What Advantage Is There With An 18v Pedal Over A 9v Pedal?

[Phaedrus]

Hi,

Why do some manufacturers make some of their pedals 18v and some 9v?

My MXR El Grande is 9v, but my mate's MXR BlowTorch is 18v - why do this?

I prefer the fuzz from my El Grande, he prefers his BlowTorch (he plays bass in a different band, and we sort of share the same pedalboard). I've wired the board up with a GigRig Distributor, but I'd have to buy extra stuff to bring the BlowTorch into my board. Pain.

Does 18v provide cleaner (less noise/hum) fuzz than 9v?


Thanks,

Mark

[Silent Fly]

For some circuits, a higher operating voltage allows more headroom for the signal.

There are some other important factors to consider though. First, powering a pedal at 9V doesn't necessarily mean that internally it operates at 9V. It may operate at 18V, 24V or even +30V. Powering this type of pedal at more than 9V is not only pointless but it is likely that it will damage the pedal.

There are other circuits where higher voltage does not have any effect on the headroom. For example, a lot of distortion pedals create the distortion limiting the voltage swing. In cases like this, a higher supply voltage can have very limited effect.

More in general terms, power supply voltage and internal operating voltage are design choices that don’t have necessarily a direct effect on the sound. In other words, there is not an “18V sound” and a “9V sound” – especially considering that pedals powered at 9V may operate at a different voltage.

Regarding the MXR BlowTorch, I am not absolutely certain about it but I believe the 18V power supply (that in this case is also the internal operating voltage) is there to give the EQ section more headroom.

[Phaedrus]

Thanks SF.