KB cabling and signal levels

[hypercubed]

Hi all - I'm starting to redesign my studio layout. I saw this from another thread and wanted to know more.

 

 

Remember that I'm running balanced, +4 signals from basically right at the synth all the way through. This is an older Trident console and high quality internal patchbays and external (Audio Accessories) patchbays. In addition, the 'backs' of the patchbays are soldered. If you're using consumer/semi-pro gear and running at -10 unbalanced and not watching your gain structure, then yes, your signal will probably be degraded.

 

 

My very limited experience with this is taking the board output into a DI box to convert the signal into balanced XLR. Is anyone else running at +4 and how are you doing it?

 

Thanks!

[xmlguy]

There really is no point to running balanced out for keyboards in a studio situation, in general. If you want the best quality, get a keyboard with a digital out and stay in the digital domain. But running unbalanced analog will not degrade the signal at all by itself. Sure, a screwed up gain structure can add noise, hum and distortion, sometimes a lot of it, but that's the problem with the person setting the gain wrong, not the hardware itself. The rule with keyboards is to keep the level hot from the start and keep it hot through the whole signal path, only cutting the level at the channel fader, never boosting a weak signal when it can be increased (or not cut) earlier in the path.

 

In a live concert situation, running balanced using a DI box is worthwhile to reduce interference over a long cable run or through a long snake. The DI box can also float the ground to stop groundloops due to differences in the ground potential between different electrical circuits used between the stage and FOH mixer power sources.

[oldgearguy]

In my situation (since you originally quoted me), I had quite a mix of stuff. Most synths run at -10, but some are running at +4. In addition, some synths have balanced outputs, but most are unbalanced. The older gear tended to be +4 and balanced, but that's not the rule.

 

On top of that, most of the effects I own have balanced, +4 I/O and my mixing console is +4, balanced.

 

Since I wanted everything brought out to patchbays and I didn't want to worry about gain structure or about balanced/unbalanced or about whether something was pin 2 hot or pin 3 hot (which matters if you're hooking up an unbalanced connection to it), I picked a standard of +4/balanced and made everything that way. At the patchbay I can patch a synth into any fx unit or into the console and not have to think twice about anything.

 

That was the main reason for doing it. If you have a smaller collection of gear, and it's all -10 unbalanced, then there's probably no need to worry about it.

[Khazul]

I partially got around the balance/unbalance issue by making my own cables - obviously this doesnt deal with levelling, but the cables mean that I have no shorting in the patch bays, so its all balanced compatible at least.

 

Cable runs are generally upto about 6M each, with the the drum on a 10M cable - noise floor very low - barely hear it with all 24 mixer channels up and the monitor volume cranked to max. I use the input gain controls at the mixer to level everything, and if nescessary, input level controls on fx processors etc.

 

The main reason I did go for near-synth DIs was actually cost and additional cabling needed - too many devices so this works as a compromise for me.

 

I have 3 x 24ch balance patch bays - all fully connected (96 connection pairs), so not a small home rig.

[hypercubed]

To date the rig has an older Sony MXP-390 mixer and patch bays to connect everything together. There's no -10db calbe runs over 20 feet and the noise floor is low, so I'll not worry about it for now.

 

Thanks for the detailed responses.