techdiy 4780 kit

[phrayed]

Is anyone familiar with the techdiy 4780 kit? Mine has high dc offset; 280-320mVDC. I removed the mute cap and 15Kr resistor, moved the 10Kr to the 15Kr spot and jumped the 10Kr spot. Still the offset persists. Suggestions?

 

[danielwritesbac]

Is anyone familiar with the techdiy 4780 kit? Mine has high dc offset; 280-320mVDC. I removed the mute cap and 15Kr resistor, moved the 10Kr to the 15Kr spot and jumped the 10Kr spot. Still the offset persists. Suggestions?

Install inverting input coupler cap and/or stiffen input load

 

[phrayed]

techdiy schematic

Here is the "official" schematic:
I showed where I had changed things.

 

[danielwritesbac]

See also an1192.pdf http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=snaa021&fileType=pdf


P.S.
I suggest to rearrange the board to use the parallel schematic at 6.2.1, to improve linearity considerably.

 

[phrayed]

System collapsed...took the 4780 and the 317...researching options...