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Noise problem with mbox and dbx 160xt
Old 5th August 2005
  #1
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Studiocat's Avatar
 

Noise problem with mbox and dbx 160xt

Hi folks,

I'm not sure if i'm posting in the right forum, but here'goes nothin'. I need help!


I'm running Protools with an Mbox. I have a dbx 160xt connected to the mbox insert, and the signal is noisy as hell.

- The insert cable is brand new. I've tried connecting to the unbalanced 1/4" connectors on the dbx and to the xlr connectors. Makes no difference (the insert signal from the mbox will always be unbalanced anyway, right?).
- Touching the chassis of the dbx makes some of the noise go away.
- All of my gear is plugged into one source (1 powerbar).
- This is my first problem with ground noise in this room.
- The ground lift switch on the dbx does nothing.


What should be my next step? Get some kind of power conditioner thing?
Maybe get a ground lift cheater and try plugging the dbx into that?

any suggestions would be greatly appreciated.

Thanks!
Old 6th August 2005
  #2
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Hey

So if anyone is interested to know what happened here:

I opened up the dbx to find 4 exploded capacitors and capacitor juice crusted all over the circuit board! Yuk. I'm only assuming that once I replace these things, the problem will go away.
Anyone care to comment? Busted caps often mean noisy signals, right?
Old 7th August 2005
  #3
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audioez's Avatar
 

welcome to the mbox...it's good for opening up sessions, worthless for monitoring...and the analog I/O is a joke, I stick with the SPDIF I/O.
Old 8th August 2005
  #4
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I'm not sure that I agree with you 100% - I mean, it has its drawbacks, but I don't think it's the ****tiest thing ever. The pre's are sufficient for many purposes, but they should definitely do away with the USB.

I would like to hear a test that compares the A/D of the mbox with all the other digidesign interfaces.

In what capacity do you use the SPDIF?

A
Old 8th August 2005
  #5
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Quote:
Originally Posted by Studiocat
I would like to hear a test that compares the A/D of the mbox with all the other digidesign interfaces.
i've done just this. mbox converters vs. 002R converters vs. apogee rosetta 200. the differences were *profound*. we rated sonic quality in the order you'd expect.

however, i do like the mbox. i use it solely for editing, though. it is cool to chop up drums while sitting at a coffee shop.

--jon
Old 8th August 2005
  #6
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max cooper's Avatar
 

I don't know what's wrong with the USB. shouldn't have to take up a Firewire for something that's only 2 in.
Old 8th August 2005
  #7
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there was a recent thread started by larry crane, and it was brought up that apple's implementation of usb (specifically 2.0, but it likely applies to usb 1.1) is very poor. this might explain why we all hate the mbox so much.

--jon
Old 8th August 2005
  #8
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smarsland's Avatar
 

I use the MBox at school (have 3 of them) for the kids to use in addition to a 001 and 002R. We do most of the recording on the 002R, obviously, and then use the MBoxes for editing only.

So, what I like about the MBox is the fact that I have 2 combo connectors and S/PDIF, so 4 channels if I needed.

What I hate about it is its shape (for portability), USB connection, and its quality of I/O.

I need a small format recorder.. between 4-8 channels of high quality for concert recording gigs.. for my personal use. I am thinking the MBox might be the only thing I can get away with cheaply. What about MOTU stuff? not too experienced with it. Does MOTU write WAV files?

s
Old 8th August 2005
  #9
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Oye,

So the original problem I was having with the dbx 160 on the insert has just become more complicated...
I assumed that when I found the exploded caps that I had found the problem, but I was wrong. I just brought the dbx over to another studio, and tested it. No buzzing.

So there's some kind of problem with my home studio, and a ground loop in the mbox? or what?
I guess I should have those caps fixed anyway, but that may not help at all now.

Suggestions?

A
Old 8th August 2005
  #10
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Quote:
Originally Posted by JonCraig
i've done just this. mbox converters vs. 002R converters vs. apogee rosetta 200. the differences were *profound*. we rated sonic quality in the order you'd expect.

however, i do like the mbox. i use it solely for editing, though. it is cool to chop up drums while sitting at a coffee shop.

--jon

So even the differences between the mbox and 002 were profound? Is it worth the extra 800 bucks or whatever? And how does one go about implementing a rosetta or any other non-digidesign interface with protools?

A
Old 8th August 2005
  #11
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Quote:
Originally Posted by Studiocat
So even the differences between the mbox and 002 were profound?
yes. especially in the top end. everything was more open (clear, insert your favorite buzzword here) and defined.

Quote:
Originally Posted by Studiocat
Is it worth the extra 800 bucks or whatever?
if you're primarily editing/mixing in the box, then i would say, "no". there was an even better improvement by using the rosetta (i.e. the 002 converters were still not great, just better than the mbox). if you think you may need more than 2 chan's of i/o, however, then yeah, i'd say go ahead and buy the 002. you also save yourself the hassle of "cpu usage is interfering with usb audio". i get around 3/4 of my processor usage, then the mbox craps out. [sigh]

Quote:
Originally Posted by Studiocat
And how does one go about implementing a rosetta or any other non-digidesign interface with protools?
you aren't actually using the rosetta as an interface (it has no provisions for that, nor (as you've noted) can you use pro tools without a digi interface. we used the s/pdif out from the rosetta into the mbox. in the hardware setup dialogue in pro tools, you can tell the mbox to use the s/pdif ins/outs.

--jon
Old 8th August 2005
  #12
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Quote:
Originally Posted by Studiocat
So there's some kind of problem with my home studio, and a ground loop in the mbox? or what?
are you hearing a 60 cycle hum in the signal (albeit perhaps mixed with other buzzes)? do you have any other gear you could try, which would narrow the problem down to either the mbox or the dbx.

the only way you could have a ground loop going into the mbox would be through the computer. is the dbx plugged into the same circuit as the computer? is anything else noisy plugged into it (a fan, mini-fridge, window a/c unit...)?

Quote:
Originally Posted by Studiocat
I guess I should have those caps fixed anyway, but that may not help at all now.
yes. get them fixed.

--jon
Old 8th August 2005
  #13
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JonCraig, Thanks for all this good stuff. I REALLY appreciate it.

I'll try a few things and post again later.

Ciao
Old 8th August 2005
  #14
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hey, no problem. that's what we're here for, right? let me know how things turn out.

--jon
Old 8th August 2005
  #15
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Quote:
Originally Posted by JonCraig
you also save yourself the hassle of "cpu usage is interfering with usb audio". i get around 3/4 of my processor usage, then the mbox craps out. [sigh]

--jon
This has been the bane of my existence. If I try to run a Rewire Reason session with a bunch of stuff going on, I'm plagued with errors. Not to mention, I have to turn off my wireless internet while I running protools, presumably because of the USB.

Oye.

A
Old 8th August 2005
  #16
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Quote:
Originally Posted by Studiocat
This has been the bane of my existence.
yep. the 002 would (presumably) take care of this.

--jon
Old 8th August 2005
  #17
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Hey.

I brought another dbx 160xt over to my place. No hum whatsoever. It's virtually identical to the one I have, with one pertinent exception: It has a two prong plug instead of a three prong. hmmm. Still hard to say where exactly the problem lies, bu it's probably the dbx, not the mbox. I guess when I get the capacitors fixed on the other one, I'll have to reassess.
Old 15th December 2013
  #18
i just discovered that 160xt's are pin3 hot. not sure it causes the problem tho...
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