need to step up guitar voltage to power analog meter

[runmikeyrun]

Hey all,

I've got a small project here.  A meter that measures the millivolts of a guitar signal with a small panel meter set into a stompbox.

Purpose:  To measure levels from the guitar going direct into the computer interface, then later matching those levels going from the interface into the guitar amp to be re-amped.  This insures the guitar amp is getting as close to the same level as it normally would by the guitarist plugging straight in, thereby getting the same characteristics of the amp.

I picked up a vintage analog panel meter that is from 0-1vac.  The different guitars I have output between 150-300mV.  The meter is moving, but not to the extent of the voltage measured with DMM.   

I tried using a tiny transformer to step up the voltage.  I took this from inside a microphone-XLR converter plug, which helped a little, but not quite enough.  It did step up the voltage (to a little above 1v as measured with my DMM) but the current was probably not enough to drive the analog meter fully because it was not displaying the same reading as my DMM, more in the range of 300-400mV.

I'm trying to keep my device passive if possible, but it looks like I might have to use a small IC circuit to boost current to drive the meter to read an accurate voltage. 

Does anyone know what ratio of a transformer would be fairly close?  I'm not sure what ratio the transformer I'm using is, or how to figure it out... the DMM readings jump around a lot so I can't tell exactly what voltage is going in/out.  Also, a little help with a link to find one would be helpful as well. 

Thanks for reading!

[PRR]

A naked guitar will not drive any standard passive meter without massive suckage (the readings will be wrong).

Transformer can't help. Not enough power out of a guitar.

A passive meter reads the *average* over a period of time. In much audio processing we really want the *peaks* which is where the damage happens.

The DMM probably has other errors. Sampled data, detector type, falling response in the top of the audio band.

[tonyharker]

What you need  is an Audio millivoltmeter ie https://sound-au.com/project16.htm or a sensitive oscilloscope.