Sovtek 6550 vs Tung-Sol 6550 new version

[jahatl513]

In the past I purchased a Premier 12 set that had Sovtek 6550's and had been told by another that these were not the ones to have yet my experience was that they did exactly what they say they will do. I have had the TungSol's on a Premier 140 and they were nice. I wonder if anyone has had experience back n forth with these two versions of 6550's? The Sovtek's in my head, won out. What was your thought?
Sovtek 6550WE - From Russia with love. If you have an Audio Research amp, this is the tube you want. These tubes are very rugged, reliable, and sound great. They have a little bump in the midrange, tight bass, good top end extension.

[Big Dog RJ]

G'day J,

I don't think there is a better tube or one is superior to the other... It's a matter of personal preference and listening enjoyment.

I have heard these tubes on ARC monoblocks, as well as two types of stereo amps. The monoblocks were the Ref250's fitted with the Sovteck's, sounded great. Very smooth, robust and full of weight and heft, typical ARC sound. The stereo amps were the Ref75se and Ref150se both fitted with these for choice as well as custom fitted for the new KT150's.

Although the KT120's and 6550's were very nice, when it came to the KT150's, all preconceived notions of tube performance was shattered!
The KT150's are outstanding! Completely in a class of its own. Right from the first note, I got a sense of realism like no other, such that the 3 dimensional soundstage was so profound that you could literally get up and walk onto the stage where the performance is taking place.

The speakers used were the Sonus Faber Aida's, retailing in Aus for 80 grand a pair! Honestly speaking I wouldn't pay that much for speakers, and although they're mighty fine dynamic driver designs, I still prefer the CLX's.

Sometime next week I plan to get these monoblocks to try out on the CLX's just to see how far these will perform above the LP125's with KT120's, which is what I'm currently using.

Down the line, I plan to incorporate the KT150's into these monoblocks, which will be an upgrade /project directly through CJ with the help of my importer.
According to him it can be done, it's mainly the idle current that requires resetting to match the 6 ohm rating that is standard on all CJ power amplifiers. The large transformers fitted on these monoblocks are capable of handling the current demands of the KT150's, therefore no adjustments are required on the trannies.

Getting back to your original question, i sincerely prefer the Sovtek's but others may prefer the Tungsols. I also received feedback from my importer that CJ and ARC heavily relied on Tungsol simply because of available production runs and no issues with reliability. Compared to Sovtek, which maybe a better tube, however had production & reliability issues...

It's certainly a nice learning curve to experience these different types of tubes/versions, it makes the hobby/passion even more exciting. However, you must remember not to go overboard as this will distract you from the music and make you go in circles...
After all, enjoy your music! That's what it's all about.

Cheers mate, and trust you keep discovering.
RJ

[Big Dog RJ]

Hey J,

An interesting turn up... Just received a call from my CJ mate, my CT5 has arrived and is ready for pick up. I'll be picking up the unit on Friday arvo, in the mean time, I was told that they have shipped some output tubes of three different sets.
1. 6550 Sovtek
2. Tungsol KT120
3. Tungsol KT150

All three types can be fitted on the LP125m's, which I'm going to try out this weekend Sun & Mon. Will report back my experience and thoughts. This is going to be very exciting and especially with the CT5 on board.

I'm just about to place an order for a set of output tubes, so before I confirm I need to check out which ones would suit best driving the CLX's. I'll also do a bias check before any serious listening, as the tubes need to set properly at its required idle current.

We'll see how it goes, cheers
RJ

[jahatl513]

Cheers and good luck listening. I am truly looking forward to hearing your thoughts.

J

[ajf75]

RJ, yes very interested to hear feedback on this. I may have missed it but I take it you've received some assurance that its safe to play around with the KT150's in the LP125m without adjusting the idle current? I believe your amps are very similar in architecture to the ART monos (and therefore similar to my ARTsa) so very interested here.

Kills me that EL34's aren't direct drop ins. A small segway on that ...I spoke with Jeff at CJ recently about converting my amp to EL34 use. He mentioned that it could be done as either the triode conversion, or remain ultralinear. So I asked him why the older Premier XS models were only offered in triode for EL34 use and that i always understood that the circuit design only allowed those models to run EL34's in triode. He said the basic circuit architecture isnt that different and there is no such limitation for either older Premier models or the ART. The reason they never officially offered a conversion to EL34 ultralinear was simply that it wasnt different enough to offer where the triode mode is obviously a different character. I was honestly floored to hear this as I always understood you had to go triode for the EL34's (on models older than the new classics anyhow). So aside from what you find with the KT150's, I think the path to bliss for me may well be EL34's in ultra mode for my ARTsa. Bliss for me being the ultimate version of my beloved MV55.

[ajf75]

Jahat, to your original point of this thread. All I can contribute is that I personally never found a 6550 that did it for me in my P11a, and never turned back after trying the KT88(which is to say I havent tried any new 6550 tubes in last 10 yrs). Gold Lion KT88s are pricey but worth it IMO. But then i last switched to kT120s in that amp. Possibly fuller in mids, but not an entirely different sound - but havent done a careful back and forth comparison there.

[Big Dog RJ]

OK here goes gentlemen, finally got to the bottom of this, as it was making me sleepless...

I tried the iterations as mentioned but not on my monoblocks, rather on the Classic 60se. This power amp took all types very nicely, no issues with the transformers whatsoever.

First with the 6550 Sovtek: very nice overall sound, smooth from top to bottom, with extended highs, focused mid-range and musical bass. A great tube for what it delivers.

Second the KT120 Tungsol : as I already know this tube extremely well, this amp was designed around the KT120, so the best performance was with this tube, no doubt! Outstanding performance in every spectrum, including the bass, marvelous!

Finally the KT150 Tungsol : just as I thought and as my CJ mate claimed would be the case, these amps are NOT designed based on the KT150's, hence will not provide the full potential of the KT150's capabilities.

Therefore, although the sound was fuller, it definitely was not well balanced compared with the others, especially the KT120's.

The KT150 did provide an extended bass and lower bottom end grunt but at the same time smeared that lush mid-range and warmth compared to the KT120. The 150 also was able to play louder, so it seemed, as if it was cruising along... But it was not an overall winner.

This was the exact same phenomenon I got when I had the MV60se and replaced the original 6550's with KT120's, it just didn't sound right. However, with an amp such as the new Classic 60se and the classic 62se, these circuits take full advantage of the KT120 topology.

Therefore, when I had the chance to audition the Art 150, that sounded so fantastic, it was miles apart from what I heard by doing direct replacements from KT120's. In summary, don't do it! It doesn't work out.

So all in all, I would say for those looking to engage in an area of much higher quality and receive the best in SOTA sound of the KT150, you would have to look at the top of the line ART amps, either the 150 or the 300's. And you will have to spend a LOT of green notes...

I am extremely pleased with the results of the KT120 tubes and what they do offer, comparing directly to the KT150, it's not too far off...
Cheers, RJ

[roberto]

Hola a todos,

I have being doing some tube comparisons too. The EL-34 still has a warmth that the other tubes lack. Sometimes this warmth to my licking is too much, and exhibits in my system, a colored sound that is over sweet. The 6550 lacks that warmth at all. It is sometimes too dry to my liking. Then the KT-120 is giving to my ears sa full pure love. It has a warmth enough that it won´t be too rich as the EL-34 and has a superb bass definition. The midrange is very dynamic with outstanding clarity. The stage opens up more with this tube. Also the cymbals are projected in the air with astonished definition. I can not use the KT-150 with this amp. I have a Classic 62Se with EL-34s and another with KT-120. I did exchange the KT-120s for the 6550c. These amps drives my CLXs easy too as my Classic 120 SE. My conclusion is: my ears are more toward the KT+-120s overall. I did play the same music material, using DSD files basically with ASIO software and HQPlayer by signalist driving the DSD files. The preamp that I did use is my ET-7.

I am, as RJ too, enjoying the quality sound that my CLXs. My ET-7 is sounding great with superb definition. It is a very good preamp. I do believe that CJ products have this quality signature that I am getting from all this gear.

Happy listening!