Hi all,

I need to get my unbalanced RCA camera outputs to go into a Sky ENG link box (XLR balanced inputs) at various race tracks throughout the country.

I am currently using a mixer to do the conversion but it is not always convenient if and when the link box is outside and it is pouring with rain.

Is there a way I can convert the RCA outputs to XLR balanced to get enough level for the link box using simple adaptors? I did use the simple RCA to XLR plug adaptors and that didn't work.

Adjustable levels would be handy, but not necessary.

Would this do the job?:

ARX IB-1 Audibox ISO Balancer Stereo RCA Unbalanced to Balanced XLR ARX-IB-1 NEW | eBay (http://www.ebay.com.au/itm/ARX-IB-1-Audibox-ISO-Balancer-Stereo-RCA-Unbalanced-Balanced-XLR-ARX-IB-1-NEW-/150718475928?pt=LH_DefaultDomain_0&hash=item2317856e98)

Cheers,

David

Lets break it down to what you want to do.....convert the RCA output (-10 level) to XLR connector with signal on pin 2 / 3 (+4 level).

So you will need to increase the level by about 14db, now the only way to do this is with a powered device like a mixer / amplifier of some sort, it might be battery or mains powered.
Yes you could probably make or get made a custom converter from RCA- XLR but the level would still be to low for usable results, the receiving end would have complaints about the low levels and background signal / noise ratios.

The box you had a link to will do the RCA - XLR convert but not the level increase, there are others around that will also do the level increase, but ideally a mixer would work better. Metering would also be useful both for H/Phones and level indication.
SKY Racing can be very busy at the studio at times and don't want to be level chasing at their end.
This is what I've found when I do OB setups for SKY Racing in Darwin, Alice Springs and occasionally Adelaide.

At a bare minimum, you need to balance the signal. I use this box to do that when I need to:

LINE BALANCER/SPLITTER - Catalog - Whirlwind (http://whirlwindusa.com/catalog/black-boxes-effects-and-dis/specialty-interface-solutions/line-balancersplitter)

Basically, you will get a transformer balanced signal off of these boxes. However, as the previous poster mentioned, you will not get a +4 signal out of it if that is what you truly need.

When I've had to do this, I use one of many products on the market like this: 124A Two Channel Level Interface | Aphex (http://www.aphex.com/aphex-products/124a-two-channel-level-interface/) I'd probably stay away from the ART and Rane boxes that do this (build quality sucks). Aphex isn't always the best sounding stuff, but it is robust and does the job well. Other companies that are worth looking into include Radio Design Labs, Henry Engineering (The Matchbox is pretty nice), Whirlwind (LM2U) and a few others.

--Ben

I have used this device with complete satisfaction, and the price is right: Rolls MB15b Promatch 2-Way Stereo Converter MB15B B&H Photo

I did make up my own 12 volt battery pack to avoid having to have access to AC power, which was a simple radio-shack job.

It's bi-directional, I have used it to receive pro-level audio into an hdv camera, and conversely, to feed my camera audio into a sat truck that needed the up-conversion to +4db, as you do. Unlike the other devices mentioned, this is an active powered mini-amp, pretty compact and rugged.

Here's an Australia dealer I found on Google: https://audioproducts.com.au/BrandProducts.aspx?Brand=ROLLS&Cat=204

What ever you get must have a tone generator in it to ID lines and to set levels..

After all I assume you are being payed as a professional, sending material to a professional organization where they would be expecting professional results.

SKY are quite fussy about material arriving at their studios, do it right and I would expect your contracts to be renewed.... give them grief of some sort or not deliver what they want would you expect your contract to be renewed next time?

Hi Brian,

I understand what you're saying, however I don't work for Sky, I freelance as an ENG cameraman.

Nonetheless I always want my signals to be as clean as possible and as close to "standard" as possible.

Just trying to get away from the bulk and vulnerability of a mixer when most link boxes are exposed to the elements.

Thanks to everyone for your advice and suggestions, too! I appreciate it.

DC

You said you want to send your camera's RCA audio outs to the balanced input. What's setting alarm bells off in my head is wondering just what audio it is that you HAVE that's appearing on the camera's audio outputs in the first place?

Sorry, not sure I understand.

Panasonic P2 camera (AG-HPX502en to be precise) that has four channels of audio. Sending the first two channels out to a Sky Television link box from the camera's RCA outputs to the XLR Balanced inputs of the link box.

Not sure why that's setting off alarm bells - apart from the fact that a professional camera only has RCA outs and not XLR...which is indeed frustrating for me, but means I do need some kind of clean conversion/level increase from the RCA's to XLR so the folk receiving the signal get a decent level and clean signal.

@David, referring to my previous post, the referenced device will do it for you, I think.

I was thinking the same thing that Mr. House posted. What are you shooting that the CAMERA AUDIO is acceptable here? Typically, broadcast operations (except for perhaps breaking news) use SEPARATE audio processing in the form of at least a small mixer which typically provides balanced professional line-level outputs and other amenities not available by simply using the built-in camera audio facilities.

...

Not sure why that's setting off alarm bells - apart from the fact that a professional camera only has RCA outs and not XLR...which is indeed frustrating for me, but means I do need some kind of clean conversion/level increase from the RCA's to XLR so the folk receiving the signal get a decent level and clean signal.

Exactly as Richard said. What is your audio arrangement such that the camera actually appears anywhere in the audio signal chain? Surely you're not using the camera-mounted microphone and its internal audio circuits to capture your commentary are you? Are you feeding your signal to Sky in real-time or are you recording in the camera and sending the footage later by playing back using the camera as the playback device? If you're feeding your signal real-time, I would expect the audio to bypass the camera altogether, your mics feeding a field mixer which in turn feeds the linkbox to Sky, though if you're also making an in-camera recording you might have a split from the mixer's output also going to the camera's audio inputs. (Mixers such as my SD442 have multiple parallel outputs to make setting up such a split a no-brainer.) But the camera's own audio circuits would not appear anywhere in the signal chain from microphone to Sky .

In ENG + SNG work I haven't used an audio cable to the link truck / Sat unit for a couple of years now, the standard way most TV networks do it now is just use the breakaway cable to the camera from a SD442 / FP33, these 2 channels are then embedded into the camera video o/p and then fed out as an SDI signal to the link truck via a single coax cable.
4 channels of audio are available this way right through to the studio but normally only 1 or 2 are used.

In ENG + SNG work I haven't used an audio cable to the link truck / Sat unit for a couple of years now, the standard way most TV networks do it now is just use the breakaway cable to the camera from a SD442 / FP33, these 2 channels are then embedded into the camera video o/p and then fed out as an SDI signal to the link truck via a single coax cable.
4 channels of audio are available this way right through to the studio but normally only 1 or 2 are used.
You are talking about digital where you need to feed audio into the camera so that it can be encoded into the digital stream. Clearly that is NOT what Mr. Cleverly is dealing with.

Hi all,

I need to get my unbalanced RCA camera outputs to go into a Sky ENG link box (XLR balanced inputs) at various race tracks throughout the country.



Dave ~

Something simple and passive like the Rolls dB24 would do the job. Small pretty rugged and rquires no power. PDF link here:

http://www.rolls.com/pdf/M_DB24.pdf

B&H have it here:

rolls db24 | B&H Photo Video (http://www.bhphotovideo.com/c/search?Ntt=rolls+db24&N=0&InitialSearch=yes&sts=ma)

Cheers
Chris

Mr. Cleverly already reveled that a passive solution didn't work because he appears to need some active gain to get from the -10dBv output level from his camcorder RCA jacks to +4dBv required by the Sky ENG link box .

Hi all, I appreciate your comments but, with all due respect I think some are making the process sound more complex than it actually is or needs to be.

Simply put, amongst other things I shoot news. With respect to news, my feeds are generally always pre recorded. Interviews for other stories. Sometimes complete stories. Main audio on channel one, camera mic on chnnel two. Channels 3 & 4 not used. All I want to do is plug the camera into the local link boxes and send the pics with two channels of audio to the networks via Sky.

Now, admittedly, I have not used the link boxes for about 12 months, but when I last did, the local link box at least did not accept embedded audio, which is a shame because that would negate the need for a solution to this problem...

Maybe all link boxes accept embedded audio now??

So, in an attempt to clarify, all I need is a way go get rca two channels of audio into the balanced xlr inputs of the link box whilst at the same time lifting the levels. Without having to use a mixer.

So at this point you are using your camcorder simply as a playback device to feed the network with pre-produced and pre-recorded material.

There are several options for consumer (-10db unbalanced) to professional (+4dB balanced) conversion. They virtually all require power in order to perform the gain boost. Some can use internal batteries, and some require mains power, typically using a "wall-wart". For your purposes there probably isn't a huge difference between them so select one based on your budget.

Mr. Crowley is correct. Consumer level audio, -10dBv = 0.316 volts rms. Pro level +4 dBu = 1.2276 volts. So the extra volts have to come from some powered source to amplify the signal.

Hi Richard. Yes this is a passive unit but it has L&R input gain pots on the RCA and jack inputs and will put out up to +4dB line level on the XLRs which is exactly what David was after so I am pretty sure it will do the job for him. Check out the link to the PDF.

Christopher the box you recommend has attenuator controls NOT gain controls... A vast difference between them.
The schematic drawing has NO gain stage in it.
Basic physics you can't increase levels without gain and gain needs energy like batteries or external powering.

Yes, Brian is correct.
A quick perusal of the specs indicate: "Max Output Level: +4 dBm, Connectors: 2 ea; XLR"
A 'true' +4dB ref. output would have the maximum output of at least +18dBm.. usually in the +20s.

Yes, I stand corrected guys. Sorry if I gave you a misguided suggestion Dave.