View Single Post
  #4   Report Post  
Posted to rec.audio.tubes
Patrick Turner Patrick Turner is offline
external usenet poster
 
Posts: 3,964
Default 6N1P conflicting heater/cathode voltage specs



Ian Thompson-Bell wrote:

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


Probably all is misleading.

I'd never run a cathode at a dc potential of more than +/- 70V with
respect to the heater.

So if you have a CF where the cathode swings maybe 135Vrms, as might be
the case if driving
an 845 grid in class AB2, then be prepared to have the filament and its
voltage supply and transformer winding
also swing as well, which may mean you also need a screened tranny
winding to prevent stray C coupling to the mains.

Never believe all the BS about heater to cathode voltage ratings, and
don't
tempt fate by allowing more than +/-70V peak to ever exist.

Patrick Turner.