Strange compressor issue - w/ video

famous beagle

Well-known member
Hey everyone,

I bought this Behringer MDX 2000 compressor on eBay, and I'm having a strange issue w/ it. I have a money-back guarantee on it, and the seller will pay the return shipping, so I'm not too worried about it, but before I tell him it's not working, I just wanted to make triple sure there's not some user error here. I mean ... I know how to use a compressor, but I've never used this particular model, so I wanted to get some other opinions just in case I'm missing something.

Here's the video, where I explain/demonstrate the problem. The short of it is that, although all the meters seem to work properly, there's no change in the audio in tone or volume, no matter what I do. And it definitely is engaged (not in bypass mode). Check it out.

Am I missing something?

Thanks!

 
Hi,
That is really odd. Can't really see the rear layout clearly but referencing other images it looks like you're in the right ins and outs.
Do the two key related switches have any effect, and does channel two do the same thing?
 
Yeah, huh?

I'm 100% sure I'm in the correct CH 1 inputs and outputs. And you can see in the video that signal is clearly passing through the compressor into Reaper. And when I unplug the patchbay, it goes away, etc.

The key switches had no effect, and CH 2 is doing the same thing. It's also doing the same thing when I use it in stereo mode with CH 1 as the master.

It's the strangest thing. I'm scratching my head.

It was a real mindf*ck at first, because when I first started tweaking knobs, I fully expected it to work. So I thought I was actually hearing some difference in tone. But then I was like, "the sound should be a bit more drastic with this much compression. What the hell?" So then I hit the bypass switch and didn't hear a difference. Then I engaged it again and cranked the output knob full and didn't hear a difference. Then I realized that it was only confirmation bias that made me think I was hearing anything different in the first place. Nothing is making any difference in the sound at all.
 
Does the peak limiter do anything?

If it was sold as tested and working, and your confident enough to open and check all ribbon/molex/hand fitted connectors, I'd pitch that idea to the seller.
As long as you have his agreement in writing, ebay will stay on your side.

If not, I can't think of anything you could be missing and I'd ask for return.
 
That's my best guess - the output switching relay must have something common to left and right, and it has failed.
The fact that it happened in transit, if it was sold as working, would definitely have me opening it and refitting all ribbon/molex connectors but beyond that, and caveats noted, I'd just return it.
 
I've got an MDX2200. If I engage the 'IN/OUT' switches on either channel I can hear a click of a relay. That might be something to listen for.

From the MDX2200 manual. Don't know if these relays are the same as I hear and tied to the 'IN/OUT' switches.
 

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"isolate the composer pro until the power rails have settled...."
Great find, if it's relevant to this model! Very good chance it is.

I guess you'd hear the relays toggling their protection when you power your 2200 on, if you have them set to 'IN'?
 
Top diagram on the unit does show relays in the IN/OUT circuit that bypass the compressor section
 

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Thanks a lot for the tips y'all. I do not hear anything when I push either in/out button at all.

I don't really want to crack it open and try to fix it myself because I paid $7.95 for a one-year protection plan, so they'll fix it and pay shipping both ways if any defects come up.

I just wanted to make sure, before I send it back and tell them it's not working, that I'm not crazy or missing anything. I don't see how I could be, but I just wanted to double check.

Here's what I did:

Plugged my Korg Volca Keys into CH Behri 1/4" input
Plugged the 1/4" CH 1 output into my Tascam interface --- just a simple series connection.
Record on Reaper

The signal is passing through to Reaper just fine whether the Behri is in bypass or engaged. But no amount of knob twisting makes any difference in tone or volume, no matter whether the Berhi is engaged or in bypass (tried in bypass also to make sure the knobs weren't reversed for some crazy reason).

So ... this can't be user error, right? I've scoured the manual and can't find anything that would address this.
 
So ... this can't be user error, right? I've scoured the manual and can't find anything that would address this.

Yeah, I really can't think of any way that it's user error unless you happen to have a second output from the synth going straight to the interface and you picked the wrong record input.
Long shot. :p
 
Yeah, I really can't think of any way that it's user error unless you happen to have a second output from the synth going straight to the interface and you picked the wrong record input.
Long shot. :p

:) Nope, I'm not doing that.

Alright, I'm gonna let them know it's coming back. Thanks y'all.
 
No worries man. Hope you get it sorted out without any problems.
I know what it's like - Sitting staring at it hoping some magic 'work' button appears! haha. It IS really easy to miss the obvious some times.
 
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