@ bravo similar look but not identical, since i will use dual op27 amp (opa2227) instead of single ones, reduced parts count, the change made a 25$ less in parts, the size is now good, it should fit ?
Here's a look of the pcb 2-3 posts down this one
I have used radial decoupling capacitors for the moment, to help the second layer, the layer thickness or width size may be too small in the power lines. And I'm limited to 2 layers unless i pay more ... it double the price for a 4 layers 1 oz pcb's
IF high voltage send me his boards, i will compare them before producing ... i have only 3 missing supply traces from the SM for a chip, i could put them and cut them if needed ??
I would like to build a potential list of buyers ?? for around 150$ CAD each, the chips are the one who cost a lot,
The 1% smt resistors are around 0.35$/each for 36 parts count, and the resistor network chip is around 8$
I used smt 1210 size to have possibility of the originals mma0204 series resistors ?? i'm not able to have all the values here in 1%.
The strange thing with the res network is some kind of thermal coupling between the 8 resistors, they are in serial (4x1k) with an common point, i can't see another functionality than this, instead of 2 single axial resistors of 4k thermally glued together
LIST:
#1 is @bravo