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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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5th Nov 2022, 5:33 pm | #21 |
Dekatron
Join Date: Jan 2003
Location: Bradford on Avon, Wiltshire, UK.
Posts: 3,310
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Re: High Voltage Variable Bench Power Supplies?
I have dug out the HT PSU with the three 6BW6 in parallel and taken some pics of it and the reverse engineered circuit. Is it OK to post them on this thread or shall I start another?
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7th Nov 2022, 11:24 am | #22 |
Octode
Join Date: May 2010
Location: Grantham, Lincolnshire, UK.
Posts: 1,177
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Re: High Voltage Variable Bench Power Supplies?
I have bought all sorts of high voltage PSUs to test valves, but 1000V at 1A is just too frightening to fix.
Then had some Roband Varex 60/1 (60V at 1A twice) PSUs, got a manual and found that you can both series and parallel these. Connected 2 in series, so maximum of 240V, the dual sections in each can be connected in series, and powered on. I was astonished, the full current limiting was available and working. From memory these PSUs can be stacked up to 500V maximum. Ended up buying any Roband PSU that came up for sale, have enough now, but the idea that it will allow a misconnection of heater across HT is really nice. The variable voltage is easy, it is the current limiting to tens of milliamps that is unusual. |
7th Nov 2022, 1:48 pm | #23 | |
Heptode
Join Date: May 2015
Location: Bradford, West Yorkshire, UK.
Posts: 512
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Re: High Voltage Variable Bench Power Supplies?
Quote:
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worried about the electrons entering the circuit and the smoke leaving Andrew Last edited by Andrew B; 7th Nov 2022 at 1:55 pm. |
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7th Nov 2022, 4:54 pm | #24 |
Dekatron
Join Date: Sep 2007
Location: Oxfordshire, UK.
Posts: 4,311
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Re: High Voltage Variable Bench Power Supplies?
A few tens of milliamps can shock you to death, as can a few tens of joules stored in that capacitor you charged from a 1mA supply. The trick is to keep the resistance of any circuit in which you play a part high (preferably tending towards infinite) . 1000V and 1A can start a decent fire pretty quickly though.
Cheers, GJ
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14th Nov 2022, 3:44 pm | #25 |
Hexode
Join Date: Apr 2007
Location: W Yorks, UK.
Posts: 407
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Re: High Voltage Variable Bench Power Supplies?
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15th Nov 2022, 7:34 am | #26 |
Dekatron
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 7,670
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Re: High Voltage Variable Bench Power Supplies?
For a 0 - 450v 500mA supply see Pete Millet's DIY supply that uses 5 807's - http://www.pmillett.com/HV_bench_supply.htm
Re pass devices in HV supplies I've read that BJT's are better than switching mosfets but now you can get linear mosfets though they aint cheap - https://www.microsemi.com/product-di...fet/732-linear IXYS do some - https://www.digikey.co.uk/en/product...ear-l2-mosfets which looking back through the thread is what Thatvalveguy used in his PSU post #7. Andy.
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15th Nov 2022, 7:08 pm | #27 |
Triode
Join Date: May 2020
Location: Cambridge, Cambridgeshire, UK.
Posts: 34
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Re: High Voltage Variable Bench Power Supplies?
I've got one of these. Seems to work OK and output seems stable. I've wired in one of the cheap voltmeter displays so it is easy to set and monitor the output.
Of course like anything high voltage needs to be treated with respect and with the usual precautions |