Dual TPA3116 board: Fixing the AWFUL noise floor.
Channel: FFcossag
Date: 2016-05-04

This amplifier board suffers from very poor distortion and noise performance out-of-the-box. In this video I explore solutions and remedy the design issues present on the board.

In a nutshell, if you want to fix one of these boards, this is what to do:

1. Swap the two gain resistors (39K and 100K, under the heatsink) of ONE of the TPA3116 chips.
2. Bridge the 10K resistor by pin 16 of the left TPA3116 with a jumper.

(This fixes the "screechy" noise caused by both TPA3116 chips trying to drive the sync input of the other.)

3. Replace the main volume and LR volume potentiometers with lower value ones (10K used in this video)

(This fixes the noise that gets worse when the potentiometers are set to the 12 o' clock position)

The potentiometers used was similar to this: http://www.digikey.com/product-detail/en/tt-electronics-bi/P092N-QC20AR10K/987-1287-ND/2408864

These two fixes combined lower the worst-case noise floor by over 10 dB, with gains of almost 20 dB under certain circumstances, which is extremely noticeable.

My original video on this board: https://youtu.be/5vNXid174fs
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