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How to connect unbal pedal to bal mixer send/return
Old 16th October 2013
  #1
Here for the gear
 

How to connect unbal pedal to bal mixer send/return

I am about to make two cables for a pedal that will be utilizing
the mixers aux send out and return in.
(For reference, the mixer is ZED 14, the pedal is Boss RE 20.)

The mixers aux out is balanced TRS (impedance-balanced)
The mixers return accepts both balanced TRS and unbalanced TS.
(though comparing the ZED14 line ins and mono return ins,
the line in sends both +Tip and -Ring to a differentiating opamp
while the mono return in(L of the stereo return) looks to send the ring to ground???)
The pedal is unbalanced TS in and out.

I was looking at the Rane interconnection table trying to find the best method, but am confused. (Sound System Interconnection)

From Mixer to Pedal -> I plan on making a cable like Diagram 9 from table...
Is this the best option? (It is 6db loss, but i dont think the pedal will mind).
Balanced on send side only.
Is there a better method (aside from transformer coupling)?

From Pedal to mixer -> I plan on making a cable like Diagram 14 or 15 from table...
Which of these two would be the best option?
14 being balanced on receiving side only.
15 being unbalanced on both.
Is there a better method (aside from transformer coupling)?

Would is be possible to just use standard unbalnced TS on both sides of both cables?
The main concern being the "balanced" output from the Aux send going into an unbalanced TS jack.

Any help greatly appreciated.


Old 16th October 2013
  #2
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BillSimpkins's Avatar
I use the equivalent of #11 in my studio to connect unbalanced gear to the balanced patchbay.
I use these well-marked "adapters" between the end of the snake and the gear.

basically:
patchbay -> snake -> bal to unbal adapter -> unbalanced gear -> unbal to bal adpater -> snake -> patchbay
Old 16th October 2013
  #3
Here for the gear
 

You will be perfectly fine using its cable.

The only thing that happens when you plug a ts cable into a balanced output is the cold lead (ring) is sent to ground and isn't used. That would not be the car if it were a trs stereo cable (you would lose the right channel), but in your case, it is fine.

All a balanced connection does is take a copy of the signal (hot) and invert the phase, giving you the cold lead. this inversion happens right before the signal leaves a unit, and again right before it enters the next one. As the two signals travel across the cable, any distortion added to the signal ends up out of phase against its copy when the phase is flipped going into the next balanced input

The end result is you lose the inverted copy, leaving you stuck with any distortion or interference that the cable picks up. It usually will not be a problem under 10 feet.

Sent from my Nexus 4
Old 16th October 2013
  #4
Here for the gear
 

#11...

From Mixer to Pedal -> Say for either transformer or cross coupled output stage.
(neither of which this mixer has, correct?)
Then goes onto say to connect ring to shield for cross coupled output.
So If the jumper is not there, it would be for transformer coupled output.
If the jumper is there, it would be for cross coupled output.
How would this work for this mixer?

From Pedal to Mixer -> Which end Would I hook up where?
According to table is says the unbalanced is input side.
But using a TRS jack on the RE20 output wont work. (unless is jumpered between ring and shield?)

Old 16th October 2013
  #5
Here for the gear
 

Thanks, I now understand I can use TS unbal jack for a balanced TRS output.
Especially on this mixer since the outputs are impedance-balanced and shorting ring to shield would just connect this resistor from ground to ground. Not sure how that would work for truly balanced outputs.

So that solves my mystery and confirms that I can use unbalanced TS on both ends of both cables.

Now which of the aforementioned configurations would be optimum?
Does not have to be the same config for the send and return cables as I will make them myself anyway
(at shielding noise or reducing capacitance in the cables?)
Old 16th October 2013
  #6
Lives for gear
#15 is the only one that has TS connectors on both ends and would be entirely appropriate for this application.
Old 16th October 2013
  #7
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The each cable run will be 20-25 ft. Still ok?
Old 16th October 2013
  #8
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BillSimpkins's Avatar
Quote:
Originally Posted by discerndnb View Post
The each cable run will be 20-25 ft. Still ok?
Try it. If not, go with #11.
Old 16th October 2013
  #9
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The Tech21 guy challenged me to prove that there was perceptible signal loss using a TS instrument cable to run from one of their boxes over 100'. I set up a looper with 120' of regular instrument cable output from one side of a Zvex SHO, and the other side drove 4' of 1/4 cable into a passive direct box and 8' of XLR into the recording interface. I could not hear a difference between the two signals. If you're driving 25' of good quality instrument cable from a buffered signal, you'll be fine (and pedals, while running at least, are usually buffered with the exception of some like the OCD and the Eternity overdrives).
Old 16th October 2013
  #10
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Have used TS cables for years on aux sends and line inputs for returns with unbalanced rack effects units. If I'm sending down a snake that's different.

A line level signal In a TS 25' cable is not as big a deal regarding picking up RFI/EMI/noise as it is with a guitar signal that's much lower. S/N ratio is higher with line level.

Make sure your pedal can handle line level.
Old 17th October 2013
  #11
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Why not just send it from a Channel -----> Output and then...you can use a TS or TRS cable. Using a TRS cable with a Pedal will not hurt, if you are going to use a balanced Input/Output you might lose 6dBu-8dBu in gain though nothing more!
You can always Return it to your Aux Return <--------------

Just Remember: Also check the Impedance of the Channels. Outputs will usually be low 50-150 Ohm. While Line Inputs will be 7-10K or Mic Pre's maybe 2.5-3K Ohm's etc. Check your manual!

An Aux Send is simply an Output ------>
An Aux Return is simply an Input <-----

Same as Channel Inputs <--------
Same as Channel Outputs ------->
Old 17th October 2013
  #12
Lives for gear
The only "gotcha" here is the you CAN'T use a TRS end that you plug into the input of the pedal. Almost all pedals now have a TRS input jack, with the shield of the cable making the ground connection between the circuit ground on the ring and the chassis ground. Use a TRS cable...no ground, no circuit, no sound.
Old 17th October 2013
  #13
Here for the gear
 

Regarding the Boss RE20 (from: Guitar Technology )
" I did, however, discover that if you accidently use a balanced jack cable to carry the output, when you hit bypass the dry signal disappears, as well as the echo! "
So , I know I cannot use a TRS jack on the pedal, (bc I will be disabling the dry output from it).

Level from Aux out to Pedal in is fine
But output from pedal out is a little low (-20dbu) for a return channel (-10dbu min?).
May have to dedicate a mono channel for it (-26dbu min).

So my best bet is just standard TS cable and TS jacks, both cables, both sides.

PS there are no channel outs on this mixer
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