10Y

Output

The choke I used is a 20H/50mA choke by Bartolucci. It was not intended to be used with a high Rp/low current tube such as the 10Y. I had it set up at a bias of 350V/15mA and a 1K6 ohm resistor in the cathode.

Square wave performance

Left is the 50kHz and right is the 100kHz. Not too good above 50kHz. I can't tell if this is because of the choke or if it's something in the rest of the circuit.

Left the 40Hz and right the 100Hz square wave. Not bad, nothing to write home about either.

Bandwidth

Due to the low induction value of the choke for a tube with such a high Rp (5K), the roll off in the low range is premature. Would I use a choke of say 80H the low end would be extended much further. It is therefore not possible to make any judgments on what the circuit does in this area.

The high end however is not too bad. 3dB point is at 192kHz, with a plate choke !!!