Hacking a mid-boost mod into a MOSFET based OD

[garcho]

you should do something like this with unused op amps:


pin 5 = +
pin 6 = -
pin 7 = output

the output should basically be 0V and you don't have to worry about current, IC freak out, etc.

Maybe use 100KΩ resistors instead of 10K, not a big deal though.

[PRR]

> In your schematic...would I not need to do something with the other pins on the TL072 (that is, pins 5, 6, and 7)?

Not sure what schematic "your" means.

Gary gave you a great reference, the Mancini OpAmp Book. Snippet:

[antonis]

IMHO, C4 value is marginally low for low Vol pot settings, Gary..

That schematic is thrown together really quickly, probably could be improved all over the place. But if the pot is 100KΩ to ground, corner is 16Hz, no? 50% is 34Hz, 25% is 66Hz. It's only -3dB, yeah? Takes a while to hear it. And why would the volume be at low settings, realistically? I'm probably not following or missing something obvious.

You don't miss anything other than following effect input impedance..

[mordechai]

I actually stumbled across the Anderton Frequency Boost circuit, and looked at some demo videos...it seems like it will do the trick in terms of isolating and bringing out a mid boost (around 1K, but I'm guessing a few tweaks can get me closer to 720Hz). 

So now my question is...if I work that circuit into the Mosfet Driver, can I just make the Mosfet Boost output a trimmer, and then take the signal and feed it into the Frequency Boost, and make **it's** output the final output of the circuit?  Or is the Frequency Boost better placed at an earlier stage, maybe before the Mosfet stages?

[garcho]

Because it's an op amp, it's a decent thing to have at the end of your signal, and that would be the easiest solution, which is an important consideration for engineering that gets overlooked. It's a boost only, no cut, so if you put it before gain stages it could mess with them. Or it could sound great...

If you feel like reading the internet for the rest of your life, check out what some (reputable) audio engineers have to say about where to put EQ in your signal chain, it's a similar concept with guitar pedals, regarding the sound, anyway. Obviously, circuit design isn't the same as patching units together.