Anybody Have Any Experience With The Gallien- Krueger 250ML?

[toomanycats]

I ask because yesterday I came across one of these 80s solid state, made in USA amps at a great price and in good shape. Some quick research reveals that this amp was used by some pretty heavy hitters, including Iron Maiden, Alex Lifeson, David Gilmour, Chuck Schuldiner, and Nuno Bettoncourt. Apparently the amp has amazing cleans, a unique unto itself distortion tone, and a luscious stereo chorus effect. It has a pair of small speakers inbuilt but can also be used as a head to power an external cab(s).

I didn't pull the trigger on it because just about the last thing I was thinking about buying is a high wattage solid state combo/head. Still, I can't stop thinking about it now.

So, any of you guys have personal experience using this piece of gear?

I'm not sure if I'm looking for somebody to talk me out of it . . . or talk me into it.

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[andrewsrea]

I've repaired about 8 of them in the last 3 decades. The good, bad and the ugly:

- The sound great and can be loud if you want.
- The reason they sound great IMHO, is because they have MOSFET output (final amplification) devices, which are tube-like. These MOSFET designs
require very tight component specification tolerances.
- Replacement MOSFETS for this era amplifiers from all brands which used them, are unobtainable and not substitutable. The high heat of these
designs cause them to go out of tolerance with each other over time, which causes failures from crossover distortion to entire banks of devices
shorting out.

My recommendation is: try it before you buy it and if you buy it, do so at a price that you won't be bummed knowing it will eventually fail without the ability to be fixed.

[toomanycats]

I've repaired about 8 of them in the last 3 decades. The good, bad and the ugly:

- The sound great and can be loud if you want.
- The reason they sound great IMHO, is because they have MOSFET output (final amplification) devices, which are tube-like. These MOSFET designs
require very tight component specification tolerances.
- Replacement MOSFETS for this era amplifiers from all brands which used them, are unobtainable and not substitutable. The high heat of these
designs cause them to go out of tolerance with each other over time, which causes failures from crossover distortion to entire banks of devices
shorting out.

My recommendation is: try it before you buy it and if you buy it, do so at a price that you won't be bummed knowing it will eventually fail without the ability to be fixed.

Thanks so much for all that info Rob. It really is tempting at $200, but you have really put things in perspective.

I've repeatedly read that this amp sounds great but that it's prone to failure. You just gave a great technical explanation for why all of that is so. Another thing I keep reading is that the foam around the speakers is usually deteriorated at this point, requiring their replacement. Speakers usually aren't to difficult to source, but your talk of unobtainium MOSFETS truly is off-putting.

Again, thanks for steering me right.

[andrewsrea]

Another thing I keep reading is that the foam around the speakers is usually deteriorated at this point, requiring their replacement.
Again, thanks for steering me right.

Actually, the foam speaker surrounds rot, to which the repair kits are common and an easy fix that anyone can do.

[tonebender]

A lot of OD type pedals I have read about and maybe owned bragged about having a MOSFET output.

@toomanycats , you must live near some cool pawn shops. There are a kazillion around here but deals dried up years ago. The innerweb ruined it. It is cool though that it is acceptable to make low ball offers unlike a retail outlet. I say that but I have enjoyed discounts at GC and others over the years by asking for a break.

[andrewsrea]

A lot of OD type pedals I have read about and maybe owned bragged about having a MOSFET output.

Most of the Ibanez MOSTORTION derivatives utilize MOSFET IC's which are becoming scarce. Some pedals claim MOSFET, but it is what they are using (more available single T0-92 little devices) as clipping diodes and occasionally, as output buffers. They have a cool sound, which respond mor like an amp.

The Dubmbilcious pedal you have, employs 2N7000 MOSFETs, Germanium and 1N4148 clipping diodes for traditional clipping and amp feel when the soft or hard clipping is engaged.

The large wattage MOSFETS are getting rarer to find and finding 8 to 14 of them, with in <1% tolerance of each other, is becoming very expensive hen's teeth.