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Any other Sophia Amplifier Experiences???

Sophia Amplifiers
I’ve been having a lot of problems with my Sophia 845 91-05 amplifiers. They are the top of the line units that Sophia makes that retail for 20K USD. I got them used from Jay at audio revelation for a reasonable deal. I had them for about 2 months and they blew an AC transformer. I sent them to a local tech who has a very good reputation who diagnosed them and ended up fixing them. Sophia did not help out with the repair at all, Jay was quite upset when they charged 400USD for a simple transformer. 2 months later and I blow the same transformer. Again the same tech does the diagnosis and Sophia says that I should get 2 transformers as the new ones are slightly different. Richard at Sophia says he will give me half off if I buy 2. I agree and my tech installs 2 of the trannies. Another couple of months go by and another one of them blows. It has been the same tranny every time but alternating between amps, the AC1 tranny which supplies the 5Z3PAT tube filaments at 5 volts/3amps and the plates on the 6au4 half wave rectifiers. This time I am worried that maybe there is something wrong with my supply so I buy a regenerator. I still have one of the old working trannies and I install that one. Everything works fine for a little over a month and now I have blown another one! The last remaining new one just went, not the old one that I just put in. Richard at Sophia has been very difficult to deal with, he won’t even entertain the idea that there is something wrong with the transformers. I’m not a wealthy individual and this has been a huge strain financially and emotionally. I have numerous other amps that I run including a pair of 300B’s that I built and they all work fine, I have never blown another transformer on one of the other amps. The thing is my speakers work the best with these 845 amps and I love the way they sound. I just want them to work. I’m at a bit of a loss of what to do next….thinking about trying another brand of transformer in there. I sent Richard a message about 4 days ago requesting the specs and he has not responded. Apparently he is out of the country at trade shows according to the response from Sue at Sophia. I can’t imagine he isn’t checking his email!!! Has anybody else had problems with Sophia amps? Any ideas on what I should do? Does anyone know what the spec would be to the plate of a 6au4?
analogluvr

Showing 1 response by almarg

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almarg
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Have you or can you or your tech determine the failure mode that occurs, i.e., whether it is a short or an open on the primary, or on the secondary winding that serves the 5Z3, or on the secondary winding that serves the 6AU4? Perhaps that can be determined with a simple multimeter, and it might prove to be useful information.

Also, do you know if the 5Z3PAT and the 6AU4 are the same versions as were originally supplied with the amp, or for example might the previous owner have substituted the 5Z3PAT for a 5Z3, or a 6AU4-GT for a 6AU4-GTA?
Does anyone know what the spec would be to the plate of a 6au4?
FWIW, here is the datasheet for the 6AU4-GTA. The curve of plate voltage vs. plate current is shown at the bottom of the second page. Not sure how helpful this will be, though, as we don't know anything about how the amp is operating the tube.

Finally, when you referred to the amp as the 845 91-05, after looking at their website I think you probably meant 845-05.

In any event, good luck. Regards,
-- Al
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