Tube DIY Asylum

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ECC99 Pin 9 confusion

Posted by banpuku on February 14, 2017 at 09:38:00:
I am confused about the filament heater wiring for pins 4, 5 and 9. I have read various information on the audio blogs and no definitive answer.

I want to use only 1/2 of the ECC99 with a 6.3V for the heater. So, which pin(s) should get the heater voltage (pins 4 only, 4 and 5, 4 and 5 tied together)? Where should I connect pin 9?

Any help would be greatly appreciated. I will be doing a nice write-up on the ECC99 and 2A3 tubes for Audio Asylum in the near future. Thus, I want to ensure that the tubes are connected correctly and biased optimally.

Thanks, Pat.