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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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30th May 2020, 1:23 am | #1 |
Banned
Join Date: Jun 2015
Location: Mareeba, North Queensland, Australia
Posts: 2,704
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NOS capacitors
So the capacitors that I ordered a couple of months ago have arrived. PIO military types.
They were made around 1964 ( a few different dates). So I have measured them and they would seem perfect for my audiophoolery . Circuit requirements call for .5Uf coupling capacitors, so I will parallel two of these up to give me something very close to that value. There are only two capacitors in the audio path, those being the couplers from the phase splitter to the driver valves fot the push/pull output quad. I did notice that they have quite high inductance, and with a bit of thought I will parallel them in opposite directions to try and counter that somewhat. Initial tests show I can reduce that inductance to almost zero. So I have a couple of questions!. Does my audiophoolery thoughts on reducing that inductance make sense, or am I just being silly?. Note the glass end seals on these caps !! Some pictures to show what quality meant back in the 1960's Joe |
30th May 2020, 10:57 am | #2 |
Nonode
Join Date: Jan 2016
Location: Stafford, Staffs. UK.
Posts: 2,532
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Re: NOS capacitors
22 MegaFarads. Wow!
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30th May 2020, 11:02 am | #3 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,511
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Re: NOS capacitors
I think MFD is a fairly standard abbreviation for microfarads?
Andy |
30th May 2020, 11:07 am | #4 |
Hexode
Join Date: Jan 2007
Location: Welwyn Garden City, Hertfordshire, UK.
Posts: 453
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Re: NOS capacitors
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30th May 2020, 11:15 am | #5 |
Nonode
Join Date: Jan 2016
Location: Stafford, Staffs. UK.
Posts: 2,532
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Re: NOS capacitors
Have to admit I missed the decimal point. And I realised it couldn't really be M for Mega, but u is what I'd expect for micro (properly greek mu), and m for milli. Always made me laugh when Tandy advertised radios with 250MW output power using a PP3.
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30th May 2020, 11:16 am | #6 |
Heptode
Join Date: Dec 2014
Location: Lincoln, Lincolnshire, UK.
Posts: 583
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Re: NOS capacitors
Maybe the lack of inductance one way is from you effectively putting together like a non-inductive wirewound resistor?
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30th May 2020, 11:53 am | #7 | |
Dekatron
Join Date: Sep 2007
Location: Oxfordshire, UK.
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Re: NOS capacitors
Quote:
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30th May 2020, 2:36 pm | #8 |
Dekatron
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,603
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Re: NOS capacitors
Do not know what type of dielectric medium these capacitors are. If a paper type dielectric than due to age they potentially could have become leaky.
If they are going to see DC voltage like a valve anode to grid coupling capacitor then to be on the safe side, would be worthwhile checking them out for leakage (if you have not already done this of course). |
30th May 2020, 2:56 pm | #9 |
Dekatron
Join Date: Sep 2003
Location: Near Swindon, North Wiltshire, UK.
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Re: NOS capacitors
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30th May 2020, 4:49 pm | #10 |
Dekatron
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,603
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Re: NOS capacitors
Aha, I wondered what PIO was
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30th May 2020, 7:40 pm | #11 |
Octode
Join Date: Jul 2009
Location: Cheshire, UK.
Posts: 1,733
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Re: NOS capacitors
They look like a hermetically sealed metal cased capacitor with plastic cover.
More info here: https://www.parttarget.com/5910-00-8...E-41DE5303C690 They sound better than the plastic PIO Sprague HV capacitors I keep finding in HP oscilloscopes, they definitely leak (their contents everywhere). David |
30th May 2020, 8:42 pm | #12 | |
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Re: NOS capacitors
Quote:
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30th May 2020, 11:45 pm | #13 | |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
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Re: NOS capacitors
Quote:
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