Sometimes, you just gotta bodge it

[Monkey_Relish]

This was just one of those builds that drive you mad.
I built a Fuzzdog Phaze 90. Nice all in one PCB that you solder the footswitch to.
Straight forward build, the only special parts were getting matched FET's.
So, I fire it up, and it works first time.

It works great, EXCEPT for a ticking noise that changes in time with the phase oscillation.

So, I do some research. Seems it's the dreaded LFO ticking.
Recommendations are to replace the LFO op amp (TL072) with a lower power version. I tried both the TL062 and the TL022, but to no avail. More ticking than a watch repair shop. Now, the problem with this particular design, is that both the LFO and the input stage share the same op amp IC, so the ticking caused by the LFO is transferred internally to the input stage. It is recommended to use a separate IC for an LFO that is not used for anything else. But the PCB can't easily be changed. There is no room for a sub board mounted to the IC socket.

So, what did I do ? BODGE IT
I used a TL022 for the LFO section, and a TL072 for the input stage, both with one half in the IC socket.
On the unused OP AMP halves, I tied the inverting input to the output, and the non inverting input to ground.
Wired the grounds and VCC between each IC. Worked like a charm.

Ain't she a thing of beauty ?

[EBK]

Ain't she a thing of beauty ?

Yes.   

[gordo]

DIY at it's finest.  Good save!

[cooder]

That's a hack and a half! Well done!

[jubal81]

After reading it, looks slicker than I'd ever imagine. Nice save!

[lars]

You have just invented a new way to try out some mods on different pedals. How about do something like this for any dual op-amp overdrive/distortion pedal, so you can use mismatched halves to get different tones? I.E., instead of one 4558, how about half 1458 and half TL072? Hmmm....
Very clever idea that can have some great uses!

[culturejam]

That's creative as all hell. Nice!