Basic Kits, such as those sold from Indonesian makers such as VEYZ and iSUSTAINER, usually consist of a "FETZER/RUBY" Preamp for the amplifier board (based on an LM386N Op-Amp and a J201 JFET Transistor), an 8 ohm "driver" modeled after a conventional guitar pickup, with or without a actual pickup in it to allow it to double as a regular neck-position pickup (or a on-board transformer that turns the driver into something similiar to a LAce Alumitone pickup). They typically come with 2 toggles, one for power, and one for the phase of the driver (which is how you switch between harmonic and fundimental feedback).

More advanced units, such as the Floyd Rose/Kramer/Fernandez/Sustainiac units, have a far more complex circuit driver board, and a far more complex driver design(s).

The original "SUSTAINER" was the "Floyd Rose Sustainer", released in 1987, and introduced on the KRAMER Sustainer guitar (as mentioned on my other page). This driver was a humbucker pickup with two large, steel, blades, and the sustainer part of the coils was a winding of wire INSIDE the pickup windings used for the "Driver" part of the functionality, this meant the pickup had EIGHT leads on it - two for each driver coil, and two for each coil of the Humbucker, which could get pretty extreme. I actually had one of these driver pickups in the bridge of my Kramer Focus 3000 in the late 1990's and it sounded awesome. Fernandez uses a one-coil design with a specially slotted blade in the middle of their pickup, and Sustainiac uses a dual coil design with a diagonally split blade in the middle. The latter two designs are intended to help with driving the higher strings which is one of the challenges of these designs.

The driver boards for these are far more complex as well. While the usual DIY SUstainer kit type thing you find on most websites and from Indonesian makers is a Fetzer Ruby Utility Amplifier with a pickup in place of the speaker or output jack, These units have several circuits in them that help with the quality of the sustain function.

Another caveat is the number of Frets your guitar has. It can range from some 18 fret wonder budget axe from the 1950's with some really short scale, all the way to 24 or more Frets. THe interplay with scale length makes this even crazier. Ideally, you want the driver to be pulling the string at it's least taught point - which is dead in the middle....thing is, that would be the 12th Fret! Making the sustainer unusable for it's most important thing, so the ideal spot, is generally the most northward on the guitar as possible, usually as close to the end of the Fretboard as you can get it. My Explorer's VEYZ unit is setu like this, and my Kramer Focus 3000 has the iSUSTAINER installed in roughly the same spot as I experimented with putting it in a position south of the neck pickup - but the Kramer has 22 frets and the Explorer has 24 frets. The Explorer is also 24.75" (Gibson Scale), the Kramer is a 25.5" Scale Superstrat (Fender scale). The 88' Vester Concert I setup used the inverse of the Kramer's setup, and still sounds great, and is a little more reactive. The AtariCaster I opted for something way different as this is a 25.5" scale guitar with a 24 fret neck, just like the Vester. So I wanted the driver up against the edge of the fretboard if possible.

Another issue is do you want your neck pickup or not. A lot of people who don't use a neck pickup will just replace their neck pickup with the driver. People like me, who like to have their cake and eat it too, but are *cheap*, will find interesting ways of mounting a standard single coil or single sized humbucker in the neck position. My way typically is a single-coil (or smaller) sized sustainer, paired up with a standard pickup in Fender single-coil size oon a custom mount of my own making.

Commercial driver coils include the Floyd Rose Sustainer, which is basically a Humbucker with inner windings to around 8ohms or so, , and those inner windings are activated when the sustainer is activated (and the neck pickup deactivated). The Fernandez Sustainers which use a special ferrous blade pole piece positioned to improve magnetic pull, especially on the higher strings. Then there's the Sustainiac variants which use 2 coils wound to 2 ohms each.

My first attempt at a driver coil was using a Harmony H802 pickup chassis, coil, and coil mount. This pickup made a great sustainer because of the sheer mass of ferrous metal that it has in it's construction. IT also sucked though because it made a bit more, uh, succeptable to microphonics and being picked up by the bridge pickup. HOwever, it could drive the Low E with my home made dual LM386 driver on a breadboard on it's own without me picking the string. This thing was driven by two Neodymium computer hard drive magnets and worked really well.

My second one was a 19ohm driver I wired up into a shortened Strat pickup bobbin. This one never worked, because getting the wires soldered was too difficult.

My third and most recent is the one currently on the AtariCaster. It's called the "MicroSustainer" and it's rougly as tall as a Jazzmaster pickup and about 1/3 as wide up and down. It has a single cermaic bar magnet and is superglued together. So far this one has worked great with my dual LM386 prototype amp.

One thing on the Guitari 2600 I did that makes it just as much a useful research tool, as it does a guitar, is having the primary 3 connectors for a sustainer circuit setup like those found in traditional IBM Compatible PCs for the reset switch and LED lights. Basically put, I can connect iSUSTAINER's board (Kramer/Vester), could easily make a breakout adapter for the VEYZ board, could hook up to SUSTAINIAC and/or Fernandez's boards should I bump into a really really cheap one (were talking under $100), and experiment with that new design.

The most basic circuit used is the Fetzer-Ruby amp from runoffgroove.com. I will be building my own, but I also did a bit of photographing of my boards and found out that iSUSTAINER and VEYZ alone, based on components used and component count, are also variants of this basic design. The design uses a preamp with a J102 JFET Transistor, and then an LM386N slamming the back end of the circuit.

It appears that iSUSTAINER uses the same circuit, however, the 1K Trimpot for (GAIN) has been removed and replaced with some kind of Electrolytic capacitor. I'm not 100% sure on the component values because the resistors look weird. It also appears that they use box-style caps. iSUSTAINER left all their traces out in the open enough that if I want to copy their circuit, I might. However, the iSUSTAINER circuit, to me, seems a bit weaker, especially in harmonic mode.

Lastly is VEYZ who appears to be using much the same circuit as well, with a 10uf supposedly linking together pins 1 and 8 of the LM386N (the gain pins). However, they epoxied their board so you can't tell or trace out the traces, but based on components, I suspect that the VEYZ uses a variation on the Fetzer-Ruby preamp as well. I think they are trying to hide the *magic* that makes a supposed "third" mode (mixed mode) work on their much simplified circuits.

As made obvious none of these have the expanded features shown on scientific guitarist's page, where he reverse engineers an earlier revision Sustainiac unit. One particular feature omitted is the "AGC" or "Automatic Gain Control" which is why these units are not as "pro-grade" as those found in Fernandez or Sustainiac's kits.

Another circuit I am exploring, is this one....the "Infinite Sustainer Board" which can be found from various Chinese sales places on AliExpress, e-bay, and probably Temu. Nobody has said anything about this circuit, nor have they used it. But it looks like if I use this one, it's going to require modification. It looks like this may have AGC, and it seems to be an in-between of the VEYS/iSUSTAINER/DIY FETZER/RUBY approach. It comes without the trimpot (supposedly some kind of gain pot probably), which I believe is 100K-1M - you provide (tempting to make a Jaguar/Jazzmaster roller control on the AtariCaster for this, lol). But it uses the same wiring scheme as the iSUSTAINER and VEYZ above.