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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, 6:48 pm | #1 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,831
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Valve equivalent
I need a 442BU rectifier valve. The R-Type web site says that a UU5 is a replacement for it. But the 442BU is directly heated and the UU5 is indirectly heated. Is that ok?
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2nd Dec 2021, 6:53 pm | #2 |
Heptode
Join Date: Dec 2020
Location: Swaffham, Norfolk, UK.
Posts: 586
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Re: Valve equivalent
Cathode tube is connected to one side of the heater, so in that respect it will be fine.
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2nd Dec 2021, 6:54 pm | #3 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,831
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Re: Valve equivalent
Please explain, thanks.
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A digital radio is the latest thing, but a vintage wireless is forever.. |
2nd Dec 2021, 7:04 pm | #4 |
Heptode
Join Date: Dec 2020
Location: Swaffham, Norfolk, UK.
Posts: 586
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Re: Valve equivalent
A circuit that uses the directly heated valve has a separate transformer winding for the heater, so there's no problem with the uu5 that has the cathode connected to one side of the heater being used.
Sorry I accidentally hit post before finishing! |
2nd Dec 2021, 8:45 pm | #5 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,535
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Re: Valve equivalent
And it'll give the reservoir capacitor an easier time on switch on since the rest of the valves will likely be coming on already as the rectifier starts to conduct. Directly heated rectifiers generally warm up faster than (indirectly heated) valves in the rest of the set resulting in a significant surge voltage on the smoothers.
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