More usable volume pot sweep

[sticky1138]

I built an Acapulco Gold clone with an added gain knob. I realize the original is a one-knob power amp emulator, but I want mine to function as a more traditional two-knob distortion.

Right now there is an A100K pot in the volume position, and unity gain comes early around 8 or 9 o’clock. Is there a specific pot I should swap to bring unity gain closer to noon so it has a more usable sweep? B100K? A different value? I don’t fully understand how pot tapering works.

 

[Big Monk]

I built an Acapulco Gold clone with an added gain knob. I realize the original is a one-knob power amp emulator, but I want mine to function as a more traditional two-knob distortion.

Right now there is an A100K pot in the volume position, and unity gain comes early around 8 or 9 o’clock. Is there a specific pot I should swap to bring unity gain closer to noon so it has a more usable sweep? B100K? A different value? I don’t fully understand how pot tapering works.

A linear pot should do the trick for you in this application.

EDIT: On the other hand, I'm thinking about my adventures with Audio pots in the Big Muff and Linear might make unity come even quicker. Sorry. I don't seem to have been much help!

 

[Bricksnbeatles]

The Acapulco gets way loud. If you don’t mind sacrificing a fair bit of the upper threshold of the potential volume on tap, you can take a 50K log pot and put a 50k resistor in series with it. That’ll make it so the range you have available is easier to dial in, and the maximum volume you can get will be roughly equivalent to what you currently reach at 70% of the pot’s rotation.

 

[sticky1138]

This pedal is indeed very loud, so dropping it to 70% is still more than enough output. I really need to read up on electronics terminology instead of just winging it, but for now, series would mean the added resistor goes between pin 2 (or 3?) of the pot and the PCB hole?

 

[giovanni]

I believe it goes between pin 3 and the pcb pad. You could also use a switch to bypass it and recover the remaining volume so you can have it both ways.

 

[daeg]

A linear pot would undoubtedly make things worse.

When a Linear Pot is at 50% of it's rotation, it's at 50% of it's total resistance
When a Logarithmic Pot is at 50% of its rotation, it's at 10% of its total resistance.

That means, if you like the Acapulco at 9-o'clock, you're at like 6/100 of the Volume that's on-tap. Another way to think of that, is you have to divide the output volume by 16.666 to keep this damned thing from melting your ears.

The Acapulco gets way loud. If you don’t mind sacrificing a fair bit of the upper threshold of the potential volume on tap, you can take a 50K log pot and put a 50k resistor in series with it. That’ll make it so the range you have available is easier to dial in, and the maximum volume you can get will be roughly equivalent to what you currently reach at 70% of the pot’s rotation.

^ This is solid advice and exactly what I would do if I built the pedal.