Drop in higher gain/volume alternative to TL072

Started by Esppse, October 31, 2022, 09:05:05 AM

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Esppse

Hey, I built a hex Fuzz that goes into a mixer to sum. I was planning to put a super hard on boost post mixer for volume compensation, but was wondering if the TL072 in the mixer can just be swapped out for a higher volume IC. There are already volume trims on each Fuzz, but they are cranked.

I just used this mixer layout for the project.

https://paulinthelab.blogspot.com/2015/05/simple-audio-mixer-stripboard-layout.html

antonis

Quote from: Esppse on October 31, 2022, 09:05:05 AM
was wondering if the TL072 in the mixer can just be swapped out for a higher volume IC.

If by "higher volume" you mean higher output amplitude, you can raise 150k feedback resistor value (the one between pins 6 & 2)..
(of course, this might result into clipping, depending on particular inputs amplitude..)
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

Fancy Lime

Which opamp you use has no influence on gain or volume in this application. It's the resistors that set the gain and thus volume.
My dry, sweaty foot had become the source of one of the most disturbing cases of chemical-based crime within my home country.

A cider a day keeps the lobster away, bucko!

antonis

Whose (resistors) net values have no influence, as well..
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

GGBB

Quote from: antonis on October 31, 2022, 09:22:16 AM
If by "higher volume" you mean higher output amplitude, you can raise 150k feedback resistor value (the one between pins 6 & 2)..
(of course, this might result into clipping, depending on particular inputs amplitude..)

^

What Antonis said.

And you could replace the 150k resistor with a 500k pot so you'll be able to adjust the output level.

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Fancy Lime

Quote from: antonis on October 31, 2022, 10:06:03 AM
Whose (resistors) net values have no influence, as well..

Antonis, don't confuse the youngins with hair splitting! ;D But you are right of course, it's the ratios between resistors, not the absolut values that set the gain. I'm afraid we are not helping to the best of our abilities here. Does someone have a similar schematic kicking about but with properly labeled components? Might make it easier to explain things to the OP. Antonis said it all in the very first response but I'm not sure it came across. No offense to the OP but based on the question, I am not entirely sure if "feedback resistor" means much to them.
My dry, sweaty foot had become the source of one of the most disturbing cases of chemical-based crime within my home country.

A cider a day keeps the lobster away, bucko!

antonis

Quote from: Fancy Lime on October 31, 2022, 04:22:05 PM
Antonis, don't confuse the youngins with hair splitting! ;D

Andy, I can ensure you for no such an intention.. :icon_biggrin:

Quote from: Fancy Lime on October 31, 2022, 04:22:05 PM
I am not entirely sure if "feedback resistor" means much to them.

That was the reason for the extra clarification:
Quote from: antonis on October 31, 2022, 09:22:16 AM
you can raise 150k feedback resistor value (the one between pins 6 & 2)..

Of course, OP can easily understand mixing procedure by studing something like this: https://www.electronics-tutorials.ws/opamp/opamp_4.html
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

Fancy Lime

Oops, I didn't notice that the pins were labeled in the schematic. My bad! With that it should indeed be fairly clear.
My dry, sweaty foot had become the source of one of the most disturbing cases of chemical-based crime within my home country.

A cider a day keeps the lobster away, bucko!

Esppse

Thanks for clearing that up guys, the 500k pot seems like a great solution to dial it in. If only hex pickups had more gain. I am already using higher gain transistors for the 6 Bazz fuzz circuits (MPSA13). Is there any other transistor that will give it more gain (distortion). It needs both more distortion and volume.

antonis

Quote from: Esppse on November 02, 2022, 07:50:41 AM
Is there any other transistor that will give it more gain (distortion).

Try MPSA14, BC617, 2N5306, 2N5308, 2N6426, 2N6427, 2SC1754, etc...

(beware of correct pin-out orientation..)

Quote from: Esppse on November 02, 2022, 07:50:41 AM
It needs both more distortion and volume.

Replace feedback diode (the one between BJT Collector & Base) with another of higher forward voltage drop..
(Ge diode < Si diode < LED )
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

Esppse