Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

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RE: What an astonishingly insightful (and iconoclastic) assessment of some formerly revered designs....

Posted by Tre' on March 21, 2017 at 21:05:07:
"Their topology(meaning it can't be cured) causes compression of the negative half of a signal relative to the positive half which is the source of the second harmonic. "

Yes, that's true with most tubes but some DHTs are very linear with even spacing between grid voltage lines.

Especially if you keep the load line reasonably horizontal using a high impedance load (higher than would normally be spec'd if max output power were the goal) keeping the tube operation away from where the grid lines "bunch up".

One also needs a lot of inductance in the single ended output transformer (most output transformer don't have enough) to keep the load line from turning into a "beach ball" in the presents of low frequencies.

One way around that is to bi amp and filter the low frequencies out of the SET amp.

Tre'