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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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29th Oct 2020, 10:30 pm | #1 |
Dekatron
Join Date: Feb 2009
Location: Chesterfield, Derbyshire, UK.
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Strange double triode
I have just come across this ,Brimar it is a double triode ct heaters 4/5 and 9 separate cathodes , no markings on the glass ef 80 size , any idea what it is . Mick.
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29th Oct 2020, 10:32 pm | #2 |
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Re: Strange double triode
12BH7?
Cheers Mike T
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29th Oct 2020, 11:14 pm | #3 |
Dekatron
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Re: Strange double triode
That's the one cheers Mike. if only I had two ,Mick.
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30th Oct 2020, 7:18 am | #4 |
Dekatron
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Re: Strange double triode
Those anodes look a bit short for a 12BH7, but can't think what else it would be. The 12BH7 is a very handy valve, great for driving hefty paralleled OP stages. I have some Russian equivalents 6H6N, there's the ECC99 that's close too.
Andy.
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30th Oct 2020, 6:53 pm | #5 |
Dekatron
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Re: Strange double triode
I'd suggest 12BH7 too; a nice little valve - operated in zero-bias Class-B push-pull it can produce around 5 Watts of audio while making a meagre and satisfyingly-low demand on HT current - great as a modulator-stage in a simple 160-Metre-band AM transmitter!
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30th Oct 2020, 7:04 pm | #6 |
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Re: Strange double triode
We used 12BH7's in the timing circuits of traffic controllers (type54)
They were operated at just 50V of HT and easily operated post office 2000 series relays. That's why I instantly recognised it. If you look at the Brimar example in the Valve Museum I would say the plates are the same length. http://www.r-type.org/exhib/aaa0177.htm Late on (Early 80's) when these were coming out of service I did have some example with slightly longer plates but I don't recall the brand. Cheers Mike T
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Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk |
1st Nov 2020, 3:15 pm | #7 |
Rest in Peace
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Re: Strange double triode
12BH7s were used to drive the reverb spring units in several models of 50s/60s Hammond organs.
A good reliable and fairly rugged (electrically) valve IMHO. Tony. |
1st Nov 2020, 3:28 pm | #8 |
Nonode
Join Date: Jun 2013
Location: Surbiton, SW London, UK.
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Re: Strange double triode
Used in my Harmon-Kardon to drive the KT66s. Very good right into the RF spectrum,
used in some RF signal generators. |