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Quick Question about Power Output on QSC PLX 2402

L

LuckyCondlins

Oct 10, 2007
469
0
41
Virginia Beach, VA.
#1
Hey guys.

allright. im looking at the power ouputs of the QSC PLX 2402.

These can be seen here

[Invalid or Expired Link Removed]

It is giving it 700W stereo mode at 4 ohms, 1200W stereo mode at 2 ohms.

In bridged mono, its 2400W at 4 ohms!

Now my question is, for the maximum available headroom, how should I set up my Amps?

They are the ampeg bxt series. 1x15 is 600 watts RMS. 4x10 is 1200W RMS.

Should I run both channels in stereo and give both amps that 700W output at 4 ohms?

Is their a way to bridge the amp, and split the 2400W output into each cab?

im just not completely familiar with the whole thing.
 
#3
alexclaber said:
Yes. Switch the inputs to parallel to give you dual mono output. And set the highpass filters at 50Hz and leave the limiters on.

Alex
Click to expand...

very cool thanks man!

Theres no way to get even MORE power out of that beast is there? not that i need 1000W coming out of my 4x10..just curious!

im off to hit the road right now, if anyone else wants to comment ill read it later!
 
#4
LuckyCondlins said:
very cool thanks man!

Theres no way to get even MORE power out of that beast is there? not that i need 1000W coming out of my 4x10..just curious!

im off to hit the road right now, if anyone else wants to comment ill read it later!
Click to expand...
It depends on the impedance of your cabs. If both are 8 ohm than you can bridge the amp and chain the 2 in parallel. However, if either cab is less than 8 it will make your total impedance less than 4 and might cause the amp to overheat and shut down. The BEST way is what has already been suggested which is to connect them in stereo and set the amp to parallel mono. This will allow you to balance the cabs with the gain controls and should produce your best possible sound.
 
#5
LuckyCondlins said:
Theres no way to get even MORE power out of that beast is there?
Click to expand...

Neither of your cabs will be able to make use of more than 700W without the speakers overexcursing (i.e. compressing then distorting then farting). Note that this is an accurately specced power amp, not a bass amp, so the power it claims to produce is the actual power it can produce. You do not need any more power, it'll just increase the chance of speaker damage!

Alex
 
#6
the plx will run 2 ohms *per side* all day without shutting down.
but, the 700 watts per side at 4 ohms is already plenty for the cabs you've listed.
 
#7
Chef said:
the plx will run 2 ohms *per side* all day without shutting down.
but, the 700 watts per side at 4 ohms is already plenty for the cabs you've listed.
Click to expand...

Yea those BXT bad boys are 4 ohms each.

Yea 700 watts per side is PLENTY loud for what I need.

Now, just as a followup question.

Could I run the thing at 2 ohms and run both cabs in series, and just limit the power sent to the 15 and up the the power a little bit into the 4x10!?
 
#8
LuckyCondlins said:
Could I run the thing at 2 ohms and run both cabs in series, and just limit the power sent to the 15 and up the the power a little bit into the 4x10!?
Click to expand...

You can't bridge the amp into 2 ohms. You shouldn't run non-matching cabs in series due to the impedance variations.

Although your 4x10" is rated at more than 700W that is merely a thermal power handling rating. I guarantee you the speakers cannot handle even half of 700W without over-excursing, so giving them even more power is futile.

Alex
 
#10
bongomania said:
No, that is not feasible. Note that the gain knobs on the front of the amp do not directly limit or reduce its wattage output.
Click to expand...

well if u dont mind me asking, what are those knobs on the amp for??

if not to limit volume...then what for.

also, the cabs are 4 ohm cabs. matching ampeg BXT's.


are you telling me that I can't control the amount of watts comming out of that power amp?

it will just automatically throw 700 watts into each amp?? thats kind of weird...
 
#11
The knobs adjust the input gain to the power amp, not the output power. Based on what is presented to the input, even if they are cut back the power amp could still swing to its full output power.

Edit to add: running two cabs in series is not a real good idea anyway; something happens, you lose all sound. :(
 
#12
slyjoe said:
The knobs adjust the input gain to the power amp, not the output power. Based on what is presented to the input, even if they are cut back the power amp could still swing to its full output power.

Edit to add: running two cabs in series is not a real good idea anyway; something happens, you lose all sound. :(
Click to expand...


i didn't know that the knobs adjust the input gain! lord, thats interesting.
and true statement about running in series!
 
#13
LuckyCondlins said:
are you telling me that I can't control the amount of watts comming out of that power amp?

it will just automatically throw 700 watts into each amp?? thats kind of weird...
Click to expand...

Yes, as slyjoe just said, the knobs control how much of your buffered input signal goes into the gain stage of the power amp. More input (multiplied by the gain) equals higher output. But there is no direct correlation between those factors and the wattage. If you play a very quiet note, only a few watts are generated; if you play a slamming loud low note with the gain cranked, you get a much larger amount of watts, up to the maximum amp the amp is rated for. Most of the time you will be generating far lower watts than the amp is rated for, but big spikes such as from slapping or boosting the lows may cause the full wattage to be generated- again, this is true even if you turn down the gain. Gain is just a multiplication factor. 10 x 10 is 100, but if you start with 100 it doesn't matter if you multiply by only 1 (no gain), it's still 100.
 

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