Analog controller for SoundStepper with HY554, "Fake SJ588" or any "B-Class-output" device like CM-108, 109 or 110 chipsets)
Drawing for SoundStepper circuit in "island" 1x1 protoboard, like this:
Only for "HY554" or other USB audio devices with "B-class" outputs, with bypassed output capacitors and 2V peak-to-peak output voltage swing (centered in 1.65V). If "center" is another level, adjust value of (47K) resistor from USB+.
Sets of resistors to be matched are colored in diagram
10K potentiometers must be adjusted to obtain 0V at output without any signal (use "Direct current test" with control at "0" position in SoundStepper test window.