ST-70 Power Supply Question

knowledge base for the classic Dynaco ST70

ST-70 Power Supply Question

Postby 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: 39
Joined: Mon Aug 18, 2014 5:06 am

Re: ST-70 Power Supply Question

Postby 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: 309
Joined: Mon Oct 23, 2006 4:19 pm
Location: Illinois

Re: ST-70 Power Supply Question

Postby 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: 39
Joined: Mon Aug 18, 2014 5:06 am

Re: ST-70 Power Supply Question

Postby 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.
User avatar
Geek
KT88
 
Posts: 3580
Joined: Sun Oct 21, 2007 3:01 am
Location: Chilliwack, British Columbia


Return to st70

Who is online

Users browsing this forum: No registered users and 1 guest

cron