Some quick numbers I gathered this morning. Bypassed 150 ohm cathode resistor. Adjusted DC current by measuring 100 ohm resistor at the plate and using a variable HV DC supply. Put 100mV 1kHz signal at grid. Measured AC across said 100 ohm resistor. 6N1P is a variant, of course. Actually surprised at how well it does at higher currents. Definitely needs rebiasing and not a drop in sub, fwiw. Note: these are just Gm tests. I kinda recall the EH being the most linear last time I monkeyed with these tubes and the 80's JAN as not-so-hot. I'll get back around to that as I'm tweaking a phono stage. Just was curious the drop in Gm below 10mA.
Obviously I'm violating some maxes here (nice plate dissipation on the 6N1P for example) so I wouldn't choose those as standard operating points. I was just swagging a fast test. I also want to retest some of these with +10% on the filament. Presume that that will be worth it.
- Shannon
6922 JAN Mar-86
54.5V 5mA 8710
78.8V 7.25mA 9660
103.2V 10mA 10480
125.6V 12.5mA 11090
147.8V 15mA 11790
JJ E88CC ~2004
46.4V 5mA 8740
68.9V 7.25mA 9740
90.8V 10mA 10460
112V 12.5mA 11060
133.5V 15mA 11530
EH 6922EH
43.6V 5mA 8380
64.6V 7.25mA 9180
84.9V 10mA 9800
103.6V 12.5mA 10360
124.2V 15mA 10780
6N1P 04 06 Svetlana Rebadge
108.1V 5mA 4940
142.9V 7.25mA 5570
176.2V 10mA 6050
207.2V 12.5mA 6450
238V 15mA 6820