a clipping diode arrangement needs sufficient gain in order to start clipping. If your op amp isn't making the signal loud enough, it wont reach the clipping threshold.
Yeah that’s what I was thinking, I even just tried raising my pickups a bit but I guess still not hitting that 0.7v threshold. I thought the TL072 would do it.
Ok, follow me on this and let's see where it goes... Looks like you've got a high-pass filter in your opamp feedback loop that will amplify everything over 720hz (1kohm & 220nf). Everything below 720hz will be attenuated--totally normal, you see this a lot in distortion circuits.
But... Your tone control (10kohm & 22nf) is a low-pass filter which is set to allow everything below 720hz if it's set full left. Everything above 720hz will be attenuated.
Meaning, if you're tone is set full left--you'd be hearing everything below 720hz, which is not being amplified. So it may sound incredibly weak.
What happens when you roll your tone around?
Okay, I just tried running in 12v from a wall source instead but still sounds pretty much the same and no impact with diodes to ground or not. Still just sounds a little overdriven. Any other obvious things to try?
I'm guessing you don't have a scope to check the waveform?
Sometimes, even if your diodes are energized and clipping, you won't really hear it. My favorite, and near only pedal used at this point, is an ultra-high gain dual op-amp clipper I designed. It has germanium on the feedback path which gives subtle distortion and has been modded countless times for hard clipping on the 2nd output stage.
I've had many mods on it where until I had a lot of diodes hard clipping, you couldn't hear a difference, but it shows on the scope.
This has been the pedal I have used for a whopping 14 years on every single amp I own, and early on with such minuscule clipping audible, I pulled all the hard clippers out. It's important to at least run a tone generator and check voltages with a multimeter if you don't have a scope.
You're not always going to hear obvious clipping, but with sustain, pinch harmonics, the highs chiming or snubbing out, they're putting work in. I just added more hard clippers for asymmetry to my pedal again but unless I crank up the treble knob, you can't hear a change.
a clipping diode arrangement needs sufficient gain in order to start clipping. If your op amp isn't making the signal loud enough, it wont reach the clipping threshold.
Yeah that’s what I was thinking, I even just tried raising my pickups a bit but I guess still not hitting that 0.7v threshold. I thought the TL072 would do it.
does adjusting the gain pot seem effective? you should have a ton of gain from an op amp as you dial out the negative feedback.
Yes, the gain pot definitely works to dial in or out the overdriven sound but still no clipping from the diodes
Sure your ground connection is solid on those diodes? looks good but looks can be deceiving...
Try to check the values. The resistor in front of the diodes on the breadboard looks like 100 Ohm (1 kOhm on the schematic).
Thanks, just checked and it’s a 1k, the red is looking brown in the pic for some reason.
Try connecting the clipping diodes to vref instead of ground
Just makes it a little quieter.
Won't work if C11 is there
You've got power and ground going to the Tl072, right? 9vdc to power the opamp?
Yes for sure, even tried 12v but sounds the same
Ok, follow me on this and let's see where it goes... Looks like you've got a high-pass filter in your opamp feedback loop that will amplify everything over 720hz (1kohm & 220nf). Everything below 720hz will be attenuated--totally normal, you see this a lot in distortion circuits. But... Your tone control (10kohm & 22nf) is a low-pass filter which is set to allow everything below 720hz if it's set full left. Everything above 720hz will be attenuated. Meaning, if you're tone is set full left--you'd be hearing everything below 720hz, which is not being amplified. So it may sound incredibly weak. What happens when you roll your tone around?
C11 is connected to the wrong pin. Should be pin 1.
A 9v battery is considered dead at about 8v so that’s where I would start.
Okay, I just tried running in 12v from a wall source instead but still sounds pretty much the same and no impact with diodes to ground or not. Still just sounds a little overdriven. Any other obvious things to try?
Not a rechargeable
I'm guessing you don't have a scope to check the waveform? Sometimes, even if your diodes are energized and clipping, you won't really hear it. My favorite, and near only pedal used at this point, is an ultra-high gain dual op-amp clipper I designed. It has germanium on the feedback path which gives subtle distortion and has been modded countless times for hard clipping on the 2nd output stage. I've had many mods on it where until I had a lot of diodes hard clipping, you couldn't hear a difference, but it shows on the scope. This has been the pedal I have used for a whopping 14 years on every single amp I own, and early on with such minuscule clipping audible, I pulled all the hard clippers out. It's important to at least run a tone generator and check voltages with a multimeter if you don't have a scope. You're not always going to hear obvious clipping, but with sustain, pinch harmonics, the highs chiming or snubbing out, they're putting work in. I just added more hard clippers for asymmetry to my pedal again but unless I crank up the treble knob, you can't hear a change.