Sustainiac Sustainer Reverse Engineering

[Ripthorn]

Hi All, several years ago I got really interested in the DIY sustainer idea and read a lot of Pete's work and others. Well, fast forward to about 6 months ago and I decided I was going to unravel the mysteries of the commercial units. I bought an original Sustainiac Stealth unit and reverse engineered both the circuit and the driver so that this information can be freely available to the DIY community. I have posted full details on my hobby site, but a quick recap is as follows:

- Circuit contains a buffer, AGC, attenuverter, and gain stage prior to a discrete class D amplifier

- Driver is two coils RWRP with a total impedance of 2 Ohms. Bobbin cores are made from transformer core laminate and the slanted pole topper pieces are actually used to reduce the size of the magnetic gap between the two bobbins so that middle strings sustain well.

You can find full details here: https://scientificguitarist.wixsite.com/home/sustainer-reverse-engineering

I have also developed my own circuit based on the original that uses a modern class D chip and reduces the number of opamp stages to reduce power consumption. You can find that circuit here: https://scientificguitarist.wixsite.com/home/fermata-sustainer

Hopefully this helps someone, as this place seems to be the forum repository for all sustainer knowledge. I've got two more circuits in the works: one totally stripped down to just the bare essentials for good operation using common parts and one that adds more features and allows for the driver to be used as a neck pickup. Those will be coming in time and will also be posted to my page. Enjoy!