Super 6BG6 vs. 6550

[wrenchone]

I've been doing a fair bit of messing about with amps incorporating a non-standard tube set, like the 6LR8 and screen-driven sweep tubes. I have a hankering to do a standard-issue triode-connected pentode amp, especially as I have a pair of 3k impedance Transcendar SE output transformers looking for gainful employment. These transformers have no screen taps, so UL is out of the question.

I have a bunch of the super 6BG6 tubes on hand as well as a quad of Reflector 6550WCs. Which is more likely to be the best sounding tube triode-connected?

[SY]

No SE experience here, but in PP, the 7027.... errr... super 6BG6 was quite a bit better than some NOS Tung-Sol 6550s I tried.

[wrenchone]

Very interesting, SY - according to scuttlebutt, the Tung-Sol 6550s are supposed to sound preety nice, so bettering them for a fraction (and a small fraction, at that) of the price is a real coup. What sort of output iron were you using?
On another note, do you think that the screens on the 6BG6/7027 would be troubled excessively by 400V B+?

[SY]

They'll laugh at 400V. I'm running them at 500V with no sweat. OPTs are Eico, 6k6 p-p.

[Original Burnedfingers]

I'm running matched 6BG6GA's in my Quicksilver converted 8417 amps in place of 6550's or KT88's. I'm also running 6BG6GA's in my Dynaco stereo 70.

I have learned to listen to SY. I just ordered another Quad of them and should receive them in todays mail.

[whitelabrat]

I'm using 6BG6GA's along with Hammond 1628SEA OPT's.

I compared them to SED EL84's, Shuguang 6L6GC's, and old Chinese KT88's. The 6BG6's won by sound and price. I had four, and then bought a bunch more.

On the same note I also tried some old Sylvania 8417's. Those were the best yet, but good luck on finding any.

[wrenchone]

Which curves come closest to approximating the behavior of the super 6BG6 in triode mode? I want to get an idea as to what sort of bias winding I'll be needing on my power supply. I've been looking at the GE 6L6GC curves for clues.

[GordonW]

Look for the Sylvania 6L6GC STR curves if you can find 'em. That's about the closest thing I know, to the plate structure in the "super 6BG6". Should work fine as a modeling tool...

BTW: I'd order a set of these... if I didn't already have a quad of Sylvania STRs... kinda obviates the need, I guess...

Regards,
Gordon.

[SY]

Originally posted by wrenchone
Which curves come closest to approximating the behavior of the super 6BG6 in triode mode? I want to get an idea as to what sort of bias winding I'll be needing on my power supply. I've been looking at the GE 6L6GC curves for clues.

http://frank.pocnet.net/sheets/049/7/7027A.pdf

These worked for me.

[Ohighway]

SY and Burnedfingers. Can you guys please contact me via email?

I've got several questions to ask about using the 6BG6GA tubes in a couple amps. I'd like to try them in my Quicksilver 8417 amps as I just don't want to have to deal with the 8417 issues, and because the EL34 conversion just doesn't sound promising. I'd also like to try them in a Stereo 70.... well..... just because.

thanks.