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19th Jan 2018, 3:59 pm | #1 |
Hexode
Join Date: Aug 2010
Location: nr. Hannover, Germany
Posts: 372
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Wanted: Circuit for HV PSU
Mods - If this is better in the wanted section please transfer.
I am looking to build a simple HV PSU - Input ca. 300V Output ca. 150-250 V variable. Current ca. 70mA, max. 100mA. Can anyone point me in the direction of a suitable circuit using EL34 or EL84 or similar as pass regulator. Many thanks
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Eddie BVWS Member. Friend of the BVWTM |
19th Jan 2018, 5:06 pm | #2 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,642
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Re: Wanted: Circuit for HV PSU
I'm sure members will have plenty of suggestions, but this simple search returns a good selection of design ideas: https://www.google.co.uk/search?q=va...w=1280&bih=873
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19th Jan 2018, 5:39 pm | #3 |
Dekatron
Join Date: Sep 2007
Location: Oxfordshire, UK.
Posts: 4,311
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Re: Wanted: Circuit for HV PSU
You can learn a lot from reading this piece by Steve (now Stephie) Bench http://diyaudioprojects.com/mirror/m...ench/reg1.html
Cheers, GJ
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19th Jan 2018, 5:58 pm | #4 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,511
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Re: Wanted: Circuit for HV PSU
Copy one of the Solartron circuits in this manual.
Andy |
19th Jan 2018, 7:45 pm | #5 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,998
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Re: Wanted: Circuit for HV PSU
Rather than using audio-valves (whose characters are somewhat less than ideal) for the series-paqss circuit, remember that there were valves specifically designed for this duty.
The 6080 being probably the most well-known example. http://www.r-type.org/exhib/aaa0725.htm Sample circuit [by RCA] using one is shown here: http://www.gammaelectronics.xyz/audi...ulated-PS.html |
19th Jan 2018, 7:50 pm | #6 |
Dekatron
Join Date: Sep 2007
Location: Oxfordshire, UK.
Posts: 4,311
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Re: Wanted: Circuit for HV PSU
Yes. If you were thinking of using an EL84 then an EL86 - similar in lots of ways but purpose-designed as a pass valve - would be a better alternative. And unlike the '84s the '86s are dirt cheap.
Cheers, GJ
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19th Jan 2018, 8:40 pm | #7 |
Rest in Peace
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Re: Wanted: Circuit for HV PSU
I realise you did state that you are looking for a valved PSU. But would a transistor type be of any interest?
Al. |
19th Jan 2018, 9:34 pm | #8 |
Hexode
Join Date: Aug 2010
Location: nr. Hannover, Germany
Posts: 372
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Re: Wanted: Circuit for HV PSU
Guys, thanks for your replies, plenty to study over the weekend.
Al, in this day of cheap FETs more than suitable for the job, it would seem the sensible option, however nostalgia rules and I would like to see filaments glowing I basically want to build a small general power supply suitable to power my small valve projects during the development/construction phase.
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Eddie BVWS Member. Friend of the BVWTM Last edited by eddie_ce; 19th Jan 2018 at 9:35 pm. Reason: spelling |
19th Jan 2018, 10:17 pm | #9 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,535
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Re: Wanted: Circuit for HV PSU
If you don't need high stability HT, what about a variac feeding a simple rectifier-filter supply?
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20th Jan 2018, 12:19 am | #10 |
Banned
Join Date: Jun 2015
Location: Mareeba, North Queensland, Australia
Posts: 2,704
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Re: Wanted: Circuit for HV PSU
Although it doesnt use audio bottles, it does work exceptionally well, and just about fits what you were after.
Joe |
20th Jan 2018, 1:44 pm | #11 |
Hexode
Join Date: Aug 2010
Location: nr. Hannover, Germany
Posts: 372
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Re: Wanted: Circuit for HV PSU
Thanks for that Joe, looks more or less just the job
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Eddie BVWS Member. Friend of the BVWTM |
20th Jan 2018, 3:07 pm | #12 |
Pentode
Join Date: Jan 2014
Location: Huddersfield, West Yorkshire, UK.
Posts: 129
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Re: Wanted: Circuit for HV PSU
on cheap valves
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20th Jan 2018, 3:50 pm | #13 |
Dekatron
Join Date: Sep 2007
Location: Oxfordshire, UK.
Posts: 4,311
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Re: Wanted: Circuit for HV PSU
Since the heater supplies for the two valves share a common 6.3V transformer winding it might be worth biasing that at some voltage between the HT output and ground. Otherwise the limit on Vhk is likely to be breached either for the EF80 (150V) or the PL504 (250V). Also if the supply's output really does go up to 370V then the EF80's Vak limit (300V) will be breached, although not by much.
Cheers, GJ
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20th Jan 2018, 4:47 pm | #14 |
Pentode
Join Date: Jan 2014
Location: Huddersfield, West Yorkshire, UK.
Posts: 129
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Re: Wanted: Circuit for HV PSU
Circuit is a kind of idea (however its work) of course biasing EF80 is necessary
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20th Jan 2018, 5:59 pm | #15 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,998
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Re: Wanted: Circuit for HV PSU
Small heater transformers are cheap: in the past when I've used valves like the 6BW6 807 or EL34 as "series gate" screen-grid AM modulators - where the cathode can often be running at 350V above ground (which is well beyond their rated H-C insulation spec) - I've just used a separate heater transformer and strapped the cathode to one of the heater-pins so everybody's happy.
A classic big juicy ex-Admiralty HT transformer often had a couple of specially-well-insulated 0-5-6.3V-at-a-couple-of-amps windings designed to feed directly-heated rectifiers; these can be used to supply 'floating' heater power if you're using silicon diodes as the main HT rectification. In the past there were also special 'high voltage insulated' heater-transformers available, designed for CRT duty: RS/RadioSpares had a range... |
20th Jan 2018, 9:20 pm | #16 | |
Rest in Peace
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
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Re: Wanted: Circuit for HV PSU
Quote:
Al. |
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20th Jan 2018, 9:53 pm | #17 |
Nonode
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,573
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Re: Wanted: Circuit for HV PSU
Hi Al.
I'd be most interested in seeing your variable regulated HV power supply circuit if you don't mind sharing it with us. Regards Symon. |
20th Jan 2018, 10:11 pm | #18 |
Banned
Join Date: Jun 2015
Location: Mareeba, North Queensland, Australia
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Re: Wanted: Circuit for HV PSU
In designing a new valve tester, I collected at least two dozen variable power supply designs. I spent a couple of months going through every electronic construction magazine on Americanradiohistory.com. None of them is as elegantly cheap and functional as the little Electronics Australia design though. I have downloaded most of those designs if you want more. I have the origional magazine for Electronics Australia .
Joe |
20th Jan 2018, 10:53 pm | #19 |
Rest in Peace
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
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Re: Wanted: Circuit for HV PSU
Symon - O.K., fine! I'm flattered that someone wants to see it!
Below is a technical description of how it works; cct. diag.; a few design remarks; photos of the front and the insides. The cct. diag. drawing is a bit rough since it is a copy of a copy (it was originally intended for my eyes only, afterall ) and I had to reduce the resolution to fit the requirements of this forum. But I think it is readable. The next post has a photo. of the control board. Al. Last edited by Skywave; 20th Jan 2018 at 11:07 pm. |
20th Jan 2018, 11:02 pm | #20 |
Rest in Peace
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
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Re: Wanted: Circuit for HV PSU
Photo. of control board.
"Huh? Transistors to tag strip?" I have been asked before. Reason: ease of prospective corrective maintenance: hopefully,that need will never arise! Al. |