Input amplitude

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Ed Llorca
Posts: 4
Joined: Mon Apr 17, 2017 5:14 pm

Input amplitude

Post by Ed Llorca »

Hi Frank.

I followed the reference design in the G01 datasheet then added all of my circuitry around that. Reviewing the schematic before layout I see that the guitar signal is going to the FV1 with a gain of 1 so it's quite a small signal. If the FV1 has a Input p-p max of 3v wouldn't the A/d yield convert better if I amped the signal up to something near the max allowable?

Thanks for all your help

Ed
Frank
Posts: 158
Joined: Sun May 03, 2015 2:43 pm

Re: Input amplitude

Post by Frank »

This is always a tricky question because if you amp it too high it could overdrive any following pedals. If you choose to add an amp stage make it adjustable so the user can change it, and keep in mind transients as a user hitting the string really hard could produce a signal far larger than the norm and you want to avoid clipping. As a general rule I always leave my circuits with a gain of 1 unless it is a boost circuit, if you put gain in the pedal then when people engage and disengage your pedal the gain of the system changes and they have to make adjustments.
Ed Llorca
Posts: 4
Joined: Mon Apr 17, 2017 5:14 pm

Re: Input amplitude

Post by Ed Llorca »

Frank,

You are so right, I put an oscilloscope on my guitar output and was so surprised at seeing 2V p-p on a hard strum! so much higher than light picking. I will probably make the pre post amps adjustable. I knew I would be learning on this project and I am sure getting that in spades.

Ed
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