Floyd Rose sustainer transformer

[space_ryerson]

I know this isn't a stompbox question, but does anyone know the value of the yellow transformer used on the Floyd Rose sustainer? This is the sustainer used on the Phil Collen PCM Jacksons and more recent Kramers. The transformer on mine is broken, which causes the sustainer driver to cease being useable as a pickup. Unfortunately, there are no markings on the tranny, but apparently this isn't always the case.

I posted a lot more info on the circuit and such for the curious here:
http://projectguitar.ibforums.com/index.php?showtopic=7512&st=4125&p=398279&#entry398279

Thanks!

[space_ryerson]

I've been working at tracing out the circuit from the PCB (to figure out what the transformer would be), and since it's a double-sided circuit board, it's taking forever. I had a close look at the non-working transformer, and it looks like the windings have severed from the legs, but are too short to re-solder them. I was thinking of trying to take the transformer apart, and somehow pull one winding off, so I'll have enough length to solder to the leg. Is that ok to do? I've been trying to get some readings with my DMM, but can't, due to the shortness of the ends of the winding.

[cheezit]

The outside winding is usually no problem.  It's the inside one that may be impossible, since there's no way to unwind the windings to make some slack.

The other thing is that any winding like this (pickup, xformer, inductor) has an insulating coating to prevent shorts.   That coating can make it difficult to graft a new lead on.  Sometimes it takes steel wool to get the coating off, which is bad news since the chaff from the wool can cause shorts.

If the xformer is totally dead, then you don't have much to lose.  But you may go beyond the point of no return quickly....

[drewl]

Is that like the "sustainiac"? or whatever it was called?
I worked on a couple a few years ago and would have to dig up my notes.

[petemoore]

  Maybe some ballpark area can be surveyed...
  What's driving the transformer and what is the transformer driving ?
  Unwind and count the windings...ou..just typed that, not at all sure that's what I'd do.

[space_ryerson]

Is that like the "sustainiac"? or whatever it was called?
I worked on a couple a few years ago and would have to dig up my notes.

Yes, it's a similar type of effect. It is also known as the 'Jackson Sustainer'. I don't know much about the Sustainiac circuit, but any info will help!

Pete: The sounds smarter than tracing out the whole circuit! I'll see what I can figure out tonight when I get out from work.

[space_ryerson]

I traced part of it out last night, and unless I'm mistaken, the transformer looks like it is used passively. The circuit board is double-sided, and traces run under large parts, making it difficult to map out. With this design, one half of a standard strat 5-way switch is used for regular use, and the other for sustainer use. The on/off switch toggles between that. I've read that much thicker wire is used for winding the sustainer driver, so I measured it's resistance: 9.8 ohms; compared to the bridge humbucker, which is 15.4k ohms! I did a rough sketch of what I've found so far here:

http://www.spaceryerson.com/sustainer/FRS_pickup_wiring.pdf

[space_ryerson]

A very nice guy on another forum took apart his Jackson PC-1, with the sustainer in it, and said the transformer had the following markings:

C9219-A
0543

I'm googling currently, but not coming up with anything. How does one read transformer markings like that? It seems to be different for each manufacturer.

[space_ryerson]

Upon a lot of reading, I found a schematic!:

Which is wired into the guitar like this:


The part I need to figure out the value for is T1 in the schematic. C9 is 100nf, and R9 is 10k. The sustainer driver/pickup is 34 in the top diagram (9.8 ohms in my guitar), and the bridge pickup is 24 (15.4k, also in my guitar). Googling what was marked on the transformer didn't yield any results, but I've noticed that these transformers are always yellow. Looking through the Mouser catalog I noticed that Xicon color-coded their intermediate frequency transformers, and yellow indicates 1st intermediate frequency (22:1). I don't know if I'm grasping at straws here.

Any ideas?

[space_ryerson]

Reading through the patents regarding this (4,907,483/ 5,123,324/ 5,200,569/ 5,233123), I found these sections of patent 5,123,324:

Although the pickup coil (of the sustainer driver) provides relatively low voltage signals, these voltages are stepped up by the transformer, so that the system provides output voltages comparable to those achieved with conventional high inductance pickups. This arrangement provides significant cost and performance benefits.

There is a lot of functional detail past that, then there's this:

(The) transformer is a low-noise transformer such as a nickel core transformer. Transformer may be an autotransformer in which the primary and secondary coils are parts of the same winding. Transformer may be arrange to provide a step up voltage ration of about 15:1 to about 30:1, preferably about 20:1 to about 25:1. Transformer is disposed in relatively close proximity to neck pickup, hence to the coil system thereof.

Judging by this, a 22:1 seems about right, but looking at the Mouser catalog, IF transformers don't look like the right part. (it had a screw adjustment head) I'm fairly inexperienced when it comes to transformers (I've only used them in power supplies and an octavia), could someone steer me to a source where I could find a transformer that meets this description? I went through the Mouser catalog, and their site, and wasn't met with much luck, or any obvious choices.

[space_ryerson]

Success!!! After reading this thread , I figured out some possible impedance combinations to get the 20:1 - 25:1 ratio I was looking for. Long story short, after a revisit to 7th grade mathematics, I found this transformer at mouser. I got it today, soldered it in, and success!!! The sustainer driver sounds a lot better as a pickup than I would have imagined. Happy days!