splitting balanced line to balanced/unbalanced

[thudclakboombap]

Quiz for the geekslutz,

currently helping sombody setup a live rig.

trying to see if I can split a balanced/unbalanced output on the mic pre of a firepod to a balanced line to send to the PA and an unbalanced patch cable to send to an effect unit w/ an unbalanced 1/4 input.


this is the (possible) solution ive came up with,

http://www.hosatech.com/hosa/products/GXP-246.html


http://www.hosatech.com/hosa/products/yxm-121.html

http://www.hosatech.com/hosa/products/GXJ-183.html


however being that ive never attempted to do this (or had a reason to for that matter) can anyone identify any no-no's I might be commiting here, or reasons it just plain wont work?

much thanks!

d

[aussie_techie]

for balanced to balanced just make up a set of Y-Splits, very simple
if the same line needs to go to un-balanced then you will want to use transformers
a simple bal to unbal with a short cable can be done just by using the hot pin from the balanced cable, if you require a long run you will need to use a transformer
dont bother with hosa cables/adapters, use a quality brand or just make up your own

that said i dont see why you want anything going from the firepod to the console, just split all the mic and DI lines comming from the stage.

[thudclakboombap]

Originally Posted by aussie_techie

that said i dont see why you want anything going from the firepod to the console, just split all the mic and DI lines comming from the stage.

thanks, i had thought of this, but for some reason figured it might be better to split the signal after it was brought to line level, but no advantage in that, huh?

[aussie_techie]

Originally Posted by thudclakboombap

thanks, i had thought of this, but for some reason figured it might be better to split the signal after it was brought to line level, but no advantage in that, huh?

it would have some advantage, as the higher signal over the longer distance will have less signal loss. the shorter your analogue cables the better, this is one reason for modular digital consoles having their i/o on stage.
but ...
my understaning of the firepod is only the first to channels have direct outs, the other pres would have to run through the AD and DA (correct me if im wrong i dont own a firepod). this would induce latency into the system and means there is an extra to go wrong and a computer crash could kill your live signal. live system need to be kept simple and stable.

the pres in the firepod arnt great quality and unlikley to any better than a decent console. depends on what console you are using. also the firepod simply wouldnt had enough pres for a full band.

[thudclakboombap]

cool, yeah, this is for only one mic,,, the artist is a solo electronic act who wants control over his vocal effects in his rack.

In the vocal chain we are only using the pre on the presonus to bring it to line level for the input on the effects rack, so there is no latency induced. I'm well aware it's not the the best pre but it works fine for now, we've also spoke about replacing it w/ somthing nice as the budget permits.

My plan was to go w/ trying the simple transfomerless balanced to unbalanced technique,as the line is only to the next rack space, very short. Im aware of this techinque, but I guess the 2 stripped down questions that I had about this paticular scenario were,,,,,

#1: Am I correct in assuming the HOSA xlr fem to 1/4 will do the balanced to unbalanced using the same techique mentioned above, it's spec mentions "balanced or unbalanced", so will this work like the original pre out and behave appropriately depending on wether a TS or TRS is inserted?. Utimatley I may just make my own, just trying to save time and keep it simple in this case.

#2: Can you split an unbalanced line off a balanced line? This was my biggest concern, as ive never done it. Mostly wondering how it might effect the remaining balanced line, if at all.

Thanks again for your thoughtful responses.

d

[qoqo]

Originally Posted by thudclakboombap

#2: Can you split an unbalanced line off a balanced line? This was my biggest concern, as ive never done it. Mostly wondering how it might effect the remaining balanced line, if at all.

Hi,

Your concern is justified. If you were splitting off BOTH signals from the balanced line (into equal loads), you'd be fine. But, you're only splitting off one of them. This will affect the common mode rejection across both signals at the other end and, my guess, will result in some external noise picked up along the way finding it's way into your FOH (depending on impedances and distances involved) since the two signals will be presented with different total loads (just run your product over sum calculation against both signals independently and the value will be different for each). There are other reasons why this may not work well (e.g. taking 1/2 the balanced signal is also taking 1/2 the level of the original signal, so whatever you're plugging this into needs to have clean gain).

In these sorts of situations, I sometimes go ahead and try it anyway, even though the math doesn't advise it. Sometimes the result is "good enough" and sometimes it ain't

[aussie_techie]

Originally Posted by thudclakboombap

#1: Am I correct in assuming the HOSA xlr fem to 1/4 will do the balanced to unbalanced using the same techique mentioned above, it's spec mentions "balanced or unbalanced", so will this work like the original pre out and behave appropriately depending on wether a TS or TRS is inserted?. Utimatley I may just make my own, just trying to save time and keep it simple in this case.

just use an unbalanced TS cable between the presonus and the FX unit

Originally Posted by thudclakboombap

#2: Can you split an unbalanced line off a balanced line? This was my biggest concern, as ive never done it. Mostly wondering how it might effect the remaining balanced line, if at all.

NO, not with a Y-Split you would need a transformer. while you may get away with it in a studio setting there is not the room for error in a demarnding live environment.
as you only have a single mic why dont you just split it into the to mic pres. or just go with a split between the presonus and FOH console.
alteritavly you could pick up a cheep splitter that would give you balanced and unbalanced outputs but the simplest way is just to split the mic line