SOLVED Aion Oc-1 build issues

[megatrav]

Hey all!
I am building an Aion OC-1 kit and I am at the testing phase and I have encountered some issues.
A couple notes before I get into the issues:
- I didn’t use a switch to go from buffered to true bypass. Hard wired buffered bypass since that was how the original pedal came.
- Instead of using an LM4040 for z1, I used a 1N4733A wired as they suggested. I will add pics below.

Issues:
1) The bypass tone is awful. As in tone suck city. It sounds like it’s distorting but has weaker output than the pedal not being in the signal.

I think I will switch it to true bypass and see if that fixes the issue.

2) when engaged, the pedal’s volume control works great, but it feels like the other controls aren’t working.
This makes me think that I may have the vactrol in the wrong way. I will post some pics of that as well.

Vactrol:





Buffered bypass wiring:

 

[megatrav]

I've built two (the first one I lent to friend and you probably know how that one goes). I can take voltage measurements. Here's some gutshots: gutshots of stuff. Unfortunately, the vactrol is hiding under a wire.

I will take a look. Thanks!

 

[megatrav]

I've built two (the first one I lent to friend and you probably know how that one goes). I can take voltage measurements. Here's some gutshots: gutshots of stuff. Unfortunately, the vactrol is hiding under a wire.

Based on your pics it looks like it should be in like this:

 

[megatrav]

This is what I can see from your pics @tcpoint

 

[megatrav]

Also, if you have any advice for checking the buffer, please feel free to share.
here is a link to the build doc Aion Oceanid

 

[megatrav]

My frustration is reaching new heights with this. Is there any way to wire a standard 3PDT instead of the bypass board?
It’s giving me trouble and I would rather just wire it in true bypass.

I understand the switch wiring for the LED. However there are 2 other resistors R38- 91R and R39- 51k. I’m not sure if those are related to the buffer or how I would wire them to the switch. It’s been an entire nightmare just trying to switch from hardwired buffered bypass to true bypass

Thanks!

 

[megatrav]

Sorry for my previous post. I edited it. I was mad at the pedal.

 

[tcpoint]

If you look at the schematic, the Cornish Buffer is integrated into the circuit. There's really no point in skipping the buffer. The buffer is used as part of the OC-1. First, build yourself some kind of audio probe. Just google it. It will make tracing the signal way easier.

 

[megatrav]

If you look at the schematic, the Cornish Buffer is integrated into the circuit. There's really no point in skipping the buffer. The buffer is used as part of the OC-1. First, build yourself some kind of audio probe. Just google it. It will make tracing the signal way easier.

I will definitely do that

 

[megatrav]

Can you tell me what steps to take or point me to some instructions for testing once I have the probe?
I would love to know how to trouble shoot the buffer and fix it.
I would still really like to wire a standard switch instead of the board.
or can that only be done for true bypass?

I have looked at the schematic and other than where it says “buffer out” I’m not sure what part is the buffer

 

[megatrav]

Just wanted to update.
I got impatient and found a schematic for true bypass. So, I wired the switch for true bypass. Once I get the audio probe made, I would like to trouble shoot the buffer.
From what I can tell, everything is working. It’s hard to tell if the compressor is kicking in but the blend is doing something and volume control definitely works!
Would anyone like to confirm I have the vactrol in the right way?

Here is the outside and inside shots too

 

[Mcknib]

The input buffer circuit is from in to the 51R resistor

Audio probing it you shouldn't hear much difference from your signal in to the buffer output it basically preserves your signal strength and frequencies / tone

You've got the 2 circuits a buffer and a compressor that are probably the hardest to actually hear what effect they have

https://www.masterclass.com/articles/guitar-101-what-is-a-compressor-pedal-learn-how-to-use-a-compressor-pedal#what-is-a-compressor-pedal

Your vactrol looks correct to me going by this image of someone's build and the labelling orientation

 

[megatrav]

The input buffer circuit is from in to the 51R resistor

Audio probing it you shouldn't hear much difference from your signal in to the buffer output it basically preserves your signal strength and frequencies / tone

You've got the 2 circuits a buffer and a compressor that are probably the hardest to actually hear what effect they have

https://www.masterclass.com/articles/guitar-101-what-is-a-compressor-pedal-learn-how-to-use-a-compressor-pedal#what-is-a-compressor-pedal

Your vactrol looks correct to me going by this image of someone's build and the labelling orientation
View attachment 11230

Thanks for the reply. Would checking voltages be a better way to test the buffer?

 

[Mcknib]

Thanks for the reply. Would checking voltages be a better way to test the buffer?

I'd just probe it's output and if it's distorting check back

Probe your in pad then the output side of the 51R it shouldn't be much different afaik it's a unity gain common collector/ emitter follower buffer

 

[megatrav]

I have the compressor working.
I have verified with Aion that I have the NSL-32 in the correct way.
If it is helpful to anyone, the dot does indeed correspond with the cathode (-).

There is one thing that I would like to say about this circuit- it distorts the signal.
I haven’t done a full resistor check to make sure all resistors are correct but I have adjusted the bias control. I have found that right about halfway is the cleanest and most pleasant compressor. However, when I crank the comp knob and set the volume for unity gain, I can hear the signal clipping, especially with chords.
I am not sure if this is part of this particular compressor’s sound or if I did something wrong.
The overall tone is not what I would consider transparent either. It’s a bit darker unless the blend knob is mostly to the right (more dry signal blended in).

 

[PJS]

This review suggests transparent tone and no distortion even with loud signals. It does sound as if something may be wrong

Pete Cornish OC-1

www.ovnilab.com

 

[megatrav]

This review suggests transparent tone and no distortion even with loud signals. It does sound as if something may be wrong

Pete Cornish OC-1

www.ovnilab.com

Time to break out the multimeter and do some testing

 

[megatrav]

Did some measuring and it turns out I goofed on about 10 resistors! It’s a miracle it makes noise at all.
I will tend to that and double check all of my capacitors as well.
I have never measured voltages with ICs but I assume that is something I should do as well?

 

[megatrav]

Swapped the resistors and it’s working perfectly now!

 

[harmaes]

I’ve just finished building the same PCB today and although its working reasonably well I do notice that it does have noise in the form of crackles. Single coils with maximum volume don’t exhibit this issue but humbucker pickups on max volume do have this issue. Reducing the volume to around 8 removes the crackles. Inside trim and playing around with the blend and comp settings don’t influence the crackles. The crackling issues is prominent with guitar and bass BTW. Same issue.

1. Could this be impedance related?
2. is this related to the LM358N or P opamp as its known for distortion issues?
3. Original uses BC549c, maybe try that instead of the 2n5088? Although I’ve never had issues with the 2n5088.

Overall it’s an OK working compressor but I’ve played better ones that have more control over attack and release like the Origin effects Cali76. The inside trimmer is not doing much to the overall behavior and I find the blend to influence the compression in a strange way. The compression feels more like volume reduction with an attack that is too quick IMO and from no compression it kicks in too heavy when turning the comp knob.

 

[giovanni]

That’s strange. You may want to start a new troubleshooting thread and maybe take some audio/video to give us an idea. And post pics of the board!