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Compressor Hell

Started by playpunk, March 14, 2020, 08:36:39 AM

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playpunk

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:



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!
"my legend grows" - playpunk

playpunk

"my legend grows" - playpunk

playpunk

I've reflowed all the solder joints, checked the wiring, tightened every nut... made sure the IC's are firmly seated in the sockets.
"my legend grows" - playpunk

jimilee

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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Pedal building is like the opposite of sex.  All the fun stuff happens before you get in the box.

playpunk

Not it, both pedals have the hissy buzz of death at every level of volume and compression, and even blend.
"my legend grows" - playpunk

alanp

What else is in the chain?

A compressor after a OD, dist, or fuzz is bad juju.
"A man is not dead while his name is still spoken."
- Terry Pratchett
My OSHpark shared projects
My website

playpunk

Nothing before the comps in the chain.
"my legend grows" - playpunk

jimilee

#7
Quote from: playpunk on March 14, 2020, 12:16:59 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.
Pedal building is like the opposite of sex.  All the fun stuff happens before you get in the box.

playpunk

Quote from: jimilee on March 14, 2020, 12:19:24 PM
Quote from: playpunk on March 14, 2020, 12:16:59 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.
"my legend grows" - playpunk

jimilee

Quote from: playpunk on March 14, 2020, 01:20:05 PM
Quote from: jimilee on March 14, 2020, 12:19:24 PM
Quote from: playpunk on March 14, 2020, 12:16:59 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.
Pedal building is like the opposite of sex.  All the fun stuff happens before you get in the box.

playpunk

Quote from: jimilee on March 14, 2020, 01:27:06 PM
Quote from: playpunk on March 14, 2020, 01:20:05 PM
Quote from: jimilee on March 14, 2020, 12:19:24 PM
Quote from: playpunk on March 14, 2020, 12:16:59 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!
"my legend grows" - playpunk

jimilee

Quote from: playpunk on March 14, 2020, 02:32:02 PM
Quote from: jimilee on March 14, 2020, 01:27:06 PM
Quote from: playpunk on March 14, 2020, 01:20:05 PM
Quote from: jimilee on March 14, 2020, 12:19:24 PM
Quote from: playpunk on March 14, 2020, 12:16:59 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.


Sent from my iPhone using Tapatalk
Pedal building is like the opposite of sex.  All the fun stuff happens before you get in the box.