Thanks - I have closed all the jumpers on JP2 and JP4, but it doesn't seem to make a difference. Is there a danger the SIDs may have been damaged?
Maybe there are some badly soldered joints on the PCB. Did you check them all properly?
What is the meaning of each of the jumpers on JP2/JP4?
The leftmost jumper of JP2 will - when pulled - reduce the voltage for SID 1 from 12 to 9 volts. This is necessary when operating an 8580 with an old mainboard, which originally provides the 12 volts which are needed by a 6581. In all other cases - like in yours - the jumper has to remain in place.
The two other jumpers of JP2 will configure the two filter capacitors for the SID type: Both set for 8580, both pulled for 6581.
JP4 works the same, but for SID 2.
i.e. Using the MINISTEREOPLAYER as a test - MOON.MUS sounds perfect with the STEREOinSID at $DE00 or $DF00. However, the sound is very garbled when it is set to $D420. The miniclip connections to the 8500 appear solid. What else could it be?
I don't know your tool MINISTEREOPLAYER. Do you have a link?
CU
Kratznagel