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Author Topic: Hybrid valve and TPA311x  (Read 1740 times)

jfetter

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Hybrid valve and TPA311x
« on: November 15, 2018, 07:52:42 PM »
Two years have tested others and this one sounds the best.
 I built it point to point but now doing a board.
The tone tilt I think beats all others. Shown here in hifi mode but easy to add scoop.
Uses 12AU7 and $3.00 D class module.

Schematic attached. The fx loop is not fully tested.
Cheers



jfetter

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Re: Hybrid valve and TPA311x
« Reply #1 on: September 13, 2019, 03:29:50 PM »
A reliable pcb pot (ie Beckman ) cost quite a lot. So I put a servo-buffer opamp and configured as a ' super triode' . It took a long time to get it right...
This plot is using a sa5532 with 6sn7 in feedback loop.

It's raw right now in fact going to a lower gain tube but the plot shows 1khz signal , 2 khz dominant harmonic , 4th etc.
Third and fifth very low.