KT88 recom. for quicksilver mini mono's

Jax2 : putting the KR brand on a Tesla tube is not what i call making a tube.
KR rebranded some KT88 but never did one.

Ah, well forgive me for not telepathically being able to interpret your personal standards. As I understood it, Riccardo Kron contracted with the Tesla factory to build his design. He was unhappy with the work they did and ceased production.

From the 6moons Interview of Kron:

You specialize in triodes though the KR KT-88 you produce is technically a tetrode. Explain this focus and why you're not interested in pentodes.

As an old-timer with tubes, I'm interested in all tube technology. However, pentodes cannot be successfully manufactured using our process. We were cooperating with another line production facility here in Prague, to build the KR KT-88. But our high QC standards could not be sustained by Tesla. The quality we received for our design was unacceptably low, unworthy of the KR brand name and trademark. With great disappointment, we had to suspend our work with the Tesla people.

Jax2 : well with your personal standard i could take a pen and write "Genelex" on any KT88.
The fact is that there's very few chances that those tubes will sound like a Genelex :)

Jax2 : well with your personal standard i could take a pen and write "Genelex" on any KT88.
The fact is that there's very few chances that those tubes will sound like a Genelex :)

Where did you see me comparing the sound of KR to Genelex? Re-branding has been a common practice throughout the history of vacuum tube making. Re-branding absolutely does NOT indicate an inferior tube, in fact there are many outstanding tubes available that are re-branded, though I don't think any were done with a pen. In this case, as I pointed out if you read the quote, Tesla was supposedly building a tube of Kron's design, and not their own as you suggested. I made no assertion whatsoever as to their quality.

Marco

One has to take Marco's quoting the 6moons.com interview of Professor Kron as the true. And, as Marco states, this was a different tube than the JJ (Telas/Teslovak).

I have no experience with the KR KT88, apart from seeing a pair of amps with them. They are far larger physically than a JJ KT88, with supposedly more power and extension. As far as the "tone" of the tube goes, or the claims of superior power/extension, obviously, I cannot make any comment regarding that. There is so little opinion avaible about them sonically that they remain more or less an unknown. I REALLY lament the missed opportunity of not giving them a listen.

One would surmise that if JJ felt the KR KT88 superior, they would have either continued on with the design. Or, if doing so violated any agreements, patents, trademarks, etc., they would have still incorporated elements of the overall design in their own tubes. Perhaps this has not yet happened, but will in the future?

Marco is also correct about rebranding tubes. This was de rigeur during the halcyon days of tubes. There are hundreds, if not thousands of examples of this, such as the treasured Amperex/Bugle Boy tubes which were made by third parties (normally by Mullard, Philips, etc.).

Aside from all of this, one has to label the second hand nature of the statements regarding the KR KT88 being compared sonically to the British Gold Lion tubes as such. While, it may or may not be true, until and unless someone who has actually tried both steps up and says this here, or we have a tube shootout, it comes across as not having much behind it.

The KT88 in current production that I like best is the JJ. For my money, they are head and shoulders better than the Sovtek and EH variants.

Finally, I hear a lot of good things by people I respect regarding the Shuguang/Penta tubes, but have not personally heard them. I will say that I wouldn't discount the Chinese tubes offhand. As utterly shocking as this assertion will sound, in my own experience, the current Shuguang 12AX7 bests a lot of the NOS sacred cow 12AX7 tubes. Now, if they'd only redo their EL34...

FWIW, Vacuum Tube Valley (VTV) magazine did a 6550/KT88 shootout many years ago. I used to have a copy, but I think it made it to the recycle bin. The top three in that review were the Genelex 88's on top, TungSol 6550's second, and JJ/Tesla 88's third. No recollections of what amps they used (this would certainly make a difference), but I think there were a few, and judging was done by four or five panelists as I recall. Perhaps someone has a copy and can give more complete results.

Marco

The quote from the 6moons inverview with Kron is on page two of that interview here.