How to adjust unity gain?

[Soeren_DK]

How to adjust unity gain?

I want to adjust the unity gain level for my stomp boxes but I don't know how. I have a signal generator and a voltmeter but I don't know how many volt I should fire throug the system. I have tried to messuere the volt level of the guitar but its a little difficult. There must be some kind of standard level for the output of a guitar but I can't find any. I don't know eather if this is possible and if this is the right way to do it.



Cheers
Soren

[anchovie]

There isn't a standard level for the output of a guitar, it will vary depending on the pickups you are using. This shouldn't really matter though as unity gain by definition means that the output signal amplitude is the same as the input.

A bit more detail on what you are trying to achieve would help here. Are all of your stompboxes quieter than your clean signal, even with the effect volume on full?

[JKowalski]

Your question is very vague. Adjusting the gain for a circuit is not as simple as I think you are picturing it - you have to figure out how the circuit works, what components alter the gain, and how to alter them.

The best way to adjust for unity gain is to find a resistor that changes the gain of the circuit and exchanging it for a trimpot, and then adjusting the trimpot while constantly bypassing/turning on the effect until the original signal and effected signal sound like the same volume.



And, if you wanted to know still, a guitar signal is from 100mV rms up to 1V rms, depending on the type and design of your guitar's pickups. That knowledge won't really help you in this case, however, as listening to the bypass/effect while adjusting is going to give you a much better unity gain then measuring values.

[Soeren_DK]

Thanks for the replys.
I asked the question because I want to have the same signal with and without the effect on but I can see the issue in that. I thought it was a easy job but I can see its not that easy to adjust the pedals with reading values so I just have to listen to it when I play and adjust it manual..

Thanks again guys
Cheers
Soren

[petemoore]

  you could set to unity into amp, then try phase, and notice that ''unity output'' is different depending on what it is input to.
  ...
  You could set to a chosen output which sounds like unity for your application, then replace the potentiometer with 2 resistors. 1rst resistor to replace Rvalue measured right from the pots 1-2 lugs, 2nd resistor to replace the value measured between lugs 2-3.
  Now you can put those resistors on a switch which routes the signal either through the volume pot, or the two fixed resistor values chosen from a volume pot set to 'unity'.