jonwhitear
16-06-2021, 08:35 PM
Hello all,
I'm building a Klon Centaur overdrive pedal clone kit, acquired from AliExpress.
The kit and circuit are as described in this TDPRI thread (https://www.tdpri.com/threads/cheap-chinese-pedal-kits-klon-clone.961187/) and circuit diagram (https://www.tdpri.com/attachments/klon-centaur-schematic-pdf.621228/).
Unfortunately, it's not working very well, and I'd appreciate guidance from someone who understands how the circuit works.
The pedal works in "bypass" i.e. buffered mode, but is very quiet in effect mode. I have checked component values, and measured supply voltages OK, e.g. at the opamp pins.
Long story short, when I feed a 500Hz signal from my scope into the input, with all the controls at 12 o'clock and the effect engaged, I see a nice clean signal at the output of the first opamp (pin 1 of U1a), a nicely distorted signal at the junction of the clipping diodes, and a significantly amplified signal at the output of U2a (pin 1.) However, I don't see any signal at the input of U2b (pin 6.) I seem to lose the signal across the 100K resistor between pin1 and pin 6.
Before I go desoldering stuff and generally making a mess of it, what would your next steps be? I have continuity from pin 1 to one leg of the 100K resistor, and from the other leg to pin 6. The resistance across that resistor measures about 14k in situ.
Cheers,
Jon
I'm building a Klon Centaur overdrive pedal clone kit, acquired from AliExpress.
The kit and circuit are as described in this TDPRI thread (https://www.tdpri.com/threads/cheap-chinese-pedal-kits-klon-clone.961187/) and circuit diagram (https://www.tdpri.com/attachments/klon-centaur-schematic-pdf.621228/).
Unfortunately, it's not working very well, and I'd appreciate guidance from someone who understands how the circuit works.
The pedal works in "bypass" i.e. buffered mode, but is very quiet in effect mode. I have checked component values, and measured supply voltages OK, e.g. at the opamp pins.
Long story short, when I feed a 500Hz signal from my scope into the input, with all the controls at 12 o'clock and the effect engaged, I see a nice clean signal at the output of the first opamp (pin 1 of U1a), a nicely distorted signal at the junction of the clipping diodes, and a significantly amplified signal at the output of U2a (pin 1.) However, I don't see any signal at the input of U2b (pin 6.) I seem to lose the signal across the 100K resistor between pin1 and pin 6.
Before I go desoldering stuff and generally making a mess of it, what would your next steps be? I have continuity from pin 1 to one leg of the 100K resistor, and from the other leg to pin 6. The resistance across that resistor measures about 14k in situ.
Cheers,
Jon