• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Jolida Score!!!!

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So... Today I checked the local on line want ads, as I usually do. Normally there isn't too much to get excited about, but today was different. A gentleman was selling a Jolida tube amp. That was exciting in itself, but the price was unbelievable; $25. I called and he still had it and to make sure the posted price was correct. The price was correct. I went to his house to pick it up, and there it was; a Jolida SJ502A with Sovtek tubes. I mentioned that he was selling this for a REALLY good price, but he was fine with that and just wanted to get rid of it since he doesn't use it anymore.
I have it running right now and so far it seems to be doing well. Does anyone know anything about these amps and things to watch for, mods, bias adjustments, etc.?
Thanks,
Mike
 

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Looks like an old one. I am well familiar with this amp -- both Chris & Jeff have one. REALLY GOOD score and a decent amp. And an excellent platform to build something REALLY GOOD (i'd recommend the DynaMutt front end from Classic Valve Design).

dave

Thanks Dave. Yes, the amp is about ten years old.
I checked the Classic Valve Design website and it only mentions the Dynaco ST70 with the DynaMutt kit. Does it work on Jolida amps as well?
I'm also thinking about a DAC since most of my music is sourced from my laptop.
Thanks,
Mike
 
Does anyone know anything about these amps and things to watch for, mods, bias adjustments, etc.?

Wow, that's quite a deal. Basically, the price of a decent case of beer in this part of the country.

Lots of tweeks/mods for the 302/502 series. Better coupling caps and small signal tube rolling are probably the most popular to start.

A multimeter with probes and a small blade screwdriver are all you need to bias the KT88's. The test points are dead center behind the output tubes. Use the millivolt setting on your MM, most have an autorange function.

http://www.ellisaudio.com/jolidamods.pdf

jeff
 

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