AMZ Overdrive Pro - High Pass Filter?

[stumper1]

I just finished an AMZ Overdrive Pro.  Seems really cool - haven't changed anything from stock so far.

The only part I don't like is the low end seems really "flabby".  I put a Boss EQ pedal in front of it and rolled off the bass below ~750 hz and it sounds awesome.  Is there a high-pass filter in the circuit that I can adjust?

[cd]

If you like a rolloff around 750Hz, change the input cap to a .022u cap.

[stumper1]

Thanks!!

I think I was on the right track but I must have had my math a bit wrong.  Somehow I came up with .0022uf instead of .022uf.  Didn't try it yet so I'll test it when I get home.
:oops:

[cd]

Thanks!!

I think I was on the right track but I must have had my math a bit wrong.  Somehow I came up with .0022uf instead of .022uf.  Didn't try it yet so I'll test it when I get home.
:oops:

Doh!  You're right, that should be .0022u - I put in .01M ohms instead of .1M ohms

[stumper1]

Cool!!

I'll try that when I get home!!!

Jack suggests (per Tonepad) switching R2 and R4 to 240k and 1.5k.  Can you tell me what changes this would make?

Thanks!!
Deric

[cd]

Jack suggests (per Tonepad) switching R2 and R4 to 240k and 1.5k.  Can you tell me what changes this would make?

That will drastically reduce the gain of the 1st transistor stage.

[stumper1]

Well.......tried a .0022uf and that was WAY too much roll-off.  Tried a .0047uf and it seems just about right.  Definately tightened up the low end.  Tried a .01uf and that didn 't seem like enough.  Might have to do some digging for a cap between .01 and .0047.

So far......it seems VERY cool.  Tons of gain on hand.  I do believe this one WILL be a KEEPER on my pedal board.

By the way......used 2 red LED's in the clipping section. While it doesn't have a ton of output, it certainly has enough to push it above unity gain when maxxed.  

I socketed most parts so I can play with it a bit.  Will try it with diodes too.

Thanks for all the help......so far so good!!!

[MjS]

How do you guys figure out which capacitors and/or resistors should be put where in the circuit for certain results?

[MjS]

Nobody?

[stumper1]

There are several mods with specific descriptions for the Overdrive Pro listed at both Tonepad and AMZ.  Other than that, lots of searching this forum - lots of reading - lots of help from all the great people here................. and some guessing/trial and error.