Using a 12 volt adapter for a 9 volt pedal

[peterg]

I modified a multi volt positive tip adapter to a be a negative tip adapter, as per Beavis Audio's instructions, to use at 12 volts with my Valvecaster and a breadboarded 6111 tube Twincaster/Pepper Shredder/ Subcaster hybrid.

Now that I have a 12 volt adapter can it be used on other pedals? I have three using the PT2399 chip and a number of EHX, MXR Dan Armstrong and Boss, etc. clones.

How can I find out if using 12 volts will fry my pedals (other than to try it out) and if there are any benefits with upping the volts?

[R.G.]

Now that I have a 12 volt adapter can it be used on other pedals? I have three using the PT2399 chip and a number of EHX, MXR Dan Armstrong and Boss, etc. clones.
How can I find out if using 12 volts will fry my pedals (other than to try it out) and if there are any benefits with upping the volts?

Unfortunately, the answer to your questions is that it will fry some pedals, work fine with others and make yet others sound different/bad.

Pedals are quite different in their circuitry and construction. Some commercial pedals are made with 10Vdc electro caps. Those are at some danger from a 12V supply and may die. Maybe not, but maybe. Pedals with discrete circuitry, transistors, resistors and caps only, will tend to be differently biased by changing the power supply if they don't die. This may cause sound changes that are good, bad or indifferent. Opamp-only circuits tend to be fairly immune, as they are usually biased to a fraction of the total power supply, and can withstand larger than 12V. Usually.

There are unlikely to be any great benefits to upping the voltage, IMHO. There may be some pedals where this causes a benign shift in operations, but that will be fewer rather than more pedals.

Pedals using the PT2399 are almost certain to use a 78L05 regulator to power the logic chip(s). These will be immune to the difference between 9V and 12V for the chips powered by the regulator. There may be other stuff in there around the PT2399 that more volts helps, hurts, or doesn't matter to.

The devil is *always* in the details.

[peterg]

Thanks RG. I've made all the pedals I own and have used 25 volt caps at a minimum. The PT2399 chip pedals have 78L05 or LM7805 regulators in them.

I'll play it safe and stick with 9v for the non-tube pedals and 12v for the tubes.