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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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2nd Dec 2021, 8:14 pm | #1 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,007
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ID this valve.
A power-rectifier, on a 4-pin base with the pins bifurcated, 5V seems to work well as heater voltage.
Indirectly--heated cathodes but with the cathodes strapped to the heaters, which sort-of hints that it is an analog for a directly-heated precursor. There's a little 'nub' on the bakelite base adjacent to one of the four pins - presumably to give guidance whrn plugging it into its socket. Intriguingly - the two anode-assemblies are rotationally offset so that they do not face directly towards each-other; this is clearly an attempt to stop them radiating the inevitable anode-dissipation-Watts at each-other.
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2nd Dec 2021, 8:58 pm | #2 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: ID this valve.
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2nd Dec 2021, 9:58 pm | #3 |
Banned
Join Date: Jun 2015
Location: Mareeba, North Queensland, Australia
Posts: 2,704
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Re: ID this valve.
5U4 with a weird base.
Joe |
3rd Dec 2021, 2:40 pm | #4 | |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,007
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Re: ID this valve.
Quote:
It comes from a push-pull audio amp using a pair of KT66.
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3rd Dec 2021, 3:39 pm | #5 |
Dekatron
Join Date: Nov 2009
Location: Lincolnshire, UK.
Posts: 5,000
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Re: ID this valve.
I've mentioned this before regarding these old B4 valves, but there were no comments on it, so I guess nobody knows. My own findings seem to indicate that it's found on very old valves made around 1929 - unless anyone knows any different?
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3rd Dec 2021, 4:02 pm | #6 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,007
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Re: ID this valve.
I've never come across a valve with that little nub before. I guess it's to make 'blind' insertion into the base a bit easier by helping you know where oin 1 is.
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3rd Dec 2021, 4:14 pm | #7 | |
Nonode
Join Date: Aug 2015
Location: Cambridge, Cambs. UK.
Posts: 2,198
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Re: ID this valve.
Quote:
Martin
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3rd Dec 2021, 4:26 pm | #8 |
Octode
Join Date: Nov 2005
Location: Surrey, UK.
Posts: 1,874
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Re: ID this valve.
I have some very early MOV triodes (ML4 etc.) with the same type of base with the locating nub.
Given that this is an indirectly heated rectifier (so not a 5U4) I would suggest that it could be a very early specimen of the MOV type MU12 or MU14. Leon. |
4th Dec 2021, 3:13 pm | #9 |
Triode
Join Date: Jan 2011
Location: Bradford, West Yorkshire, UK.
Posts: 44
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Re: ID this valve.
Yes I've often wondered what the pip was for, I have several 4 & 5 pin valves with this feature, I wondered if it was for the radio servicing chaps, the back of a radio can be very dark to see what your doing, so the pip can easily be used to work out the pin biasing in conjunction with feeling for the screwhead or rivet securing the valve socket in the chassis.
Nearly all 4/5 bases I've come across have the same orientation & if it's wrong first time just rotate 180, no forcing/bent pins. Many noval valves use that idea, having the widest pin gap facing one of the mounting flanges, of course more difficult on skirted bases but still doable,.
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