by EWBrown » Fri Oct 24, 2008 7:56 am
The cathode will be positive in reklation to the "ground" buss, effectively making the grid voltage negative in relation to the cathode.
-10V G to K voltage will give you a pretty low plate / cathode current with a paralleled 6SN7, I'd SWAG that 1K or eevn less, would get you closer to ideal operating conditions.
The 6BL7 can handle a combined plate dissipation of 12W for both sections, or 10W for a single section in TV vertical deflection usage, which is serving "hard time"... , though this can be pushed somewhat higher for audio use. The 6SN7 is good for about half of this rating.
I chose 6BL7GTA only because I have a quantity of them, 6BX7 is also good, but then I only have one on my collection, and it has been used hard and long, so it is near being "comatose". These seem to be harder to find at the fleas and swaps.
Another possibility is the older metal-shell 6N7, but the pinout is different, as it has a shared cathode for both sections. 6N7 is the ancestor of 6SN7 and 6BL7.
/ed B
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