Can i power an 18V electric mistress with my 9v power supply

Started by sjaltenb, February 13, 2008, 11:57:01 PM

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sjaltenb

Hey im wondering....

if i get an 18v old style electric mistress, that uses two 9v batteries....cant i just replace the 2 battery leads with 2 leads from my 9v power supplies in my cornish board to power this pedal properly? Let me know, thanks!!!

elecktrokatt

Hi,
If it works at all It'll prob sound like hell....But, don't give up hope!
There is a chip 8pin dip called a max 1044

http://datasheets.maxim-ic.com/en/ds/ICL7660-MAX1044.pdf

That can take a single +9Volt DC supply voltage and generate a -9Volt DC supply from it.
So you end up w + & - 9VDC supplies or a single 18VDC supp.
The Newly generated -9V output voltage is good for a limited amount (around 30mA ?) of current though, so that can sometimes be a drag.
I dunno if the EMistress uses a bunch of current or not, but I've used this chip successfully on a few 2 x 9V Battery Stomp
Boxes, to convert them ti a single 9V Batt, in the past, works good as long as the current draw isn't too much.
Last one was the Craig Anderton Compressor, from EPFM, works good.
The single 9V, will need to be changed twice as often as the 2 9Vs were... so basically you end up eating up the same number of batteries,
for a given number of operational hours (actually a little more batteries because, while the chip is surprisingly efficient, it does use SOME power,
"You never get something for nothing", Eh?)
Hope that helps,
Ekatt ;D

george

If it's the deluxe electric mistress it won't work at all because it has a 15V regulator inside which needs 17-18 volts minimum to work.

FWIW I built a GGG DEM clone and bypassed the regulator to power the circut directly from 9V.

I had to twiddle the BBD bias trimmers a bit but it works fine - I use a strat which has low output pickups.  The lower headroom may cause a problem wth distortion if your guitar has active pickups or humbuckers ...

YOu would probably need to hack up the pedal to do that sort of thing - sounds like the MAX1044 is the go if it can provide the necessary current ...

I suggest you forget about batteries with any BBD based effect unless you like changing them every half hour

Paul Marossy

QuoteI suggest you forget about batteries with any BBD based effect unless you like changing them every half hour

Yeah, that's not too far from reality.  :icon_frown:

oldschoolanalog

Beware of heterodyning when using a MAX1044 or similar in a BBD based pedal. ;)
Mystery lounge. No tables, chairs or waiters here. In fact, we're all quite alone.

paperhouse

i bought a broken electric mistress and the battery clips are missing. is there an easy way to tell if it's 9v or 18v?

george



george

hmm good pics but I was kinda hopng to see the top of the board ... I was hoping to see maybe a 15V voltage regulator that would be the clue if it took a 9V or 18V power supply.

Is there any sign of where the battery clips would join to the PCB?  And is this a "Deluxe" electric mistress or not?