Franky

Actually, it does not sound sharp like the time I tried the sustainer.. It's more like this: http://rapidshare.com/files/132240551/ebow_prueba_1.wav I didn't record it, someone had the same problem, it sounds a little like this.. And it gets really loud when the driver comes close to the active pickup. Ahh, I didn't mention it before: I've got a strat, with 3 single coils.. Hum okay, I'm going to try to play with the circuit... Yep, anyway I wound them by hand, so they must be not as tigh as if I used a mechanical winder.. I finally found some super-glue, which i couldn't find the composition, but it did work pretty well on the pickup. Indeed the driver is vibrating a little, when I try to remove the magnet from it, I can hear a really tiny noise coming from it, and some vibrations.. I tried, just after taking this picture, to put the battery elsewhere, on the top of the PCB bar that holds the coils. So now the battery AND the circuit are on top of this bar, cause anything put under blocked the vibration of the strings (that wouldn't have happened if the polepieces were 0.5mm longer.. grrr) And the noise is still here. Yeah, when I swap the driver, it enters harmonic mode, but when the string starts moving, there is a fuzz effect (like a crazy setting on a Fuzz Factory) on the sound in the amp, even if the eBow is far from the PU.. Swapping the magnets and input coil didn't gave anything concluant about the noise.. Anyway it works, when I put the driver above the 17th fret, there is no more hearable noise, but you were right, it's really hard to play it.. And only the 4 biggest strings are affected, nothing happens with the G B E strings.. Good end of night! (or good morning when you read this.. )

OK, i've just finished all the thing, it works, but it makes an awful noise in the amplifier, and it takes a long time to the string to vibrate.. It looks like this:

Great work Pete, congrats! If your driver is still too high, it might be due to the thickness of the magnets? Anywar it looks great, and your circuit seems to be very compact, how did you make a AGC fit into this? Is it a special feature of the 386?

Okay, I didn't do anything about the eBow today, I just finished my little tube amp this morning, and I couldn't resist to play it all day long.. :D I did measure the impedance of my driver, it appears to be 4ohms.

Thank you for the enlightments Pete! About driver shielding, I was thinking about interferences, but it's something that only the pickup needs (the driver is powered by a great energy source, so the interference may not be that important..) You're right, it's the magnetical shielding we're seeking, so maybe only a small partition made of steel between the two coils would be enough to stop the EM field leaks. But as it's spread in the direction of the strings, and not in a radial direction, it might be useless. I'll see about that later. About electronics, yeah, maybe the classic F/R, I've got enough parts to experiment a little.. But not like Col did, with its AGC, anyway it wouldn't fit into the case.. Which would be a simple piece of wood, that holds the PCB, the coils and the battery. On each end, some PCB guides to hold the eBow on the left & right strings, and maybe an LED to make it easier to find the position. For what I can see in the orginal eBow, it makes me want to say: the simpler the better. But I pretty love the glove idea, that would be really tricky to get something out of it, but it could open some new ways of playing guitar.. The best would have been to have 6 fingers, but.. Night time again (f***ing time lag), tomorrow's program: circuitry.. Oh, last idea, don't really know what it's worth: did you try push-pull with 2 LM386? I don't even know if it's possible..

Thank you for the links! I just wound my driver, 200 turns with 0.2mm wire (I'm not quite familiar with the AWG norms).. About potting, I used a kind of multi-usage glue, that I used for retolexing a cab.. And I just reduced the coil height, it's about 6mm now. I hope to get a compact design, so 11mm was too much, and all the pictures were showing small coils.. Based on the AWG article on Wikipedia, making 3.4Kohms with a AWG40 wire (like the one I have for the pickup), needs 1km of wire.. This is huge.. With a little math, there must be about 200m of wire in the 1000 turns needed, so yeah, we're still under the Kohm.. But if I had to make a real pickup (understanding "with an impedance about 5Kohms"), around only one polepiece, the diameter would be 3 or 4 times larger than the driver. Which does not seem to be the case in the commercial ebow. So yeah, there is no really choice but underloading the LM386.. I'm also planning to add some shield to the coils, with aluminium tape.

Yeah, patents are a good source for inspiration, but that does not make all the work.. The input impedance of the LM386 is said to be 50kOhms, which is really high for a coil, I wish I can reach the kOhm.. The DC motor didn't work, the wire broke after a few turns.. I grabbed a little transformer, the secondary coil seems to be made with 0.3 wire (looks little thicker than my 0.2 wire), and the primary is made with a very thin wire, I hope it will hang on a manual winding, to make the pickup coil. My DMM is out of battery, but I've got to check the primary impedance before to start winding. If it's too small, it doesn't worth it.. I just hope the dimensions of the driver chassis are right.. On the french forum, the man said some people use some wood glue to waxpot their drivers, on my first driver I used some first price glue in tube, which didn't dry at all.. Maybe some hot pistol glue could do it, when it's all done.. I also drilled two little (0.8mm) holes on a side of the driver chassis, to have an easier access to the wire once wound. It's night here, so time to sleep, I continue tomorrow.. Edit: ahh, the CAG (french acronym for AGC), it was my electronics practice test in the final exam for graduation this year.. Passed well! But the design was awfully thought, with inductors and filthy filters..

Okay, here's what I've made: (click on the pictures to see them larger) I used a 5 euro cent coin as a template for the epoxy bits, they are 5mm centrer drilled, and the polepiece is inserted by force, hammer-style.. I let the polepiece out on a side to be able to fix it to the handle once it's done. This makes a coil height of 11mm, and the diameter of the epoxy rounds is about 21mm. For the pickup wire, I've got some small DC motors, maybe it can be helpfull..

OK, I've read the end of the french tutorial, it's a little confused, I don't really know what he used for the input coil.. Anyway, I've just hacked a cheap Tele bridge pickup, which gave me 6 polepieces, 18 mm long. I've got to find some powerfull magnets, I think I found some neodymium ones in a dead CD player, they're powerfull but really small..

Unless your translator is familiar to rough french expressions, you are ready to laugh a lot (I love using these translators, always fun...) The scheme is from an old design, which didn't work with the driver and pickup as drawn. The guy had to rewind both to make it work. And I think he came here to find some info.. So the electronic part in the schematic is right, it works, but then he explains how to make the driver (we all know it here, 0.2mm wire, 8 ohms, and about the size, its driver is 8mm long). But there is a lot of text explaining how and why he failed at first tries. The Aaron Stompboxes design is great, looks cool, maybe it just needs some pieces to hold it on the strings, like the original ebow.. My way of playing "with infinite sustain" does not involve my right hand that much, so the ebow seems a good device for me, and as you said, it can be used on every guitar..

I found a french tutorial on how to make an ebow with a transformer.. I don't have read all the tutorial so far, but if you guys are interested I can try a translation.. I warn you, it's heavy.. He's unwinding a transformer to get the 8 ohms for the driver.. http://forums.audiofanzine.com/index,idtop...dcat,45031.html There's a video from the man using the thing: http://fr.youtube.com/watch?v=ercK0UMJvjc

I'm not really surprised that it's glued, a lot of cheap pickups are made that way (and it's a cheap one).. Well, I think a permanent sustainer is not a good solution for me, it needs to mount and unmount the strins a lot, which I can't stand, and it leaves the problem of routing a cavity for a driver.. With an "external" sustainer maybe, like an ebow, but 6-strings wide (you guys must have think about this) would fit on every guitar, and would not affect them permanently in their look.. And a standard guitar is ideal for testing, as the circuit is not electrically related to the signal.. So yeah, the ebow project that was released a few posts ago seems intersting.. even if it is one string wide, there must be a way to extend it..

Bad news.. The coil is glued to the plastic case.. I can remove the polepieces and the magnets, which means that I could put the driver under the P90, but it wouldn't work..

Thank you Pete, I've got the skills to do it myself (I've made a lot of DIY projects for the last 3 years), but yet I don't have any real experience in sustainers.. The driver I made last time was maybe OK, but I had some troubles to make the circuit work, and I didn't had a dedicated guitar to try it... Building the top plate is not really a problem, I've made some precision work like this before.

Even those ones? That's the one I own, I'm going to open it and take a look at the room available..