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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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5th May 2020, 12:13 pm | #21 |
Octode
Join Date: Jul 2008
Location: Gloucestershire, UK.
Posts: 1,043
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Re: What valve has the highest heater voltage?
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 Last edited by Mr Moose; 5th May 2020 at 12:29 pm. |
5th May 2020, 4:40 pm | #22 | |
Heptode
Join Date: Mar 2017
Location: Cedar Grove, Wisconsin, USA.
Posts: 823
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Re: What valve has the highest heater voltage?
Quote:
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. |
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6th May 2020, 11:14 am | #23 |
Dekatron
Join Date: Jul 2008
Location: Charmouth, Dorset, UK.
Posts: 3,601
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Re: What valve has the highest heater voltage?
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 |
6th May 2020, 4:57 pm | #24 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,398
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Re: What valve has the highest heater voltage?
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....
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6th May 2020, 10:25 pm | #25 |
Tetrode
Join Date: Mar 2019
Location: York, North Yorkshire, UK.
Posts: 95
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Re: What valve has the highest heater voltage?
The Eimac 8974 has a double-section heater with 640A each. That's 1280A at 16.3V ....
Max anode dissipation is 1.5MW !
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John G4FDD G-QRP 431 |
7th May 2020, 9:55 am | #26 |
Dekatron
Join Date: Jul 2008
Location: Charmouth, Dorset, UK.
Posts: 3,601
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Re: What valve has the highest heater voltage?
That's big. A pair of those would make a good linear - or maybe one.
Peter |
7th May 2020, 11:23 am | #27 |
Rest in Peace
Join Date: Apr 2011
Location: Matlock, Derbyshire, UK.
Posts: 1,378
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Re: What valve has the highest heater voltage?
Four would give a good stereo amp.
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7th May 2020, 1:15 pm | #28 |
Nonode
Join Date: Jan 2010
Location: North Somerset, UK.
Posts: 2,130
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Re: What valve has the highest heater voltage?
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. |
7th May 2020, 2:37 pm | #29 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,536
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Re: What valve has the highest heater voltage?
Wouldn't hum problems just go from 100Hz to 300Hz with 3-phase vs 1-phase ac heaters?
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7th May 2020, 3:11 pm | #30 | |
Guest
Posts: n/a
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Re: What valve has the highest heater voltage?
Quote:
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8th May 2020, 5:46 pm | #31 |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
Posts: 4,203
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Re: What valve has the highest heater voltage?
Also there's more overlap between the phases.
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9th May 2020, 10:10 pm | #32 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,536
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Re: What valve has the highest heater voltage?
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.
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