Do Boss PSA pedals have reverse polarity protection ?

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Incubus:
I've just discovered the sense of humor that are built into Boss pedals
these days......that some require an ACA adapter and some a PSA, and that
you can't use a PSA on an ACA type pedal.

I was attempting to power my older ACA pedals with a switchmode adapter
but the LED was very dim. I dug around the net and found a solution which
involved bypassing the resistor/diode combination used for (I think ?)
reverse polarity protection, incase the adapter is plugged in the wrong
way around. All is well now, but I'm wondering.....

If the newer PSA type pedals require a more regulated DC voltage, then
given the fact that bypassing the protection in older pedals makes them
work, then what, if anything, do the newer pedals do for protection ?

I'm a little paranoid about using my pedals without any protection, so if
they've come up with another solution, I'd love to know what it is so
that I could incorporate it.

Any help much appreciated.

petemoore:
My gues would be yes...but you can look for a 400x type diode on, or very near [just past a small resistor] the PS's V+ input.

jplaudio:
Quote from: Incubus

I've just discovered the sense of humor that are built into Boss pedals
these days......that some require an ACA adapter and some a PSA, and that
you can't use a PSA on an ACA type pedal.

I was attempting to power my older ACA pedals with a switchmode adapter
but the LED was very dim. I dug around the net and found a solution which
involved bypassing the resistor/diode combination used for (I think ?)
reverse polarity protection, incase the adapter is plugged in the wrong
way around. All is well now, but I'm wondering.....

If the newer PSA type pedals require a more regulated DC voltage, then
given the fact that bypassing the protection in older pedals makes them
work, then what, if anything, do the newer pedals do for protection ?

I'm a little paranoid about using my pedals without any protection, so if
they've come up with another solution, I'd love to know what it is so
that I could incorporate it.

Any help much appreciated.


You can use a  PSA type adapter with an ACA pedal under the following conditions.
1. If the ACA pedal shares a common ground with a non-ACA type pedal the PSA or other regulated power supply will work properly when powering both pedals..
2. If the ACA pedal is modified to accept a regulated 9VDC input like a PSA supply.
Here are some instructions for the mod:
http://www.jpl-audio.com/images/acapsa.pdf

All PSA powered Boss pedals have a power protection circuit. If you follow the instructions above the original protection diode is moved to provide the same protection as the newer Boss design.
You can if you want substitute a heftier diode like a 1n4007.

Carl:
Thanks jplaudio!

I e-mailed Boss about powering my old PH-1 and PH-1R and they told me that the PSA would be ideal... Even though I told them that I am also using a new SD-1 and a PS-5.

They obviously don't have a clue...

/Carl

BTW None of the links at your website's first page works.

Incubus:
Yeah, I have to say thanks to you guys also.

I became aware of being able to use the pedals with a PSA adapter as long as they share a common ground, when I was digging for an answer, but I wasn't happy with this because I felt that I wanted to be able to just use one pedal if need be.

I also became aware of the jpl-audio pdf file that you posted a link for, but for some reason, about 3 days ago the link appeared to be dead. It works now though and I've downloaded it...thanks again.

What I have found is that in my Boss compressor (CS-3), after I shorted the diode/resistor combination, I went back in and saw that instead of the zener diode that I was expecting to find (the one in parallel with the 100uF electrlytic cap), it actually had a 1n4005 rectifier diode. I changed it for a 1n4004. I know I didn't need to, but I did anyway. From memory, and I'm not 100% on this, the 1n40xx series of diodes tells you what the peak inverse voltage that can be applied to it by looking at the last two numbers and reversing them. So a 4001 is 10 volts max., 4004 is 40 volts, 4005 is 50 volts, 4007 is 70 volts etc. Also the maximum forward voltages are diferent for each of them, but it's in the hundreds of volts so it will be fine.

I also put one in each of my Tubescreamer (from tonepad) and EH Smallclone Chorus (also tonepad). I was going to put one in my MXR Microamp (tonepad again), but this already has a 1n914 in it, although that one is in series with the positive rail, not parallel like the others. Oh, and I put one in my Vox wah, which I've recently done the axis mods to, as well as an input buffer.

Thanks again for the hep.

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