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Can the GSG drive a pair of 6b4g's in parallel?
I search the threads but did not find a discussion on this
Thanks

You would have to make many modifications to run parallel 6B4G's.
The power transformer is not big enough for the extra current, the DC filament supply wouldn't be big enough. You'd need to change the cathode resistor system. The output transformer primary impedance would need to be half of what it is now. Not sure about the 6SL7 drive.
Seems like a lot of trouble for not much benefit.

... tom

Tom, Thanks for the information.
I was considering trying paralleling the 6b4g's since I had an extra PA060 power transformer. I would have to get the voltage down to 300V but
it should handle the current and has two 6V filament taps. You are right, probably not worth the effort.

It might be less complicated to use 300Bs, though they would require higher B+ voltage and current, in order to gain the full benefit. filaments require 5VDC at 1 A, just add a series resistor (1.2 or 1.3 ohms, 5W) to drop from 6.3VDC. Sovtek or E-H 300Bs are fairly decent quality and not too pricey.

https://frank.pocnet.net/sheets/084/3/300B.pdf

If understand correctly, the 6B4G tubes are constructed as two triodes in parallel already. They are normally thought of, and are used, as a single triode.

jwhitmor wrote:If understand correctly, the 6B4G tubes are constructed as two triodes in parallel already. They are normally thought of, and are used, as a single triode.

Yes.... and because of their construction, you'll never get them to hum balance

Use DC on them.

Cheers!

jwhitmor wrote:If understand correctly, the 6B4G tubes are constructed as two triodes in parallel already. They are normally thought of, and are used, as a single triode.

The 6B4G is a single triode.