I am trying to sort out an Electrocompaniet (EC) AW-100 DMB amplifier and wanted to ask for help from the experts on this site.
The idling current (bias) and the DC adjustments have been made to the manufacturer's recommendations. In use the amplifier lacks treble and is bass heavy. The first image shows the square wave response at 10kHz across a resistive load and the lack of high frequencies. EC will not give me the circuit diagrams to identify where filtering is taking place. However, they did say there was filtering in the input section. The second image is a circuit diagram found on the internet which appears to cover this amplifier.
I think the only filtering is due to C1 and C14 which at 1000pf seems too large. If this is correct, would I see any significant improvement by reducing it’s value to 47-100pf?
I would appreciate any comments or further suggestions if this is wrong.