I think I've been cursed by the ghost of vactrols past, or something, because I can't build an optical compressor that actually works.
I finished building and boxing the Convex and Oceanid projects from AION FX over the past couple of days, and have had a persistent problem: terrible hissing and/or distortion when the comps are on.
Here are some pictures of the board side of the compressors:
(https://imgur.com/gallery/iadxlf9)
And here are some audio clips of the behavior.
Recorded with low output (Lambertone Crema) humbuckers. The same behavior occurs when I use my Tele with single coils.
https://soundcloud.com/andrewbrautigam/oceanid-sound-samples
https://soundcloud.com/andrewbrautigam/convex-sound-samples
I am stumped.
IC voltages for the convex are
1:4.53
2:4.55
3:4.51
4:0
5:4.28
6:4.53
7:4.52
8:8.98
Q1
G: 1.85
S: 4.47
D: 8.98
Q2
C:3.98
B: 0
E: 0
Q3:
E: 7.48
B: 3.93
C: 0
Q4:
C: 0
B: 8.25
E: 9.1
Q5:
E: ???? Draining slowly from 1v to 0???
B: 0
C: 9.09
Oceanic:
Ic1& IC2 - essentially the same a few milivolts lower on IC2
1: 4.89
2:4.89
3:2.44
4:0
5: 2.44
6:4.89
7:4.89
8:2.44
IC3
1: .01
2: ..01
3: .03
4: 0
5: 0
6: .05
7: .025
8: 8.84
Ic4
1: .14
2: .14
3: .04
4: 0
5: .08
6: .14
7: .72
8: 8.85
Q1: C-B- E
9-4.43-4.6
Q2 : CBE
7.98 - .69 - .10
I hope there's some clue in these numbers. I'm going nuts!
Attempt at pictures again:
https://imgur.com/gallery/iadxlf9
(http://imgur.com/gallery/iadxlf9)
I've reflowed all the solder joints, checked the wiring, tightened every nut... made sure the IC's are firmly seated in the sockets.
On that pedal, the level sets the pregain. If I'm reading it right, it was moved from inside, which means at the right setting, it should remove the distortion. Lots of opticomps I've seen just leave it internal because you should be able to set it and forget it.
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Not it, both pedals have the hissy buzz of death at every level of volume and compression, and even blend.
What else is in the chain?
A compressor after a OD, dist, or fuzz is bad juju.
Nothing before the comps in the chain.
Quote from: playpunk on March 14, 2020, 07:16:59 PM
Nothing before the comps in the chain.
Have you used a spare LED to make sure that both the vactrol is the right way round despite the dot? I've seen it wrong before. What are you using in Q1?
Sounds like it's time for an audio probe to see where it is being introduced.
Quote from: jimilee on March 14, 2020, 07:19:24 PM
Quote from: playpunk on March 14, 2020, 07:16:59 PM
Nothing before the comps in the chain.
Have you used a spare LED to make sure that both the vactrol is the right way round despite the dot? I've seen it wrong before. What are you using in Q1?
Sounds like it's time for an audio probe to see where it is being introduced.
I used the spare LED before I installed the vactrols.
Quote from: playpunk on March 14, 2020, 08:20:05 PM
Quote from: jimilee on March 14, 2020, 07:19:24 PM
Quote from: playpunk on March 14, 2020, 07:16:59 PM
Nothing before the comps in the chain.
Have you used a spare LED to make sure that both the vactrol is the right way round despite the dot? I've seen it wrong before. What are you using in Q1?
Sounds like it's time for an audio probe to see where it is being introduced.
I used the spare LED before I installed the vactrols.
What about after you installed it, if you touch the legs of the LED to the legs of the vactrol, does it light up?? What are you using in Q1?
Sounds like it's time for an audio probe to see where it is being introduced.
Quote from: jimilee on March 14, 2020, 08:27:06 PM
Quote from: playpunk on March 14, 2020, 08:20:05 PM
Quote from: jimilee on March 14, 2020, 07:19:24 PM
Quote from: playpunk on March 14, 2020, 07:16:59 PM
Nothing before the comps in the chain.
Have you used a spare LED to make sure that both the vactrol is the right way round despite the dot? I've seen it wrong before. What are you using in Q1?
Sounds like it's time for an audio probe to see where it is being introduced.
I used the spare LED before I installed the vactrols.
What about after you installed it, if you touch the legs of the LED to the legs of the vactrol, does it light up?? What are you using in Q1?
Sounds like it's time for an audio probe to see where it is being introduced.
That's a good idea, I'll give it a shot!
Quote from: playpunk on March 14, 2020, 09:32:02 PM
Quote from: jimilee on March 14, 2020, 08:27:06 PM
Quote from: playpunk on March 14, 2020, 08:20:05 PM
Quote from: jimilee on March 14, 2020, 07:19:24 PM
Quote from: playpunk on March 14, 2020, 07:16:59 PM
Nothing before the comps in the chain.
Have you used a spare LED to make sure that both the vactrol is the right way round despite the dot? I've seen it wrong before. What are you using in Q1?
Sounds like it's time for an audio probe to see where it is being introduced.
I used the spare LED before I installed the vactrols.
What about after you installed it, if you touch the legs of the LED to the legs of the vactrol, does it light up?? What are you using in Q1?
Sounds like it's time for an audio probe to see where it is being introduced.
That's a good idea, I'll give it a shot!
I just had that same problem last week.
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