Question to 6L6 tube experts

Who can tell me whether the NOS TungSol 6L6 WGB tubes are suitable replacements for Sovtek 5881/6L6 WGC tubes? I am a complete nube in 6L6 variety and I am afraid of making a mistake!
Type 6L6 GC can handle higher voltages, output more power and have lower transconductance than the other 6L6 variants. I would be careful about using a GB in place of a GC - it will depend on the design of the amplifier. You need to ask the manufacturer to be sure. My McIntosh MC240 is a GC design with 430V on the plates and -50V control-grid, which would be enough to shorten the lifespan of a GB significantly.

Looking at a Tung-Sol 6L6 GB datasheet I happen to have, max plate is 360V for push pull apps which would be no where near enough to be used in my amp, for example.

What amp is it you have?

This should help
Arthur: My amp is Nightingale ADM-35 integrated ( powered with eight Sovtek 5881/6L6WGC tubes.
Sorry to bump an older thread. I stumbled upon it while trying to research some questions. I have a Baldwin 6L6 tube amp that I can't find much information on.

Here are the current tubes in the amp.

3 12AU7 tubes
2 Harmon Kardon 7408(6V6GT)tubes
2 Baldwin 6L6GB tubes
1 Baldwin 54UGB tube

Max Robinson from was nice gent who responded to my inquiries very quickly & suggested that my amp should be running with 4 6L6 tubes rather than the split I have now.

I've been listening to this tube amp for some time now with the current tube complement and I really do enjoy it. It is matching well with a pair of KEF 103/3 speakers I have along with an Accuphase C-200 preamp.

Does anyone have any experience or thoughts on a quad of 6L6GB tubes vs a pair of 6L6GB and 6V6GT tubes sound quality wise? Is the 6V6GT tube close to a 6L6GB tube in terms of SQ? Would I be gaining a lot by going to a quad of 6L6GB tubes?

The reason I ask is that I can't find any other info on the Baldwin tube amp I have and I have no idea on how to rebias it should I want to change power tubes. That and I don't know if the current tube complement I have is what is meant for it. As of right now I don't have the funds to take it to a quality tech for review. Also a wallet friendly matching NOS quad of 6L6GB tubes is hard to find too.

Thanks in advance.
Jedinite24, as per articles by Jeff Day and others I would contact Jim McShane, inquire about the NOS 6L6 Russian tube 6N3C-E also known as a 6P3S-E, cost is around $65.00 per quad, very reliable and sound great! I have a quad in my Primaluna Dialogue 1 and they completely transformed that unit. Read Jeff Day Blog, he has them in his Leben amps. Jeff wrote on them at 6 Moons.
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I use new Gold Lion kt66 in my Eico's and they are wonderful.
I didn't think KT66 tubes were an exact replacement for 6L6GB tubes. Thanks for the lead Mcgarick. I'll have to do more research.