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Patching unbalanced synths in a balanced patchbay
Old 3 weeks ago
  #1
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Patching unbalanced synths in a balanced patchbay

Hey guys

I have loads of unbalanced rack mount synths that are currently patched in with TRS cables in a TRS patch bay. I noticed that I lose a bit of volume at the patch bay connection and I lose MOST of my signal when I run those synths through balanced gear.

I did some tests and it seems that connecting my synths with TS cables (as opposed to TRS) in the TRS patch bay will solve my issue. Does this solution make sense to you guys? Should I worry about ground loops or added noise once I introduce unbalanced cables in my chain?

I'd like to know your thoughts before I got ahead and buy 25+ TS cables and spend half a day re-wiring my 20U rack.

Much appreciated!
Old 3 weeks ago
  #2
Gear Maniac
 

Actually using a TRS cable when the source unbalanced and the receiving end is balanced can be a problem if the source doesn't tie together the ring and sleeve, which many don't. I do not recommend universally just buying TRS cables like this unless you know what you're doing.

To re-iterate, TRS and TS cables are NOT just interchangable on unbalanced gear. It totally depends on whether the gear was designed to account for a TRS cable or not, many unbalanced devices do not have anything to short the ring to ground! I only had one device which did that out of many that did not!
Old 3 weeks ago
  #3
Here for the gear
 

I was wrong in assuming that TRS can be universally used in lieu of TS cables then. I'll swap the TRS cables going from my synths to my patch bay for TS cables.

My rack FX (some balanced and some unbalanced) are all wired with TRS and they seem to working fine. What's up with that? Is it because they are not sound sources?
Old 3 weeks ago
  #4
You've gotten lucky so far, some unbalanced gear flat out doesn't output at all with a TRS cable. Guitar pedals are notorious for this, always make sure you grab the right cables before a gig hehehe.
Old 3 weeks ago
  #5
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I'm sure it's more then just luck! Anyone have an explanation as to why some unbalanced gear connected via TRS cable to a balanced patch bay work when technically they shouldn't?

Here's a list of my unbalanced gear that I've successfully patched in:
Roland RE-201
Korg DRV 1000
Ibanez DM1000
Yamaha SPX90
Korg SDD 3000
Roland SRV 2000
Old 3 weeks ago
  #6
Gear Addict
 
Murky Waters's Avatar
 

Quote:
Originally Posted by turbocharbo View Post
I'm sure it's more then just luck! Anyone have an explanation as to why some unbalanced gear connected via TRS cable to a balanced patch bay work when technically they shouldn't?

Here's a list of my unbalanced gear that I've successfully patched in:
Roland RE-201
Korg DRV 1000
Ibanez DM1000
Yamaha SPX90
Korg SDD 3000
Roland SRV 2000
There is no "technically it shouldn't". One determinant however is whether the ring (R) of the TRS is being grounded or left open at the device output. The grounding scheme of the patchbay can also play into things.
Old 3 weeks ago
  #7
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subdo's Avatar
I patch unbalanced eurorack outputs with a 1/8" TS to 1/4" TS cable into a balanced Samson S-Patch and never had any issues other than the modular level to line level mismatch which really has nothing to do with the patchbay and is easily fixed with attenuation in a number of ways.
Old 3 weeks ago
  #8
Quote:
Originally Posted by subdo View Post
I patch unbalanced eurorack outputs with a 1/8" TS to 1/4" TS cable into a balanced Samson S-Patch and never had any issues other than the modular level to line level mismatch which really has nothing to do with the patchbay and is easily fixed with attenuation in a number of ways.
If you stick with unbalanced cables you're good to go. Its when you start using TRS cables on TS jacks where problems will start. As already mentioned it depends on what they've done with the ground.

I have some cables called 'floating ring' cables from Expert Sleepers that are TRS on one side but have the ring left open on one end, for sending voltages from your interface to a modular. I guess using a regular cable can be bad for the audio interface. I do notice in Logic that the CV output is constantly going so makes sense. I was doing it with a couple of Hosa 1/8" to 1/4" TS cables but gave in and bought the $6 ones just to be safe.
Old 3 weeks ago
  #9
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Quote:
Originally Posted by Murky Waters View Post
There is no "technically it shouldn't". One determinant however is whether the ring (R) of the TRS is being grounded or left open at the device output. The grounding scheme of the patchbay can also play into things.
What would the outcome of the ring (R) of the TRS is being grounded or left open at the device output?

I noticed all my unbalanced devices work fine when patched with TRS cables but the signal is 6 to 10db quieter then if I had them patched with TS cables. Are TRS cables inherently quieter then TS cables?
Old 3 weeks ago
  #10
Gear Addict
 
Murky Waters's Avatar
 

Quote:
Originally Posted by turbocharbo View Post
What would the outcome of the ring (R) of the TRS is being grounded or left open at the device output?

I noticed all my unbalanced devices work fine when patched with TRS cables but the signal is 6 to 10db quieter then if I had them patched with TS cables. Are TRS cables inherently quieter then TS cables?
If the ring on the output connector of the device is grounded it essentially reduces the cable to a TS cable.

You should not get a drop in signal level using TS vs TRS. Something may be funky in your patchbay.

TRS cables are not inherently quieter. They will however allow a noise picked up by the cable, usually in long runs, being cancelled out at the input device if that device's inputs are balanced.

Personally I use both balanced and unbalanced patchbays, and devices patched into the appropriate patchbay with the correspondingly appropriate cables.
Old 3 weeks ago
  #11
Quote:
Originally Posted by Murky Waters View Post
Personally I use both balanced and unbalanced patchbays, and devices patched into the appropriate patchbay with the correspondingly appropriate cables.
But at some point you still have to interconnect the two no? That means one way or another an unbalanced to balanced connection has to happen.

Mine is mixed. My patchbay is one of the standard old balanced Neutriks. My MOTU interface is all balanced, none of my synths are. MOTU is connected with all balanced cables to the patchbay, synths are all connected and routed to the MOTUs 8 analog ins with regular TS cables. Dont have any problems blowing up the inputs of that thing with any of my synths, I have a Waldorf Blofeld most of the factory patches are already over clipping heh. I have an unused unbalanced Behringer patchbay somewhere (no clue where that came from either) but eh. Dont need the extra I/O yet and seeing as how the synths have to go into the MOTU one way or another, there's no point.
Old 3 weeks ago
  #12
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MarkF48's Avatar
Although may not address the OP's original question, this is a handy reference for interconnecting unbalanced and balanced gear...

http://www.rane.com/note110.html
Old 3 weeks ago
  #13
Here for the gear
 

Ive read through that Rane document. Insightful read but unfortunately the solutions that it proposes aren’t ideal for my budget.

If I understand this correctly, if the ring of the TRS was floating then the signal would not pass at all? The loss of signal I’m experiencing is probably due to other factors then the TRS-TS conversion that’s happening in my rig?
Old 3 weeks ago
  #14
The only thing I can think of is its your audio interface input settings.. Did you possibly change the inputs to +4dbu? Balanced outputs are usually +4dBu, sometimes switchable to -10dBu. All of your unbalanced gear is -10dBu. Your interface is balanced, its more than likely got a switch somewhere for +4/-10. If the inputs are set to +4dBu you're going to hear a weaker signal from your unbalanced gear. Set the inputs to -10dBu and listen to everything come back in nice and even. I actually do this for my Waldorf Blofeld and Microwave heh. Some of the patches on them can easily get out of hand and overload inputs. I set both inputs on my MOTU to +4dBu and they have a crapload of headroom. If I set them to the -10dBu theyre supposed to be, I can clip the inputs no problem with certain patches. Most of the Blofeld's patches will do it out of the box heh.
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