As found years ago during the first traces, the 814 is a sublime companion and remarkably linear. I traced the curves today with the uTracer with great results. From my load lines I could confirm that 10W can be obtained at half distortion compared to the 4-65a.
I will publish results shortly. …
Ale
Interesting! I’ve yet to curve an 814 on my Sofia. Relatively easy tube to find. You might want to check out it’s sibling, the 828. Similar, but with a 750v g2 rating. Would love to see your curves sometime!
Haven’t got an 828. Nice you have a Sofia tracer!
In triode mode you don’t need to worry on the G2 voltage rating 🙂
That can be valve-dependent, I suppose some are more tolerant of exceeding Vg2. I have not experimented much with Vg2 limits, so I only have others’ words to go by. Exceeding Vg2 was a concern in Morgan Jones’s Crystal Palace amplifier.
My application was different, too. I was experimenting with 828’s in PP ultra-linear.
I look forward to you experiments with the 814. A pretty bottle! 🙂
Indeed. I did some tests before connecting G2 and G3 with a 340 ohm resistor to the anode as recommended by Paul LeClerq. It worked at 600V, my power supply failed due to CCS wasn’t able to cope the HT levels (I used an existing DN2540 pair instead of 01N100D ones), but not the 814. I will redo the tests now that I have a robust power supply and a 1kV CCS to test.
The secret is in triode-strapping 🙂
Just did a quick test: G3 to cathode, G2 to anode with no resistor and cranked my bench supply to 600V. No fireworks 🙂
Will do other tests later…