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In Reply to: RE: Ping Mike Samra - re film PSU caps for LEAK amps posted by Michael Samra on August 19, 2016 at 00:41:55
I know what the original caps were, I bought the amps in OEM condition. ? Nice amps but they hummed and farted, due to poor replacement NoS caps and 'not wonderful' new 'GZ34' s - which weren't within a bull's roar of a real GZ34. We measured! And there was no OOMF to the sound. No slam either.Good real NoS GZ34s which are the ONLY good GZ34s around now, and back then, were silly money.
(That experience put me off VRs, and my experience since has confirmed for me that VRs are a waste of time and money.)
So we ditched them and could and did use the big caps, 'cause we now could.
As I've mentioned before, in this series of posts about using the LEAKs to drive the QUADs, there are 4 Soft Recovery SS diodes in a bridge in each amp. Lots of OOMPH and slam and valve sound, to boot!
What about adding a choke or two and cutting down from four big caps to two, or three, say LCLCC? or even LCLCLC? Chokes store energy too, don't they?
TIA
Warmest
Tim Bailey
Skeptical Measurer & Audio Scrounger
Edits: 08/19/16Follow Ups:
"Good real NoS GZ34s which are the ONLY good GZ34s around now,"
Did you try the recent releases - the Genalex U77, or the Tung-Sol or Mullard branded 5AR4/GZ34s?
This was back in the mid 90s, and we put a third Nichicon 400V 470uf cap where the octal socket was. The bass duty amp had a 4th cap underneath. Click below.I briefly used a DH VR, a 5AS4?, whose heater current draw was too high for the PTs.
And both amps sound fine. Slam, nuance, etc.
And, in their new role driving 63s strapped to mono blocks (40W pentode) and filtered 150Hz 1st HP, they won't be working all that hard.
We've replaced some valves.
I am happy.
Warmest
Tim Bailey
Skeptical Measurer & Audio Scrounger
Edits: 08/24/16 08/24/16
There are a lot of people who don't realize how good the 3 rectifiers I mentioned are, so I thought I'd ask if you knew of them.
A VR tube must be used where it's appropriate. Saying only that they're a waste of time and money is way off base. VR tubes reduce distortion when used to regulate screens, and they can stabilize preamp circuitry with much less complexity than active regulators.
--------------------------
Buy Chinese. Bury freedom.
not valve regulators.
Warmest
Tim Bailey
Skeptical Measurer & Audio Scrounger
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