Stockade Overdrive Op-amp Substitution

J

Jarrett

New member
I was ordering parts to build the Stockade and I got everything but the Lm833n. I thought I had them but what I have is the Lm358n. The pinout looks the same but the specs are pretty different, though I dont really know what they mean...

Would I be able to sub the 358 for the 833 or is this going to change the character of the pedal?
 
LM358 will be dirtier and can be unpleasant sounding in TS builds like the Stockade/Palisades is. Do you have any 4558, 4559, 4580 or 1458 type op amps lying around?
 
Unfortunately these are the only op amps I have lying around. I'll see if I can salvage one from something else Im not using, but otherwise I'll wait until I get ready to order another batch of goodies. Maybe I'll socket this one in until I get the right one.

Thanks for the reply!
 
I ended up substituting a TL072. The circuit works and sounds great on the Gain A side, but as soon as I engage the middle footswitch for Gain B I'm having some issues.

I typically get no sound on Gain B no matter where the knobs are set, but I have noticed that sometimes I get a quiet fizzy sound, especially if I strum really hard or use a hotter pickup. I've been analyzing the circuit and cant understand why this might be the case because the only part of the circuit this switch seems to affect is the impedance between pins 1 and 2 of the TL072. Depending on where I have the pots turned to, A and B could be contributing the same value, right? But I have no issues with the A side.

Do I just have a bad B1M pot? Or could there be something else causing the problem. FWIW - I have tested the 3PDT footswitch and it is making connection as it should. I also measured the resistance on the B1M and it seems right, but it took my DMM several seconds to ramp up to the correct measurement. Full counter-clockwise reads ~0 ohms immediately, but full clockwise reads 100k and rising to 1m. This could just be because I have a cheap meter though.

1644900013812.png
 
I already have it boxed up. Here is the component side if that helps. Can take it apart if I need to, of course.
 

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It could be an illusion with the photo but it doesn’t look like there is much solder present on both the A500k and B1M pots. I’d start off by reflowing those joints with some more solder and then test again.
 
Yeah, I realized that after I added that photo. I soldered those from the other side and Im pretty confident that it is making a connection, but before I add any more I just want to be sure I'm not going to have to desolder the pot.
 
JamieJ said:
It could be an illusion with the photo but it doesn’t look like there is much solder present on both the A500k and B1M pots. I’d start off by reflowing those joints with some more solder and then test aga
Click to expand...

Jarrett said:
Yeah, I realized that after I added that photo. I soldered those from the other side and Im pretty confident that it is making a connection, but before I add any more I just want to be sure I'm not going to have to desolder the pot.
Click to expand...
Okay I did end up resoldering those pots, but Im still having the same issue.

Am I correct in believing the issue can only be in the part of the circuit that I clipped from the diagram and posted here? Or is it possible that the TL072 doesn't have enough output for the higher impedence pot of the Gain B circuit?
 
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