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

Hello.

Just picked up a new Jadis today, and I'm none too pleased with the sound. As I have had blissful sonic experiences with two of the models lower on the Totem Pole from this manufacturer, the only thing I can trace it to is the Sovtek 6550. Can they really be THIS bad???

I already switched out the JAN Philips 12AX7 and Golden Dragon 12AU7 for Mullard Blackburn and Ei respectively. The improvement has been subtle, but it still ain't working for me...

I have used ElectroHarmonix 6550 in the past, and while they didn't float my boat, I'm told that EH represents a signficant step up from the regular old Sovteks. JJ E34L and KT88 just have sounded really splendid to me. So, now I'm looking at picking up 8 new output tubes if I don't wish to live with such uninspired sound.
trelja
nsgarch's avatar
nsgarch
2,524 posts
 
Chuck, you're right, it could be something else. I'd have to hear it in person to make even an educated guess.

what I do know is that when I swapped (all sisteen!) of the Sovteks in my ARC monoblocks for the Svetlanas, it was like night and day. True, the Sovteks were getting old, but still functioning. In any case, I sure was happy with my decision.
trelja OP
3,223 posts
 
Thanks for the replies. Of course, it is possible that something is wrong. That cannot be really known until I retube.

One thing is for sure, it won't be with 6550. I'll get two quads of JJ Blue Glass E34L. Because of my impatience, I was thinking of trying my quad of JJ KT88 in one channel just to see.
marakanetz's avatar
marakanetz
5,473 posts
 
can't tell ya about 6550 sovts but EH to my experience has a record short life that may be very distructive to the component circuitry.
i've used eh EL34 and will never place them again in my VTLs. i now use either svets or yugos. during 1+year period measuring the bias i found that it didn't change even slightly.
therefore i suggest
#1 ask manufacturer if it's OK to go with EH since some of the brands are OK... i assume that EH lack the lifespan to all other tubes significantly in any component
#2 find yourself the best match for performance/reliability and nevertheless budget as well.
maxxc
177 posts
 
Come on, Trelja you been around for awhile. "new Jadis today." Can we say burn in time :) I wouldn't even look at rolling tubes till 200 hours of burn in.

I have Soveteks el84's in my Yarland with no complaints.

BW MaxxC
jafox
1,465 posts
 
A few years ago I changed the Sovtek 6550s to JJ Tesla KT88s in the ARC VT130. Wow, the musical enjoyment was dramatically improved.....until a tube blew. These KT88s did not seem to have a very good reliability. Several went out around the 6-month mark. And unfortunately, when they did, they took out a power resistor in the amp in the process. It was easy to resolder in a new one, but it was a hassle to put up with these tubes. So be forewarned about this issue. Perhaps they have imporved over the last few years.
John
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