Help with a QSC CX702 Amp to RTi12's

dcuz383

Is any familiar with a QCS CX702 amp? If so what do you recommend for the settings on the back of the amp? I am going to use the amp to push my RTi12's. I never used an amp on them before only the receiver.

Eric W

That's a PA amp, but I am familiar with their amplifiers.



Here it is on their website:
http://www.qscaudio.com/products/amps/cx/cx2/cx2.htm

For your speakers, you'd want to use the STEREO MODE.

If you run alot of bass heavy material at high volumes you may want to use the "33 Hz filter" and turn on the "CLIP LIMIT."

DO NOT use parallel mode, bridge mono mode, or the 75 Hz filter.

dcuz383

When you say that this is a PA amp what exactly does that mean? Is this not a good amp for my HT setup? I purchased this amp a week ago at ADI and my sales rep strongly recommended it. I have not used it yet. I do not want to damage my RTi12's with the wrong amp or have crappy sound from them either. I just want to power them with a amp instead of the receiver. I do listen to lots of bass that's why I bought the 4000 sub. With all the money I have in this setup I just want to perform to it's potential. Thanks for the help.

Eric W

dcuz383 wrote: »

When you say that this is a PA amp what exactly does that mean? Is this not a good amp for my HT setup? I purchased this amp a week ago at ADI and my sales rep strongly recommended it. I have not used it yet. I do not want to damage my RTi12's with the wrong amp or have crappy sound from them either. I just want to power them with a amp instead of the receiver. I do listen to lots of bass that's why I bought the 4000 sub. With all the money I have in this setup I just want to perform to it's potential. Thanks for the help.

A PA amp is a professional audio amp- think live bands, night clubs, etc. These amps are made for industrial use, which means super high reliability and can be run full blast all night.

You can use a PA amp in the home but there's a few considerations.

First, that amp will be a pretty good match powerwise for the RTi12's. It will have clip lights so you'll know when you're hitting the max of the amp.

Second, you'll have to customize the inputs because pro amps use either 1/4" TRS or XLR connectors. Both are "balanced" design. This amp has XLR inputs and the "phoenix" style inputs for bare wire. Your typical home audio component uses RCA/unbalanced connections. You can try wiring it up unbalanced but there's a chance you may get some noise or humming through the sound system. If it does hum, DO NOT use a "cheater plug" to lift the ground pin.

Third, the fan and transformer may be a little noisy. Same thing with the signal lights, they tend to be bright. Not a big deal in a packed night club or noisy concert but may be annoying in a quiet home theater.

dcuz383

The salesman who sold me the amp also recommended Excellines PRXM-5 cables they have XLR on one end and a single RCA on the other. I bought two of them. Is this a good connection? If not what do you recommend?

I turned the amp on to see how loud it is. It was very quiet with no load on it.

Eric W

dcuz383 wrote: »

The salesman who sold me the amp also recommended Excellines PRXM-5 cables they have XLR on one end and a single RCA on the other. I bought two of them. Is this a good connection? If not what do you recommend?

I turned the amp on to see how loud it is. It was very quiet with no load on it.

Sounds good. You should be quite happy with the setup.

WilliamM2

XLR to RCA is really your only option, and it should work as well as any other cable.

Do keep in mind that it is not a balanced connection, in order to get a balanced connection you need all the components to be balanced.

dcuz383

I am not sure what a "balanced connection" means. How do I balance my components?

Eric W

To balance your components, you get a single huge audiophile spike and put it at the center of gravity of each component. Then it will be balanced. That way, you have minimal surface contact with the rack so you get maximum isolation

Wiki has a pretty good description of balanced audio:
http://en.wikipedia.org/wiki/Balanced_audio

The easiest method is to buy components that already have XLR outputs on them. Higher end components may have them and some "good value" models too like the Outlaw 990.

You can also have the component modified with the proper transformers (completely non practical, but it's possible).

You can send an unbalanced signal to an external balancing transformer box as well. This is sometimes done in car audio.

Either way, unless you're running 50+ feet and have noise problems (common in pro audio- think of a concert where the mixer board and processors are several hundred feet from the stage) you're not likely to gain any sonic benefit.