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RE: here we go again.......

Posted by drlowmu (M) on August 20, 2016 at 08:29:23

In Reply to: RE: here we go again....... posted by Palustris on August 19, 2016 at 11:33:16:

May I critique your SET amp's supply ??

Power supplies in SET amps ( or P-P ) should avoid any form of a "C" input filter ( 30 uF in your case ).

The ideal tube amp supply really needs to be L1/C1/L2/C2.

Your L1 is too high in DCR by a factor of 2.5 times, needs to be 20 Ohms or less. I like 10 Ohms or less. Also, the inductance is far too high, ruins the dynamics and listening FUN that is possible.

Your L2s are also 5 times too high. 105 Ohms DCR is very poor.

That amp will be DEAD sounding, versus a LSES type supply. !! Compressed dynamics and boring.

Look up LSES posts from eight years ago up here, or, send me your email address as Vinnie did and I will send you my write up on such a amp design and also, ALL the chronological posts by EEs Swenson and hasquin on such a power supply as I suggest.

Going to RMAF this year in Denver, October?? Be sure to stop in at Serious Stereo, where you can listen to ALTEC 604 MLTLs, using a JJ 2A3-40 amp like yours, with, I believe, UNDER 5 Ohm L1s and L2s !!

Have FUN hearing what I suggested, ..... I am !!

Jeff Medwin

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ADDENDUM,

To make it easy, I have included a simple discussion of LSES principles by E.E., and AA Forum Member John L. Hasquin, that I quite like:

A choke's behavior is to oppose change in current flow. A cap's behavior is to gobble up and store as much current as it can. When the amplifier demands an increase in current the caps initially release some current, but then begin to compete with the amplifier for current because they want to maintain their charge.

Then if you have large inductance chokes, they prevent the power transformer from delivering current to the caps because they are opposing change in current flow. This in turn means the more current the
amplifier demands, the more the caps compete for the limited amount of current.

The result is dampened dynamics because the amplifier is current starved. Big caps and chokes = dampened dynamics and a current starved amplifier. Low DCR power transformer with low value chokes and caps = dynamics.

Edits: 08/20/16 08/20/16 08/20/16

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