Sumo andromeda II - Broken..

[Sponkii]

I recently got hold of a andromeda II..

my only problem is that one of the channels seems to been blown (i have only plug it in once to test, and it gave a bad smell, smell of burned transistor and resistor, i took it apart an correct, a black resistor, but i was not able to find any broken transistors..

is it worth a try to fix it, and if i take some pics, is it possible to get some help..

i would also like to have a schematic or pbc.
the only thing i could get hold of it this:
http://www.davidsaudio.com/andromedaII.pdf pretty poor res..

any ways in working order, how much is it worth ?..

[llwhtt]

Years ago I was given an Andromeda II, it was missing one complete channel, circuit board and output transistors. The one channel that was in it had many "afterthought" fixes and burned spots on the circuit board. This amp had been repaired at guess where........Sumo!!!!! I stripped the remains and am in the process of making it into a Pass A40. I've tracked down all of the original parts for the A40, including Signal xfmr and Lambda output transistors. Try doing that for the Sumo parts especially the mosfet output transistors, I say use the chassis and heatsinks for something else.

Craig

[Sponkii]

Okay.. :S.. sad history :S..

this one seems to be "intact"..

but is it worth fixing, or ??

otherwise i would take it apart and only use the working side, and mount that in a another casing, using it only as a bass driver..

[mullardel34]

Most of the Sumo amplifiers were designed by Jim Bongiorno, a legendary power-amplifier designer from high-end audio's early days, who was responsible for the Dynaco 400 (an early high-power solid-state amplifier), a large portion of the SAE product line-up and the GAS (Great American Sound) Company's various Ampzilla designs (some of the first commercially-available, fully-balanced power-amplifiers). However, the Andromeda-II came along after Jim left Sumo. While the original Andromeda was a reasonably well-regarded MOSFET-based balanced power-amplifier, the Andromeda-II used a BJT-based output stage and was not considered to be as compelling as the original in delivering the musical goods.

[Sponkii]

ehrm...

[llwhtt]

MullardEL34 has that backwards, the first Andromeda was BJT output stage and the II was Mosfet. That's why I said good luck trying to find those Mosfets. I've also owned a couple of the first Andromedas, that's easy to repair since it IS a bipolar output stage. Andromeda II is a different animal that was NOT designed by James. The first Andromeda was almost like Ampzilla III, a kit from the the 80s. The whole design story was in an issue of Amateur Audio, 1984 I think.

Craig

[Sponkii]

aa okay.. yes i can see that it is mosfet driven.. ..

but I don't think that it is the output stage that is broken..

[llwhtt]

I've looked for info on the II and all I've found is the schematic you found, not very much and not very good. There is a yahoo group called SAE Talk, it deals with SAE, of course, but GAS and Sumo as well. MAYBE you can get some info there. Right now I'm trying get in touch with my friend who knows(knew) all of the guys that were at Sumo and maybe find some more info. I think I know who was "in charge" but don't want to say anything just yet. This is the same friend that gave me my II cadaver. I've also been looking for more dead ones as it is a pretty decent platform on which to built A40s, etc.

Craig

[Sponkii]

Ouuh... thanks, sounds really good ..
I'm hoping for a positive reply :P

[Sponkii]

Have you found any info yet?..