Brett
Well-known member
Hello everyone!
I built this up a couple of weeks ago and things were working although the compression seemed a little lackluster and the LED was godawfully bright (can we just agree that super bright LEDs are criminal?
). I decided to do a couple of things to try to improve both of these shortcomings and when I attempted to use the pedal after the minor adjustments, it no longer works when engaged.
To address the LED brightness issue:
I attempted to replace the CLR resistor to tame the bright LED. In doing so, I managed to fubar the pad and had to add a jumper wire to get 9V to the supply side of the 4K7 resistor. I jumpered the wire between the two spots shown:
This brought power back to the CLR, but the LED was still blinding. I proceeded to change out the super bright LED to a regular, 3mm diffused red. The LED brightness is now acceptable.
To address the lackluster compression:
I originally used the LDR and LED that was specified, the GL5516 LDR, and the super bright white 5mm. Upon reading through just about all the PedalPCB forums I could find on the subject, it became clear that the lackluster compression may have been caused by a bum GL5516 or the LED being too bright so I replaced the LDR with a Waitrony KE-10715 from Tayda (based on recommendations elsewhere in the forum), and a diffused green 3mm LED (per @Chuck D. Bones suggestion in another thread). I tested the LDR using my DMM just to make sure that the resistance change was fast, and it appeared to be much faster than the previous GL5516's that I purchased previously. I don't have an oscilloscope, so I can't be certain of the time between states on the LDR.
As previously stated, when I plugged everything back in last night, the pedal works fine on bypass but does not work when engaged. I've tried just about all I can think of to troubleshoot this so far before posting here asking for someone more knowledgeable for guidance.
Troubleshooting steps that I've taken so far:
Voltages when the pedal is active:
Source Voltage: ~9.75V
IC1: OPA2134
IC2: TC1044
I built an audio probe this morning for testing.
I get sound all the way up to Pin 3 of IC1. Pin 2 does not produce sound with the probe. During this testing, I accidentally bridged Pin 1 and Pin 2 of IC1 with my probe and got sound, but no sound on Pin 1 or Pin 2 on their own. This led me to believe I had a defective IC, so I swapped it out with a 4558 and the problem persists.
Again, I don't believe this is a case of using the wrong component because the pedal was working prior to me making the aforementioned changes. The pedal has sound when in bypass but does not produce sound when engaged. I feel like I'm hitting my head against the wall trying to figure this out because I rarely run into these types of issues. I hope that someone with a fresh set of eyes can point to some glaringly obvious issue or something that I'm overlooking.
Thank you in advance!
I built this up a couple of weeks ago and things were working although the compression seemed a little lackluster and the LED was godawfully bright (can we just agree that super bright LEDs are criminal?
). I decided to do a couple of things to try to improve both of these shortcomings and when I attempted to use the pedal after the minor adjustments, it no longer works when engaged. To address the LED brightness issue:
I attempted to replace the CLR resistor to tame the bright LED. In doing so, I managed to fubar the pad and had to add a jumper wire to get 9V to the supply side of the 4K7 resistor. I jumpered the wire between the two spots shown:
This brought power back to the CLR, but the LED was still blinding. I proceeded to change out the super bright LED to a regular, 3mm diffused red. The LED brightness is now acceptable.
To address the lackluster compression:
I originally used the LDR and LED that was specified, the GL5516 LDR, and the super bright white 5mm. Upon reading through just about all the PedalPCB forums I could find on the subject, it became clear that the lackluster compression may have been caused by a bum GL5516 or the LED being too bright so I replaced the LDR with a Waitrony KE-10715 from Tayda (based on recommendations elsewhere in the forum), and a diffused green 3mm LED (per @Chuck D. Bones suggestion in another thread). I tested the LDR using my DMM just to make sure that the resistance change was fast, and it appeared to be much faster than the previous GL5516's that I purchased previously. I don't have an oscilloscope, so I can't be certain of the time between states on the LDR.
As previously stated, when I plugged everything back in last night, the pedal works fine on bypass but does not work when engaged. I've tried just about all I can think of to troubleshoot this so far before posting here asking for someone more knowledgeable for guidance.
Troubleshooting steps that I've taken so far:
Voltages when the pedal is active:
Source Voltage: ~9.75V
IC1: OPA2134
| Pin 1: 16.96V | Pin 8: 17.97V |
| Pin 2: 0.775V | Pin 7: 8.97V |
| Pin 3: 7.32V | Pin 6: 8.97V |
| Pin 4: 0V | Pin 5: 8.95V |
IC2: TC1044
| Pin 1: 9.46V | Pin 8: 9.46V |
| Pin 2: 4.81 | Pin 7: 6.12V |
| Pin 3: 0V | Pin 6: 4.62V |
| Pin 4: 0V | Pin 5: 0V |
I built an audio probe this morning for testing.
I get sound all the way up to Pin 3 of IC1. Pin 2 does not produce sound with the probe. During this testing, I accidentally bridged Pin 1 and Pin 2 of IC1 with my probe and got sound, but no sound on Pin 1 or Pin 2 on their own. This led me to believe I had a defective IC, so I swapped it out with a 4558 and the problem persists.
Again, I don't believe this is a case of using the wrong component because the pedal was working prior to me making the aforementioned changes. The pedal has sound when in bypass but does not produce sound when engaged. I feel like I'm hitting my head against the wall trying to figure this out because I rarely run into these types of issues. I hope that someone with a fresh set of eyes can point to some glaringly obvious issue or something that I'm overlooking.
Thank you in advance!
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