Power supply for Boss\PSA

[alex1fly]

Do Boss pedals truly require PSA adapters to function? Or can you run them off a isolated power supply like the MXR ISO Brick? I'm trying to clean up my pedal and cable game, and two of my pedals say on them "PSA Adapter only", so I was wondering this before going and buying a dedicated power supply.

I THINK I've used a one-spot adapter with one of these pedals before. Not certain.

 

[Securb]

I have never noticed that warning. I don't want to point you in a direction that might screw up your pedals but I plug my BOSS pedals into my OneSpot and ISO Brick with no problems. Been doing so for about 20 years.

 

[beaubrummels]

I've used BOSS with my MXR ISO Brick. Still works as designed, doesn't seem to have hurt it. I also had BOSS pedals in a daisy chain from a 1-Spot on my pedal board for a couple years. Never had a problem. I seem to recall reading a warning a long time ago that using the 'right' power supply helps reduce noise in the circuit, but I haven't tested that out.

 

[superpete]

you'll be fine

 

[misterwhizzy]

I'm with Bruce. I've run Boss pedals with a OneSpot for years and years without issue. A pedal (particularly an analog one) doesn't have circuitry telling it the power is being supplied by a Boss adapter. Neither, as far as I know, does the Boss adapter have any circuitry to negotiate with analog pedals.

 

[alex1fly]

Checks out. Thanks. Just wanted some backup before buying a power brick. Ugh, pedals and their needs :smack:

 

[PFDarkside]

PSA is basically THE STANDARD for pedal power. 2.1mm barrel plug, 9VDC regulated center negative, up to 500ma. All the Voodoo Lab, MXR, CIOKS, etc. are replicating this standard. So yes, you are fine.

For future use, determining the power requirements go in this order:
1. AC or DC (sometimes you’ll see a sine wave for AC and the dashed/solid like for DC)
2. Voltage (unless explicitly stated on the pedal or in the manual, always match the required voltage)
3. Current (use a supply that can deliver at least the pedal’s requirement or more. The supply won’t supply too much current, but under supply can be an issue)
4. Polarity (for DC pedals, confirm if they require center negative, center positive, or for a 3.5mm which is positive/negative)
5. Connector (it obviously won’t work without the correct connector, but by confirming this last you won’t fry with a pedal with AC or too much voltage)

There are some exceptions, but these rules should set you straight. As mentioned, the Boss PSA set the modern standard for pedal power, most supples adhere to it and many pedals require it.

 

[GuitarStv]

Any 9v power supply that provides enough current into a 2.1 mm negative center barrel adapter will work just fine.

The reason that boss pedals say to use a PSA adapter is because before the late 90s Boss used an unregulated 12 volt adapter (called ACA). You can still power them with PSA adapters, but the LED will be super weak and the pedal may sound a little funny because it's starved for voltage. The 'only for PSA adapter' sticker is because running the ACA adapter (providing 12 voltes) on a PSA pedal (expecting 9 volts) is a bad idea.

 

[dystrust]

You can still power them with PSA adapters, but the LED will be super weak and the pedal may sound a little funny because it's starved for voltage.

This can vary from pedal to pedal. I have a few vintage ACA BOSS pedals and most of them work as you describe, but at least one or two of them won't turn on at all when using a PSA supply. Your best bet with an ACA pedal is the ACA output on a Pedal Power or similar supply, or on a daisy chain with a PSA pedal which somehow regulates the voltage.

 

[GuitarStv]

This can vary from pedal to pedal. I have a few vintage ACA BOSS pedals and most of them work as you describe, but at least one or two of them won't turn on at all when using a PSA supply. Your best bet with an ACA pedal is the ACA output on a Pedal Power or similar supply, or on a daisy chain with a PSA pedal which somehow regulates the voltage.

I remember reading about the daisy chaining somehow fixing the weirdness when using ACA pedals with PSA, but have never pulled apart an ACA pedal to figure out how the circuit accomplishes this.

 

[alex1fly]

Thanks. Boss does make it a little confusing. But like you all have said, the Boss pedals should take any adapter with the right readings. My pedal in question is currently running off a One Spot AC Adapter. I picked up an MXR ISO Brick since it has a lot of different voltage options. If I remember, I'll report back when it arrives.

 

[devastone]

The ACA power supplies actually put out around 12V, and there was something in the old Boss circuits that dropped a few volts off to knock it down to 9V, I don't remember exactly why a single pedal won't work, but multiple pedals will, probably has something to do with putting resistances in parallel. It is an easy fix to convert an ACA pedal to a 9V/PSA pedal, I think it just involves bypass one component (either a diode or resistor, don't remember off the top of my head). It's easy to find with google.

But as said, the PSA pedals will work with any 9V power supply that can supply enough current.