Hi Ed,
I've now checked all the resistors and was surprised to find all but one within an acceptable margin, the 2M2s were about 2M5. The faulty 100k was more then 200K so I replaced it. I found a schematic for something similar here: A.P. 32112 My amps are type A.P. 32020.
This particular resistor is the anode load of the second preamplifier.
The first pre-aplifier is not used, it has a microphone transformer input feeding into the second preamplifier which also has an input from the front panel jack socket.
Last night I played some bass heavy music through it into the lowther horn speaker, much better than my other speakers. The workshop was rocking.
Picture shows new components fitted.
I've now checked all the resistors and was surprised to find all but one within an acceptable margin, the 2M2s were about 2M5. The faulty 100k was more then 200K so I replaced it. I found a schematic for something similar here: A.P. 32112 My amps are type A.P. 32020.
This particular resistor is the anode load of the second preamplifier.
The first pre-aplifier is not used, it has a microphone transformer input feeding into the second preamplifier which also has an input from the front panel jack socket.
Last night I played some bass heavy music through it into the lowther horn speaker, much better than my other speakers. The workshop was rocking.
Picture shows new components fitted.
