“This Reissue does Not sound like the Original, of which I still possess 24 x JAN examples (1969/70 Vintage). It does Not have the Airy Top End of those Tubes. It also appears that the Diameter of the Reissue is a bit Smaller than the Original, suggesting that the Glass is Not as Thick. One the other hand, this Reissue is Superior to the E-H KT-88, which comes from the same manufacturer.”

Helpful Report

Posted 7 years ago

“I can only tell you what they sound like in McIntosh MC60 amps. They are more dynamic than the New Sensor Re-issue Gold Lion KT88's that I have. They also seem to have less graininess. Additionally they draw far less plate current. In comparison with my set of original Gold Lion (M-O Valve) KT88's they are a touch less delicate and reveal the speaker location a bit more. But the differences are subtle and not deal breakers. So, when I can't use used or NOS KT88's in my macs, the re-issue Tung-Sols are my choice. Note that I have not used other brands so this review is limited to the tubes mentioned and for all I know there may be another fantastic tube out there somewhere.”

Helpful Report

Posted 9 years ago

“Cryogenic treated tubes produce crystallized tube elements which create crystal clear sound.”

1 Helpful Report

Posted 9 years ago

“This is my first review on any tubes and my mileage in the world of tubes is somewhat limited. Firstly, I got my first tubeamp last year, a PrimaLuna Prologue Premium, and it came pre installed with PrimaLuna EL34s silverseries. I quickly got some PrimaLuna KT-88s Goldseries from the retailer to try out and compare. Interesting comparison and two very different tubes. Both with their strong sides and what I had read about the differences seamed to be true. During this time I switched preamp(12AU7s) tubes to Ciftes bought here at Upscale. Wow...what a difference. I ended up using the KT88s as they gave a more 'solid' performance overall, but still couldn't forget that lovely midrange and highs from the EL34s. More sublime and not so direct in your face. Read alot on the web for information about different tubes and NOS etc. but they were expensive and not very easy to come across. So after already having bought from upscale I took the chance on these, and can only say they sound beautiful! Good foundation/bass, clear and big soundstage and kind to my horn speakers' top end. Have had these tubes now for about four months and absolutely love them. Will for sure buy them again...or maybe try some NOS :) I ordered them as a matched quad and Cryogenically treated. Happy Listening!”

5 Helpful Report

Posted 9 years ago

“These are the first 6550 I have tried (Tung Sol) and I find them enticing. Previously it was the KT 88's. My recent pair of Quad II-40's came with Golden Lion KT88's and another trio I have also have KT88's (in the AV room for the front speakers). However, for my analogue stereo listening I find the 6550 superior. Whether its the Beatles, opera, or orchestral on vinyl, the 6550's produce a seductive sound without being rich or bloated. I'll be trying the Svetlana SED "winged C" next - since I avoided them in the first round because of the step up in price. Of course these were matched pairs and the packaging for shipping was very robust.”

2 Helpful Report

Posted 9 years ago

“Just installed and biased these to replace a set of worn-out Golden Lion KT88s. So far, all is good. Very good clarity and dynamics. I'm not really familiar with KT88/6550s so can't give a very educated assessment. I ordered nine valves in case one was a dud. As it turned out the specs on one valve were way different from the others - perhaps this should have been picked up?”

Helpful Report

Posted 10 years ago

“Time to retube my Audio Research 130-SE, I went back to Upscale Audio because of their inhouse testing. I was advised to go with the Tung-Sol's over the Winged C's and decided to buy the cryoed Tung-Sol's. To my ears this is a bit like a Kt-88 meets an El-34 with the power of a 6550. Liquid midrange, controlled bass, a smidge of roll off in the highs. I should add both the EH and Winged C's sounded a bit dry compared to the Tung-Sol's.”

Helpful Report

Posted 12 years ago

“This is the best my system has ever sounded since I replaced the EH KT88 with the Tung-Sol 6550. The bass is more dynamic and controlled, the mid-range is true, but the highs are missing a little bit of sparkle. However the balance is perfect for my system. Kevin Deal assured me that he knew what he was doing when he recommended these tubes for the Cary V-12 mono blocks (24 tubes) to drive my Maggie 3.6's speakers. Right now I'm tickled to death, and having an audiogasm. Thank you Kevin!”

3 Helpful Report

Posted 12 years ago

Tung-Sol 6550 No Cryo Reviews