[jbryngelson]

I have a pair of DIY/Custom Mono Block tube amps that will have new 6550 tubes (Groove Tubes baby) coming in a week or so. I have been told the amps are tested and able to handle KT-88/120/150. They also will have a switch to allow for either Pentode or Triode mode with a tube based screen regulator. What tube would you spend $ to get the most out of them??  Where would you find your recommendation? TIA - Jeff in Detroit

[FullRangeMan]

I have a pair of DIY/Custom Mono Block tube amps that will have new 6550 tubes (Groove Tubes baby) coming in a week or so. I have been told the amps are tested and able to handle KT-88/120/150. They also will have a switch to allow for either Pentode or Triode mode with a tube based screen regulator. What tube would you spend $ to get the most out of them??  Where would you find your recommendation? TIA - Jeff in Detroit

Congratulations seems a nice amp, a Triode/Pentode switch is great since Pentode are better sound than UL. Favorite shops are Upscale and VTS, Andy at VTS have large experience and answer customers by the phone.

You will find that the best ones have a price, KT88 GENALEX Made in England are famous great sound also KT88 Svetlana C-Logo, however beware of the fakes on these famous tubes and rebranding, buy on a reliable shop.

[jbryngelson]

Thanks, I will give Andy a call.  I have heard great things about upscale audio. Sounds like Andy offers a fairly liberal return policy.  Might make for some really cost effective tube rolling! 

[twitch54]

For years Jim has been my 'go to' guy for tube recommendations.........

http://www.mcshanedesign.net

[opnly bafld]

For years Jim has been my 'go to' guy for tube recommendations.........

http://www.mcshanedesign.net

+1

[jjss49]

i believe the russian made genelax gold lion kt88's are the best among the direct 6550c subs on the market today (leaving aside more powerful versions like kt120 kt150 etc etc)

[mick wolfe]

For years Jim has been my 'go to' guy for tube recommendations.........

http://www.mcshanedesign.net

Yep, I'll only buy Genalex Gold Lion KT 88's from Jim. And yes, that tube is my favorite of the 6550 family mentioned by the OP.

[Tubefly]

For years Jim has been my 'go to' guy for tube recommendations.........

http://www.mcshanedesign.net

Ditto

[rpf]

Congratulations seems a nice amp, a Triode/Pentode switch is great since Pentode are better sound than UL. Favorite shops are Upscale and VTS, Andy at VTS have large experience and answer customers by the phone.

You will find that the best ones have a price, KT88 GENALEX Made in England are famous great sound also KT88 Svetlana C-Logo, however beware of the fakes on these famous tubes and rebranding, buy on a reliable shop.

The original Genalex KT88 (England) are pretty much unavailable NOS now. If you could find a set - which is very unlikely - they would be astronomically expensive. What's more many say (including the well respected Jim McShane mentioned above) that the Genalex KT88 re-issue are their equal or superior. I've never heard the original but the re-issues are indeed very good. I did however prefer the Shuguang KT88 SC (previously sold as the Penta KT88 SC and now sold by TheTubeStore under their Preferred Label). The latter is a bit more refined than the Genalex. However I'd like to re-try the Genalex, cryo'd this time from Upscale Audio. That might close the gap between the two brands and Upscale has a stricter selection process than the other company.

The Svetlana "Winged C" line hasn't been made in several years (a shame as they - particularly the 6550 type - were superb) and the quality stocks of those tubes are long gone. The factory released some lower quality tubes at the end of their run and those are the only ones still floating around. Not recommended.

I haven't cared for the Tung-Sol re-issue power tubes. I've tried their 6L6GC and 6550 (tubes I normally love), and KT120. The first and third variety in a Rogue Cronus Magnum and the second in a pair of Quicksilver Mono 100s. All of these tubes had an overemphasized, even thick, bass. In fairness I don't recall hearing this in a pair of Rogue Apollo mono-blocks running KT120s I listened to one afternoon.

Aside from the above, it might be worthwhile trying the Sovtek 6550s from Upscale. They have been intriguing me for a while now as I always preferred the 6550 to the KT88. I'll buy them cryo'd if I do order them.

If your amp can take them and you don't need the extra power, the Genalex KT66 re-issue is excellent. Even better is the Reflector 6P3SE (6L6GC equivalent) which is getting a little hard to find now.

Good luck.

[jjss49]

mick wolfe can speak for himself but i don't think he meant original uk made and branded genalex gold lions...  he meant current russian made ones sold under the purchased trademarks

[rpf]

mick wolfe can speak for himself but i don't think he meant original uk made and branded genalex gold lions...  he meant current russian made ones sold under the purchased trademarks

I quoted Full Range Man - who was referring to the originals - not Mick Wolfe.

[jbryngelson]

Great Info.  I will sort through this and try at least one set of Genalex KT88s RPF mentioned, and a set of Sovtek 6550s.  I need to talk to Andy as he is in my area, so I will put some trust in him first.  Thanks.  My amps are designed to handle power upto the KT150s, so I am confident I can go up and down the KT line.  The Triode/Pentode switch will be interesting.  My 6ohm 87db sensitive speakers may have a strong preference for one over the other - we shall see.

[mick wolfe]

mick wolfe can speak for himself but i don't think he meant original uk made and branded genalex gold lions...  he meant current russian made ones sold under the purchased trademarks

Thx. Yes, I certainly meant the new re-issues. I'd never pay what's asked for "supposedly" NOS power tubes.

[Tyson]

I've always felt the new Russian tubes were a bit dry in the mids.  I recommend the Psvane Ti series for KT88's.

[jjss49]

using old stock pentodes like 6550's are truly for those with more money than sense in this day and age 

[FullRangeMan]

I think similar, most tube audiophiles persist year after year using commercial grade tubes at high prices to 2000 hours time life while there are top quality Russian military tubes at $20usd each.

[ASMAN]

+2 for Jim McShane.
I only buy power tubes from him. Haven't gone wrong yet. Stick with a reputable dealer.
I like the GL re-issues for KT88. I will try the Shuguang some day. I have heard good things about them.
As a close second is Tungsol KT 120. Last place for me is Tungsol 6550.

[thorman]

I will second on the Russian Reflector 63PSE . Incredible tube and hard to find but worth it if/when you do..It is all about System Balance and in the Leben CS600 I found this Reflector tube out did all others mentioned. Your mileage may vary, but if you can find a nice Quad of the Reflectors, they are worth every penny.

[FullRangeMan]

I will second on the Russian Reflector 63PSE . Incredible tube and hard to find but worth it if/when you do..It is all about System Balance and in the Leben CS600 I found this Reflector tube out did all others mentioned. Your mileage may vary, but if you can find a nice Quad of the Reflectors, they are worth every penny.

Seems Russian Reflector 63PSE is a typo, you may referring to the 6P3S or 6P3S-E or 6n3c-E which are plenty available at GSTubes from Reflector or Foton at low prices, which are definitely good news.
http://www.gstube.com/catalog/?key=6p3s&submit=Find

[Tom Bombadil]

Seems Russian Reflector 63PSE is a typo, you may referring to the 6P3S or 6P3S-E or 6n3c-E which are plenty available at GSTubes from Reflector or Foton at low prices, which are definitely good news.
http://www.gstube.com/catalog/?key=6p3s&submit=Find

It should be noted that the 6P3S-E is not a 6550 equivalent.  It is a 5881 / 6L6GB equivalent with a 19 watt plate limit. 

In my amps I find the new Gold Lion KT88 to be superior to the 6P3S-E.