Best Gauge Wire for Amp to Mixer Cable

[Bobbsy]

I think ecc83 is talking about using the DI box to split the INPUT to the amp rather than using it on the high power speaker out of the amp. At least I hope so.

FYI, I checked the manual on your Nady mixer--it's all unbalanced line inputs so, as long as you can get some form of line out from the mixer you'd be good to go to plug that into your mixer without worrying about anything blowing up.

 

[ecc83]

I think ecc83 is talking about using the DI box to split the INPUT to the amp rather than using it on the high power speaker out of the amp. At least I hope so.

FYI, I checked the manual on your Nady mixer--it's all unbalanced line inputs so, as long as you can get some form of line out from the mixer you'd be good to go to plug that into your mixer without worrying about anything blowing up.

No Bobbs, I do mean the full fat speaker out! Those boxes are rated to handle up to 3kW amps. They do NOT of course contain a load! They must be used in parallel with a speaker.

I DID hesitate to post it Bob, but on balance if the OP is in the brown stuff and that is the only feed he can get?

N.B! To OP and others, there is no need to "break into" speaker lines to use such a box. It can be simply "tacked in" at any convienient (prob' amp terms) point and best to get a technical bod to do it.

Dave.

 

[Bobbsy]

Well, live and learn. Digging into the specs for that box I see it has switchable attenuation up to 40dB. Despite 40 years playing with this stuff, I've never encountered that sort of thing or the need for it!

That said, I'm hard pressed to visualise a situation where that would be the best option. If I'm at the back of an amp and have a choice of splitting the line level input or letting that signal be given 40dB of gain (with the attendant extra distortion and noise an amp will provide--amps are brute force and ignorance rather than subtlety) then split that and attenuate it back down to line level, I'll split the input! I guess you could end up in a situation where the amps are in a locked room and the only option is to grab things from the speakers themselves...but luckily I've never been in that sort of position! But I'd rather bribe the caretaker to let me into the locked room!

 

[bouldersoundguy]

Well, live and learn. Digging into the specs for that box I see it has switchable attenuation up to 40dB. Despite 40 years playing with this stuff, I've never encountered that sort of thing or the need for it!

They're usually used on guitar and bass amps to get a bit more of the tone than a direct output from the amp. It occasionally comes in very handy.

 

[ecc83]

"Well, live and learn."

We all do Bob! (or should).
Yup, the boxes are far from ideal but it has to be said that their main purpose is to pinch a level from a guitar amp speaker line and of course, all the attendant "non-fi" that goes with it!

As for tapping into speaker lines when no other access presents itself? One bit of kit in my PA armoury from years ago was a 100V line traff (70.7V over'pond for some unknown reason!). XLR on the low Z side and a flying lead on the 100V side terminating in two darning needles!

(Two other gadgets FYI: A 13A rated RF mains filter box on 10mtrs of heavy,shileded cable. "REP" coils, 1:1 audio transformers with electrostatic interwinding shileds. Cleaned up powerful MF transmitters a treat!).

Ah! The good old days! (bloody weren't, we would have KILLED for todays kit at todays equivalent prices!)

Dave.

 

[bouldersoundguy]

Second scenario: Let's say I get there and all the line out jacks coming out of the mixer (or maybe amp) are balanced? Being that my mixer is unbalanced... how would I convert the signal? Is there some other device I should look to for an unbalanced signal (pre-amp, etc.)?

This looks like a job for Rane Note 110.

 

[Bobbsy]

They're usually used on guitar and bass amps to get a bit more of the tone than a direct output from the amp. It occasionally comes in very handy.

Ah, now that makes sense. However, I'd guess that the "bit more of the tone" that's beneficial to a guitar sound might not be so good on a quiet wedding ceremony like the OP is talking about.

Then again, heavy metal grade distortion might have suited my first marriage well enough....

 

[bouldersoundguy]

Ah, now that makes sense. However, I'd guess that the "bit more of the tone" that's beneficial to a guitar sound might not be so good on a quiet wedding ceremony like the OP is talking about.

Then again, heavy metal grade distortion might have suited my first marriage well enough....

The pad takes the signal down enough to prevent added distortion, and it takes any noise down just as much as the signal. So if using a PA amp that isn't adding a lot of distortion (most are a fraction of 1% at clip) or noise (S/N better than 100dB is not unheard of) the output of the DI will be a nice clean signal. So if it sounds good through the speaker it should sound good from the DI.

 

[ecc83]

The pad takes the signal down enough to prevent added distortion, and it takes any noise down just as much as the signal. So if using a PA amp that isn't adding a lot of distortion (most are a fraction of 1% at clip) or noise (S/N better than 100dB is not unheard of) the output of the DI will be a nice clean signal. So if it sounds good through the speaker it should sound good from the DI.

Was gonna say all that BSG but got too tired!
BTW we used the trick to pinch PA conference signals when we could not get at the gear but an MD wanted a recording of the event.

Dave.

 

[amanisdude]

Should it be the case that a speaker connection is the only one available you could use one of these..

ART Z Direct DI Box | Z Direct Passive D.I. Box by ART | ART Specialist

Behringer and others make similar boxes.
Dave.

Wowzers! Thanks, Dave! I'll definitely look into something like that if I need to, though I would like to avoid getting another device if at all possible. At any rate, I'm sure the church'll have some sort of mixer output. I'll let you guys know if they don't.

This looks like a job for Rane Note 110.

Thanks, bouldersoundguy!

The note was very helpful! I'll now be able to identify a ground loop if I hear one. Moreover, the article is clear with regard to the cable assembly diagrams in the case of converting a balanced signal to an unbalanced one if transformer isolation is not an option.

However, the note doesn't do much in the way of describing how to correctly do transformer isolation, aside from an electrical diagram. I'll definitely look it up, but are there any tried and true methods of doing DIY transfomer isolation and making baluns? Thanks guys!


~~~

Finally, I stumbled upon this cable on Jameco. Now, I know it's not professional grade, but how well do you think it would work for building REALLY LONG unbalanced mono cables (~50‒100 feet)? How about short cables (~3‒10 feet)?

According to the datasheet (Part# 8451), the cable is shielded in a thin layer of aluminum-coated polyester foil (beldfoil). It's not the best shield for audio, but do you guys think it would be sufficient? Thanks for all your help, everyone!

~~~


‒amanisdude
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[ecc83]

Nothing wrong with foil shields for audio Dude!

In fact foil gives 100% coverage against RF whereas braids and laps do not. You cannot screen a cable against MAGNETIC interference (traffs, mains cables) that is why we "balance".

I have several leads made up with Belden V9534 2pr and it is lovely stuff! Wish I had another 100mtrs!

It is true that foil shielded cable is not as flexible as good quality braided and so is not the best choice for "road" use but a VERY cheap way to get long runs of 4pr shielded cable is CATx FTP cable. Even the solid core stuff will last quite well if on a drum and only reeled out a few times a years.

Transformers and balancing. If going this route best to buy the right boxes (Art, Orchid Electronics) and do as it says on the tin.

For long, unbalanced runs a "shielded return" setup will help keep out etherial crap.

Dave.

 

[Bobbsy]

Yeah. I have a lot of FST (foil screened twin) cable in my set up for permanent install stuff or short interconnects. The last TV studios I worked in had many miles of the stuff!

However, you really need to do your site survey and see what you're getting into....

 

[amanisdude]

Hi everyone!

So I have some stupid news. It turns out that the church does not generally use their audio system for weddings .

BUT, all is not lost. Just take everything about what I said about plugging in to the church's audio system and apply it to the reception!

That's right. The reception hall has EXACTLY the type of audio system that I was expecting the church would have. Here are a few pix of the reception hall system:

______________

The primary setup rig with the main mixer on top:




The main mixer (Allen & Heath AH-WZ3:12:2 Mix Wizard WZ³ 12:2):




Under the main mixer:








A second mixer ...for some purpose unknown to me (Behringer EURORACK UB1832FX-PRO):





I tried my best to get pictures under the Allen & Heath WZ³ 12:2, but it was in an awkward location and those are the best pictures I managed to scrounge. As for the Eurorack, I couldn't photograph underneath.

At any rate, it does seem like they should have some kind of line level outputs, but maybe not. I'll look through the manuals, but maybe some of you already have experience with these types of units.

Remember, I'm planning on taking the main line level output from the necessary mixer and transporting the signal about 100 feet (~30.5 meters) away to an itsy Nady MM-242 set up on the balcony, which will further split the signal by sending it to a Behringer HA400 MicroAmp. Thanks for your help!

~~~~

Now, for actually transporting the signal that 100 feet to the rear balcony.

Nothing wrong with foil shields for audio Dude!

In fact foil gives 100% coverage against RF whereas braids and laps do not. You cannot screen a cable against MAGNETIC interference (traffs, mains cables) that is why we "balance".

I have several leads made up with Belden V9534 2pr and it is lovely stuff! Wish I had another 100mtrs!

It is true that foil shielded cable is not as flexible as good quality braided and so is not the best choice for "road" use but a VERY cheap way to get long runs of 4pr shielded cable is CATx FTP cable. Even the solid core stuff will last quite well if on a drum and only reeled out a few times a years.

Transformers and balancing. If going this route best to buy the right boxes (Art, Orchid Electronics) and do as it says on the tin.

For long, unbalanced runs a "shielded return" setup will help keep out etherial crap.

Dave.

By "shielded return", I assume you mean grounding the cable shield at one or both ends. (Sorry. Newb, remember. )

Yeah. I have a lot of FST (foil screened twin) cable in my set up for permanent install stuff or short interconnects. The last TV studios I worked in had many miles of the stuff!

However, you really need to do your site survey and see what you're getting into....

Does this mean I could use the Belden 8451 as an audio cable for 100+ feet? (I'm not sure how short are short interconnects. )

What I'm planning to do is plug one 1/4" TS or TRS on one end of the cable into the reception hall's mixer's line level ouput (if it has one), then duct tape the whole 100' cable to the floor and up the wall to the balcony, and plug the other end with the one (or two) 1/4" mono TS into my Nady mini-mixer.

Also, can I use the Belden 8451 for unbalanced stereo signals? I'm not sure if the 'drain wire' in the technical specification is one of the two twisted conductors or a separate conductor attached to the shield. (Again, amanisdude == newb. ) If so, I assume that the wire would be fine for unbalanced stereo connections. Again, thanks for your continued help, guys!


‒amanisdude
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EDIT:

> From Page 11 of the MixWizard WZ³: 16:2 and WZ³: 12:2 User Guide Issue 5:
Where long cables runs are required, balanced interconnections should be used. However, line level interconnections between more affordable 2-wire (signal, ground) unbalanced equipment and the console are unlikely to cause problems if the cables are kept shorter than 10 meters or so. Refer to the wiring diagrams on the opposite page.

Wow, I feel dumb. So I guess my 100-foot unbalanced stereo or mono run won't work with the Belden 8451 without some special wiring. Might have to heed the instructions in RaneNote 110 that bouldersoundguy linked earlier and make a good assembly or find a good balun.
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EDIT 2:

Okay. I thought about it a bit, and I think I figured out why they have two mixers.

One is for all the mics and vocal inputs, and the other is for all the other device audio inputs. (They have a karaoke machine, a DVD player, HDMI connectivity, computer VGA/3.5mm connectivity, and more.)

From the setup, I assume the MixWizard is for the accessory device audio (DVD player, etc.), and the EURORACK is for vocal inputs from microphones and whatnot. (I can't say for sure, though. I'll have to go back and take a look at the wiring, but it's a good bet that I'm right.)

If this is the case, I might need line level output from BOTH devices and have TWO 100' cables going up to the balcony! (Oy vey.) Alternatively, I guess I could take only mono signals from each and ram both through the 100' cable. I'll have to think about that one.
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EDIT 3:

Well, I feel dumb, again. The uses for each mixer are clearly labeled under the gain controls of the mixers themselves.

And it turns out that they use BOTH mixers for BOTH purposes (devices and mics). That certainly complexicates things...

Looks like I'll have to either be sure which mics they are using and keep them on the same mixer, or I will need to send two signals, one from each mixer, to the webcast control station on the balcony. This is to say of the mixers aren't connected to each other. I guess I'll have to go there again and take a closer look.
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EDIT 4:

Sorry for all the edits! I figured it'd be less confusing than making new posts.

One final question. I've been thinking about the Belden cable and how simple it seems. Do you think the same effect could be achieved by, or would any of you advise against, me just buying some 22 AWG stranded wire from Fry's Electronics, twisting it together, and wrapping it in a non-insulated stranded copper wire?

Or better yet, getting one of these and smoothly wrapping it in aluminum foil with a non-insulated drain wire? Would that be much different? Thanks!
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[Lt. Bob]

[
One final question. I've been thinking about the Belden cable and how simple it seems. Do you think the same effect could be achieved by, or would any of you advise against, me just buying some 22 AWG stranded wire from Fry's Electronics, twisting it together, and wrapping it in a non-insulated stranded copper wire?

Or better yet, getting one of these and smoothly wrapping it in aluminum foil with a non-insulated drain wire? Would that be much different? Thanks!
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why would you go to all that trouble to save only a few dollars?

Yes, technically you caould accomplish that. But if it doesn't work right are you gonna have time to redo your entire wire when there's noise you can't get rid of?
Or will you have to go over there a bunch of nights in advance to make sure it's working right?
And if you don't check it out far enough in advance will you have time to go buy the Belden you should have bought in the first place and get that wired up?

A LOT of extra time and effort and no guaruntee of success.

And with all due respect, it seems to me that you don't have a lot of experience at this or you would know about line level outputs without asking ( and yes, those boards will have plenty of them) so you're not a good candidate for making your own shielded cables out of zip cord and foil and most of us that DO have the knowledge would never bother to try that.
So no ...... that's about the silliest idea I've ever heard ........... it could be done but would be a silly project for no good reason.

 

[Bobbsy]

The most common reason I can think of for having two mixers with the same inputs is to have one feeding the main "front of house" system and the other feeding on-stage monitors. Or, maybe you're REALLY lucky and they're used to doing live web feeds and one mixer is to do a custom feed for you!

Assuming the second guess is fantasy, my suggestion would be to get them to do a mix for you using the Auxes on the Allen and Heath Mix Wizard. If they're willing (and it's the sort of thing I've often been asked to do) you can specify whether you want exactly the same as the room is hearing or emphasis on the mics or whatever.

And I'm with Lt. Bob. Just buy some audio cable and put the proper connectors on the end. FST cable is cheap as chips and you know it'll work.

 

[amanisdude]

why would you go to all that trouble to save only a few dollars?

Thanks Lt. Bob. That's a good point. I guess this question was a bit more about how far I could push the whole DIY thing than saving money.

A LOT of extra time and effort and no guaruntee of success.

Well said.

And with all due respect, it seems to me that you don't have a lot of experience at this or you would know about line level outputs without asking ( and yes, those boards will have plenty of them) so you're not a good candidate for making your own shielded cables out of zip cord and foil and most of us that DO have the knowledge would never bother to try that.
So no ...... that's about the silliest idea I've ever heard ........... it could be done but would be a silly project for no good reason.

True, I don't have much experience with mixers and audio equipment... yet. This is the first time I've ever had to plan out a whole audio rig months in advance, and I can't say that I haven't loved every minute of it.

On the other end of things, I have made Faraday cages out of aluminum foil in the past, so my thinking is that a cable shield is nothing more than a very long Faraday cage.

Anyway, you may be right. It may be a silly project for another time and place, I suppose.

The most common reason I can think of for having two mixers with the same inputs is to have one feeding the main "front of house" system and the other feeding on-stage monitors. Or, maybe you're REALLY lucky and they're used to doing live web feeds and one mixer is to do a custom feed for you!

Assuming the second guess is fantasy, my suggestion would be to get them to do a mix for you using the Auxes on the Allen and Heath Mix Wizard. If they're willing (and it's the sort of thing I've often been asked to do) you can specify whether you want exactly the same as the room is hearing or emphasis on the mics or whatever.

Haha, thanks Bobbsy. I don't think they would be willing to do that in my case.

The whole function of having a separate mixer on the balcony is so that the webcast operator can control which of the various audio inputs he wants to actually feed into the cast on the fly. Communicating with a separate operator on stage might be a bit difficult and may even prove disastrous if the communication isn't fast enough. (Plus, there is a good chance that the stage operator may not speak English.) Good idea, though. I didn't even think of that!

And I'm with Lt. Bob. Just buy some audio cable and put the proper connectors on the end. FST cable is cheap as chips and you know it'll work.

Lt. Bob did make a very good point regarding the cable. I've already gone ahead and ordered the Belden cable. Thanks for all your help, guys. I have learned much from these forums. I'll refer to the manuals before posting any other questions to this thread.


‒amanisdude
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[ecc83]

Well a very long foil shield IS a sort of Faraday cage but only at audio frequencies. It will have significant inductance and so will not be at equal RF potential each end, thus a current must flow. This current can then induce RF into the conductors, bad news. This is where transformers with interwinding screens score.

In the newtork industry the RF currents in shields can get alarming large, cables get warm! Parallel Earth Cables (PECs) are often used to bypass much of the current.

I mentioned CATx cable before and anyone dabbling in sound repro' could do worse than find a network installler and bother the A off him for some "scrap" FTP cable, don't have to be pretty and although a kink or two rules it out for Mbps, at audio no matter.

Box each end of 50mtrs with XLRs and you have a very cheap 4 port mic (or anything else) tie line. (it would also almost certainly pass~100 Mmbps over 50mtrs anyway).

 

[Bobbsy]

Yeah, it's very common nowadays to use CAT5 cable for permanent audio installs--works really well and is very easy to work with. The last studio facility I built (just before I retired) we flood wired the place with CAT5 and terminated as required for phone, data, audio and even some video with the appropriate drivers. Worked a treat. (In the main tech area we used more conventional audio multicores but that was just because it worked out to be easier with the volume of cabling we had.)

However, I'd personally restrict its use to balanced circuits where CMR is your friend and would stick to more conventional audio stuff for runs of unbalanced signals (such as what the OP is talking about since all his inputs are unbalanced).

 

[ecc83]

Yes Bobbsy.
I asked Belden a few years ago if their FTP cable was ok for audio. They came back to say it was superb and that many people put it in studios and the like. Often to run analogue audio at the start but with the intention of going digital as funds permit.

I was interested to read that video can be sent successfully using matching boxes. I intend to do this to get video from my garden up to my TV (at present I have 75R co-ax going thru' absent son's bedroom but he will be back for Crimble!)

Re a long unbalanced run. Quite! Not a good idea. I have 4 ways going to and fro in 2 cables to a Teac A3440, 5mtrs and not a trace of hum but 50mtrs????

What the OP needs is some un-balancing INPUT traffs but good ones are a bit dear.

Dave.

 

[Bobbsy]

You have lots of different options for video over CAT5...basic composite, VGA, DVI and even HDMI nowadays. For good value economy stuff, have a look at the bits and pieces CPC/Farnell sell. For example, at the most basic video only THESE or for Video and Audio THESE. There are far better quality ones too...or cheaper on eBay...but I know these models work.