Sovtek 6550 - Can they really be THIS bad???

Bob, will you be coming over next Saturday??? Hopefully, the answer is yes.

I did try the Sovtek 6550s in the DA30 last night, and I must say that while the amp runs out of steam before its big brother, though still within the limits of being acceptable to all but the really power thirsty, it's simply a better component sonically. Even with these tubes, while not as glorious as the JJ KT88, the sound was commendable. Despite its homely looks, whatever purity was designed into it originally, later iterations seem to have lost to some degree. Not that the DA60 is not a very good amp, it is, just that the older amp is INCREDIBLY special. The sweetness, naturalness, and even excitement is wonderful. I guess, sometimes, the old stuff really is that good.

Hi Trelja. Thanks for mentioning the possibility of the JOR being "loose" - I took this to mean that the little bolts on the casing could be loose, and sure enough tightening them virtually eradicated the hum - presumably the service guy who biased the new tubes left them a bit undone and so the casing amplified whatever resonance the transformer was creating.
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Hope your new amp works out. Regards, Rob.

Rob, I'm so happy about the JOR not having a "real" transformer issue. That would be quite painful.

You read me 100% correct in my saying "loose" meaing what you thought it meant. My idiotic ramblings are so all over the place, it's a wonder anyone can understand me sometimes. It's easy to see how a loose transformer could really buzz. The biasing of the amp should not involve loosening the transformers whatsoever, only reading a few resistors, and adjusting the respective potentiometers until the voltages on those resistors falls into spec. Still, I'm sure it could have loosened any number of ways.

Good luck with that JOR, it's one of the finest sounding amps I have ever encountered, if not the finest.

Joe,
I need to make a correction. I think the stock tubes for my CAT JL-2 are 6922--and I haven't changed them.
You're still welcome to come over and have a listen of course.
Bob

Well, after spending a few more days trying certain things, and talking to a few people, I wanted to update things.

In my situation, the crux of the problem is NOT the Sovtek 6550. I wanted to clarify that I have been listening to them in my DA30, and while certainly no match for the JJ KT88, they still allow the Jadis sound to assert itself. I feel obligated to let everyone know that while they are not going to become my favorites, they are not the root cause of the poor sound I am experiencing.

I guess for many, sadly, they would not think anything was wrong with the DA60. However, I have become quite familiar with the Jadis magic, and this amp does not possess that. Amplifiers from other companies simply do not have it. Someone not familiar with it might not be able to tell, but I was. And, it is through no fault of the tubes. While a legitimate Jadis, I have discovered the amplifier has been modified by folks who have somehow bled what is special about a Jadis out of it. And, along the way, have done a lot of wrong to the amp, manifested in the way it works. This was in no way devulged to me by the seller, and the amp was listed in very good - excellent condition. I am not sure what my recourse is. But hey, caveat emptor, I bought a used component. Though I have purchased new Jadis products, as I said, there was no way I could swing $11,800 for this integrated. Worst case scenario is that I have found a person expert in Jadis, and has the ability to get the DA60 to where it should be. At which point, I can accurately determine how it compares to my JOR and DA30.

But, again, I feel it necessary to make sure I apologize to Sovtek in regards to their 6550 output tubes. They are NOWHERE as bad I initially inquired about,
Joe