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ST-70
Power Supply Question

knowledge base for the classic Dynaco
ST70

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4 posts • Page 1 of
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ST-70
Power Supply Question

by
joeztech
» Sun Aug 31, 2014 3:28 pm

Several people I have communicated with indicated that they
had observed improved audio after bridging a non-electrolytic capacitor across
the electrolytics in a power supply. Have any of you seen any improvement in the
performance of a ST-70 by doing this? If so, what mFd value did you
use?

Joe

joeztech

Posts: 31

Joined: Mon Aug 18, 2014 5:06 am

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Re:
ST-70 Power Supply Question

by
dcriner
» Sun Aug 31, 2014 4:54 pm

What value caps did they use? I can't understand why this would
make a noticeable difference. You can try it yourself, and report your results.
But without double-blind testing, many people might not be convinced. That would
take two identical ST-70s, except for the extra caps.

Doug Criner

dcriner

KT88

Posts: 278

Joined: Mon Oct 23, 2006 4:19 pm

Location: Illinois

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Re:
ST-70 Power Supply Question

by
joeztech
» Sun Aug 31, 2014 5:26 pm

The only reason given that has been mentioned was that
electrolytic capacitors do not have good bypassing properties at higher
frequencies, so potentially it could provide some improvement in the high
frequency harmonic content of speech and music. Personally at 71 years old now,
I doubt I could hear any difference. One other way to tell would be to do some
frequency response tests with out any added bypassing and another run with one
installed. It could perhaps also have an influence on tone bursts to test
transient response.

I am not personally one of those who believe in
monster speaker cables. After all, the conductors in vacuum tubes, audio output
transformers and internal to many semiconductors are quite small. My speakers
are never more than 12-15 feet from the output amplifier, often less. I am
currently using 16AWG stranded speaker wire, but have also used 12AWG and 14AWG
lamp cord with good results and no complaints on my part.

Joe

joeztech

Posts: 31

Joined: Mon Aug 18, 2014 5:06 am

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Re:
ST-70 Power Supply Question

by
Geek
» Mon Sep 01, 2014 12:38 am

I use anywhere from 47n to 470n.

You can eliminate
most noise with straight electrolytics by using ones rates for SMPS use, because
they're usually ESR guaranteed to at least 100KHz.

Cheers!

-= Gregg
=-
Fine wine comes in glass
bottles, not plastic sacks. Therefore the finer electrons are also found in
glass bottles.

Geek

KT88

Posts: 3171

Joined: Sun Oct 21, 2007 3:01 am

Location: Chilliwack, British Columbia

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