Potato Cakes
Well-known member
Got a chance to circle back and work on this.
I pulled the diodes and matched 8 different pairs out of the new batch of 1N715As I used the two that measured the highest voltages, which I don't think actually matters. One of the channels is now clean but the other still has the same noise. However the channel that is clean still has several issues. I can't seem to get any of the fine tuning steps to actually do anything. Adjusting the trimmer does not change the waveform to what is supposed to look correct. I can adjust this properly on the noisy channel. I also cannot seem to do a proper adjustment on for fine tuning II. I do not have a distortion meter, but when I look at 1k on the scope I can see all the THD bumps on the sine wave, but adjusting R22 does not change any level of the distortion. I do not know if this is related to the fact that I cannot perform fine tuning I. The compression circuit is working, but it does have some weird things happening like when it comes to a quiet passage in the program material, the gain reduction circuit is being maxed out by several low frequency pulses about 2 seconds apart, then disappears. It does not do this with the side chain HPF. The noisy channel does not have this problem.
Another weird thing is that I get a pop on both outputs when I bypass either channel, but not when I engage the compression. I am using the square push button switches from Don Audio to control a pair of relays.
For now, I need to fix the noise that still persists on one of the boards. Then I can focus more on the other guy. But I am a bit surprised of how much trouble I am having with the quiet channel. I'll get back on it tomorrow. I hope.
Thanks!
Paul
I pulled the diodes and matched 8 different pairs out of the new batch of 1N715As I used the two that measured the highest voltages, which I don't think actually matters. One of the channels is now clean but the other still has the same noise. However the channel that is clean still has several issues. I can't seem to get any of the fine tuning steps to actually do anything. Adjusting the trimmer does not change the waveform to what is supposed to look correct. I can adjust this properly on the noisy channel. I also cannot seem to do a proper adjustment on for fine tuning II. I do not have a distortion meter, but when I look at 1k on the scope I can see all the THD bumps on the sine wave, but adjusting R22 does not change any level of the distortion. I do not know if this is related to the fact that I cannot perform fine tuning I. The compression circuit is working, but it does have some weird things happening like when it comes to a quiet passage in the program material, the gain reduction circuit is being maxed out by several low frequency pulses about 2 seconds apart, then disappears. It does not do this with the side chain HPF. The noisy channel does not have this problem.
Another weird thing is that I get a pop on both outputs when I bypass either channel, but not when I engage the compression. I am using the square push button switches from Don Audio to control a pair of relays.
For now, I need to fix the noise that still persists on one of the boards. Then I can focus more on the other guy. But I am a bit surprised of how much trouble I am having with the quiet channel. I'll get back on it tomorrow. I hope.
Thanks!
Paul