Have you replaced the output tubes? you may be getting an oscillation that is taking out the xfrmr
I have replaced the output tubes, the last time I had a brand new pair of TJ's in there. That's another story, I've only had 4 tubes go bad on me in my life and they were all sophia/TJ tubes. Again they sound good but absolute crap reliability. But back to the problem at hand, even if the tubes were oscillating wouldn't they take out the output tranny instead of the AC?
And regarding dealings with Richard, it was definitely not a case of misunderstanding, more a case of "there's no way my trannies are bad!!!" They seem very conscious of the bottom line, and if they were to take some responsibility it would cost them.
Mt10425. Read the last 3 sentences of my first post, they outline exactly what I am after.
And also I am very unhappy with the way I've been treated by Sophia. I think people should know what kind of service they can expect if they choose to buy sophia.
As far as Jay at audio revelation goes, he has been great. He paid for the first defective sophia tube and paid 100% to have it fixed the first time. I really don't expect more. Also I want to keep the amps, I want a transformer that works!
So, your experience with Richard should be seen as representative across the board? These forums are bandwagon driven. Many wait for someone to start a 'I'm getting screwed' thread so they can fall in the 'me too' line. Jay seems like a pretty good guy with quality stuff. I'm not defending Richard at all but, painting Sophia service with such a broad brush is a bit unfair.
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,
Thank you almarg, some good ideas there. I like the idea if trying to focus in on what part is failing on the trannies.
Mt10425 what's your problem?? Did I say my experience was indicative of how it is across the board? Noooo. I'm merely detailing my experience. I guess because you own a Sophia you can't stand any negative postings about it. If you don't like the thread, don't read it! I think I'm being balanced, I'm saying it sounds great and I want to keep it. I have had problems with reliability and am looking for help with one I'm having currently.
Almarg I have corresponded with the original owner and the tubes are original. Fwiw he had an issue with it as well and wasn't totally happy with the way things were dealt with. When he got it the filaments died as the transformers for that were underspeced. So Richard redesigned one of the transformers and added windings for those filaments. Seems like a common theme.
Analogluvr- My bad (sort of)! There were some problems with the 300b mono-blocks that JA measured but not (apparently) w the OPTs. Check out the measurement section and you will see that there is something unusual going on w those amps. And if you read carefully (not even having to go between the lines) you can see that S-phile was less than pleased with the way Sophia responded to their initial concern...by sending them back different amps after Sophia's testing indicated no problem.
May I humbly suggest you send the amplifiers back to the manufacturer to have them checked and repaired?
The manufacturer can completely checked out the amplifiers. Provide the manufacturer ALL the information about your system: front end components, speakers, wires, power line, power conditioner, stand and configuration, etc. I'd include photos.
This way, the manufacturer can inform you if there's something wrong with your set up.
If the manufacturer repairs the amplifiers and they continue to have the same problem, the manufacturer should provide you support to ensure the issue gets resolved. If there's the same repeating problem with the amplifiers after they're fixed, and the manufacturer confirmed your system set up, they should fix the amplifiers without charge.
This is the level of support I expect from a reputable manufacturer, and as a person with multiple businesses (none of which I'm referring to are in our industry) - it's the level of support I provide my customers.
If the manufacturer does not provide you this support, you'll have to realize you are on your own.
Personally, if I purchased any product - new or used, and I went to the manufacturer for support and was not supported properly, I wouldn't use that product.
If you do not allow the manufacturer to inspect, test and repair the amplifiers - and to confirm your system, then it's possible this issue will continue. And the manufacturer is not at fault because you are not asking / allowing them to support their product.
While it may be more expensive to allow the manufacturer to inspect, test and repair your amplifiers - it will be cheaper to get them fixed properly and eliminate this repeated problem. It will also allow you the ability to go back to the manufacturer for help should repeated failures occur.
If they do not offer you comprehensive support, then I personally wouldn't use their product.
'I think people should know what kind of service they can expect if they choose to buy Sophia.'
Do you even read what you write? I'm not a Sophia apologist. I do own and like my amp(s) from Sophia and have not had any issues with reliability. I hope you get yours fixed.
1. It was purchased used.
2. People other than Sophia have worked on it.
3. Take tjassoc post seriously.
People here always get spun when threads ask for experienced responses and get folks who no knowledge of the equipment.
So just an update on my Sophia 845 amplifiers. After I blew another one of Sophia's crappy transformers my friend convinced me to replace them with equivalents from Hammond. So I bought 4 transformers from Hammond (2 high voltage and 2 low voltage filament ones). My 4 transformers from Hammond cost me just under $200 USD while one of the crappy Chinese Sophia ones is $400USD. And the Hammond ones are far heavier and just all round better built. So at first I only changed out one amp so I would see if there was any sonic difference and to see how things would go. Things worked great and I could hear no difference between the modified amp and the factory one. Well after about 2 months I blew another tranny! Any idea which one?? You guessed it, the crappy Chinese Sophia. So I swapped out that one for 2 hammonds and things have been working great for over a year now. And when I investigated the blown transformers it was always the filament winding that was an open circuit. They did get pretty warm so we speculate that the inner 5 volt winding expanded and contracted at different rates than the outer 1100 volt winding. Seems like a bit of chintzy corner cutting to incorporate 2 into 1 on a 20k amplifier!
anyhow things are working great now and I love the way they sound. And in response to the suggestion that I should send them to Sophia to get fixed, I can predict exactly what would have happened. They would have put one of their new crappy Chinese transformers in there, it would have blown in a month or 2, and the second time that happened they would have said it is a problem with the power in my home and washed their hands of it. They were already saying that without seeing anything. And I would have had a 1k bill each time.
If anyone else owns these amps and is having issues feel free to contact me for the part numbers and basic instructions.
As I say I love the amps now and the way they sound but the company is another matter entirely. And I've had similar experiences with their tubes. Same deal, sound good but zero reliability.