Peter,
Thank you for your reply.
Ultrachrome,
The only significant readings for your AKSA are all measured in DC, just as Peter says. You want to know:
1. The DC voltage on the output spades of the power supply pcb. These spades are connected to wires and thence to the modules. On the 100W AKSA they are nominally +/-49V, with a maximum no higher than 52V, and on the 55W AKSA they are nominally +/-36V, not exceeding 39V.
2. The voltage between the emitters of the output devices. This is 55mV on both amplifiers, and is measured across the two outer devices on the 100W AKSA. The reading across the two inner devices on this amplifier should be within 8mV of this reading.
3. The offset voltage at the output with respect to ground on both amplifiers. This is an arbitrary figure, but should not exceed 30mV, plus or minus (it can be either; only the magnitude is important.) If the offset is negative, you can reduce it by INCREASING the value of R3, which feeds the diff pair. If the offset is positive, you can reduce it by DECREASING the value of R3. A typical offset of 30mV will be reduced to close to 0mV with a 3K3 increase or decrease of R3.
There are other voltages of note on the AKSAs, but if the offset is correct, and the bias is correct, then you have a perfectly functional amplifier. It is worth knowing that ANY circuit fault will affect one or both of these readings, no exceptions.
Hope this is helpful,
Cheers,
Hugh
