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Username: jix

Post Number: 49
Registered: 1-2009
Posted on Wednesday, April 28, 2010 - 12:27 pm:   Edit Post

Hi everyone,

Looking for a bit of advice on what cables to use to hook up my F1-X to a new power amp (QSC RMX2450).

I'm guessing that the F1-X's 1/4inch outputs are all unbalanced; the QSC can take a balanced or unbalanced input.

Will it make much of a difference if I use unbalanced cables to go from the F1-X to the QSC? I've used George L's for everything in the past but this is my first real venture into preamp with dedicated power amp and not sure if there will be some hum that is picked up by the unbalanced cables.

If I have to use balanced cables then does anyone have a suggestion which are good to get to match the rest of this set-up.

Very many thanks for any help anyone can give me on this.
Senior Member
Username: edwin

Post Number: 600
Registered: 5-2002
Posted on Wednesday, April 28, 2010 - 3:35 pm:   Edit Post

I've used unbalanced cables for this purpose for many years with no problems. The amount of noise that might be introduced by a short run (I keep my cables in this situation to less than a foot if possible) is way less than the system generates by itself.

Think of it this way, this part of the signal path contains a much more robust signal than that which is coming off the bass into the preamp, so a short unbalanced run shouldn't harm things much at all.

Some people have found the output of the F1-X to be a little low with QSC amps, but that's not really been my experience. If you do experience this, there is a mod that most QSC techs should know about to fix it.

Have fun!
Username: willgunn

Post Number: 52
Registered: 2-2007
Posted on Thursday, April 29, 2010 - 10:53 am:   Edit Post

I've been using an "F1-X" to drive various QSC power amps with great success for the past 8 years; utilizing the "F1-X"'s front panel balanced XLR output for that purpose. Additionally, I utilize an on/off switchable Neutrik female XLR plug going into the "F1-X"'s front panel, providing me with a very handy standby/mute switch. And since it's a balanced line-level signal, cable length is a non-issue...particularly if I want to position the pre-amp some distance from the power amp & speakers. And for those instances when a balanced signal is additionally required for the "house", I simply utilize the un-used INPUT jack of the channel of the QSC receiving the "F1-X"'s output signal for that purpose (since the QSC's inputs are wired in parallel, the unused input can function as an output). Doing so DOES require a short balanced patch cable with a male XLR plug on the "open" end, in order to match up with a "standard" mic cable running to the "House". Furthermore, if attenuation is needed for the "House" signal, I utilize a Shure "A15AS" switchable (-15/20/25db) attenuator in-line to the "House"....-20db seems to keep the sound guys happy.
Utilizing the "F1-X"'s XLR output for this purpose provides an additional bonus: being able to switch between "Pre" & "Post" EQ output, effecting both the "Stage Amp" and "House" simultaneously. And some folks insist that the "F1-X" is lacking in features.....!
Username: jix

Post Number: 50
Registered: 1-2009
Posted on Friday, April 30, 2010 - 2:02 pm:   Edit Post

Thanks ever so much, guys.

I really appreciate the help - really useful, and has made things a lot clearer for me.

Many thanks again.

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