[Jon Yaeger]

in article , Engineer
at wrote on 2/17/07 1:54 PM:

Hi, Vacuumlanders.
Just a speculation but has anyone built a P-P audio ampliifier with
the 6080 (6AS7) tube? (twin power triodes used as the series element
in voltage regulators)
OK, why would you want to?... it's low voltage, high current, high
bias, likely difficult to drive, you don't need to since there are
plenty of better alternatives, etc...
My answer: I have several 6080's (mostly NOS); getting bored with
designing for 6V6, 6L6, EL84, EL34, etc (well, not really!); you get P-
P in one envelope; I have a couple of spare universal replacement
OPT's (the Hammond 125E) so a choice of plate-to-plate impedances from
3000 ohm up (low enough?) is easily obtained; two O/P tubes for
stereo; and, finally, the 6080 sort of looks nice!
So, any opinions on this?... including don't bother! g
Cheers,
Roger



John Stewart is very knowledgeable about using this tube for an amplifier.

The RCA tube manual had a 6080 OTL circuit that was also without a power
transformer. I think I'd pass on that one . . .

There are a ton of 6AS7 circuits that could sub the 6080, e.g. an OTL
circuit from the 2/90 issue of Glass Electronics, etc.

Win de Haan designed what looks like a nice hybrid 6AS7G amp using a
long-tail phase stage and an E88CC driver stage; the OPT was 3.4K @ 25W.
Specs on this one a

THD @ 1W = 0.08%
5W = 0.21%
10W = 0.26%
GAIN = 20 dB
Damping = 13x
Feedback - 0 dB!


He calls it "6AS7G Push-Pull Amplifier" - 5965 & E88CC based driver stage.

Some of the other "problems" with the 6080 series include bad matching of
sections and high amperage filament draw.

You can find out Wim's contact info with Google or e-mail me.

Jon