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Alex Alex is offline
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Default 6N1P conflicting heater/cathode voltage specs


"Ian Thompson-Bell" wrote in message
...
I have two data sheets for the 6N1P, both Russian with English
translations, which seem to give conflicting values for maximum heater
to cathode voltages.

One specifies Ukh as +100V and -250V. As the k precedes the h I assume
these are cathode voltages relative to the heater, so this spec says the
cathode can be at most 100V positive with respect to the heater.

The other describes these parameters in words. It says: Voltage between
cathode and heater:

- with heater at positive potential 100V
- with heater at negative potential 250V

I take this to mean the heater can be up to 100V above the cathode or
250V below it, which seems to me to be the exact opposite of what the
other spec says.

So, which is right?

Cheers

Ian


I doubt it can reliably stand 250V. Quality control was not that good at
Russian factories to guarantee such strong insulation.

Also measuring cathode-heater leakage I found that Russian tubes 6N1P, 6N2P,
6N6P might have up to 10uA leakage even at about 10V between caathode and
the heater, while European, Japanese and American tubes ECC83, ECC85, etc.
leakage well under 1uA.

Excessive leakage in Russian tubes can cause hum, if cathode to ground
impedance is not low.

Regards,
Alex