What valve has the highest heater voltage?

[Mr Moose]

Hello,
I believe the wire mesh is an electromagnetic screen (presumably operating on the Faraday's cage principal), rather than a safety screen.
Yours, Richard

[usradcoll1]

Originally Posted by Craig Sawyers

The 117Z4 was an octal based rectifier with 117V heater.

Craig

I only saw one radio that used a 117Z4, as most used a 117Z6, a dual rectifier, with both halves tied together.
I had a old Motorola pre-war suitcase portable that used one. The heater used to flash brightly when the set was first turned on, but never burned out.
Back in the early 50's that tube was $4.35, which was rather expensive.
Dave, in this too long! That was over 65 years ago.

[Peter.N.]

The highest voltage heater I remember here is the 50CD6, line OP valve in KB sets, likely made at the same factory in Foots Cray - that's where Brimar valves were made.

Peter

[turretslug]

On a tangent, I wonder which valve had the highest heater current! The sort of thing that russell w b might have encountered, or maybe someone who worked on Duga-1 follows the forum....

[Granitehill]

The Eimac 8974 has a double-section heater with 640A each. That's 1280A at 16.3V ....
Max anode dissipation is 1.5MW !

[Peter.N.]

That's big. A pair of those would make a good linear - or maybe one.

Peter

[TrevorG3VLF]

Four would give a good stereo amp.

[broadgage]

Some very large valves for broadcast transmitters not only used heater currents of hundreds of amps, but a few even had three phase heaters.
This saved providing large and expensive rotary converters for DC heaters and avoided line frequency hum from single phase.

The largest heater currents that I have met personally was about 20 amps at 4 volts for large directly heated power rectifiers.
These had a screw base like a lamp for the cathode and a top cap anode.

[Herald1360]

Wouldn't hum problems just go from 100Hz to 300Hz with 3-phase vs 1-phase ac heaters?

Wouldn't hum problems just go from 100Hz to 300Hz with 3-phase vs 1-phase ac heaters?

Yes, but the heater's time constant comes into play. much much less variation at 300Hz than 100Hz.

[Maarten]

Also there's more overlap between the phases.

[Herald1360]

Only if you're rectifying the three phase or you have something like three separate heaters, one for each phase which are effectively trifilar in arrangement.