, I just have the driver and bridge hooked up. When the driver is in the necks previousl location, I get good feedback when it's out of phase with the strings (harmonic mode). However, when I change the phase with the DPDT to go into normal sustain mode, the driver sends some sort of feedback through the bridge pup. I'm assuming it's some magnetic field produced from the driver that induces currents in the bridge pup because when I move the driver away, I can get the noise to stop but when it's close to the bridge, it makes a high pitched squeal, and when I move it really close to the bridge pup, the squeal drops to a lower sort of rumble. Any thoughts?

I have cheap, standard single coils that come with strats. I'm really anxious to get my electric playable again, and I just want to know if the F/R would work with this. My driver is 8ohms of 31AWG 3mm thick, just what everyone on this forum says you need for a driver. Should I build a more powerful circuit? Can I have more gain from a circuit using just one 9v, or do I need more voltage, or can the F/R take more voltage? P.S., Thanks for putting up with my electronic ignorance