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Balanced cables to extend patch bay reach? Urgent Question!
Old 26th May 2019
  #1
Gear Maniac
 

Exclamation Balanced cables to extend patch bay reach? Urgent Question!

Hi there, so I have my main recording gear rack/rig that has two balanced patchbays loaded with various in's and outs. All of this is just dandy.

Then i have my desk which has it's own balanced patchbay. I wanted to run the various desk gear through this desktop patchbay and then have a couple of balanced lines run from the desktop patchbay to the main patchbay.

My question is this:

If i plug local desk gear (effects, synths, pedals), much of it being unbalanced into the balanced patchbay on the desk and have say, 8 balanced 1/4" cables run from that balanced patchbay to the main gear balanced patchbays, will this help shield the unbalanced signal for the duration of time that the unbalanced runs through the balanced patch bays?

I understand running balanced cables into the gear directly isn't going to be balanced, but i'm trying to see if running them into a nearby patchbay and have that be where the signal is balanced till it reaches its destination might help cut down on any potential noise being picked up.

Otherwise i would basically need to run lots of 6'-12' unbalanced cables to the main rig.. which just introduces room for plenty of noise to be picked up.

Maybe balanced patchbays are rendered useless if at any point an unbalanced signal is in the mix?

Thank you in advance for any insight you might have. I'm hoping to rewiring some things this weekend and i feel kinda stuck on this question before i commence to moving a bunch of stuff around only to see that it makes no difference it makes a huge difference.

it seems like this must be a reasonable approach because I can imagine in big music studios where things are not all closely packed together.. unbalanced gear has to get its signal from a musician in a sound room to some patchbay / mixer / recording device. I guess knowing how the pros manage long distances with unbalanced signals

Thanks,
Caleb
Old 26th May 2019
  #2
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A good 12' line level unbalanced cable isn't going to pick up "plenty of noise" unless you have a truly atrocious environment in terms of interference sources. It could pick up a miniscule amount, but I very much doubt you'd ever come close to noticing in a real mix with anything resembling appropriate gain staging. 12' is not anywhere near a long cable run, in any event.

Anyhow, running an unbalanced signal through a balanced cable doesn't make it balanced, even if the cable is connected via a patch bay. The patch bay has no circuitry to convert unbalanced to balanced or vice-versa; it is just connectors and cables, nothing more. To balance the signal, you need something like a transformer (a "balun") or an electronic converter or some such. One example, probably not quite what you want here, is the ubiquitous direct box.
Old 27th May 2019
  #3
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Richard Crowley's Avatar
 

I can't think of ANY good reason to use unbalanced cable for mic-level or line-level connections. Even if the source and/or the destination is unbalanced. And the patch bay(s) should be completely balanced everywhere.

Unless you are setting up to operate on the other side of the wall from an early 19th century "buzz box" light dimmer, you may not be in a situation as dire as you are imagining. Don't go out looking for trouble where it doesn't exist. OTOH always plan ahead for remediation where necessary, and using only shielded, balanced cable will allow you to do that. Using unbalanced wiring is just shooting yourself in the foot. Never recommended. (Except for the special case of high-impedance electric guitar/bass cables.)
Old 27th May 2019
  #4
Gear Maniac
 

Well i just had some issues with running effects IN/OUT of unbalanced patch bays in the past like my BOSS SE-70.. but if i ran an instrument straight into the same effects (with the outs still going through the patchbay i'd get no hum but if i ran the ins and outs of the patchbay through the same patchbay i'd pick up some unwanted noise.. thought maybe going balanced might help minimize this. I have an BOSS GL-100 also that works very well but has 60hz hum to it..

So yea my basement is relatively fine i think.. i have two power conditioned strips to power everything. each plugged into a separate outlet on two different walls. So I know that on some level it's maybe more of a grounding patchbay issue, but it felt like balanced cabling / patchbay might help address that.
Old 28th May 2019
  #5
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Richard Crowley's Avatar
 

As I said in my previous response, the patch bay(s) should be wired as balanced everywhere. If the patch bay connects to an unbalanced source or an unbalanced destination then the unbalancing should be done at the far end (not the end connected to the patch bay). So your mention of "unbalanced patch-bays" is a red flag in my book.

Another red flag is using two "separate outlets on two different walls" THAT could very well be a contributor to your noise symptoms. I would operate ALL the gear from a single outlet to ensure that there are no ground loops. Especially if it is a situation with older wiring.

Of course, you should never exceed the total power available from the mains outlet. But unless you are running gigantic speaker amplifiers, it seems unlikely that you are drawing enough total power to worry about overloading a single branch circuit.

Since you have not completed your user profile to reveal what country you are in, we can't make any more specific observations about your power situlation. The voltage, current, grounding, and topology of mains outlets varies widely between different countries.
Old 28th May 2019
  #6
Gear Maniac
 

Hey there, thanks for that! I'm in the Boston area. I'll fill out that profile stuff today.

I thought for some reason the separate outlets was good for some reason.. i thought i read that regarding a old fender quad amp I had and minimizing grounding noise or something.. but that was awhile go... clearly i got that wrong.. yes my studio is probably ok. i do have some power strips in power strips.. but nothing is drawing hi amperage.. i have a computer, a 37' tv (monitor), two smaller powered monitors and a mackie 1402 mixer.. and everything else is pretty much rack gear and a couple of synth keyboards.. i also do not turn everything on all the time.. i keep most items off so that much less draw is ever going on at any given time.

I will balance everything up and test it out tonight if I have time.. kinda busy work day and then a class after work.. but later tonight i can do some quick testing to see if the grounding issue is a thing with all balanced stuff. Thanks again for the insight. I'm on the verge of doing a major redo with the desktop patchbay so having this insight beforehand will help me make some better decisions.

The desktop patchbay was meant to be a kind of "breadboard" of effects and instruments that i could route in and out to each other and then ultimately devote 8 points to (balanced) travel over to the other balanced patchbays that ultimately lead to the mixer or 2408 Mk2 to record in...
Old 28th May 2019
  #7
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nosebleedaudio's Avatar
 

Quote:
Originally Posted by part12studios View Post
Hey there, thanks for that! I'm in the Boston area. I'll fill out that profile stuff today.

I thought for some reason the separate outlets was good for some reason.. i thought i read that regarding a old fender quad amp I had and minimizing grounding noise or something.. but that was awhile go... clearly i got that wrong.. yes my studio is probably ok. i do have some power strips in power strips.. but nothing is drawing hi amperage.. i have a computer, a 37' tv (monitor), two smaller powered monitors and a mackie 1402 mixer.. and everything else is pretty much rack gear and a couple of synth keyboards.. i also do not turn everything on all the time.. i keep most items off so that much less draw is ever going on at any given time.

I will balance everything up and test it out tonight if I have time.. kinda busy work day and then a class after work.. but later tonight i can do some quick testing to see if the grounding issue is a thing with all balanced stuff. Thanks again for the insight. I'm on the verge of doing a major redo with the desktop patchbay so having this insight beforehand will help me make some better decisions.

The desktop patchbay was meant to be a kind of "breadboard" of effects and instruments that i could route in and out to each other and then ultimately devote 8 points to (balanced) travel over to the other balanced patchbays that ultimately lead to the mixer or 2408 Mk2 to record in...
To test IF the outlets are the issue all you
have to do is plug ALL gear into same outlet...
Most likely they are on the SAME phase, which is what Can produce hum, but most houses are wired ONE circuit per room...
BUT, get an extention cord and run to other outlet and see what happens..
Seems like you could have other "Audio wiring" problems..

Another thing to check is: Keyboards, do all have the newer polarity type AC 2 pin or the older NON polarity AC that can be plugged in either way? Follow me?
The fact is there are several things that Could be your problem..
Even one AC outlet is wired Wrong..
Old 29th May 2019
  #8
Gear Maniac
 

ok so you're saying if I can find another outlet in my room that isn't on the same circuit breaker that's going to help?

I'm 99% sure that yes both outlets in my studio are on the same circuit breaker. What would be the ideal solution if I had to bring an electrician in?

if i brought the extension cord in and plugged in one single unit separate from everything else (my BOSS SE-70 for example), it being on another circuit should remove the hum?

Well for keyboards that make sound, I have a 1986 DW8000 which has a two prong cord which IIRC doesn't really care which way it's plugged in. I have a microbrute also which also is a 2 prong unit, but it's much much newer and I think does have the prongs that force a certain way to plug in.. but it's currently not even hooked up.

If there is some reasonable corrections that could be made via an electrician, I'd love to know. I have an electrician who's done work before and reasonable rates. I just want to be sure I can verify which audio issues (if any) he can fix.

Thanks!
Caleb
Old 29th May 2019
  #9
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nosebleedaudio's Avatar
 

Quote:
Originally Posted by part12studios View Post
ok so you're saying if I can find another outlet in my room that isn't on the same circuit breaker that's going to help?


if i brought the extension cord in and plugged in one single unit separate from everything else (my BOSS SE-70 for example), it being on another circuit should remove the hum?

Well for keyboards that make sound, I have a 1986 DW8000 which has a two prong cord which IIRC doesn't really care which way it's plugged in. I have a microbrute also which also is a 2 prong unit, but it's much much newer and I think does have the prongs that force a certain way to plug in.. but it's currently not even hooked up.

If there is some reasonable corrections that could be made via an electrician, I'd love to know. I have an electrician who's done work before and reasonable rates. I just want to be sure I can verify which audio issues (if any) he can fix.

Thanks!
Caleb
IM saying IT COULD be part of the problem.
Very easy to check, esp if they have the type of two prong that is NOT polarized.
But I have seen several studios that the only way to 100% eliminate to hum was a Passive DI box into Mic pres on a Mackie ect and being able to lift the ground..
IF it is a AC outlet problem It could be from a couple of things; ...
But first Just plug ALL gear into same outlet, IF still hum reverse the KB that CAN be reversed and see..
If you have a Passive DI Box try it..
Old 29th May 2019
  #10
Gear Maniac
 

I will check the microbrute closer. it's only a few years old while the DW is very old and i would assume it's not up to any modern AC standards.

This weekend I'll do some experimentation with wiring and see once i have all balanced patchbays how things sound. maybe things will be OK this time around? Probably not, but I need to catch things in the act.

I like that my GL-100 has stereo XLR outputs on the back of it, but I'm still trying to see if there is any way to make it quieter.. because while it's unplugged (no instrument in) it's silent.. but once a 1/4" cable is plugged in it makes hum.. but gets queiter once plugged into a guitar.. but still some hum under it..

I have a noise decimator g-string which helps but any pedal still is basically just a noise gate at the end of the day and thus its tough to get away from the choking if you play dynamically..

I don't have a DI box, but just doing a quick price check I can see they are not to expensive.. like $25 and up.. so That's nice to factor in..

One thing I do have that might be a DI equivalent is a "Buzz off" but when i tested it awhile back it didn't seem to make a difference but I may not have been using it right..

https://www.ebay.com/itm/Rolls-HE18-...torefresh=true

Definitely going to get to the bottom of this. I've been researching items I have that are balanced vs unbalanced also to see what gear may support or not.. my aural exciter, rocktron imager/exciter and bbe sonic maximizer all appear to be unbalanced, but my DBX Spectral enhancer does support both balanced and unbalanced..

i'm wondering/hoping some of my effects processors support balanced but i'm sure most if not all won't be balanced capable.
Old 29th May 2019
  #11
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nosebleedaudio's Avatar
 

The DI box is for Isolating grounds, just any DI may not accomplish what it does..
Old 29th May 2019
  #12
Gear Maniac
 

so how do i identify a DI box that will isolate vs one that doesn't? or are you referring the the Buzz off as a DI box? Obviously I just want to make sure I'm getting the right accessory.

The part I'm trying to figure out is why I would not experience a grounding hum with an effects processor when plugging an instrument directly into the effect and have that effect come out of the patchbay, but if i run the same instrument into the patchbay and rout that into the effect AND out of the effect hum is audible.

maybe if i have the patch bay in and out be to two different patchbays?
Old 29th May 2019
  #13
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nosebleedaudio's Avatar
 

Somehow Missed the post you having hum thru bay, and Not with out bay...
So, forget the DI box...
Old 29th May 2019
  #14
Gear Nut
I agree run everything from one outlet so long as you don’t exceed power draw.

Option #2 if you have to stick with two outlets is to buy a new outlet receptacle. I had one in my old house that was causing issues, cleared right up with a replacement. Funny thing is it passed the testing done by electrician. My UPS when connected would go bonkers so that was the red flag for me...
Old 29th May 2019
  #15
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nosebleedaudio's Avatar
 

Quote:
Originally Posted by superscan View Post
I agree run everything from one outlet so long as you don’t exceed power draw.

Option #2 if you have to stick with two outlets is to buy a new outlet receptacle. I had one in my old house that was causing issues, cleared right up with a replacement. Funny thing is it passed the testing done by electrician. My UPS when connected would go bonkers so that was the red flag for me...
If he used one of those $7.00 testers then no surprise, they don't show/tell the whole story..
Old 29th May 2019
  #16
Gear Maniac
 

gotcha about the DI Box.. but would you say that "buzz off" is a DI Box?

if I had to turn everything on at once i have approximately 45 wired up items... most of them being rack gear..

but in reality I'd only say 10-15 things would ever be on at once.. i'm doing fairly linear multitracking not doing lots of direct live ins / outs with my 2408 mk2 (balanced).

some things have no on / off switch so i have them going to the second power conditioner which i don't always turn on. A few things are an exception like my dbx preamp which i use enough to go ahead and have it on my main conditioner.

oh and yea i had my electrician ground both of the outlets and he used a grounding tester, but certainly was likely something in the $7 price range.. simple hand held device with a single light IIRC.

NOTE that in my particular setup as you can imagine with that many pieces of equipment I have power strips in power strips.. ultimately they are all grounded power strips so i'm hoping that would make things ok, but each power conditioner only has like 6-8 outlets on each so there is no way i could power everything off that many outlets..

I am working on scaling back my studio some, but i wouldn't say i'm going to get it down to 10-15 items either..
Old 30th May 2019
  #17
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Richard Crowley's Avatar
 

Quote:
Originally Posted by part12studios View Post
gotcha about the DI Box.. but would you say that "buzz off" is a DI Box?
tl;dr The Rolls HE18 is an isolation transformer, not a "DI Box"

No offense to you, but this is one of my petty peeves.
The term "DI Box" is vastly (and incorrectly) overused these days.

In my book a "DI Box" is a product specifically designed to take a high-impedance, unbalanced signal out of an electric guitar or bass, and convert it into a low-impedance, balanced signal indistinguishable from a modern microphone. That allows you to send the signal into the same infrastructure as if it were a microphone signal.

OTOH, there are many products out there that are isolation transformers. Exactly like the Rolls HE18. An isolation transformer is designed to take a line-level (either consumer line level, -10dBV, or pro line level, +4dbV) signal, either balanced or unbalanced, and ISOLATE the source on its continuing path towards its destination. The specific purpose of this isolation is to break ground loops, etc.

I keep several Rolls DB25 isolation transformers in my "remote kit" where I need to tap into a venue sound system to pick up the PA system audio when I am shooting video productions.

Typically, you shouldn't need isolation transformers in an established home/studio configuration. If there is a problem with a ground loop, ideally, the root cause should be identified and resolved. An isolation transformer is only needed where one cannot resolve the underlying problem. And that is often the case out on location. But it should not be necessary "at home". At least that is my very subjective opinion.

I have even been known to take an audio device with an unbalanced output and substitute a balanced connector (for example a TRS replacing a TS) and then adding a resistor to the Ring to make an "impedance-balanced" output.
Old 30th May 2019
  #18
Gear Maniac
 

ah that's great to know.. though kinda of a bummer that i wasted money on something that won't really help me. Oh well, live and learn

No offense taken! I'm open to learn what i'm doing wrong and eager to know how to do it right.. i'm going to try the same outlet and just test things out. I'm thinking also about separating the ins and outs to two separate patchbays and see if that helps.

I remember one time I had two DW8000s and when they both were in the same patch bay there was this really bad hum.. but when i moved each to it's own patchbay (the two patchbays were next to each other) and that cleared it up. i'm sure it could be for several reasons.. like they might have shared the same power strip as well.. so we'll see.

Thanks to everyone so far for your insight and help! I hope I can find a solution and share what worked for me so others might have some luck with their stuff.
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