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Topic: Looping Non-Sync Audio Source

Manny Knowles
"What are these things and WHY are they BLUE???"

Posts: 4247
From: Bloomington, IN, USA
Registered: Feb 2002

posted 06-13-2002 08:39 AM

Thank you Oscar...I will check the color of those connectors and follow-up via email.

As for the DA-8...I have more information that may mean something to you (or others present on film-tech) in terms of knowing what the problem is.

The DA-8 is mounted in the rack for Theatre #1. In that auditorium, the hum is present but not overpowering; you can hear it a little bit during silent or quiet passages on a CD.

Over at Theatre #2, the hum is a little louder. It gets louder as we move further away from the DA. Down in Theatre #5 we hear more noise than signal. It's just a razzy sounding hum.

[Edit: since we're now on page 2, I'll just remind everyone reading that this entire Non-Sync system was wired using computer cable...probably Cat. 5 Ethernet cable]

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 06-13-2002 09:23 AM

Cat5 if used is totally inapropriate as it is non shielded. I would really doubt thzt is what was used (I hope)
It is interesting that a quad twisted pair cable and good balancing transformers can transmit hum and noise free audio under some conditions.

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Manny Knowles
"What are these things and WHY are they BLUE???"

Posts: 4247
From: Bloomington, IN, USA
Registered: Feb 2002

posted 06-13-2002 09:53 AM

Gord: That's why I kept mentioning the wire, because just by looking I could tell that it wasn't really the right wire. Certainly it is computer wire of some sort.

I'll make a note of the jacket markings on that wire next time I'm there.

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Brian Tristam Williams
Film Handler

Posts: 93
From: Johannesburg, South Africa
Registered: Apr 2002

posted 06-13-2002 03:11 PM

Guys, thanks for the replies.

I know that you can get amplification UNITS from DA distributors. However, I don't want to sit around and wait for imports. What I want, if anyone can point me to it, is an amplification CIRCUIT - one that I can put together myself with common electronic components. It will also save a few pretty pennies.

Thanks.

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System Notices
Forum Watchdog / Soup Nazi

Posts: 215

Registered: Apr 2004

posted 01-20-2012 10:31 AM

It has been 3507 days since the last post.

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Alban Birch
Film Handler

Posts: 63
From: Luxembourg-city , Luxembourg
Registered: Jan 2007

posted 01-20-2012 10:31 AM

Hi

We're going to wire our Background-music all together and thinking of purchasing the Component Engineering or the Odyssey distribution because of the daisy-chain method.
2 Questions:
since the source is in the middle of the booth, is it possible to run 2 wires in opposite directions?
do we need the receivers on basis-processors as they have balanced inputs?
Thanks and have a nice Weekend

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 01-20-2012 03:59 PM

I have never liked the daisy chain method try to get a USL or a used Smart DA

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Harold Hallikainen
Jedi Master Film Handler

Posts: 906
From: Denver, CO, USA
Registered: Aug 2009

posted 01-20-2012 10:23 PM

From my work in broadcasting for many years, I'm a big fan of balanced audio lines. The CD player probably has an unbalanced output and the processor probably has an unbalanced input. With a long line, this is asking for ground loop hum. Something like this ( http://www.henryeng.com/matchbox.html ) could be used both at the CD player and at each processor. At the CD player, the unbalanced high impedance output would be converted to low impedance balanced where it could drive twisted pair cable to each destination (daisy chain would be fine). At the processor, another MatchBox would bridge the balanced line and convert it to unbalanced suitable for driving the processor NS input.

Harold

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Alban Birch
Film Handler

Posts: 63
From: Luxembourg-city , Luxembourg
Registered: Jan 2007

posted 01-21-2012 05:49 AM

What's not OK with the daisy-chain method? I prefer the idea of only pulling half of the cable. I'm uncomfortable wth 400ft of unbalanced low-level signal.
If somebody wants to get rid of said units or wants to make a quotation with delivery to europe, drop me a PM

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Tony Bandiera Jr
Film God

Posts: 3067
From: Moreland Idaho
Registered: Apr 2004

posted 01-21-2012 11:46 AM

quote: Alban Birch
....... I'm uncomfortable wth 400ft of unbalanced low-level signal......

As you should be.

One thing I haven't seen mentioned yet in this discussion is that the SMART DA (and perhaps the USL) actually amplify the signal before sending it out, to help combat cable losses and improve the signal to noise ratio.

And if you put a request into the "Equipment Wanted" forum I am sure someone will come up with a Smart or USL unit for you. And if you end up with a Smart, I have 4 output cards you can have for postage cost. [Big Grin]

quote: Harold Hallikainen
.....Something like this ( http://www.henryeng.com/matchbox.html ) could be used both at the CD player and at each processor......

Harold, no offense, but that is just crazy in terms of cost ($225 PER UNIT) and I also did not see any mention that you could feed several units from one. Have you done it and how did it work out?

Also the specs, while fantastic, are total atomic overkill for non-sync.

Having said that, I will give you sincere thanks for that link as those units would be very handy (and cost-effective) for a variety of other uses. They just aren't, IMHO, the right solution for multi-point distribution.

Now here's another option: Component Engineering's AD-1 system.

LINKY

I have used these in 20-plex complexes with great success, and they are meant to be daisy-chained which saves a TON of wire. [Smile]

And each AD1-RX (the receiver end) has individual channel level adjustments so you don't have to run back to the master rack to set levels in any given auditorium.

I forget the cost (been a while since I used them) but they were pretty reasonably priced. (And they are still available.)

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Alban Birch
Film Handler

Posts: 63
From: Luxembourg-city , Luxembourg
Registered: Jan 2007

posted 01-22-2012 03:02 AM

Thanks
Ii I would use the Component Engineering or Odyssey, could I wire the signal directly into the QSC Basis, as these have a balanced input?

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Tony Bandiera Jr
Film God

Posts: 3067
From: Moreland Idaho
Registered: Apr 2004

posted 01-22-2012 12:46 PM

Alban, generally speaking, to wire an unbalanced output like the CE's to a balanced input, you would use a short cable (no longer than say 5 feet or 1 metre) and wire as follows:

Pin 1 of balanced input, tie to Pin 3, connect to the ground/shield of the unbalanced output;
Pin 2 of balanced input to the Signal/+ of the unbalanced output.

Those instructions apply if Pin 2 of the Balanced input is + (or "hot"). If Pin 3 is the + or "hot", then swap Pins 2 and 3 in the above instructions.

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Alban Birch
Film Handler

Posts: 63
From: Luxembourg-city , Luxembourg
Registered: Jan 2007

posted 01-22-2012 01:22 PM

I thought the CE uses balanced transmission to the receivers

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Tony Bandiera Jr
Film God

Posts: 3067
From: Moreland Idaho
Registered: Apr 2004

posted 01-22-2012 01:37 PM

It does, but the output of the receiver (which is what you need to tie to your BASIS system) is unbalanced.

Be warned: you cannot, with the CE system, try to directly connect the output of the transmitter to your non-sync inputs!! It is an amplified, constant voltage signal and you WILL damage your inputs, the transmitter, or both.

The lines between the CE transmitter and any and all receivers, are of course balanced lines and need to be wired as such.

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Alban Birch
Film Handler

Posts: 63
From: Luxembourg-city , Luxembourg
Registered: Jan 2007

posted 01-23-2012 12:35 AM

Thanks Tony
That's the answer I've been looking. So I can't spare any receivers, except running the non-sync into one Basis and then transfer it over CobraNet to the far end of the theatre where the other two booths with Basis-processors reside

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