Moog Music Forum

i mess around with feedback loops on my pedals/effects stuff. i just use splitters that i got from radioshack (they have one 1/4" male plug and two 1/4" female plugs) to split the signal, sending one back into the input and the other out. i either put a volume pedal after the feedback loop or within the loop to control things somewhat.

my question is, can this do any sort of damage to the moog pedals? is there anything i have to avoid or be careful about when i'm doing this? they're too expensive to mess up so i figured i'd ask the forum...

the other day i was doing this with my 104 and it got funny. it wouldn't delay/repeat at all, it would only output the dry signal (after i put it back in just a regular guitar chain). i unplugged the power and then it worked fine, but it did make me a little nervous for a minute

thanks for any help

I've been wondering the same kind of thing.

Moog says that when one is playing around with multiple control voltages "use the mixer" (251) to avoid problems.

When playing around with audio signals the answer is not so obvious.

The volume pedal should help, but when the pedal is at full is there any attenuation?





I'm wondering if there is a resistor value or something that could be used in-line with the audio signal to limit potentially damaging audio levels.

Any Ideas along this avenue of thinking?





By the way, I think I just fried something last night. I'll let every one know what I did after I find out what broke - it might be a while. I think I have to send it in: cp251 barbeque. No smoke, no warning, just no worky worky.

Since you're splitting the signal (one output to two inputs), I wouldn't think you can hurt anything. The trouble starts when you combine two signals (i.e. DON'T use a Y-cable to combine two LFOs into one input). You need a mixer for that, a mixer safely mixes two signals so their maximum combined voltage doesn't exceed the maximum allowed voltage.

I may be wrong though. I'm not libel for any damaged equipment!

We're talking about audio - not cv.

So am I. Its basically the same thing, its all just voltages.

OK - So now the problem is that I was running audio through the mixer - out through the negative out. It worked just fine. I did not notice any problems during the time I had it all hooked up.
The next day I hooked it all back up, and it no longer worked. The offset is acting funny. The 251 mixer seems to be processing cv ok, but I am not really sure. The positive output seems to be working, but that's not what I need.

I need the negative output to hold the carrier voltage at a high position so that sound will go through the 102 (normal input) without the audio signal present (playing) at the carrier in.

The negative output does nothing unless the offset is set to zero (with audio). With cv, like I said, it seems to work. I need to do some more checking before I contact the tech guys. But I'm pretty sure I messed something up - I just don't know which part. I'll open the thing up and start looking for fried resistors or something.

Anybody else have any experience frying their gear?

kb wrote: The volume pedal should help, but when the pedal is at full is there any attenuation?

hhmm... i'm not sure what attenuation is. i'm not really sure about the your 251 problem but i hope your equipment's not fried!


anyways, i dropped moog an email to get an official answer (maybe some other people are/will be interested so i'll post it for reference):

Dr. Moog assured me that the inputs of the Moogerfoogers had more than
enough protection for very hot audio signals. If you were to accidentally
plug the 100V speaker-cabinet output from your Marshall stack into the input
of one of these pedals it would be bad news (and I've seen this,
unfortunately), but the Moogerfoogers should be able to handle even the most
brutal audio signals with aplomb. When the Drive LED goes red, that just
tells you that your signal is being clipped... you can go ahead and play
with it that way if it sounds good to you. In my experience, it usually
does!

Well it seems as though my 251 is OK. Thanks for the concern asd. You can tell from the size of my last post that I was worried. I think that the problem was related to the patch cords.

I still have to play with the Offset and listen for when things sound right. I thought of another way to trick the carrier into staying at a high position, but I was drifting off to sleep and have not tried it yet.

I don't have a way to mp3 the results of my experiment yet, but when I do, I just might flip some lids.


Anyhow - The original question for this post remains. Does any one know how to limit a signal to 5 volts.

Modular I/Os can boost audio up by 10, 100, and 1000 (Blacet). So obviously an audio signal is at a lower voltage than cv (I knew that much).

But what if the audio signal is boosted by another means (super hard-on?) and going into a cv in.

Is there a way to allow a signal to go all the way up to a maximum voltage threshhold but not past it without attenuation?

kb wrote: But what if the audio signal is boosted by another means (super hard-on?) and going into a cv in.

If Im not mistaken, the Super Hard-On has mostly to do with impedence matching. In the Zvex site it says that the max output of the SHO can exceed 8 Vpp, which isn't very much. It would probably just exaggerate the effect of the audio signal, which is what the attenuator does I believe. Also, it would distort the audio signal. If the audio signal was, for example, a sine wave, it would look and sound more like a square wave.