Boss PSA 220 AC adaptor story.

Posted by on 15th April 2014 in 2002 Guitar Technical Matters

What is so special with Boss PSA 220 AC adaptor ?

First of all I have been using it for the last 20 (twenty) years without any problem at all.

Here is the full specification:

Pri 220V – 50Hz 8 VA

Sek 9V – 200mA

T500mA T25/E ———— this one I do not know what is it all about?

Roland Corporation MADE IN JAPAN.

Well anyway, this magical minimax piece had served very well and contribute a lot to my guitar practice and one stage performance. I am very lucky to have two of this minimax piece. What I mean by minimax is it is mini in dimension with a maximum unbeliebeable  output. 20 years of service. Zero complain. Believe it.

My first complain on Boss PSA 220 AC adaptor.

I found out I have problem with this Boss PSA 220 AC adaptor only after I checked every single Boss guitar pedal effect in my Boss box to find out what is going wrong with one of them. There must be something wrong with one of it because I lose the effect output. One of the troubleshooting method I did is to turn every pedal individually. Everything works fine. So why when I put them back in series the Boss PSA 220 AC adaptor  may fail at anytime at all?  I checked the Boss Power Supply & Master Switch PSM-5 too. Nothing is wrong in its circuit.

Now what should I do…?

How the Boss PSA 220 AC adaptor problem was solved.

At first I did not realize that the main problem is in the Boss PSA 220 AC adaptor. Because as I said I had tried my pedals individually and all of them were working properly using this adaptor. It was only after one evening when I went to a friend’s studio to attend a regular practice. In the middle of a solo on a song I write, it happened again. I am lucky as my lead guitarist had ever the same problem. So happy to find out the problem is at the Boss PSA 220 AC adaptor output cable. Just about the output plug. Looks like the copper wire is worn out inside. Kinked it to certain position and everything back to operate normally.

I know what to do. Either to replace the whole length of cable. Or cut the broken length and resolder the original plug into the new tip. Next time I will post the original photo of what I am telling you about.

Moral of the story: always use genuine Boss PSA 220 AC adaptor for your Boss sound effect gears. I have learned.

For now I am planning to order a newer series of it:

Boss PSA-120S Power Adapter:


Boss PSA-120S Power Adapter


  • Works with most BOSS pedals
  • Industry Standard BOSS power supply
  • LED indicator for quick visual verification of on/off status, Power cable length is increased to almost 10 feet, New design which does not cover adjacent power outlets



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