Adiel

Hi Al s. It is very interesting to see and be able to take part in such a fruitful, fun and successful thread. Your idea is very nice, I got almost the same results as you did with the fz amp and an old telephone transducer stuck to the headstock, but the acoustic type of 'sustainer' I built had too much feedback of the unwanted kind. Maybe I did something wrong, but I think I will stick to the magnetic type anyway, following Pete's advice and wiring it on the top of the pickup... By the way, Pete, do I have to wind about 112 turns to have a thin 8 ohm coil using 0.2 (awg32) copper wire?

It is really very interesting to see how the phase affects the effect (not on purpose...), and my first attempt to build the coil was of no success, but I did not follow the instructions thoroughly, though. I disassembled an old 3W speaker and used its copper wire to wind a coil on a ferrite bar, and put a magnet behind it (lol). As you may have guessed (and must be laughing wildly), all I got was a faint oscilation. The nearest I could get to the real thing was still with the small 'membraneless' mini speaker, which works like a poor man's e-bow. I am going to get an old damaged single coil pickup and start again from scratch. I really liked the idea of using the TDA7052 as the amp, for it simplifies the circuit a lot. The circuit I have built is also working perfectly, my problem now is going to be the driver. Maybe I will try to push the magnets a little upward and wind the driver on the top of the mid pickup, like your idea of a thin driver. I will keep you posted.

Thanks a lot for your detailed response. Actually, I live an hour and a half from Rio, in the state of Rio de Janeiro (nice city, though a little violent...). If you ever come around, let me know, ok? About the project, one idea that could work is to use 6 mini modem loudpeakers without their membranes, inside a pickup cover (I have an Ibanez H+S+H guitar, that's why I intend to use the system in the mid pickup position), or assemble a dedicated pickup. As soon as I have something more tangible, I will post pictures and details. All the best, and see you soon.

Hi everybody. I am from inner Rio de Janeiro, Brazil, and I have been following this thread for a while. I have built my own version of the amp, a modified F/R, with a BC550 instead of an FET, configured as a unity gain emitter follower to reduce load as a pre-amplifier/buffer. I have successfully tested it both as an acoustic device using a small telephone loudspeaker stuck to the headstock (which generates a lot of unwanted microphonic feedback) and with a disassembled modem mini loudspeaker, using its coil next to the strings. I don't know if anyone has already tried it, but I'm thinking about wiring the 8-ohm driver coil around the mid pickup, just like a normal ac transformer, instead of stacked coils. This arrangement should save space and lots of hassle. The idea is to turn off the mid pickup whenever I turn on the sustainer system. I plan to build a basic system without altering the front looks of my guitar, just adding push-pull pots and the works. I also want to congratulate Pete on his patience, dedication, ingenuity and generosity. Best wishes.