Need To Get From Mixer To Amp Over Around A 40meter Strech?

[vibemobilediscos 0]

hi there, first of all loving the new features!!!

 

right, i need to run a cable from my mixer to a 'office' where the amps are, it is a stretch of around 40meters i would say just to be safe, what would be the best way of doing this? i looked in to wireless ways and transmitters etc but it just look hurm well dodgey?

 

the only thing i would be worried about it loss of frequency?

 

it will be on a 2 phono output into a 2 phono input, any one got any advice?

 

obviously i would have to get the cable made up so has anyone got any prices at all for that too?

 

i would be very grateful!!!

 

elliott

[otronics 0]

You do not want a 40-metre-long phono to phono lead - all sorts of bad things will happen - signal loss, interference etc.

 

This is why XLR cables exist (balanced ones), so use these if you can.

 

Wireless is an option, but before we go into that:

 

1) Where is this going to be set up (specific location, ie/ school hall, theatre..)

 

2) What is this going to be used for (live sound event, disco....)

[Welsh Audio Man 21 0]

Can make you a 40m, twin RCA- twin RCA for £45 plus P&P....

 

But agree with Otronics, its not recommended at all. You can get twin male XLR- twin RCA, and twin female XLR- twin RCA, but as RCA's are unbalanced, you would have an unbalanced signal being run.

[Danno13 0]

Yep, you need to use a balanced cable run.

 

If your mixer doesn't have balanced outputs then you need to buy a DI box and connect the mixer to this. It will then output a nice balanced signal that you send to the amps over a pretty long distance.

[Welsh Audio Man 21 0]

Yep, you need to use a balanced cable run.

 

If your mixer doesn't have balanced outputs then you need to buy a DI box and connect the mixer to this. It will then output a nice balanced signal that you send to the amps over a pretty long distance.

 

 

:wall: why didn't i think of D.I boxes!

[EdBray 0]

Why not buy one of these. As well as being a ground loop isolator they will convert an unbalanced input signal into a balanced output signal. Cost around about £15 when I bought mine. Keep the phono to mono jack input leads very short.

 

If your amp does not have either balanced xlr or jack input, you could also buy another for the amp end to convert the balanced signal back.

[superstardeejay 0]

then you need to buy a DI box and connect the mixer to this.

 

DI Boxes aren't meant for this.

 

A DI box takes a high (speaker) level output from an amp or instrument eg guitar amp and converts it into a low level balanced or unbalanced input for a mixer....hence DI, ie Direct Injection.

 

 

The Carlsbro wireless transceiver kit (discussed on here before) is ideal for this but pricey.

 

 

If your mixer only has unbalanced (phono) outputs then you'll need a Balun to convert it to balanced, you can get these built into XLR plugs or in-line adapters.

 

If the amp rack in the office doesnt have balanced inputs then another Balun will be needed at that end as well.

 

 

There are also devices coming onto the market which allow sound to be transmitted through a CAT5 twisted pair, you need a set of these at each end. However I've never used one.

 

 

Using plain phono connections with a single screened cable for each channel will be a good way of generating a loud hum through the bass bins over this distance. You won't really lose the high end because audio frequencies aren't too bothered by small cable capacitances...it's more of a problem for RF and video. Unbalanced connections may also pick up your local radio station.

 

Look here:

 

baluns

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Andy Westcott 0]

For what it's worth, I don't think 40 metres over a balanced line would be a problem, as long as the output impedance of the mixer was sufficiently low, as there may be some loss of the highs due to the cable capacitance if not. Any decent mixer should be fine in this respect.

 

I've used runs of more than this length before, although not in connection with disco, and had no problems at all, although I was feeding the line with an emitter-follower stage (for those who know what that is), which offers a very low output impedance. I've even used a 25 metre run of balanced line fed simply by a microphone, and still had no problems - indeed this isn't that unusual on larger stages anyhow.

[superstardeejay 0]

For what it's worth, I don't think 40 metres over a balanced line would be a problem, as long as the output impedance of the mixer was sufficiently low

 

Yes but he's going out of an unbalanced phono into another unbalanced phono input.

[Andy Westcott 0]

I've done it again, haven't I??

Failed to read the post properly......

 

But do you think there would really be any issues with an unbalanced line at line level? He would have to ensure the lead was away from longish parallel runs with mains wiring to prevent mutual hum induction, but other than that, I'd have though it would be OK, but that's just an expectation, not an experience.

[vibemobilediscos 0]

hmmmm im a liitle confussed lol!

 

so if i run the 2 phono to 2 phono lead (which is unbalanced?) over 40meters im likely to get bad feedback / poor sound quality?

 

but if i run it through a 'balanced cable' i will be ok? but this will be expensive?

 

basicly its a favor a a friend at pitcher and piano ( a pub in town ), he wanted to try a dj in the bar for a saterday night. now, to get from the place where he said he would like the dj to be its a strech of at least 40m.

 

so in simple words, what are his/my options?

[Welsh Audio Man 21 0]

If its only a trial, at present, is it really worth spending the money on something that may fall through after a few weeks, then you end up with 40 metres of cable and components, rotting away in your garage/storage, whatever....

 

Why not hire for now... :shrug:

 

At least this way, you can try a few different options, and see what works best.

[superstardeejay 0]

Well you can certainly try it phono to phono (unbalanced) but you can bet that the hum loop you'll create (at the least!) will make the old bass bins buzz and rumble. After all, the phonos will be earthed at the amp end and at the DJ end as well. And that's one giant loop of earth wire to pick up all that 50 Hz hum. I bet it will make the system unuseable.

 

At least going balanced, like I recommend with the Balun in my link, will not only remove the hum loop but will reject all common-mode noise between the two sites. It's really the best way! The CAT5 UTP cable is also LOTS cheaper than screened stereo phono lead of the quality you'd need...about 7 or 8 quid for 100M 3-pair is about the going rate these days and available from any computer shop.

 

 

4 pair CAT5 UTP cable:

http://www.tlc-direct.co.uk/Images/Products/size_3/CACAT5.JPG

 

 

Audio Balun:

http://cache.smarthome.com/images/7821ds.jpg

 

CAT 5 Balun:

http://www.cyberselect.co.uk/photos/balun_audio_HiFi.gif

[djn 0]

Im not technically qualified in any way, Just had lots of experience in fitting systems into venues of all sorts , (including a full range sound system in a football stadium)

I've run approx 25 mtrs of phono to phono cable to get a sound signal from a SKY box to a PA amp with no problems, but I did make sure I kept away from any other cable runs. I used ready made cables bought from E.bay for about £12

[superstardeejay 0]

This is a little different, the output from the sky box will be permanently at full level and you'd regulate the volume at the PA end, meaning at lower volumes the noise will be lower as well.

 

And 40m is longer than 25!

 

As a professional offering advice, I can't recommend this, what you do in the privacy of your own home is up to you! I would not wire up a 40m run 'on the offchance' that it worked 'ok' when this is not accepted installation practice. The stuff we do has to work flawlessly first time under all circumstances.

 

 

 

 

 

 

 

 

[Welsh Audio Man 21 0]

take a looksy!!

 

Take a looksy at what ive just found on Thomann. Surely that would be suitable for converting the signal to balanced!

[EdBray 0]

take a looksy!!

 

Take a looksy at what ive just found on Thomann. Surely that would be suitable for converting the signal to balanced!

 

Not exactly cheap though, and you would need one the other end if you only have a phono connection there as well.

Superstardeejay's option is the cheapest.

[Welsh Audio Man 21 0]

take a looksy!!

 

Take a looksy at what ive just found on Thomann. Surely that would be suitable for converting the signal to balanced!

 

Not exactly cheap though, and you would need one the other end if you only have a phono connection there as well.

Superstardeejay's option is the cheapest.

 

Just giving another option.. thats all!

[EdBray 0]

As was I!

[superstardeejay 0]

Yep the Thomann one is fine, it's a balun as well but just a mono one so you'd need to double up for stereo.

 

Balun = short for Balanced / Unbalanced

 

You'd also need to use twin screened balanced mic-style cable and XLR's, not that cheap compared with CAT5 cable.

 

Methinks you will go ahead and try the phono to phono anyhow....?!?!?

 

 

[vibemobilediscos 0]

well, i have been thinking, i can easly make my own 2 phono to cat5 converter.... right?

 

because surely its just the cables going together.... if you no what i mean? as long as i get perfect connections etc would that do the trick.?

 

as i dont want to be blowing aload of money on something thats not sure of yet???

 

 

[Andy Westcott 0]

If you are going to attempt the phono route, it's not a good idea to use unscreened cable, which is what the data cable is. You'll need co-axial screened cable otherwise you'll be picking up every CB and taxi operator for miles, not to mention every click of every light switch and thermostat on your phase of the mains!

 

Bite the bullet and hire the necessary equipment to enable you to use balanced lines if this is mission-critical. Any of the other suggestions are either going to result in dodgy performance or wasted expenditure on your part.

 

On the other hand, if you do buy a load of balanced cable, you could always cut it up afterwards, make up some shorter runs with XLR terminations and flog them on eBay. smile icon

 

 

[superstardeejay 0]

i can easly make my own 2 phono to cat5 converter.... right?

 

 

No. The converter box is not just a box with the appropriate sockets at either end. The signal is converted to a suitable format to transmit across cat5 cable and then converted back to audio at the other end...it's done differently by different manufacturers but typically uses A-D and D-A techniques, or high frequency carriers (as in a modem.)

 

Audio baluns use either passive matching transformers or, more cheaply nowadays, electronic servo-balanced drivers. These convert the audio with push-pull chips (line driver/receivers) which can either be dedicated chips or op-amp based circuits.

[Andy Westcott 0]

Quote:

"The signal is converted to a suitable format to transmit across cat5 cable and then converted back to audio at the other end"

 

That's pretty cool!

I wasn't aware such a system existed. Learn something new every day.

[RonanRaver 0]

If its a local pub and its a plug in gig have a trial set up a few days before with the phono connections...