Running the Abyss at 9v I get some distortion when I dig in, play with hotter pickups, or with my bass. If I strum lightly/normal it’s fine for most of my gear. On a whim I plugged it into 18v (my caps are all of the appropriate voltage) and everything is clear as a bell. I know runnning higher voltage raises the headroom, very nicely in my case, but has anyone else experienced this?
SOLVED Abyss distortion issue
- Thread starter Diynot
- Start date
Placed a 240ohm at R26, replaced the 1M at R2, and lifted the LDRs. Sadly, this did not resolve the issue. It’s perhaps better, but even with voice and throb at zero it’s fuzzy at the edges. With bass it’s total fartsville. Going to have to put this aside for awhile and come back to it. Can’t remove that rate pot many more times without killing the board. Just for my own curiosity, the clipping would more than likely be from the ICs, not the mpsa18s, they aren’t seeing audio signal, correct?
Chuck D. Bones
Circuit Wizard
That's right, the transistors only carry the LFO signal.
Either you are putting a HUGE signal into the Abyss or there is something not quite right going on.
If and when you come back to this, there are some easy checks we can do. We already checked the IC voltages and they look good. You'll need an audio probe for the next part. Have you verified R3 - R13 are all correct? Turned the THROB pot all the way down?
Either you are putting a HUGE signal into the Abyss or there is something not quite right going on.
If and when you come back to this, there are some easy checks we can do. We already checked the IC voltages and they look good. You'll need an audio probe for the next part. Have you verified R3 - R13 are all correct? Turned the THROB pot all the way down?
I have played it with single coils (Strat and tele) and a p-90 loaded guitar. The hottest signal would be the bass which is a sterling stingray with active electronics. I have checked my components, but will go over them again. After that, I will probe it like an alien on a human subject.
Feral Feline
Well-known member
Aight folks, after taking a bit of a break from staring forlornly at my PCB, I went back over my components again and low and behold, it is with much chagrin that I report I had a 4.7k resistor in place of a 47k at R3
. I have not had the moment to swap it and test, but I have much hope that this will resolve the issue.
. I have not had the moment to swap it and test, but I have much hope that this will resolve the issue.
Chuck D. Bones
Circuit Wizard
Did I read that right? Visual Inspection found the problem?
Sometimes it takes fresh eyes to see these things.
Sometimes it takes fresh eyes to see these things.
Chuck D. Bones
Circuit Wizard
I hear ya. I use a lot of light and a lot of magnification.
The second thing to go is eyesight.
I forget what the first thing is.
The second thing to go is eyesight.
I forget what the first thing is.
I did my part way back coz your resistors are standing up & that would have been the resistor value I would have spotted if they were the correct size & laying down.Here is a Resistor Calculator to check your Values are correct?
Click on Bands for 5 Bands:
Resistor Calculator
Resistor Calculator is an App developed by CherryJourney to help the user find the value of a resistor.resistor.cherryjourney.pt
You assured me that you measured each resistor before putting them in so hopefully you learn from this & measure twice or fit the recommended resistors for the Build.
Cheers music6000
I appreciate everyone’s help and am embarrassed that it was such an obvious oversight. To be honest, I had caught a similar error at R23 and R25 and corrected that before I even started the thread. After that, I had gone over the board again, but missed R3 somehow. I think we all can appreciate using what you have on hand. Had I at least turned the resistors away from the IC, I might have caught it earlier. Live, build, and learn
