Pedal / power question

[JackB1]

Anyone else have the MXR Mini ISO Brick? Question….one of the outputs is for 18v. Can I plug in a pedal that’s 12v into the 18v output? The manual says “make sure your pedal is not rated higher than the output”. So should be OK right?

The 12v pedal in question is the TC Helicon Harmony GXT. It’s says it’s power is 12V, 300mA. The MXRs 9V outputs say they are 300mA each. So can I connect the Harmony pedal to the 8v output? I guess I’m confused as to which one shouldn’t be higher? The power supply rating or the pedal rating?

[jonfields45]

It might work or it might work only for a while...

You want the voltage to be the same and the current rating of the power supply same or higher.

If you're a gambling man, it is likely there is a switching power supply inside the Harmony-G that will tolerate more than 12 volts since the digital guts of that pedal need all sorts of different voltages and switchers very efficiently discard volts they don't need. The current rating of the MXR is plenty high.

Voltage is a measurement of electron energy, and current is a measurement of how many electrons pass during some defined time interval (multiply them together to get power). It the voltage or current rating is too low for the circuit as designed, it generally won't power up (likely no harm to the device). If it is too high, it might burn up, or it might handle it fine. You could ask TC-Helicon, but likely the guy answering emails is just going to read you the side of the box which says 12 volts.

[JackB1]

Originally Posted by jonfields45

It might work or it might work only for a while...

You want the voltage to be the same and the current rating of the power supply same or higher.

If you're a gambling man, it is likely there is a switching power supply inside the Harmony-G that will tolerate more than 12 volts since the digital guts of that pedal need all sorts of different voltages and switchers very efficiently discard volts they don't need. The current rating of the MXR is plenty high.

Voltage is a measurement of electron energy, and current is a measurement of how many electrons pass during some defined time interval (multiply them together to get power). It the voltage or current rating is too low for the circuit as designed, it generally won't power up (likely no harm to the device). If it is too high, it might burn up, or it might handle it fine. You could ask TC-Helicon, but likely the guy answering emails is just going to read you the side of the box which says 12 volts.

OK so if the pedal is 300 mA / 12v and the power brick is 300mA / 18v. Is that OK?

[Petty1818]

Originally Posted by JackB1

Anyone else have the MXR Mini ISO Brick? Question….one of the outputs is for 18v. Can I plug in a pedal that’s 12v into the 18v output? The manual says “make sure your pedal is not rated higher than the output”. So should be OK right?

The 12v pedal in question is the TC Helicon Harmony GXT. It’s says it’s power is 12V, 300mA. The MXRs 9V outputs say they are 300mA each. So can I connect the Harmony pedal to the 8v output? I guess I’m confused as to which one shouldn’t be higher? The power supply rating or the pedal rating?

Make sure your pedal can take the extra voltage. This can lead to damaging the pedal. It's fine to have an output with more ma, but you are gambling a bit with higher voltages. For example, if your pedal is 9v at let's say 200ma, you can use a 9v, 500ma outlet. If your pedal is 9v, 100ma, you shouldn't use an 18v, 100ma outlet, unless you know that it can take it.

Some overdrive pedals can work at higher voltages, but typically the manufacturer will indicate this. I would be hesitant to try it with the TC Helicon pedal. There are adapters out there from Truetone that will bring the voltage down from 18v to 9v, but I am not sure if they have an 18v to 12v option. 12v is often a bit unique.

[Marty C]

Didn't see it here, but make sure which polarity the pedal needs - positive or negative center.

[jonfields45]

Originally Posted by JackB1

OK so if the pedal is 300 mA / 12v and the power brick is 300mA / 18v. Is that OK?

Not OK, but probably will work with some chance of burning out the pedal.

There is one small convenience with this experiment, the TC Pedal power plug is negative tip, as is the stomp box standard 9 volt, 5.5/2.1mm OD/ID tip. Hard to tell by just looking at a picture, but TC might have used a 5.5/2.5 mm OD/ID female plug to keep you from plugging in a standard stomp box pedal power supply.

[JackB1]

Originally Posted by jonfields45

Not OK, but probably will work with some chance of burning out the pedal.

There is one small convenience with this experiment, the TC Pedal power plug is negative tip, as is the stomp box standard 9 volt, 5.5/2.1mm OD/ID tip. Hard to tell by just looking at a picture, but TC might have used a 5.5/2.5 mm OD/ID female plug to keep you from plugging in a standard stomp box pedal power supply.

The TCH pedal can take a standard 9v power supply plug. It fits.

[Petty1818]

Originally Posted by JackB1

The TCH pedal can take a standard 9v power supply plug. It fits.

Honestly, I wouldn't try it or at least reach out to TC. Why risk burning out the pedal?

[cliff_the_stiff]

With electrical circuits impedance matching is important.
If the Voltage doesn’t match, neither will the current or resistance.
So will probably work for a while but it will burn out one of the two circuits if they don’t match.
It’s Ohms law.

[RogerPease]

Originally Posted by Petty1818

Honestly, I wouldn't try it or at least reach out to TC. Why risk burning out the pedal?

We used to call it “letting the purple smoke out.”

_RP

[Chipotle]

Originally Posted by RogerPease

We used to call it “letting the purple smoke out.”

"Any machine is a smoke machine if you operate it wrong enough."

[Cuki79]

1) don’t do it
2) if you have both analog and digital pedals don’t even bother to think about it. You have good chance the Harmony G pedal will pour the ground with digital noise and degrade the signal on all your analog pedals anyway
3) if you only have digital pedals, consider a DC-DC converter like Gigrig Supa Nova that turns 9v to 12v. They are many for any conversion and can be found cheap on the internet.