Need Kt88s Genelex? or Shuguang?

What aspect are you trying to 'up-grade'. Tone? FR? Clarity?
For example, I use SED KT88's on one amp which may be a tad needy of some upper bass warmth and a little upper mid's and highs 'sparkle' but I use SED 6550's in another amp where I need tighter deep bass and linear tone thru the mid's and slightly soft highs.

I think it will help you in your search if you take a moment to define what you are looking for. There is no 'best sound' - its a matter of taste and synergy. FWIW the SED's are about as rugged and reliable as a family of tubes come.

Newbee, good points. The midrange is currently on target with my preferences - lush and detailed. I'm looking for more mid and upper bass definition, more lower bass impact and more extended (sparkling?) highs.
The McIntosh-branded Electro Harmonix tubes that came stock with the 275 were nothing special and developed the "blue pulsating glow of death" after less than 500 hours. So, durability is an issue.

The reissue KT88 Gold Lions may be just the ticket for you. I've read about the reliability issues. Sonically, as they have been described to me, they may be just the ticket. May be. I've not heard them in your amp. I would suggest that you would want to buy them from someone who carefully screens/tests the product and will stand behind them. In that regard, look up Jim McShane - he posts on Audio Asylum and has an outstanding reputation. He also has a history and you might discuss your situation with him before any purchase. Good luck........

I'm extremely happy with the KT-88 Genelex Gold Lion reissue. I've had them for about 6 months. They're great tubes, top to bottom. My amp is a Music Reference RM-200. Solid bass, mellifluous midrange, excellent on up, very nice all around. They're a big step up from the stock tubes (branded RAM but I believe they were fairly generic chinese tubes). I don't think you can go wrong with them. Jim McShane is a good guy, btw, and knows his tubes. Triode Electronics. Or any number of places sell factory matched quads. Jim McS's matching may be more precise than the factory matching.

Hi,

I also have 2 Mac's 275's and I have heard form members here that the PentaLabs/Shuguang KT88SC's are quite good. I am changing my 12ax7's and 12at7 first beofe I change the 88's but I may go with the PantaLabs or GL's.

Rick

I purchased a Shuguang 502B integrated amplifier from Pacific Valve. It comes equipped with Shuguang KT88-98 power tubes. After upgrading the coupling caps and beefing up the power supply it really put out some good sound but, I noticed a loss of resolution at the high frequencies. At a friends suggestion I replaced the KT88-98 tubes with the Genelex Golden Lion Rebuilds. This cleared up the high frequency response beautifully. I recommend spending a few extra bucks and buying the tubes from a dealer who actually matches them. However, I don't recommend buying anything from Pacific Valve. They misrepresented the features of the amplifier.

Thanks for all the advice. Following it I've ordered the Genalex KT88s from Jim McShane and can't wait for them to arrive.
BTW Jim said that there were, in fact, some reliability problems with the Genalex tubes but that they were limited to about 2% bad tubes from a single, earlier production run.

I think you'll be very happy with the Genelex tubes.

Jgiacalo, please keep me posted on the new GL tubes. I'd be interested!!

Rick

Drubage:

What features of the Shuguang 502B did Pacific Valve misrepresent?

Quant100, The pictures posted on their website showed the volume control knob had a blue led on it to indicate it's position. The amplifier I received from them had no led. Shuguang did about 90% of a good job. The amplifier was advertised as having high end audio components. It does, now that I have replaced the cheap coupling caps with polyproplene caps and beefed up the power supply resistors with wirewound non inductive resistors. I was disappointed with Pacific Valve but not with the amp. With the upgrades to the components and tubes the amp performance is well worth the costs.

I am running Audio Valve Challenger Mono Blocks which are auto biasing and can use EL34’s, 6550 or KT88’s. The wattage also changes with the type of output tube; the real negative side of this is that each amp takes (6) SIX tubes! When you are buying Genalex Gold Loin KT88’s x 6 matched prs that is $550 BUCKS- well call me stupid but I dropped it for 12 bad boys and it was well worth it.

My amps came with Electro-Harmonix EL34’s and putting these bad boys in was a huge improvement, starting with just plan more power and with power comes more AC needed to keep the room cool and believe you me it sure gets hotter now; then a much bigger sound stage more controlled deeper bass. The EL34’s have a real luscious mid sound but the KT88’s really rock, especially with Swing Jazz (Big Bad Voodoo Daddy) and Blues (Buddy Guy). Well worth the investment for me, however now I got curious and went and picked up 12 Ruby Tubes (6550’s) and $250 less.

No issues at all so far with my KT88's they have done nothing but performed admirably