EHX - OLD Low Frequency Compressor

[zombiesonore]

Hello everybody,
a friend of mine give this very nice effect.
It works properly but only with battery and I would like to modify it and put a DC jack.
The problem is that I've trouble understanding the wiring and really what kind of current this effect needs.
It use 2 9V Battery and I don't know if it needs 18V or maybe bipolar 9V...
I was thinking using a "road rage" board but if it need bipolar supply, I don't know how to do it...
For info, the switch at the top is an on/off switch.
Can you help me?
Thanks,
Etienne 

[Scruffie]

It's bipolar, look at a charge pump datasheet and it'll show you how to do it or someone might have a suggestion for a ready made pump board.

Although... you sure you want to drill in to a vintage EHX pedal for DC?

[zombiesonore]

Thanks Scruffie!
I made it works with the -9V and +9V output of the road rage.

Although... you sure you want to drill in to a vintage EHX pedal for DC?

You mean that it will loose $$$ value? How much do you think this effect could be sell?
Not that I'm about making money... Just for my knowledge...

[Scruffie]

Wait! Not sure it is bipolar, I have a schematic for a bipolar version and an 18V one.

Can you post a shot of circuit side of the board?

Value... check ebay completed listings, personally, I just think it's a shame to mod a vintage pedal that seems to be in quite good condition.

[zombiesonore]

Here is the photo...

[Scruffie]

You're good, it's bipolar, phew!

Me and Keefe might do a PCB for this (I love EHX stuff so we will) if you wanted to keep it stock...

[zombiesonore]

Yes, a PCB would be nice.
Like I've said, I tried to power it with a road rage and it worked, but I felt that the sound was weak...
So I will keep it like it was.
Thanks again.

[TGP39]

Good call. I'm with Scruffie on this one. These old EHX pedals are works of art. You wouldn't want to drill Mona Lisa would you?  Perhaps I could have worded that better! 

Steve.