7581A/KT66 recommendations?

[scottfan]

I'm looking for new power tubes after testing 50 year old 7581A's, in my Scott 296. With a Hickok 800, all 4 were 7500-8500 mhos - 5900 being the minium. On the emmission tester they were 57-62%. The tubes still sound great but was thinking about buying NOS 7581's, Gold Lion KT66 or Shuguang Treasure KT66Z's. The NOS(when found) and Treasure run roughly same price. GL's would be cheapest.

Anybody have experience KT66 with Gold Lions or Treasure series tubes?

Thanks.

 

[skriefal]

I assume that the reference to 7591A in the first sentence is a typo. 7581/KT66 are not compatible with 7591A.

Unfortunately I have no experience with the 7581/KT66 tubes that you are looking at.

 

[scottfan]

Yea, 7581 (so used to typing 7591 lol). The 7581A is a 6L6GC based tube, but supposedly hotter and designed for audio applications. Strange though, the 7581A looks IDENTICAL to the same vintage GE 6L6GC which I've also run in the 296 - have 2 spares.

Was leaning towards the Treasure but don't like sending/giving China anymore business.

 

[Bluelobster]

Yea, 7581 (so used to typing 7591 lol). The 7581A is a 6L6GC based tube, but supposedly hotter and designed for audio applications. Strange though, the 7581A looks IDENTICAL to the same vintage GE 6L6GC which I've also run in the 296 - have 2 spares.

Was leaning towards the Treasure but don't like sending/giving China anymore business.

Outside it does but the grids, which you can't see, are beefier to handle to higher voltage and current.
You could also try the Svetlana 6l6gc as they will handle the voltages handily and really do sound good. I was using them in my Citation V when old stock 7581a were going through the roof. After hearing them and comparing to the GE 7581a I do have I figured why bother to chase old.
I am curious to hear any responses you get as I would be interested in the Gold Lion myself.

 

[GordonW]

Bluelobster, I assume you mean Winged C 6L6GCs? The new "Svetlana" (made in the Reflektor factory) are the virtual same as EH 6L6GCs or Sovtek 6L6WGBs and such...

If so, I will concur... the Winged C 6L6GC is pretty good.

As for the similarity between the GE 7581A and the GE 6L6GC- that's no surprise- in later years (mid-late 1970s), GE looks to have consolidated some of these tube types, for cost-cutting. It was cheaper to just run one line of 7581A "guts" and label them as both 6L6GC and 7581A... since the 7581A was heavier anyway, it worked fine in anything specified for 6L6GC. So, many of these later GE 6L6GCs did indeed get the 35 watt plate structure.

Regards,
Gordon.

 

[Bluelobster]

Bluelobster, I assume you mean Winged C 6L6GCs? The new "Svetlana" (made in the Reflektor factory) are the virtual same as EH 6L6GCs or Sovtek 6L6WGBs and such...

If so, I will concur... the Winged C 6L6GC is pretty good.

Gordon I stand corrected. These days they are Winged "C" 6l6gc.

 

[diamondsouled]

I am running the KT66 GL reissues in my Quad II amps and they sound quite decent. If I could afford it I'd be running gray glass KT66 originals but ...

Cheers

Lar

 

[JonL]

I have some 7581A and Winged C 6L6GC experience in guitar amps from around 15 years ago. (Guitar amps are different animals, so YMMV.) IME the Winged C was the best of the new production tubes available at the time (mine were original Svetlanas). They sounded pretty good, but not as good as RCA blackplates which are magical in Fender amps. After finding some RCAs I took out the Winged Cs. I also have some Sylvania 7581As running in a Super Reverb. I'd say they have a similar sound to the Russian tubes. The RCAs have superior low end (which isn't all that low in a guitar amp) and have a way of responding to the guitar (and player) dynamics that other tubes can't match. Biased on the hot side, they have harmonically rich sustain and can provide beautiful controlled feedback when pushed hard. These are not factors in a hi fi application. The Russkies and Sylvanias are perhaps more balanced tonally, more "hi-fi" sounding, and stay cleaner and more neutral even when pushed hard. The Russian tubes were very cheap when I got them, I don't know how they are priced today, but I think they're worth trying. Are 7581As getting very expensive now? I haven't checked pricing in a long time.