6A6 double triode.

[Geordie McBoyne]

Any experiences of the 6A6 twin triode? Checking out eBay there still seems to be plenty available at low prices.
The 6A6 which has a 6.3 volt heater and the slightly older type 53 which has the 2.5 volt heater are general purpose double triodes. As a push-pull output valve 10 watts is possible. The valve operates at zero grid bias and 300 volts on the anodes.
Link to the Radiomuseum: http://www.radiomuseum.org/tubes/tube_53.html The circuit of the push-pull output stage is shown on this page.
The driver triode is another type 53 or 6A6 with both sections in parallel.
The electrically identical 6N7 has the international octal base.
I am considering this valve as the CRT deflector plates drivers for a future TV construction project.
The 53, 6A6 and 6N7 can be used for other purposes such as a normally biased AF amplifier. It was used in the timebase oscillators in many American TVs.
The valve does have some disadvantages, high heater current @ 0.8amp and a common cathode connection.

Geordie McBoyne.

[pwdrive]

Dr Wobble on 'tother forum was doing something with a 6N7, did you see the thread? He might have more info.

Lawrence.

[Geordie McBoyne]

Dr. Wobble is considering the 6N7 as a cathode follower.
It's a quite extraordinary valve, in a zero bias push-pull output stage it draws something like 33mA anode current and in a normally biased audio amplifier about 6mA Ia.

6N7 is the metal version. Glass bulb types are the 6N7G and 6N7GT.

Geordie McBoyne.

[Ed_Dinning]

Hi David, you may need to consider the A to A max volts if being used as a TV deflection amp, especially if you are using a high tube EHT.

Ed

[Geordie McBoyne]

Hi Ed,
The CRT will be the VCR97 or something similar, likely the EHT will be <4KV. Looking at the circuits of the timebases of post war small screen American TVs they were getting away with 6SN7GT and 6SL7GT double triodes as the deflector plate drivers. Also used in many early RCA TVs with electrostatic defection CRTs, the 6F8G: http://www.radiomuseum.org/tubes/tube_6f8g.html

A timebase valve used for larger screen TVs with electrostatic CRTs was the Mazda AC/P4.
http://www.radiomuseum.org/tubes/tube_acp4.html Good for 700 volts on the plate.

Geordie McBoyne.

[Murphyv310]

Hi.
I have a few 6N7's here, one valve I have never really used.