As I posted on the thread mentioned in Tvad's post, I have used a number of KT-88s on my PA100/100. I am assuming that tube and types/sound would be similer between my amp and the Avatar KT-88, or at least a guide to your question.
I have now recieved my cyro'd Valve Art KT-88s after a long back order. I have to say they are exceptional sounding tubes. Very extended top to bottom and a nice hump/touch of midrange lushness and bloom. Much better than the Valve Art non-cyro and EH I have been using up to this point.
Interesting findings. I have tried JJ blue glass, VAC stock tubes and now some Golden Dragons. So far I think the best are the Goldn Dragons(I'm not sure of the vintage) but I have found that the VAC is the least susceptible to tube rolling of any amp I've had. It just always sounds fantastic no matter what tubes are in it. Don't get me wrong as there no doubt are subtle differnces but either the stock tubes are really good or my "upgrades" aren't really that. I have heard dramatic differences with altering 12au7's in other amps but not so much with the VAC. Always interested to hear what others find though. I have seen some talk about the Valve Arts on AA. hmmm.... interesting....
It seems that I recall reading that Kevin Hayes "voices" all his amps to the tubes that come with it from the factory. I read a thread, I think in the amp asylum website, where several people replaced the factory tubes with expensive NOS tubes and ended up going back to the factory tubes. If I were you, I'd give Kevin Hayes a call to get his opinion. He probably keeps a record of your unit and if he's found better tubes to keep with the "voicing", he'll recommend them to you or sell them to you, if he has some available. I also have a VAC Avatar on my short-list to power my Reference 3a Dulcets.
Pardon me for seeming " unrefined " with thi statement, but I find it steps from absurd to accept a designer "voices " and amplifier aroud the sound of a cheap Chinese tube. Now, I am not saying that a circuit may be " adjusted " to accomodate a particular character of measured specs, but I find the reason why designers, any deigners use these tubes is not because the mplifier is voiced around them, it's because they are inexpensive and plentiful, and considering even a master like Kevin in terms of building a quality amplifier, which he does not need to prove by any means, might employ 12-18 tubes in any or most of his designs. It just makes economical sense to utilize an inexpensive, but reliable tube or the cost of the amplifier would be driven up by perhaps 20%. I am an owner of the last version of the well reviewed VAC Avatart SUPER and I have found changing out the front line 12AX7 an 12AU7 did more for this amplifier than power tubes did, however, I personally found the cyo'ed Svetlana KT88 winged C to provide the most uniform and transparent sound, but again, this could all be due to my up and downstream components. i have found no one solution fits all, there is no standard IMHO.
I have the Penta KT88SC's in my Cary SLI-80 and they are the best I have tried and I have tried most of the major players in the KT88 field, with the exception of the JJ's. Also, in my opinion the sound of the solid plate Penta's and the version with the three holes in the plates (KT88-98) are so similar that any differences are imperceptible to me. So I can heartily recommend both.
I am interested in the recently introduced Genelex Gold Lion KT88's that purport to be an exact copy of the vintage Genelex's. But the cheapest I have seen them is for $210 a quad, so I am trying to wait on some reviews before I bite the bullet. Has anyone tried the new Gold Lions?
Zodiac, I have recently had qc issues with tubes directly from Kevin, but he has been good about getting replacements out but even those don't hold up. TVAD's advice is spot on from my experience.
Onemangang - I guess you really do love the VAC Avatar Super! What do you recommend for the brand and vendor for the pre tubes you mentioned. Thanks.
Onemangang's opinion does make sense to me when looking at a manufacturer's point of view. Kevin himself told me that he tries to use good tubes that are "readily" available. So from a "voicing" standpoint, he basically finds a good, readily available tube that works best in his circuit. He also mentioned that maybe 10% of the NOS tubes that he's experimented with might be better sonically than his stock tubes. He didn't tell me what those 10% were and I was reluctant to ask him. I guess tube rolling's the audiophile way, but it sure can get expensive in a fast way; but then again, VAC's stock tubes are pretty expensive, so what to do?
Grant, Assuming I still have my VAC Musicblocs when the stock tubes begin to wear out( they still have some good life in them) I am definitely going to go the Penta or Shuguang versions per your recommendation. I feel confident that these are equivalent to VAC's stock power tubes, and there are good dealers for these who will sell them as matched pairs or quads.
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