| Author | Message | ||
| jazzyvee
Senior Member Username: jazzyvee Post Number: 4405 Registered: 6-2002 |
Oops i worded the title wrongly. It should be more like "Should i be plugging my F1-X output into the balanced input of my power amp. I have a rig that is quite common for us alembic players. F1-X, SF-2 and QSCPLX power amp. The output from my pre-amp goes into the unbalanced jack input of my power amp but i'm wondering if I should really be plugging into the balanced XLR input to my power amp to get the best signal quality? What do you think? (Message edited by Jazzyvee on February 21, 2015) | ||
| willgunn
Member Username: willgunn Post Number: 73 Registered: 2-2007 |
Both the XLR and 1/4" inputs on the QSC "PLX" Series are balanced (with the 1/4" jacks being TRS and internally paralleled with the XLR's for a given channel). However, sending an unbalanced signal to a "PLX" won't really degrade the sound quality or cause any problems. If you want to perform a sonic comparison of balanced VS unbalanced, try sending a signal from your "F-1X" via the front panel, balanced XLR DI jack to the XLR power amp input - if you can hear a difference, you have far better hearing than I do! | ||
| moongerm
Member Username: moongerm Post Number: 99 Registered: 8-2013 |
Hey Jazzy, If you have balanced inputs on your qsc then it couldn't hurt giving it a whirl. Here is a thread with some great feedback on this topic from Will Gunn: http://alembic.com/club/messages/394/79311.html?1272661335 Interesting topic as I only used the f1x xlr for recording. -Brian | ||
| moongerm
Member Username: moongerm Post Number: 100 Registered: 8-2013 |
Hey there's Will. Hey Will!  I have been running my F1Xs into two seperate bass amps where they dont have balanced inputs. Now I am wondering if it makes more sense to consolidate with a stereo power amp like a QSC? I like the idea of your approach Will. | ||
| keith_h
Senior Member Username: keith_h Post Number: 2161 Registered: 2-2005 |
As Will says both inputs on QSC amps are balanced. When you use the 1/4" output from an unbalanced source into the QSC 1/4" jack it becomes unbalanced. If you were to wire an adapter to use the XLR input this too would be unbalanced. Due to the short cable runs you have in a rack running balanced or unbalanced will make no difference. Where balanced or unbalanced come into play is longer connections where externally induced electrical noise can become an issue. Keith | ||
| jazzyvee
Senior Member Username: jazzyvee Post Number: 4406 Registered: 6-2002 |
Ok cool, glad I don't have to chance anything. Will I doubt if my hearing is better than yours. Maybe our response to frequencies is different. :-) | ||
| edwin
Senior Member Username: edwin Post Number: 1929 Registered: 5-2002 |
The balanced input only really becomes necessary if you are running long cable lengths, especially in questionable environments. You definitely want to use the balanced input from a front of house console or EQ, etc., 80 feet away, but a foot or two won't really make a difference unless the environment is extraordinarily noisy or if the preamp/amp combination has some serious interactions (not the case here). | ||
| rustyg61
Senior Member Username: rustyg61 Post Number: 1625 Registered: 2-2011 |
I have a related question, I too am running a F-2B mono output to channel A on my SF-2 set for mono & out of channel B of the SF-2 into the 1/4" input on my QSC GX7. The QSC doesn't have a switch to tie both inputs together to run the same signal to both channels, they recommend going into the XLR jack then using a TRS 1/4" cable to jumper from channel A to B. In order for me to do that I have to run the SF-2 output through my direct box to convert the 1/4' output of the SF-2 to a balanced XLR cable & when I do that it looses a lot of gain. Has anyone tried using a 1/4" Y cable to run a single signal to both sides of a power amp, or should I get a 1/4" to XLR cable & use the TRS jumper method that QSC recommends? | ||
| keith_h
Senior Member Username: keith_h Post Number: 2204 Registered: 2-2005 |
Just use an XLR jumper. As I recall both the TRS and XLR are in parallel so you should be able to jumper either one. Keith | ||
| edwin
Senior Member Username: edwin Post Number: 1992 Registered: 5-2002 |
A Y cable should be fine, too. Definitely no sense in converting via the DI. That turns your signal into mic level, where the amp wants to see line level. | ||
| rustyg61
Senior Member Username: rustyg61 Post Number: 1626 Registered: 2-2011 |
Thanks Keith, you are correct, the 1/4 TRS & XLR are parallel inputs so I can jumper with a XLR cable too, never thought of that! Edwin, I knew that the DI reduced the signal level, but it didn't dawn on me that it does convert the high impedance line level signal to mic level to go to the mixer. Thanks! |
