SET Asylum

Single Ended Triodes (SETs), the ultimate tube lovers dream.

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RE: "a more linear driver tube"...

Posted by Paul Joppa on June 15, 2020 at 08:55:37:
Yes, answering questions is OK - and I am happy to do it.

You used the term "original Paramount" - that used a 12AT7. There were some issues in certain specific cases which led to a revision incorporating a slow-start driver power supply and a few other tweaks. We switched to the 5670 at that time. There was an upgrade kit for earlier amps.

Incidentally, we did do a few before-and-after distortion measurements. I was pleased to find that both drivers produced essentially the same distortion harmonic spectrum at the output, suggesting to me that the distortion was dominated by the output tube - the current source plate load made the 12AT7 more linear than a [Sovtek] 2A3.