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Old 27th October 2010, 07:56 PM   #11
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Wavebourn, no need to apologize for your English; your written skills are much better than the verbal skills of many native American English speakers I know.

I recently completed a VTA ST-70 build, and I went with the Russian PIO cap upgrade. I can't say they made a difference as I didn't hear the amp before installing them. I can say the amp sounds very nice. I was struck by their physical size though. They're relatively huge!

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Old 29th October 2010, 03:32 AM   #12
ervinl is offline ervinl  Indonesia
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What about K75? I use this since it has higher voltage range than K40 or K42 (so I think it should be safer for tube coupling cap).

Ervin L
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Old 29th October 2010, 05:18 AM   #13
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К75 capacitors may be very very different. For example, K50-63 are made of paper & foil,
K75-93 are metalized film impregnated, and so on.
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Old 29th October 2010, 07:13 AM   #14
ervinl is offline ervinl  Indonesia
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Quote:
Originally Posted by Wavebourn View Post
К75 capacitors may be very very different. For example, K50-63 are made of paper & foil,
K75-93 are metalized film impregnated, and so on.
I use K75-10. It is claimed as oil (PILO). It has a rating up to 800V DC (500V AC), instead of K42 that only 250V DC OR 160V AC (CMIIW).
I use B+ of around 220V DC, this voltage is marginal.

Thx,

Ervin L
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Old 29th October 2010, 08:15 AM   #15
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K50-10 are metalized, but made for high currents in pulse regimes. AC rating is given for 50 Hz.

Tangent of angle of losses is 0,008
24 gigaOhm insulation.
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Old 29th October 2010, 02:15 PM   #16
M Gregg is offline M Gregg  United Kingdom
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Quote:
Originally Posted by Wavebourn View Post
K50-10 are metalized, but made for high currents in pulse regimes. AC rating is given for 50 Hz.

Tangent of angle of losses is 0,008
24 gigaOhm insulation.
Just for information,

Do these capacitors contain PCB?

Polychlorinated biphenyl - Wikipedia, the free encyclopedia

This link is for those that may not be aware of PCB's used in some components!

Regards
M. Gregg
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Old 29th October 2010, 02:57 PM   #17
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Quote:
Originally Posted by M Gregg View Post
Just for information,

Do these capacitors contain PCB?

Polychlorinated biphenyl - Wikipedia, the free encyclopedia

This link is for those that may not be aware of PCB's used in some components!
I am not aware if Soviet capacitors ever contained PCB. Paraffin, bee's wax, mineral oils - what I've seen there.
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Old 29th October 2010, 05:01 PM   #18
piano3 is offline piano3  United Kingdom
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I have used either K75-10 or K75-24 in every amp I have built but always as either bypass caps for the power supply electrolytics or in the snubbing network in choke input PSU. I think it would be hard to find better caps for this purpose.
I guess they might also be suitable for parafeed caps.

Ervinl; K40U-9 and K42U-2 are available up to 1600V. Excellent eflog seller Dmitriy Kolevatov (user name uralspirit) has good selection at higher voltage and is happy to sell small numbers.
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Old 29th October 2010, 05:19 PM   #19
M Gregg is offline M Gregg  United Kingdom
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Quote:
Originally Posted by Wavebourn View Post
I am not aware if Soviet capacitors ever contained PCB. Paraffin, bee's wax, mineral oils - what I've seen there.
Trade name from the link

Former USSR
  • Sovol
  • Sovtol
Regards

M. Gregg
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Old 29th October 2010, 05:26 PM   #20
piano3 is offline piano3  United Kingdom
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Surely PCB's were mainly used in capacitors utilised in power generation- not in the kind of ones we all use?
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