# MXR EQ 10 Band



## dino (Jan 6, 2009)

I recently purchased a used MXR 10 band EQ. The guy who sold it to me said he daisy chained his power supply off his 9 volt tuner to the MXR. The MXR is 18 volts so how much difference does it make to be run at 9 volts rather than the 18 volts ? 

Thanks , Dino


----------



## mhammer (Nov 30, 2007)

Not that much. Maybe a bit of a difference in clean headroom, but then clean headroom depends on what you feed it for signal, right?


----------



## forum_crawler (Sep 25, 2008)

I would stick with the recommended 18V just to make sure that no damage occurs to your pedal. If you run the pedal on the effects loop of your amp, it is possible to make it clip if your are running too hot a signal.


----------



## Cort Strummer (Feb 16, 2009)

no damage will be done running at 9v as it would be pushing a weaker signal, however running the EQ at 9v rather then 18v will lower the headroom which is really the opposite of what you want with the EQ. So for best performance or the pedal and best tone I would highly recommend running it at 18v.


----------



## mhammer (Nov 30, 2007)

Like I say, the degree of headroom advantage it provides will depend on the signal you feed it.

Let us say you feed it a signal that average +/-100mv. The chips in the pedal can probably swing to within 1 to 1.5v of the supply limits. Let's be conservative and say 1.5v. That means the chip can *cleanly* amplify the signal up to point where it swings over a 6v range (+/-3v). Beyond that, it clips. So, dividing +/-100mv into +/-2v we see that the signal can be amplified by a factor of 30x before clipping sets in. If the EQ pedal applies that much gain, then 9v will impose headroom limitations. In many instances, it will not be that much of a limitation for guitars. However, keyboards, which have a much greater dynamic range, will most certainly benefit from the extra headroom that 18v provides, and if you feed the EQ a boosted guitar signal and want the EQ to behave itself, then 12-18v will help. Note that you have more choices than *just* 9v or 18v.


----------

