David McGown wrote:
Grover,
Fantastic results! Congrats!
Where did you get the plastic rings around the holes in the topplate for the 6SN7 and KT66? Those look really handy to dress up the holes cut in the plate.
On the cap across the feedback resistor, how does that compare with what you were getting on the handwired version? I think based on your (or Dave G.) experiments on stability you found that even a 0pF cap worked fine. I think that is what I did on mine. Been too busy of late to put my amp under the scope.
David
Those are co-called "2-inch" cable grommets. They actually fit a 1-7/8" hole:
https://www.amazon.com/dp/B0B9R4BL62?re ... tails&th=1A cheap way to dress up the needed holes for the tube sockets.
The response from the p-to-p version wasn't as even or consistent from tap to tap. That's a remarkable result for all three taps, they usually vary much more than that. There's definitely a cleaner high-frequency response with the PCB, better HF extension calling for a some extra capacitance across the feedback resistor. You can hear it, too, there's more detail and definition in the top end. I noticed it immediately on organ recordings, there's more character to the colorations and voicings in the mid- and high-register voicings. But everything sounds better, more presence and energy.