1980 Boss OD-1 Power Question

builttospill · October 2017

Recently acquired this lovely pedal from @rossyamaha, as Ross pointed out to me the power socket polarity has been reversed at some point. (any reason for this change? a little perplexed why someone would do this)
Ross kindly sent me a polarity reversal adaptor and it works great with a 9.6 volt 200mA EHX power supply. I've not tested it yet, but is there any reason why it shouldn't work with my burkey pedal power (outlets at 9 or 12 volts @100mA centre negative) I basically want to avoid fucking up a pedal that sounds great. Help greatly appreciated.

ICBM · October 2017

It's probably been bodged to run with whatever adaptor someone had.

Best to fix the socket properly. It would be wise to find out whether any other changes have been made, eg removing the reverse-voltage protection diode and resistor in the ACA-adaptor circuit - this is often done to use a PSA or other regulated 9V adaptor. If so this leaves only the shunt protection diode, and that can burn out…

If it was me I would return it exactly to stock including the ACA circuit, and use a 12V supply, which is how it was designed to be run.

builttospill · October 2017

ICBM said:

It's probably been bodged to run with whatever adaptor someone had.

Best to fix the socket properly. It would be wise to find out whether any other changes have been made, eg removing the reverse-voltage protection diode and resistor in the ACA-adaptor circuit - this is often done to use a PSA or other regulated 9V adaptor. If so this leaves only the shunt protection diode, and that can burn out…

If it was me I would return it exactly to stock including the ACA circuit, and use a 12V supply, which is how it was designed to be run.

Many thanks @ICBM, I don't suppose you can tell from the images in the link of any more changes http://www.thefretboard.co.uk/discussion/115950/fs-vintage-boss-and-dimarzio#latest
So you are saying once it has been rectified you can run it at 12 volts dc centre negative?

steamabacus · October 2017

The Boss ACA adapter is an UNREGULATED (nominal) '9V' supply - it actually gives out 12V or more unloaded. If you are using an old Boss ACA pedal on its own, you will need a 12V regulated supply. If you have another (moderrn PSA Boss) pedal connected to it, you can use a 9 V regulated supply.

Explanation here ...
http://stinkfoot.se/archives/726

ICBM · October 2017

builttospill said:

Many thanks @ICBM, I don't suppose you can tell from the images in the link of any more changes http://www.thefretboard.co.uk/discussion/115950/fs-vintage-boss-and-dimarzio#latest

It does at least look like the ACA diode and resistor are still present - they're on the left of the pic, D4 and the resistor next to it, which some people remove when converting - but the mod can (and should) be done by just soldering across the pins on the back of the board, so I can't tell if it's been done or not.

builttospill said:

So you are saying once it has been rectified you can run it at 12 volts dc centre negative?

Yes, that's the closest to the original ACA spec as steamabacus said.

builttospill · October 2017

Not sure I would like to attempt this myself a bit OCD with pedals, would anyone be up for modding this back to it's normal state? calling @juansolo ;

builttospill · October 2017

anyone else?

Howdy, Stranger!

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1980 Boss OD-1 Power Question

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