DOD Floor unit PSU question

[Mark Hammer]

I recently picked up a DOD TR3-M floor effects unit at a music store garage sale.  Things don't come much cheaper than this did ("Ah, just take it").  The unit has a "metal" distortion, 4-knob chorus, and a digital-delay/sampler.  Unfortunately, it came without a power supply or any documentation and the DOD site doesn't acknowledge the existence of this particular product.

The rear skirt of the chassis has a barrel-jack input for power and indicates 10V@500ma but has no indication of whether this should be AC or DC.  That absence of markings could be because AC wallwarts *have* no + or -, but it could also be because the original instruction/owner's manual provided the missing information.  I'm reluctant to experiment because I don't want to spend more money on something that might well be already fried (though there are no outward signs this has happened, like discolorations on the board).

The board itself has the usual complement of dual op-amps and 4007's (for DOD standard CMOS /FET switching) in addition to several digital chips (RAM and VLSI chip for delay/sampling functions) and several regulators for deriving supply voltages suitable for digital and CMOS chips on board.  I picked up an inexpensive 10v/500ma DC adaptor, and when I plug it in all the switching functions work but I get no output.  Moreover, the supply voltages on the linear chips seems off.

Those on-board regulators that put out much less than 10vdc will certainly function with a 10vdc input, so perhaps the CMOS switching circuitry is perfectly happy with what I'm giving it.  But I'm wondering if providing a DC supply voltage to a regulation circuit that thinks it is going to get 14.14V after rectification is screwing up the audio path.

Does anyone here know anything about what sorts of power these beasts want?

[sir_modulus]

What does the power go to first. If it is a digital circuit, it should go to a bipolar supply circuit to get the opamps working right. If there is a bipolar supply circuit, then it's DC (it most likely is anyway).

[Mark Hammer]

On the surface, it *looks* like it goes to the same sort of circuit that PAiA uses to derive +/- from an AC input, namely a pair (rather than a ring/quartet) of diodes.

[Ry]

according to:

http://www.harmony-central.com/Effects/Data/DOD/TR3M-01.html

It uses a 9v AC power supply.

Ry

[Mark Hammer]

Thanks, Ry.

You have confirmed what I thought I discovered about 20 minutes ago....that I am officially an idiot.

I was cleaning up my office (finally) and picked up the bottom/rear panel assembly to the thing and *finally* noticed that right beside where it says 10v it also has a little drawing of a triangle wave.  Now, yes, I suppose it *doesn't* say "AC", but what, pray tell, did you think that triangle wave drawing was supposed to mean, Hammer?  Hmmm, was it there just to be pretty or was it there to indicate a power source that went, oh I dunno, maybe UP AND DOWN?

Sheesh.  Apparently the nose on my face isn't as plain as I thought it was.
Thanks one and all.  If I can get my son help me to move his huge sheets of particle board today and get at my drawer-of-adapters, I may just be able to try it out.

[Mark Hammer]

Success!!

Had a 9.5vac wallwart in the drawer-o'-trannies.  Plugged it in and it worked great.  Now I have a sampler that can delay as much as 1sec and can repeat the 1sec sample on demand.  The chorus is pretty bland (may do a clock cap mod eventually, but not today) and the fuzz is your basic diode über-clipper.  Sweet deal for $0 though.

Looking through the other wallwarts, I found a few others that had the same little triangle-wave squiggle without otherwise indicating AC or DC in letters.