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

I recently bought a pair of used VTL 750's from an authorized dealer who had completely re tubed these amps with matched Sovtek 6550's.

These particular tubes were TRADE MARKED as "Svetlana" which are the same tubes as Sovtek / Electro Harmonix for those that don't know the name Svetlana was bought by a large distributor.

The dealer said they had 200 hours on them and testing with my Hickok 752A tester showed no shorts, no gas and "new" transconductance readings.

After listening to these for about a month, and unable to get rid of high frequency distortion and dissatisfied with imaging and dynamics, I replaced all 24 Sovtek/Svetlana 6550's with new SED Wing C 6550's.

The upgrade was almost equivalent to replacing the amps. Everyone who visited the next Tuesday listening session (with only 10 hours on them) asked where the upgrade came from.

Can't wait to hear what the Wing C can do when they are completely settled in. I think this is the best new 6550 around and as others have already commented, the Sovtek may be the worst.

If anyone wants these Sovtek / Svetlana, I will be practically giving them away. Look for on an ad at Audiogon soon.

I feel I should add this for those that don't already know.

The Svetlana 6550, EL34 (etc) of three years ago is the SED Wing C of today.

Those who sing the praises of Svetlana bought some time ago are saying they like the (present) SED Wing C.

Same tube !

It's unfortunate that this confusion exists. The trademark lapsed or was negotiated for, I don't know the legal part involved.

Bottom line is the names Sovtek, Svetlana, Tung Sol, Mullard and Electro-Harmonix are all owned by ONE COMPANY. They market various tubes, very similar in construction, and all produced in the Reflector (Reflektor) plant in Russia.

SED Wing C was the previous owner of the name Svetlana and responsible for giving it the sterling reputation that made the trademark valuable. The SED is built in a completely different factory in St. Petersburg.

Hope the above explanation helps more than confuses.

Cool, further explanation of why you like and recommend them. We choose the same tube :^).

The name change is very confusing, probably only helpful to the new trade mark holder who is selling off the reputation of the previous factorys work.

As for comments by Justlisten, I would take that to heart. By no means am I suggesting the answer to your problems are switching to the same tubes I bought.

I do think it's important for everyone to report their experience with performance of various tubes so each can make up their own mind.