This week we have gone big! The mighty 845 (or it's equivalent the 211 or VT-43) is a directly heated triode.
Originally designed as a radio transmitter valve, now favoured by audiophiles, it has some massive stats. Listen to this, from the RCA data sheet:
Base: Jumbo 4 pin
Maximum anode volts: 1250
Anode dissapation: 100 watts!
The anode or plate is machined from solid graphite to avoid physical distortion at maximum power. To emit enough current the cathode filament consumes 3.25 Amps at 10volts and the recommended grid bias is a whopping -145 volts.
Because the cathode is thoriated tungsten, broken tubes should be treated with care. Thorium is both radioactive and very toxic.
Originally made by RCA in 1931, the 845 is still in production in China and now manufactured with either graphite or metal anodes.
Originally designed as a radio transmitter valve, now favoured by audiophiles, it has some massive stats. Listen to this, from the RCA data sheet:
Base: Jumbo 4 pin
Maximum anode volts: 1250
Anode dissapation: 100 watts!
The anode or plate is machined from solid graphite to avoid physical distortion at maximum power. To emit enough current the cathode filament consumes 3.25 Amps at 10volts and the recommended grid bias is a whopping -145 volts.
Because the cathode is thoriated tungsten, broken tubes should be treated with care. Thorium is both radioactive and very toxic.
Originally made by RCA in 1931, the 845 is still in production in China and now manufactured with either graphite or metal anodes.
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