Power supply board was designed for both amplifiers (12VDC) and all LPFs (10VDC for relays in series), including logic circuits (5VDC). MICREL ICs MIC5219 are used in 10V and 5V sections with 0.5A max. load in each section, 12V sections are rated at 1.2A each. Electrolytic capacitors with low ESR were selected.
Independent power supply condition for both signal channels has been fullfiled. Values of R2 and R3 were changed during first measuring from 1k5 to 1k2 to have as close as possible 5V on the LPF relay coils.