Hi guys,
I built this one
https://tagboardeffects.blogspot.com/2018/10/jhs-angry-charlie-v3.html
The only sound I get is a beeping sound.
Audio probe in the video.
The non inverting input of the LM833 is still ok although there is already some beeping noise, the output is already noise only.
The jumper between 7 to 9 is due to an extra cut I made.
The 2 jumpers on 7 and 9 are at the back.
The red wire at the top right if for the enclosure LED.
I checked for any bridge but could not find any.
(https://i.postimg.cc/G8NzfyZw/Whats-App-Image-2024-09-22-at-9-58-32-AM.jpg) (https://postimg.cc/G8NzfyZw)
(https://i.postimg.cc/fS95QbN3/Whats-App-Image-2024-09-22-at-9-58-32-AM-1.jpg) (https://postimg.cc/fS95QbN3)
(https://i.postimg.cc/bSPmhFgy/20249-M00-topic-132444.png) (https://postimg.cc/bSPmhFgy)
Hi & Welcome.. :icon_wink:
m4268588 above suspects a heavily oscillating Vref (directly driving capacitive load) in conjunction with Vref resistive voltage divider smoothing cap absence (strongly dominating op-amps PSRR)..
The former could be remedied with a small value series resistor between op-amp out and that 100μF cap and the later with a cap to GND on 22k/22k junction but, for an already existing board, just moving cap's positive leg one row down is a smart and easy issue fix.. :icon_wink: