2022 reissue filter calibration: When should self-oscillation begin?
Posted: Sat Jul 05, 2025 3:09 pm
At the moment I have 2 Model D reissues side by side in my studio, and I’m trying to decide which one to keep. In comparing the 2, the biggest difference I have noticed between them is in the filter response. Namely, with all oscillators switched off and the cutoff on both set at -1, the filter on one begins to self-oscillate when the emphasis/resonance is a smidge past 7. On the other, I have to go all the way to 8 before self-oscillation starts.
I found an old service manual online that details a filter calibration process and notes that self oscillation should begin when the resonance/emphasis is between 7-8. However, I don’t know if this applies to the reissues.
At any rate, I am wondering if anyone here could share at what point their Model D filter goes into self-oscillation.
I found an old service manual online that details a filter calibration process and notes that self oscillation should begin when the resonance/emphasis is between 7-8. However, I don’t know if this applies to the reissues.
At any rate, I am wondering if anyone here could share at what point their Model D filter goes into self-oscillation.