Sander deWaal wrote:

You bet there are differences.
Since the 1950s, many new approaches to amplifier design were
developed (SRPP, OTL/Circlotron etc).
Not to mention better components like caps and resistors.


Sander,

I understand that point. But as I found out, back in 1975 there
was a big contest in a british hifi magazine for expensive amps.

Both the amps and the testers were from the who-is-who of the
high end hifi amp scene, but the magazine covertly added some
candidates from an earlier epoch - one of which was the STA-25.

To everyone´s big surprise it clearly won that competition.

Usually, when an old amp falls into my hands, and it's not a
collectable, I strip it entriley, and mostly only the trannies are
used for new projects.

Good idea, but I´ll better leave my STA-25 untouched.

Instead I´d like to build me a copy of it with state-of-the-art
components... and I of course would like to know if there has been
significant progress in tube valve amp circuitry design since 1975!

Earlier I had the idea of an improved CSV-60 clone which has been
suggested somewhere on the net - but now the STA-25 looks like a
better platform to me.

SETAs is an entirely different subject, I mostly build PP amps.

I must confess I´m a total rookie... I thought of doing a layout
for a STA-25 clone PCB, add some ground layers and shielding.

Maybe I´d better keep this for myself until I got it working...
Want to suggest improvements? Go ahead: walther at in4tec dot de.

Regards

Walther