what is the best Kt88 to get


 guys- trying a set of Sylvania 6sn7 bad boys now need to know what is the best kt88 to try- my amps came with the Mullard brand- does the KT88 effect the sound as much as the 6sn7's do?- thanks for the rec=
bopper
In my Ayon Spirit 2 I found the Shuguang Black Treasure KT88s to provide a fuller more pronounced sound than JJ's or even the Gold Lion's . 
Yes, output tubes will also affect your system’s sound/presentation. My previous octet of output tubes(in Cary monoblocks), were 1970’s, GE 6550As. Two sets of the same and a couple octets of Sylvania 6550s, before those(all mentioned being NOS, at purchase). Both of those were chosen, for their very clean, extended, uncolored sound, and wide, deep staging(like your Sylvania 6SN7s). One of the last eight shorted, after a few years of faithful service(50% of GOOD left, on a Hickok tester). Given the prices/scarcity of NOS 6550/KT88 types, I looked for alternatives. TC Tubes found a close match, for the GE 6550s, in their, "too weak to sell as new" NOS pile and gave it to me. Mean time: I bought a quad of the Russian KT88s, made by New Sensor and labeled as Genelex. With a quad of each installed, and my source in mono, I compared my amps. After a few hours, they were very close in presentation, with the(half life) GEs still having a slight edge in bottom end definition and dynamics. I have an actively biamped(bypassed during listening tests) bass system, so- no issue(for me). Now I’ve got an octet of the Russian KT88s and my ears are happy, once again. They’re pretty too! https://tctubes.com/images/view.aspx?productId=1463 The, "BEST" new production tube, would be the EAT KT88 though (to be honest), IF you’ve got the juice. https://www.tubedepot.com/products/eat-kt88-diamond-power-vacuum-tube-matched-quad Sorry for the verbosity!
Verbosity is good as hand signals or morse code rarely gets the point across around here. In recent years I tried (mostly in a factory modded Jolida 502P I recently sold...great amp) new version Tung Sol 6550s that were certainly clean, along with Sovtek KT88s (no longer made), and various others like Gold Lion KT88s, KT120s and 150s. When I bought a small SEP Dennis Had amp it came with Gold Lion 88s which are great, and the Sovteks also sound killer in this amp, but I returned to a fave, the KT120s, as somehow they work for me...plus my last quad was used enough to wear 'em out over a couple of years, so I guess I like the sound.
I replaced my stock McIntosh tubes with Psvane Black Bottles KT88s in my MC275 and was a noticeable improvement. This was 4.5 years ago and still sounding great.

FWIW I purchased 5 in case one failed, on rotate then every 2 months so they all age similarly. No failures.
What amp do you have? KT88s can sound different depending on the amps design.  I found Gold Lion KT88 to sound very good in my Primaluna Dialogue Premium versus other KT88s. The worst was Preferred Series from the Tube Store.  This doesn't mean they sound bad in another amp so I'm not trashing the tube.  It just had too much detail and energy for me. 
I had a pair of "preferred series" 7025s that didn't sound as good as Gold Lion 12AX7s in my hifi rig, but work fine in a guitar amp. Who knew? I'm happy to share this revelation with others, as hey...I'm a giver.
What amp do you have? KT88s can sound different depending on the amps design. I found Gold Lion KT88 to sound very good in my Primaluna Dialogue Premium versus other KT88s. The worst was Preferred Series from the Tube Store. This doesn’t mean they sound bad in another amp so I’m not trashing the tube. It just had too much detail and energy for me.

My experience is precisely the opposite in my VAC 300.1a. Just goes to show how much the amp affects the performance of a tube.
Don’t forget how much tastes in sound differ.  Many may not like a certain tube's presentation, regardless of the application/component.
Interesting, I love the Preferred Series KT88s in my Rogue M-180s.  Overall excellent, colorful, dynamic, very good bass, with a creamy top end.  They replaced an octet of KT-120s.  

I did get them for nearly half price during a Black Friday sale.  Otherwise I would have stuck with KT120s.
PSVANE Gray Glass KT88s are the best I have tried. Even out do NOS RCA/Tungsol 6550s, GE 6550s  and all of the Russian Re-issue tubes.
I have been on the KT88-6550 search for a few years with a Mcintosh MC60. Penta, Psvane, JJs,TungSol reissues, and NOS TungSol 3 hole grey plates,, Sophia Electric KT88s and now some new Gold Lions.
I have some hope that the GLs will, after burn in provide me with accurate timbre and send the right signal to the subwoofer amps in my ZU Def 4s. It’s a tradeoff. NOS TungSols are glorious in so many ways but give a subtle softness in the bass region and with the speaks lose a touch of punch. Rolled in different input and driver tubes to tighten up the bass.
Hoping the GLs prove out to be the best balance. Surprisingly, the Tung Sol reissues provide the best shove and overall dynamics, bass included, and every time I reintroduce them I like them. Put the NOS Tungsols in and it’s very musical. Pents, Psvane, JJ all too hard.
The Zus are very revealing and their is no doubt as to the differences. More than ever after reading threads on this, unless you can reference the amps being used as well as the speakers-just say each persons reference point has to be different, so yes Rodman,opinions of the different tubes come out differently.

Just a follow-up...

Depending on the taste of your music! You can install a Genalex original $500.00 per tube and it might not suit your taste. On my amp I like putting real strong tube. (I don’t like burn-in tubes). Some of them tend to loosen up the tone. Sounds like an off dialed 60’s tube amp weak power. There are such times I use a quad of PSVANE KT-88 I and listen to classic pops and some jazz. The bass in thundering with excellent highs. When I’m downstairs I can hear it pounding, but when I’m in front of the music room its not loud. the time I found the matching speaker for my amp with sound I’m looking for, even if I switch to a brand new genalex, there will be a change, but its not gonna be dramatic. irregardless if your speaker is high definition, Its all about using the correct speaker wattage to match your amp. If you can achieve that, Its like an open gate to a new world. Otherwise it’ll be an endless buying of different tubes, to amps, then to preamps etc..

I just found a NIB quad of Gold Lion that I had picked up a while back and forgot I had them in storage.   I just put them in my Quicksilver Mid Monos.   I had a quad of these a few years ago but didn't like how they sounded with my speaker at the time.  They are a great sounding tube in the right system.  Plenty of power and huge dynamic sound with my Heresy III.

......Klipsch Heresy

Most guys that I saw buying those speakers are aficionados. They do sound very good. I wish I can use a 12 inch woofer on my monitor but my music room is not as big as I want it to be. The beauty of it is I have my office in it and my guitar jam room so its a perfect size for me. I can dial my amp to 7 (out of "11") and it feels like I’m inside the show with Phil Collins doing a drum roll. Its a shame to put a subwoofer next to it..