Dynaco design?

[Guest]

I'm scouring the earth for a manual or schematic for an old solid state amplifier I have, an ESS M500.

As I understand it, ESS acquired the remains of Dynaco after it crumbled. As I understand it, ESS then started producing amplifiers/ preamplifiers.

This is interesting if you just want to read a bit:

http://home.indy.net/~gregdunn/dynaco/history.html

I'm wondering this; without a schematic but with both channels burned, is there any way to rebuild this amplifier. My dad and I have tested all the output transistors and found one that's seriously different from the rest in terms of minimum/maximums, but all check good (16 MJ410s). You can see a burned resistor on one pcboard.

There appears to be something, maybe a bias adjustment?, on the boards and I have no idea how one sets such a thing. We have an audio signal generator and tracer, oscilliscope, VOMs, etc.

What we don't seem to have is anything to tell us what we are looking for.

Bret

[ar_pro]

I seem to recall a beautiful ESS amp & preamp from the mid '70s - I think it was called "Eclipse". Have you tried the current company for a copy of the schematic?

[Guest]

>Have you tried the current company for a copy of the schematic?<

Yes. Someone went way out of their way to find "specs" on the amplifier but said she had no other information, whatsoever. I was pleased to get anything at all.

I can replace the transistors that are "questionable", if I can find suitable replacements for Motorola MJ410s.

I can replace the burned resistor and all that jazz, but I still won't have a clue if it's right. Or is that likely a phase adjustment? Or bias? Or voltage to the output transistors?

Bret

[Guest]

You might find this link interesting and enjoyable if not exactly gratifying.

http://www.audiocircuit.com/9121-solidsamp...9121IMAI-SE.htm

Bret