Problem using external preamp with M-audio Omni I/O

C

CanopuS

Amateur music since 1847
Hi, I'm having a problem with using the Studio Projects VTB-1 with the M-audio Omni I/O. I've been running a SP B1 into the Omni preamps, and the sound levels are to be expected (have to turn the knob to about half way in order to get decent vocal levels), but as soon as I try and use the VTB-1 with the Omni the levels just drop. If I use the VTB-1 to one of the line inputs, I have to put both Input and Output level on the preamp to almost full (both pointing right) to get any decent level. I've tried using the Mic Inputs 1 and 2 (as they are 1/4 TRS accepting too) but I had to actually turn up the volume on those to get a good signal.

I've checked using the VTB-1 with another card and it was no problem. I'm confused, somewhere along the line a lot of sound is dropping and this means lots of lovely hum and hiss. I don't know if its the Cable I'm using from Line out on the VTB-1 to the Omni (I used one unbalanced - like a guitar lead, and one balanced - althought one of the ends was 1/8" so I had to use a jack extension - would this cause problems?) or what.

Any help is great. Cheers! :D
 
When you put the your cable in line input 3 (or 4), in the back of the Omni from your VTB-1, are you also going into the Omni Monitor Mixer page of your software and raising the H/W in 3/4 to full attenuation and unmuteing it?

If this is alright, and you have set up your recording software correctly, then I'd look into your cableing.
 
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Yep. I am doing so. I guess it probably involves cables, but can cables really lose like 50-60% of sound?? Anyway, thanks for your help :)
 
CanopuS said:
Yep. I am doing so. I guess it probably involves cables, but can cables really lose like 50-60% of sound?? Anyway, thanks for your help :)
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Perhaps, if one of the connections is Stereo. Are you sure you are using mono cables/connectors all the way through? I'm guessing that somewhere you are splitting the signal in a stereo signal, and then only getting one of the tracks into your sound card. That could lose half the volume. :)

What cables/adapters are you using with the Omni that you weren't using with the other card (the one that worked OK)?
 
Well I guess thats a possibility, I am thick enough :D. OK - I used:

1) A "non-balanced" guitar lead, in other words, we had a spare guitar lead hanging around thats 1/4"
2) A "balanced" lead (TRS) but that had 1/8" at one end so I had to use an adapter in order to use it with the Omni

I'm probably doing something very stupid :)
 
Your problem is "probably" a 1/8" stereo mini-plug going into a 1/8" x 1/4" mono adapter. Can't tell for sure based on what you gave us, but that would be my guess.

Does the 1/8" end of the TRS cable have two rings on it. And does the 1/4" end of the adapter have a single ring? If so, there's your problem.

Time for a trip to GC or Radio Shack.
 
Hmmm yeah the adapter is Mono..... so that could well be a problem.

The thing is though, the options I listed above were BOTH going from Line out of the VTB-1 to the Omni (I never used them both at the same time, they were just the two things I tried). Would the guitar cable, being unbalanced cause the same problems? (The cable is mono too me thinks - but I didn't think that the Line out on the VTB-1 was stereo)

Thanks
 
Actually, now I think about it, we did try a stereo adapter as well, so I'm not so sure thats the problem now :( Ah well
 
CanopuS said:
Hmmm yeah the adapter is Mono..... so that could well be a problem.

The thing is though, the options I listed above were BOTH going from Line out of the VTB-1 to the Omni (I never used them both at the same time, they were just the two things I tried). Would the guitar cable, being unbalanced cause the same problems? (The cable is mono too me thinks - but I didn't think that the Line out on the VTB-1 was stereo)

Thanks
Click to expand...

If you went straight from the VTB-1 to the Omni with a 1/4" TS cable, then I am probably off-base with my guess as to the problem.

However, if it was a TRS cable (two rings on each end), then perhaps the VTB-1 does not accept a balanced cable. (I'm not familiar with the VTB-1).

I know the Omni will accept a balanced cable, but I'm not sure about the VTB-1. Regardless, if you used an unbalanced cable (TS), then it's a non-issue.
 
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