GEC KT88 single-getter vs. triple-getter tubes

I recently received a Unison Research Sinfonia integrated amplifier and tried various tubes with it. As output tubes, I tried three-getter GEC KT-88 tubes which are great but I felt that they are overblown and rather fat sounding and lack air and HF extension. The stock tubes (Sovtek KT-88 marked "Unison Research") and somewhat lighter and brighter in a good sense and I thought I would keep them as output tubes, until I inserted the earlier vintage single-getter Genalex KT-88 tubes, which have more high frequency extension and transparency and don't have such excessive "bloom" I was suffering from. Has anyone had similar experience with these two varieties of GEC tubes? I will also appreciate any tips about a reliable source of NOS/NIB GEC/Genalex KT-88 tubes.
You could also try the Chinese GEKT88, they are head and shoulders above other current production KT88 tubes i tried in my system.
They also are very affordable.

I did not had the chance to test a GEC NOS yet.
It's really hard to find these tubes now except on ebay. All tubevendors no longer have any of this stash.

I have a set which i cherish over the last 10 years...they lasts and lasts.

IMHO, these are undoubtedly the most natural organic sounding tubes that will give you that analogue or "LP" flavour sound.

I have tried Tungsols(NOS), Ei, Svets KT88 and 6550, GEKT88, GE 6550. GEC has proved the most reliable and lasting tube that i have tried to date. I have lost too many Tungsols and current tubes which just had heartstopping failure in my Conrads over these years.

There does not seem to be that difference as i had some single getters. Have you havd your tubes tested as the difference seems to be typical of wornout tubes.
I have Unison Research Performance amplifier,it is same as Sinfonia beyond one Kt88 plus for each channel.
I am happy with Shuguang KT88/98 power tubes and for the 12au7 I could not find out any better than stock EH12au7s (I do not know it is because of this amps circuity or what reason?) and for the 12ax7s I have the best sound with both Ei and Shuguang 12ax7s.
I also replaced the stock icel brand capacitors (one 0.47 for each channel)with
Vcaps and made this amp much better.
Thank you, it's very interesting - about V-caps and everything. A year ago I replaced the stock 0.22uf caps in my Cary SLI-80 with V-caps and after a long, long burn-in (though their flavor was apparent at the outset) the amp opened up. Still, I believe thay are colored.
jtaysk: I don't have a tube tester. I ordered three-getter GEC tubes from HK as NOS two years ago and they appeared as such, but who can tell...

I've seen GEC tubes at Tejatubes, they also occasionally appear at Brent Jessee Recording, but the price is US$1500-1660 a quad.
Was able to compare the Shuguang made KT-88/98 (which are superior built and sounding than other KT-88 types including the so called new production Gold Lyon Russian power tubes) after 3 months or so compared them with GEKT-88 also Chinese and the improvement was a major step.
I have not tried sinlge getter KT-88 since the 88-98 has one side getter and another (halo up on top) now the GEK-T88, has 3 getter and it sounds really good.
I've found a guy selling the GEC "originals" blue sticker which reality says they are originally made in china outsourced fromm Genelex in the 1980'2 qndd 90's (SOUND FAMILIAR??) the British KT-88 GEC have been out of reality reach for the last 10 o 12 year at the every least.

Today's choices are clear, GEK-T88 from China is a steal for the price quality is very musical, organic presentation, smooth top end, bass authority etc. etc.
Sounds really good, that's what I can say, now . . mind you the little that I know about tubes is that nobody can predict how a particular tube will sound in the context of the particuloar circuit and also interaction with the other tubes in the equipment, and that is a fact.
example some people swear by Mullard small signal tubes (12AX7) now sometimes Mullard sound with no bass, no top end to speak of and no timbre distinction, is that a problem with the Mulards?? i don't think so is just the inetraction with the other tubes and the synergy of that interaction. on that application teh best sounding 12AX7 was indeed a Sylvania 12AX7 NOS that can be had on e-bay for a few bucks, Luckily I have good friend tube addicts that we exchange our tubes to see what works best with what other and the surprises are many that way . . .
Another word of advice, some of the new generation of chinese amplifiers made with tubes are really of superior quality, the problem, most of them are designed to work off 110 Volts. this country of ours hasn't had 110 Volts for at least 15 or 20 years, in my neck of the woods the norm is 123 Volts for the grid, si using a step down trasnformer or simply a Variac is a must otherwise reliability of these amps becomes a factor, since plate voltages multiply, in reality a plate voltage of 450 Volts for a KT-88 tube ends up being almost 570 volts with the extra voltage coming form the grid, that blows up anything.
Go ahead discover some of teh wonderful Chinese tube amps you see in the market doem of them based KT-88 and 300B are truly wonderful pieces, than in time maybe swap capacitors for betterquality for a top notch sounding tube amp thta couls easily rival $10 to 20,000 esoterics for under $1K, now you know it . . .
enjoy tubes they are the real music and tone of real instruments vibrating in space, somehow trnsistors no longer cut it for me, they can sound very nice but not as real, melodic or tibrally correct as the tubes.
Compare $15,000 SS amp to $1,200 tube integrated yhou'll see for yourself.
Hope it helps a little;

God Bless!

Well this is the first time I saw someone saying something bad about the New Golden Loin KT88.
Pretty much any review anywhere online gives very very positive results. You will find reviews saying they are as good as the real NOS KT88 and some say even better.
All I know is I bought a Quad of them off Jim MacShane on Audio Asylum and these New Golden Loin KT88 are in a leaque of their own. No other New production tube can hold a candle to them. I replaced my Shuguang made KT-88 with the New Golden Loin KT88, the Shuguang KT-88 were good indeed, but isn't in the same leaque as the New Golden Loin KT88.

Prehaps with the other poster his diver + gain stage tubes were not a good match for the New Golden Loin KT88.
Synergy with the other tubes does have alot to do with it, along with the circut. Some amps will show more diffences than others when it come to tube rolling and this is where alot of fun can be had in fine tuneing.
I compared new GL KT-88 with 1977/78 vintage British-made GEC KT-88. They are not the same. Here are my comments:

I played the new Gold Lions for approx. 20 hours (perhaps its not sufficient). My first impression was that they sounded very similar, but it is not so. They are similar in terms of power - they have a very dynamic and powerful sound, with overblown midrange and truncated highs. The original GEC tubes have more air and midrange delicacy - yes, it's delicacy which the new GL tubes lack. Besides, the new tubes have a characteristic Sovtek-style metallic sheen in the midrange, which is not present in the original tubes.

The amp is Cary SLI-80.
I personally found the reissue GL to be fantastic in my Jadis DA-60. The Chinese tubes I had in another amp were thin and lacked definition simply no comparison. I am an unabashed fan of the Reissue and highly recommend it. BTW the input and driver tubes in the Jadis are rolled without any diminution of the KT-88s quality.
Im my other amp (Hans Audio KT88), the reissue GL sound fantastic - clear, lively, dynamic and powerful.
After many more 6550 and KT 88's tried and tested I have to go back to my recommendation for the Shuguang made GEKT-88's not the same as the KT88-98 not to be confused.
Also the newer Treasure line of Shuguang made tubes are fantastic.
I still keep a stash of (NOS circa 1960's)Tung-Sol 6550 as in triode strap mode sound the very best I've heard in delicacy, defnition, timbre, tone and balance. period!! then if you wish for more bass the Ei made KT90's are it for sure though it sounds slightly harder than the NOS Tung-Sol (I'm nitpicking here)the bass in terms of shee grip slam and definition is 2nd to none, so, again fun to roll between these 3.
I have not heard the Golden Lions is such a long time I could not possibly speak intelligently about them, here is my short list.
I was not lucky enough to be exposed to a $2,000 quad of Genelex KT88 so can't mention them either, but just about heard everything else in my system, Including some GE 6550's and other Tung-Sol made versions (Sylvania branded and RCA branded).
6550 is a must listen for some music fans since it might interact better than KT-88's in some circuit designs and with some other tube drivers in the circuit.

I also heard some of the newly made russian and Chinese 6550's my my heart was not won over them, I would consider more suitable for like a Hammond Organ tube amplifier or something of the likes maybe lesser resolution system.
My system nowadays will pick on every little detail and throw it in your face due to silver cabling througout and high efficiency speaker drivers, extremely transparent and musical if the chain is very good

Chinese amps to recommend, Yaqin, Music Angel, Cayin, Shanling
For Cheap of course by no means any of the manufactured Chinese stuff will improve upon the quality fo US manufacturers such as Quicksilver Audio, Audio Research, and a few others.