# Which Pedals Can 'Take' 18v



## keto (May 23, 2006)

I'm putting together a pedal board and am momentarily out of 9v supply. I have 3 extra 18v supply, I want to know if I can safely put them in the following:

-Bad Monkey - I'm pretty sure yes
-Marshall JH-1 Jackhammer
-Keeley Java Boost (guessing 'no')
-Menatone Red Snapper
-Marshall ED-1 Compressor
-Way Huge Swollen Pickle (Big Muff variant)

Thanks


----------



## Archer (Aug 29, 2006)

Unless the literature on the pedals says they can take 18 then assume they can't.


----------



## keto (May 23, 2006)

Thus my post above LOL :wave:


----------



## kat_ (Jan 11, 2007)

Google says that none of them are 18V.

http://www.sweetwater.com/store/detail/BadMonkey/

http://www.marshallamps.com/product.asp?productCode=Jackhammer&pageType=SPECS

http://www.robertkeeley.com/manuals/java_boost.pdf

http://www.pedalgeek.com/cgi-bin/new_shop.cgi?command=link--mtrs

http://www.marshallamps.com/product.asp?productCode=Compressor&pageType=SPECS

http://www.gearwire.com/dunlop-wayhuge-swollenpickle.html


----------



## keto (May 23, 2006)

I know they aren't natively. Bad Monkey definitely runs, with more clean headroom. Not sure if I like it or not but it definitely runs.


----------



## keto (May 23, 2006)

This is what I'm trying to sort out, what a mess LOL. Built the board itself last night. Going to use cable ties, so I have lots of drilling to do in that particle board once I finalize order.


----------



## mario (Feb 18, 2006)

I run my Fulltone Fulldrive2 and OCD on 18vt. They sound great.

EDIT I missread your thread. You were asking about specific pedals...not Fulltone.kqoct Sorry about that.


----------



## mhammer (Nov 30, 2007)

The appropriateness of supplies greater than 9v will depend on a few things: 

1) The semiconductors in use. Most transistors used in discrete circuits will do just fine with 18v, and the vast majority of op-amps will too. There may be other chips which either do not benefit whatsoever from 18v or risk damage at 18v. For example, while Boss uses a discrete transistor circuit for the electronic switching, DOD generally uses CMOS chips (CD4007 most often) for switching. And even though the rest of the circuit may do just fine with 18v, CMOS chips die a horrible painful death above 15V. 

Any analog chorus pedals in production these days generally use an MN3207 or equivalent, and that chip was intended to be used with a 5V supply. There is usually an onboard regulator to drop the 9v battery (and one would assume any external supply) *down* to +5v, but the 18v feeding it provides no particular advantage. In the case of the CE-5, it uses an MN3007, which CAN take and use a supply voltage higher than 5V or 9V, but doesn't seem to be especially at ease with more than 15V. Trust me, you do not want to blow that chip.

2) The adjustment of the semiconductors in use. Many devices, especially transistors, and especially FETs, can be designed around some anticipated bias voltage in order to produce certain desired sonic characteristics. If the bias is produced by simply dividing down what the pedal-maker assumes you will be supplying, then dividing 18v in half is NOT the same outcome as dividing 9v in half. The pedal may not self-destruct, but it may not sound that s**t hot either. Sometimes, there are trimpots to do the final adjustments and the right bias CAN be achieved...but it's up to you to relocate the optimum bias.

When LEDs are used as part of an LED/LDR combination, the supply voltage used in the LFO to lighten and darken the LEDs may produce different modulation characteristics if the LEDs are made generally brighter by the use of a different supply voltage.

If one has a noise-gate, limiter, compressor, or other envelope-controlled device, often there may be use of a threshold of some kind and the circuit does what it does by comparing the incoming signal to some reference point. Often that reference will be a voltage based on the supply. If the supply voltage is different, the reference point is different, and the pedal will behave differently. It CAN be adjusted by component changes, but you have to know the pedal to be able to do that.

3) The purpose of the pedal. Higher supply voltages allow for greater clean headroom. This is often something you want for an EQ pedal, a clean booster intended to produce clean tone, or a compressor. A great many other pedals either are decidedly intended to have as little clean headroom as possible (e.g., many fuzzes). Under those circumstances, hiking up to 18v may be of questionable advantage.

Having said all that, there are a number of commercial pedals that expect to see more than 9v, and as much as 18v on their adaptor inputs.

Now, I'm not trying to dissuade you entirely from considering the use of an 18V supply. The thing is that you have to have some familiarity with the innards of your pedals to know that:
a) it is safe to use that high a supply, and
b) if safe, the intended tone of the pedal will be retained with that high a supply.


----------



## BoogaBooga (Mar 1, 2009)

Most opamps can have a maximum supply of +/- 18V so thats 36V... but as said above, there are other components that could burn out before the opamp.


----------



## traynor_garnet (Feb 22, 2006)

Tim/Timmy
OCD
Catlinbread Dirty Little Secret

All ok at 18 volts


----------



## mhammer (Nov 30, 2007)

Pedals behave "better" at higher supply voltages if the goal is cleanliness. None of the pedals you list are intended to be clean, with the exception of the Marshall Compressor. Since the ED-1 uses a mechanical, rather than JFET switching arrangement, at least you know there are no CMOS chips to blow up. At the same time, the 3080 chip used in the ED-1 is not all that happy with hotter input signals, and the current-control that dictates how it moderates gain, is likely to be screwed up by use of a higher supply. You *could* use a higher supply with it, but not unless you engaged in some trial-and-error tinkering with the relevant resistor values in the circuit.


Final tally? Leave well enough alone.


----------

