KT88 recom. for quicksilver mini mono's

I recently aquired a set of mini's and am looking for sugestions on tubes. Of what I have tried so far I have found I like the sovtek 6L6's. Upscale recommended the EHkt88 for a clean,dry, less warm sound, since I think that is the direction I am going in. What would you guys recommend that you have tried, what would you not recommend? Thanks, Matt
I just received an announcement that Genelex KT88's were in production in the Reflektor plant in Russia. The claim is:

In 1957 Marconi-Osram Valve Co. (Genalex) introduced the "King of Power Tubes", the legendary Gold Lion KT88. This tube became the heart and soul of such classics as the Dynaco Mark III, McIntosh MC275, and Marshall Major. Unfortunately, Genalex ceased tube production in the early 1980s and the Genalex Gold Lion KT88 has become very expensive and hard to find.

After extensive research and engineering, New Sensor Corp. has reissued the famed Genalex Gold Lion KT88. This tube has been recreated down to the finest detail with gold plated grid wire, carbonized screen grids, and a tri-alloy clad plate structure for exceptional performance and sound quality.

I have no idea if this tube has ANY merit, but it is something to keep your eye on. I don't know the retail price yet.
I owned Mini's for a while -- sweet amps indeed -- and got the best performance out of Svetlana SED "Winged C" KT88s -- warm and musical, but not fat or dull. I found the EH KT88s to be a little bright for my taste but you might like them.
Sovtec resides at the bottem. Svetlana is really good as are some NOS (new, old stock).
I agree Unclejeff.

I am a Wing C guy, which IS STILL the original Svetlana and still built in the St. Petersburg factory. This is the factory and the tube that built the old Svetlana reputation and made the name famous.

Unfortunately, the Svetlana sold today (and for the last couple of years) is built in the Reflektor plant right along side Sovtek, EH, Tung Sol, Mullard and Svetlana, all names BOUGHT and owned by New Sensor.

I will say, the Sovtek 12AX7 (9 pin miniature) is a good tube for the money and I always hold hope that a new product like the Genelex KT88 (mentioned above) will be worthy of consideration.

As I mentioned in my first post, I don't know if it has any merit but worth keeping an eye on.
I liked the JJ Tesla's over the Svet C's in those amps. Sorry to have to add yet one more option to your responses here. It's been too long to know my reasons, but I do remember that preference.

Shoot Mike Sanders an email - it may take a day or two, but he'll surely respond - or try giving him a call. All his contact information is on his website.

I'd definitely look into the Genelex tubes Albert is suggesting too.

I use KR KT88s. I love the sound. I was told by an owner of both the British Gold Lions and the KR KT88, that the sound quality and construction quality are just about equal. I think you'll be very satisfied. Albert's suggestion, also, sounds very intriguing.

I personally did not like KT88's in the Mini Mono's, liked the 6L6 tubes, but found the Ei KT90's were the ticket. The sound stage became huge with great depth with the KT90's. I liked the mini mono's so much, I moved up to the Mid Mono's and found KT88's were best in the mid mono's. Amps, IMO, are all different and why we roll tubes to find the sound that makes us stop and listen.
I second Upscale's recommendation for the EH-KT88's. I am using them in my C-J Premier 12's They have a more "modern" sound; less colored, better high-end extension, and tighter bass.
Have a look at EAT valves KT88's - this is regarded as thè audiophile tubes for amplifiers.

Best regards,
Dewald Visser
Warrenh : i don't think KR ever made a KT88.
Suggest checking out the Valve Art Cyro'd KT88.
11-30-06: Ndeslions
Warrenh : i don't think KR ever made a KT88.

I believe they did. It was made in the Tesla factory.

Thanks Guys, Tried some chinese kt88's this morning. No name tubes, but didn't like them regardless. will try some more and still look forward to your ideas. Thanks, Matt
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.
I have a pair of KR KT88s made in Czechoslavakia.
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.

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.


The quote from the 6moons inverview with Kron is on page two of that interview here.
12-03-06: Jax2
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.
VTV Issue 19. Available from VTV as a back

System: 80 wpc Air Tight ATM-2 PP KT88, Ait Tight ATC-1 preamp, Air
Tight ATH-2 Moving Coil Step-Up Unit, Quad 989 loudspeakers,
Clearaudio Maximum Solution TT, Graham 2.2 tone arm, Koetsu Onyx
Platinum MC phono cartridge, Shunyata Lyra ICs, Shunyata Aries speaker

Order of finish: Genelex KT88 Gold Lion (1969) - 4.87, Tung-Sol
6550 1963 Grey Plate - 4.77, JJ KT88 (2002) - 4.63, Ei KT90 (1990) -
4.52, EH KT88 (Reflector 2002) - 4.16, Svetlana 6550 (2001) - 4.13,
Svetlana SVKT88 (2002) - 4.09, Svetlana SV6550C (Reflector 2002) -
3.98, Philips 6550 (Sylvania 1970s) - 3.98, Chinese 6550 (Valve Arts
2002) - 3.89, GE 6550A (1970s) - 3.78

I think it's important to note the production dates of these tubes. Things
have changed since 2003 when this article was published, and these
rankings may or may not apply today.

Also, based on my limited experience with a VAC Phi 110/110 PP tube
amp, it's my opinion that amps are voiced with certain tubes, and they
will sound best with those tubes. No matter what I swapped into my
VAC, it always sounded best with the Chinese sourced (Shuguang) VAC
stock tubes, and my experiments included the much heralded Genelex
Gold Monarch KT88 (1969).
Thanks Grant. I agree, it will depend upon the amp you are using them in. I've had similar experiences where one tube type sounds better than another in one component, but is bested by the one it beat when rolled in another component. Never had any draw me to the few Chinese tubes I've heard, but still, that doesn't surprise me in the least...I've always seemed to find the ones I've heard rather hard and edgy. The best thing to do, if you can afford the price and the time, is to get various sets of tubes (preferably ones that have been previously burned-in) and roll them in the equipment you are going to be using them in. Pretty much like everything else in this hobby: use your own two ears, your own system, your own room, your own music, and your own judgement. What someone else thinks is best, may not be what works for you, and you'll never know unless you try. Ask any question as to which ________ is best here in these forums...virtually anything....and you are bound to get a virtual rainbow of responses. Do a search if you want an example...best tube, best monitor, best CD player under...blah, blah, blah. Or just look at the responses to this query. There is no one right answer, and anyone who believes they think they know there is one single answer for such a question that applies to all individuals has their head deeply entrenched in their own rectal cavity...IMNSHO People and their preferences are as unique as their fingerprints. Threads like this, and others like it, are merely a good place to start.

Cobra213 had compared the KR KT88s to the British Gold Lions. He owned both and when I purchased his Audion Sterling, he was going to include the British Lions, but they got damaged. He included the KRs and said they are the Lion's equal. I wish he were here to put his three cents in. He knows his tubes...warren
With all the debate on the "best" KT 88's, has anyone found them superior in the Quicksilver Mini Mono's? Personally, I know two other Audiogon members and myself who did not care for the KT 88 tubes in the Mini Mono's compared to other tubes. If you owned the amps, what was your verdict?
I only rolled KT88's in the Mini-Monos. I was quite happy with the performance of them so did not try the warmer, more tubey 6550 approach (at least that's how I'd guess they'd sound). Perhaps I was missing out, but I really liked those amps with the KT88's in them. As I said, I ended up with JJ's. Clean and punchy and versatile, those amps mated well with many speakers. What did you end up preferring, Elsneb?
Jax2, Got to wonder what you mean by "tubey 6550 approach"? In compared to KT90's yes, but in comparison to KT88's? I would think the KT88's, at least the ones I have heard, have all sounded warmer, more sparkly, and less linear than 6550's. Did you have something specific in mind?
I once tried some GE 6550 in my VAC amp. Compared the the KT88, the 6550 were rolled off and had looser bass. I would characterize the VAC stock KT88 tubes as sounding more linear in that particular application.
Tvad, FWIW, in three different amps, each of the 6550's and KT88's (both SED's) had the same sonic signature, albeit the overall sonic preference was different because of the design of the amps (Cary, Sonic Frontiers, & Primaluna). The KT88's had a warm(er)upper bass, and bright(er) in the upper mids. The KT88's seemed a bit more extended and had an overall tone much more (to me) reminescent of 'tubey sound'. The 6550 has a slightly rolled top end, neutral mids, and deep powerful bass without upper bass emphasis. The sonic's of the 6550 reminds me of the KT90 except for the roll off, and maybe a bit more power from the KT90 in the bass.

My observations about the overall nature of tube types seem consistent (to me anyway) with comments I have heard from others. Obviously different brands of each type will sound different and the application (to amp) is critical. FWIW I bought the Cary mono's with KT88's - the bass was big dense thumps, I replaced these with 6550's and the bass became clean, impactful, and linear. To compensate for the soft uppers, I put some compensating tubes in the driver position in the amp as well as in the source(s) used with the 2 amps in which I use the 6550's. Now, with one amp (SF) the KT88's provide a perfect couple with a Wadia CDP driven direct. I've never liked 6550's in that amp - just too cool for me.

JMHO, I'm sure everyone has their own valid opinion.
Your observations and mine illustrate that there is no universally applicable observation, which brings me back to my original point that tube amps are generally voiced with a particular type and brand of tube, and it's likely that any other tube used in that amp will not sound as well as the tube that was used to voice the amp.
Did you have something specific in mind?

Yes, my experience rolling one type against the other was in a Mesa Baron (tri-tube) amp. There I found the KT88's to be a bit too hard and clean for my tastes, giving the Baron an almost SS sond to it. I longed for something a bit more warm in comparison. At the suggestion of a few folks (Jon at the Tube Store, and the tech guy at Mesa among them), I tried 6550's instead...I think they were Svets, but it's been a while...maybe in a previous post of mine...anyway, sure enough, in that amp and system, and to my ears, the 6550's sounded warmer and had a wonderful midrange, with a bit of sacrafice to the bass. On that amp the bass compromise was no problem as it is a prodigious performer there. The tubes were Svet's in both cases as I recall. This is over five years ago I think, so details are open to correction, but the overall impression is quite accurate, I'm sure.

Marco, Mesa Baron Tri Tube mod was 6L6, EL 34, and ?. I was under the impression that it limited to KT types, not 6550's.

I thought the tri tube mod in the Mesa Baron was 6l6's, EL34's and KT88's. I was not aware that it would also take 6550's. I never made the conversion on my Baron (I just stuffed it into a box into my attic where its gathering dust) to the tri-tube - a little birdy at Mesa talked me out of it - so I can't be absolutely sure. I googled this out of curiosity and found no authoritive comments contrary to my belief's.

Could you perhaps have been given a demo of the difference between the KT88 and EL34's? That would be my WAG based on your description of the sound.
No, you are absolutely right Newbee. I was confusing the 6L6 with 6550's. My bad, and thanks for pointing that out. Strike my comments on the 6550's and give me a good swift boot in the ass. It sucks getting old. I don't think I ever tried the EL34's in the Baron because I was steered to the 6L6's from my complaints about the KT88's. I got mine as a Tri-tube.

In my case, I liked the KT90's in the mini's. They had more depth that the small transformers seemed to lack. In the Cary amp I owned, I switched between the Winged C and the EH KT88's, but the mini mono's just needed more for my setup. The mini mono's were very good and a steal for the money. The mid mono's are a whole different level with the large transformers and seem to tube roll much better for me. The KT 90's were just too much or fat in the mid mono's. Besides the sound, tube amps are fantastic to fine tune your sound to your particular tastes and the reason I love tubes.
From what people here and elsewhere have said, it seems there is a strong following in the el34 crowd. I have a set of older brown base el34 tesla's, some svetlana el34's, and some sovtek 6l6, and I tried the chinese kt88 (didn't care for). Of these I have tried to truly figure out the differences, not just what my expectations may have been. Instead of just kt88 responces, what have you guys heard that you liked in mini's?? I have a guy offering a set of Ei kt90's, any thoughts on them?
Chinese in the Linestage preamp made all the diference, I cound't care less if they were green or square, the chinese ones Mike sends them out with sounded best to me. I just didn't care for the particular chinese kt88 I tried. Although with no brand markings, i couldn't tell you what they were :)
Count me among those who prefer a good EL34, such as the JJ, over the 6550, KT88, and KT90. The midrange, which gives "life" to the music is simply light years better. That being said, I have seen more than a few amplifiers that for whatever reasons (maybe improper bias?) that can run both, and just do not come alive with an EL34.

Another option is the JJ KT77, or the 6CA7 which is offered by Ei and ElectroHarmonix. My experience with the KT77 was that it was a good compromise between the JJ E34L and their KT88 - powerful lows of the bigger tube, with superior mids (though still not close to the E34L).

I've been meaning to write up the tube shootout our audio group did in three separate systems - 1960s Mullard XF1 EL34, JJ E34L, EH EL34, JJ KT77, JJ KT88, but have never gotten around to it. For what it's worth, the conclusions were pretty consistent...
I actually had the mini monos for some time and found that Russian tubes in general were not the best in these amps. The Tesla E34L is very good as are JJ E34L. Saratov KT66 (I think Groove Tube packages these, two styles I've seen) was very nice but hard to find and not very duable (hot spots on plates). Sylvania 12ax7 are nice on the input.