"Use Boss PSA Adapter Only 9V DC" is what it says on a new pedal I bought from someone and he didn't give me the power supply. what does it mean?

Do I really have to pay Boss money or will any generic Radio Shack 9V DC power supply work?

Maybe he didn't give me the power supply because he was using the Boss power supply and its expensive and he can use it to power other things?

A pecularity I noticed about the power input socket(s) is that there are 2 of them! One says "IN" and one says "OUT". Why are there two power sockets? No I'm not talking about the 1/4 inch input and output jacks.

Why would DC power need to leave the pedal when shouldn't it complete the circuit inside the pedal?

I took a generic radio shack power supply and it read on my multimeter 8.4 volts DC, greater than 250mA DC current, and it didn't show any resistance on the x10 ohm setting.

I found on a forum somewhere that it says that the boss power supply your supposed to use with it is 9V DC voltage maximum and 500mA DC current.

The LED isn't lighting up.

To humor myself I stick the one multimeter lead on the tip of the "IN" socket and I stick the other multimeter lead on the tip of the "OUT" socket and the multimeter readings are: voltage: 0V (makes sense) current: 0mA (makes sense) resistance: 100 ohms on the x10 setting and 5k ohms on the x1k setting

So it appears that there is a 5k resistance from the components inside so it appears that the circuit is completed and it is not short circuiting to anything like if it wasn't including the component resistances it would have 0 ohm resistance like the power supply.

So the INPUT and OUTPUT do apparently complete a circuit, but why?

Next experiment: I connect my guitar with a guitar cable to my audio interface and pluck a string and I hear sound in my headphones. I connect a 3 inch patch cable from the output of the pedal to the input of the interface and connect my long guitar cable to the input of the pedal (the pedal is not plugged in to the socket) and I hear no sound in my headphones.

Next experiment: I repeat the previous experiment except with turning the pedal on and off (the pedal is not plugged in to the socket) and I hear no sound in my headphones. To verify that the patch cable is working, I unplug it from the pedal while still plugged into the interface and now I hear mains hum in my headphones. The mains hum is quieted when I touch the shield of the patch cable to ground the mains hum and when it is quieted also now i can hear voices very quietly. So if radio signals can pass through the cable certainly guitar signals can.

Next experiment: I repeat the previous experiment but with the power supply connected to the socket this time and now the LED lights up and now I hear my guitar in my headphones!

The pedal is the Bose Noise Suppressor NS-2.

Next experiment: I turn the "threshhold" pot on the NS-2 to "MIN" and I hear mains hum like the guitar isn't connected to the NS-2. Now I turn off the pedal and I hear mains hum like the guitar isn't connected to the NS-2.

Next experiment: I turn the "threshold" pot on the NS-2 to "MAX" and I hear no mains hum and the "reduction" LED lights up. When I pluck the 1st string of the guitar I hear no sound in the headphones and the "reduction" LED light stays on. When I pluck the 6th string of the guitar I hear sound in the headphones and the "reduction" LED light goes off and as the note fades out the "reduction" LED light goes back on.

Next experiment: I turn the "threshold" pot on the NS-2 to 3'o clock, which was the position it was at when I bought it from the guitarist. The "reduction" LED light goes on. Now when I play the 1st string on the guitar it is heard loud and clear in addition to the 6th string.

Next experiment: I disconnect the power supply from the socket and then i hear no sound when the power LED light goes out. Interesting that it must be plugged in or you can't bypass the effects circuit at all; that seems counter intuitive.


(1) So if it is doing what it is supposed to do with only using a power supply in the power socket labled "IN", then why do I need to connect a power supply to the power socket labled "OUT"?

(2) If the generic radio shack 9V DC power supply around somewhat over 250mA (a guess from the multimeter reading) works just fine, then why pay Bose for their special expensive adapter?
The out is for a pass through so you can daisy chain other pedals to your power supply. Any adapter over 10-15mA at 9VDC (center negative only!) will work. You don't have to buy a Boss labeled adapter.
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Not all power supplies are equal. Some are made with lower noise tolerance for audio applications. If your supply is 9V DC center negative and it's not making any unwanted noise, you're good.

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"Use Boss PSA Adapter Only 9V DC" means, "Give us your money, ****er."
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You don't need a Boss adapter.
Any adapter that does 220V to 9 or 110 to 9 (depending on your country), should work.
Just pay attention to the jack that connects to the pedal... it must obviously fit.

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Your Radio Shack probably didn't work because of being positive center. Any 9VDC negative center (and preferably regulated) power supply with the proper connector will do.
Okay thanks for the advice.

Yeah that's what I figured; that the answer to the title of this thread is boss wants my money.

Yeah it works perfectly with the generic Radioshack 9V DC 300mA adapter (the approximate values I measured are greater than 250mA current and 8.4 V DC).

So the out is to power another pedal so I don't have to buy another power adapter.

So I can use the NS2 DC power out to daisy chain to the next pedal so I don't need to buy another adapter from RadioShack.

I instead just need to buy a daisy chain negative center cable from RadioShack.
Last edited by dietermoreno at Nov 5, 2013,
Pretty much what everyone else said.

Answer to #2 :
I have found Radioshack power supplies to be a bit noisy.
The difference between the Boss one and the Radioshack ones are the Boss ones are made for pedals. The Radioshack ones are for generic usage and are cheap crap. Although you may luck out and find a decent one.

A better option is the Visual Sound 1 Spot.
They are a bit more expensive than the Boss and Radioshack ones, but they are way better than either of those. Plus, you can theoretically run like 30 pedals with the 1 Spot.

Don't take any of this as a recommendation for the Boss power supply though.
Last edited by CodeMonk at Nov 5, 2013,
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"Use Boss PSA Adapter Only 9V DC" means, "Give us your money, ****er."

Exactly this. Its just a way of them getting extra $.
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