Questions & Answers

Instrument input attenuation cables

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asked Feb 15, 2020 in AudioBox USB by johnspeth (120 points)
I'm using a new Audiobox USB 96 and I'm working to get the cabling just right. I'd like to drive the Audiobox instrument inputs from my mixer line out jacks but the line levels cause distortion. I want to try to use some home-built attenuating cables, which very easy and inexpensive to build. The problem is I don't know the maximum instrument input signal (probably some dBu figure). When I know the max input level, I can formulate my attenuator resistor values.

Does anybody know the maximum instrument input level? It's not published in the product specs but, oddly enough, that figure is published for the mic input.

Has anybody successfully built and/or used attenuation cables with good results? If so, please tell us about them.

Thanks - John Speth

1 Answer

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answered Feb 22, 2020 by aka_busker (32,890 points)
Hi, John.

Instead of cables, get (or build) a passive d/I.  -  reasons to get a d/I so you don't blow your instrument levels.  -  how to build a passive d/I.  

Essentially the passive d/I box can turn your line to mic level and you can do the rest on your audio box.  

I use a passive d/i for my active guitar pickups.  They're too hot for hi-z (instrument level),  so I use a d/I (cheap £20 one) to get them to mic level.  My d/I box is made by Stagg and was cheap but effective.  It takes the active pickups and dumps them out as both mic level AND instrument level.  The hi-z (instrument) then goes to a boss fx rig/guitar amp, while the "dry" mic level (low-z) goes to my audio box.  

I hope that helps some.  Good luck if you go for the homebrew approach as it doesn't look too difficult to build.  

Cheers, Jake.