FMR RNC & GT Brick hookup problem!!!

Posted: Sat Apr 21, 2007 12:12 pm

I noticed that my Brick has a balanced output but the FMR RNC needs an unbalanced input!!!

How do I handle this? Can I "unbalance" the line before it hits the RNC?

Out of curiousity I tried going into the FMR RNC with a balanced cable anyway and it works but there is some hum. It's also pretty low level and I have to crank up both the Brick and the RNC to get decent levels.

Can someone help me on this? Does the RNC output need to be balanced also?

My signal chain is GT Brick -> FMR RNC -> E-MU 0404 PCI interface card

Posted: Sun Apr 22, 2007 1:07 am

There should be no problem taking the balanced output and shortening pin 3 to pin 1, which then becomes your shield whereas pin 2 is the hot/high side that will go to the tip of a 1/4" plug. Since the RNC requires an unbalanced input, care must be taken to prevent ground loop hum, by hopefully having both plugged into the same power circuit.

You probably think the output level from the preamp is low into the RNC because you're only taking one half of the circuit. Of course that will happen along with the increase in noise that you have discovered.

This should solve your problems.
Ms. Remy Ann David

Posted: Sun Apr 22, 2007 1:48 am

Thanks for ur reply!

RemyRAD wrote:

There should be no problem taking the balanced output and shortening pin 3 to pin 1

I know very little of this sort of thing. What do u mean "shortening pin 3 to pin 1"?

Thanks!

Posted: Sun Apr 22, 2007 1:54 am

http://www.fmraudio.com/FAQ.htm#question8

I JUST READ:

8. What cable/connector types should I use to hook up the RNC?

It mentions some HOSA cables that would work. Is it that simple?

http://www.sweetwater.com/store/detail/PXF105/

Posted: Sun Apr 22, 2007 8:08 pm

JLiRD808 wrote:

Thanks for ur reply!

RemyRAD wrote:

There should be no problem taking the balanced output and shortening pin 3 to pin 1

I know very little of this sort of thing. What do u mean "shortening pin 3 to pin 1"?

Thanks!

What Remy means is to short pins 1 & 3. In other words connect pins 1 & 3 together on the XLR. This will take the balanced output and unbalance it.

Posted: Sun Apr 22, 2007 11:05 pm

Tks for ur reply!

Is that some sodering work? I don't know how to connect the pins. Yeah I'm a noob when it comes to this but I'd like to learn. Seriously.

Posted: Mon Apr 23, 2007 9:04 am

Yes, that will take some soldering, certainly not rocket science and something you should learn to do properly, even if this is just a hobby.
The Hosa cable that FMR is referring to has to do with patching the RNC into a mixing board's "channel insert". I use a Brick into an RNC and you will have to be careful about something else:matching levels. The Brick has the capacity to drive a very HOT signal from its' output, and there is no control onboard to tame it. You might shop around for an "inline attenuator" that will lower the signal strength from the Brick before it slams the RNC. Otherwise, you may have a situation where the poor RNC is always trying to "clamp down" on the material, regardless of its' settings. Anyway, look for an Audio-Technica AT8202 attenuator online.There are other makes, but the AT lets you select from 3 different values rather than a fixed value like the others have. It will come in REAL handy in many situations, and simply plugs inline between the Brick and the RNC via the XLR cable. Cheap insurance.

Posted: Mon Apr 23, 2007 11:07 am

Unless absolutely critical, you may have much better luck tracking directly with the Brick and then using the RNC on a buss or insert to color to your taste.

A mix of the 2 might be just what you need.

My .02

Phil

Posted: Mon Apr 23, 2007 11:38 am

Does the E-Mu card have that facility? That would certainly be the ticket, I was under the impression that it was a simple soundcard without that provision...

Posted: Mon Apr 23, 2007 1:25 pm

I think its a little more than a simple soundcard, and you might have to get a little creative with wiring and outputs from the card, but I think you should be able to track and then send that out mono or via spdif as an aux send depending on your software and come back in via the other input. Correct me if I'm wrong. Either way, I think you'd be using the units as they're designed which is much more likely to get you a better sound without noise and/or possible damage.

Phil

It all depends on if you need the comp for real compression pre fade or just dynamics/ color within the mix.

Posted: Mon Apr 23, 2007 6:39 pm

Big_D wrote:

RemyRAD wrote:

There should be no problem taking the balanced output and shortening pin 3 to pin 1

What Remy means is to short pins 1 & 3. In other words connect pins 1 & 3 together on the XLR. This will take the balanced output and unbalance it.

Would this be just the same as using an unbalanced cable then like the unbalanced HOSA XLR to 1/4"?
In case I forgot to mention, the input into the FMR RNC is 1/4".

Brick output: Balanced XLR
RNC input: Unbalanced 1/4"

I have a balanced XLR to 1/4" cable running between them now. Is there some soldering that can be done on the 1/4" side to unbalance it?

Also, someone recommended a transformer like the Shure A95UF. I looked at it but it seems it just controls impedance. Does it also balance/unbalance?

Putting the compressor as an insert is a possibility and I'll look into it. I'll have to do some creative rewiring and reconfiguring in my software but who knows, maybe that's the easiest thing!

Posted: Mon Apr 23, 2007 6:55 pm

moonbaby wrote:

I use a Brick into an RNC and you will have to be careful about something else:matching levels. The Brick has the capacity to drive a very HOT signal from its' output, and there is no control onboard to tame it......

So how is urs setup as far as the balanced/unbalanced requirements go? With my balanced cable I feel like my levels are TOO LOW and then there's the hum when I try to crank it up. There also seems to be too much treble!!!

Thanks for everyone's help. I just feel like with the money I've spent I'd like to get the most out of everything!

Posted: Mon Apr 23, 2007 7:59 pm

"With my balanced cable I feel like my levels are TOO LOW and then there's the hum when I try to crank it up. There also seems to be too much treble!!!"

What you're describing here is most definitely only 1/2 of the balanced signal, coming from your preamp, to your compressor. You're not connected from your Brick, to your RNC properly. A balanced 1/4" patch cord is TRS on both ends. If this is the cable that you're using, then the RNC is an unbalanced input requiring only TS and not TRS. So the ring (of the TRS) is not getting connected to the RNC. The balanced output level should be the same as the unbalanced output level. In that respect, there should be no difference in level. The fact that you indicate that the signal is too low and has too much treble is indicative of only 1/2 of a balanced circuit feeding your input to the RNC. Use a standard mono, 1/4" guitar cable that is simply TS at both ends. You should then have no problems, no hum, no buzz and a flat, full-bodied sound. If you still have some buzz, disconnect the power cord ground pin on one or the other units, with a 3 into 2 electrical cheater plug. Make sure both units are plugged into the same electrical circuit.

Balanced in an unbalanced way
Ms. Remy Ann David

Posted: Mon Apr 23, 2007 8:45 pm

OK so if I got TS on boths sides I'll need an XLR-1/4" adapter plug. If I'm not mistaken I tried this also with the same results. I'll try it again tonight.

A local retail shop mentioned the transformer. They said that the transformer brings signals from low impedance to high impedance and vice-versa. They also said that high impedance is unbalanced and low impedance is balanced (otherway around?) so the transformer should turn my signal from one to the other. Would this work?

Posted: Mon Apr 23, 2007 11:34 pm

FYI: The E-MU 0404 PCI has unbalaced I/O but will accept balanced cables/loads. Just use a balanced cable and it should work fine. Or unbalanced a XLR or TRS cables with an adapter.

With certain combinations of gear and how they are wired together, it is often normal to lose 6-10db of gain when you go from balanced to unbalanced. A balanced to unbalanced transformer is the right tool and should be part of every audio tool kit.

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