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Hello,
I've blown up a pedal two times now by using it with my mixing board's aux send and return. It isn't an issue of overloading it with a signal- the signal was as faint as could be in the moment that I hooked the pedal up, and as soon as it touched my board, it just died. I spoke with Electro Harmonix (the pedal's manufacturer), and the tech guy is 99% certain that the problem is the voltage of the board. It is a Soundcraft 200 B, which is +/- 17 V, whereas the pedal in question won't deal with anything over 16.

Being on a budget, and really wanting to use the pedal in mixing, I'm told that a "reverse DI box" will eliminate the risk of destroying the pedal with voltage. Now, my question is how should I have the settings on this thing for running between and aux send and a pedal, and also between the pedal and the tape return:

http://www.computersunlimited.com/image ... s20015.jpg

1) by "reverse DI box," does that mean that the aux send should plug into the OUT of the box, the IN of the box should then go into the pedal, the pedal should then go into the IN of the other box, and the OUT of the other box into the tape return?

(the above question is what I mean by impedance "for dummies" in my subject)

2) I was also told that the old Soundcraft boards used really crappy couplers. Is this something that, in the opinions of the people on this discussion forum, I should look into having replaced, or even replacing myself?

any thoughts are appreciated, and also if anyone can explain how I should rig up the DI box to prevent further pedal frying, that would be very awesome. thanks a ton.

Here is a reamp style box that I built that should help with some of this stuff -- http://www.jensen-transformers.com/as/as092.pdf

I use it when hooking any line level signal to a guitar pedal.

dont drop bombs wrote:1) by "reverse DI box," does that mean that the aux send should plug into the OUT of the box, the IN of the box should then go into the pedal, the pedal should then go into the IN of the other box, and the OUT of the other box into the tape return?

Correct, although I'm not sure you'd necessarily need the DI box after the pedal.

It's a slightly odd problem which I've not actually encountered myself. Overloading an input usually resultings in clipping/distortion, and usually not blowing up a device unless you really hammer it. It's possible something more complex is happening which is causing the problems. What pedal is it?

In the case of using a DI box in reverse, you'll need to use a "passive" model. This means it requires no power, and in the case of a DI box, relies on a transformer to perform the balancing/impedance conversion (and inherently change in voltage). I'm not convinced the Behringer model will be of this type.

2) I was also told that the old Soundcraft boards used really crappy couplers. Is this something that, in the opinions of the people on this discussion forum, I should look into having replaced, or even replacing myself?

I'm not sure what people might be referring to as "couplers". Soundcraft don't make bad equipment, and probably nothing that would harm other pieces of equipement if used correctly.

when you say the pedal "blew up" what exactly happened?

the +/-17v of the soundcraft is the supply voltage, unless you are trying to power the board off of the soundcraft PSU, I'm not sure how this would effect it...

like rodabod said, what pedal is it? when you say "as soon as it touched my board" do you mean physically or through a cable? is it possible the pedal is positive ground?

outoftune wrote:when you say the pedal "blew up" what exactly happened?

the +/-17v of the soundcraft is the supply voltage, unless you are trying to power the board off of the soundcraft PSU, I'm not sure how this would effect it...

like rodabod said, what pedal is it? when you say "as soon as it touched my board" do you mean physically or through a cable? is it possible the pedal is positive ground?

"blew up"- my dramatized way of saying that it stopped working before I even passed a signal through it (so it's not an issue of overloading it with signal or anything like that), and now only sends a signal while in bypass mode. once the pedal is activated, no sound passes through it.

it stopped working when I inserted a cable into the aux send and the other end of it into the pedal. The pedal is a Holiest Grail, and the Electro Harmonix tech guy was fairly certain that the voltage coming from the Soundcraft is what casued its untimely demise.

I want to protect & use the Holiest Grail by taking his suggestion to place the "reverse DI" in between.

"In the case of using a DI box in reverse, you'll need to use a "passive" model. This means it requires no power, and in the case of a DI box, relies on a transformer to perform the balancing/impedance conversion (and inherently change in voltage). I'm not convinced the Behringer model will be of this type."

That's definitely good to know- I will be sure to seek out a couple of passive DI's. I'm not sure I understand how the lack of a power supply makes it safer to use for this purpose, but you & the EH tech guy both said "passive," and so it will be.

The tech guy seemed to think that it would be a good idea to make the set-up failsafe and bulletproof by placing another box on the other end, after the pedal and before the tape return.

I guess it won't literally be "bulletproof"- no one will be permitted to take firearms into the studio (Phil Spector barred)- but you know what I mean.

thanks everyone.

will this do the trick?

http://www.musiciansfriend.com/product/ ... sku=182498

I notice it doesn't have adjustable attenuation settings like some others, and I wonder what the purpose or benefit of having that as a variable would be? also doesn't have the ground/lift switch, and so I also wonder if that's important for my purposes?

dont drop bombs wrote:will this do the trick?

http://www.musiciansfriend.com/product/ ... sku=182498

I notice it doesn't have adjustable attenuation settings like some others, and I wonder what the purpose or benefit of having that as a variable would be? also doesn't have the ground/lift switch, and so I also wonder if that's important for my purposes?

It has a ground lift. That's generally a good thing.

It will probably do the job. You may need an adapter or two to hook things up the way you want to.

endofanera wrote:

You may need an adapter or two to hook things up the way you want to.[/quote]

so I wouldn't just run an instrument cable from aux send to DI OUT, another instrument cable from DI IN to pedal? what sort of adapter might be needed?

thanks for all the help. this is very good.

dont drop bombs wrote:

endofanera wrote:You may need an adapter or two to hook things up the way you want to.

so I wouldn't just run an instrument cable from aux send to DI OUT, another instrument cable from DI IN to pedal? what sort of adapter might be needed?

thanks for all the help. this is very good.

The DI out is typically an XLR and aux sends are sometimes 1/4". That was where I imagined you may possibly need an adapter. If your aux send is an XLR, then youll be golden.

Sweet.

So I took the Holiest Grail to the post office today to send it off to be serviced. The closest post office to my workplace is in a building with super tight security. I sent the package through the x-ray machine, and the security woman got very serious: "excuse me, sir, what IS THAT?"

I imagine the Holiest Grail could conceivably look like some weird terrorist contraption. I began to tell her about what it is and what it does, and she quickly hurried me along- "okay, okay, go ahead."