After a lot of time doing some other projects and having some family issues that kept me off the soldering, I'm trying to get back to this compressor.
I had a few issues that I found were wiring related and I fixed that. No more problems with input gain pot. It passes signal as it should.
But still there's an issue with amount of compression that my unit is experiencing.
The problem is whatever level of signal it gets, it barely touches it. I can crank up the input gain to the point distortion is very obvious. If I push more signal into it, it actually severely distorts (in a nice way!). But compression is not happening. Just some slight compression that the meter is showing but it can't be heard. Yes, I see some of it on the recorded waveform, but when A/B-ing signal it's negligible.
Also, potentiometers are very non-responsive. Changing attack and release barely does anything. I can notice when release is set to longer value it makes GR needle respond slower but there's no change in sound. Treshold may make it enter into more gain reduction on the meter but that doesn't sound any more compressed. Ratio seems as if nothing happens wherever I set it.
I've tried replacing tubes. Got 8 different 6BA6 (two pairs plus four different singles) and I tried all of them. Couple of them were crappy and just made sound more distorted and lacking low end. I guess those were dead ones or fake ones. But other didn't make any significant change. Just a bit of color change (or maybe it was placebo...).
Then I tried changing 6AV6 to a couple of the same brand (NEC) and nothing happened.
I'm using 6N2P-EV instead of 12AX7 but I guess it's not an issue. I have used this tube twice before when I had no 12ax7 and it was okay. To me it even sounds better (or again another placebo...). It is supposed to be russian equivalent.
I assumed it could be that compressor is not biting enough because I used 1:1 input transformer so I replaced it with a 1:6 transformer I had around (OEP A262A3E). That didn't help neither. It just made the unit get more volume on the input and subsequently enter into distortion earlier.
I put back the 1:1 transformer and then tried bypassing input pad - the change was similar to having 1:6 input transformer. Higher level and more distortion...
Pots are wired correctly and have their resistor added where needed. Heater voltage is spot on.
Voltages from the PSU are a bit different than what is noted in first post, but not that much
B+ 220V
A 8.15V
B 217V
C 217V
D 186V
E 1,16V
F 1,16V
G 219V
H 219V
Looks as if D is 30v higher and E/F are double than they should.
Are those voltages too off?
What can I do to lower the treshold or in any other way make it compress more?
I've watched the video posted here of the compressor in action and it's compressing way more than mine is.
Luka
