Dyna PAS3X, SDS PSU Board and some Wine - TimeConstant - Vintage Asylum

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Dyna PAS3X, SDS PSU Board and some Wine

TimeConstant

I am sitting here scratching my head trying to figure out why.

About two years ago I purchased un un-built Dynaco PAS3X, a few missing parts but most of the Kit was intact, well apart from a soldering error on the Channel Selector Switch, was this Factory or deliberate not sure, as I think these parts came factory pre-assembled..

Okay here is my story.

Soon after getting the PAS3X built the Selenium Rectiifiers pooped out with a loud POP.

I decide to order an SDS PSU Board and replace it.

I did just that and decided to use the Diodes instead of the 12X4 Tube Rectifier for whatever reason, I thought to myself "less load on the Power Transformer".

So..... two years later, last night I decided to modify the PAS3X and re-install the stock Dynaco labeled 12X4 Rectifier Tube.

The sonic difference is HUGE. Apart from a loss of upper treble grain, the sound is totally relaxed, with air between the instruments and the voices are sublime.

Is there really that much of a difference between the 12X4 and a pair of Diodes?

Of is this a case of slightly lowered filament voltage on the 12AX7's now that the Tube Rectifier is loading the SDS board along with the filaments of the four tubes?

I have not had the chance to experience a Diode vs. Tube Rectifier thing in the past as normally it is one or the other, but this is a revelation.

I am not going back to the Diodes. The 12X4 stays in place and the sound is so much better I have to think Tube Rectifiers and Preamplifiers equal up to some type of synergy.

Thoughts?

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Topic - Dyna PAS3X, SDS PSU Board and some Wine - TimeConstant 04:20:44 07/12/15 (10)

use of SS diodes requires circuit changes IME&O - Timbo in Oz 19:10:49 07/15/15 (3)

RE: use of SS diodes requires circuit changes IME&O - Cleantimestream 09:56:43 07/16/15 (0)

RE: use of SS diodes requires circuit changes IME&O - TimeConstant 06:49:31 07/16/15 (0)

RE: use of SS diodes requires circuit changes IME&O - airtime 06:01:15 07/16/15 (0)

Is there really that much of a difference between the 12X4 and a pair of Diodes?"... - Cleantimestream 09:32:31 07/12/15 (1)

Well then you're pretty lucky - airtime 06:01:33 07/13/15 (0)

RE: Dyna PAS3X, SDS PSU Board and some Wine - airtime 08:12:53 07/12/15 (1)

If you didn't make other adjustments that isn't surprising - Timbo in Oz 19:19:19 07/15/15 (0)

RE: Dyna PAS3X, SDS PSU Board and some Wine - Eli Duttman 06:36:11 07/12/15 (1)

RE: Dyna PAS3X, SDS PSU Board and some Wine - TimeConstant 07:22:13 07/12/15 (0)

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