Hello 
I have a issue with a Neumann microphone preamp .I have a feeling i have all the clues necesary to figure this out, but i guess my understanding of how the circuit works is not adequate, so i hope some of you would take a look and point me in the right direction Here is what i know:
I have a issue with a Neumann microphone preamp .I have a feeling i have all the clues necesary to figure this out, but i guess my understanding of how the circuit works is not adequate, so i hope some of you would take a look and point me in the right direction Here is what i know:
- The sound from the output is thin and distorted.
- When i run a testsignal through the the unit (1Khz sinus) the negative cycle is clipping, measured at the output. Tracing back the signal it seems the clipping occurs by Trs2/Trs3.
- I have noticed that when the unit is powered up, for 2 seconds or so the signal looks good, and then slowly the negativ cycle flattens out. I have also noted that on power up the collector dc voltage on Trs2/Trs3 starts on 14vdc and then slowly drops to around 9,5vdc. Am i right in assuming that the collector voltage should be around half of the supply voltage, and that it being 9,5 would explain why the signal is being clipped?
