ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  
Pages: 1 [2] 3  All   Go Down

Author Topic: QSC Amp Choice  (Read 6317 times)

Bob Leonard

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4669
Re: QSC Amp Choice
« Reply #10 on: January 05, 2008, 04:46:56 pm »

John Roberts  {JR} wrote on Sat, 05 January 2008 14:54

Bob Leonard wrote on Sat, 05 January 2008 11:39

This is a discussion that's been had many times. What you'll get for replies will be varied so the only thing I'll say is that I pulled a 3602 off of my subs and went to the 4050HD. I don't care about the weight and that has never been a part of my criteria when purchasing an amp. What I feel is a big part of amplifier performance is reserve power. In my opinion the use of a seperate power supply for each side of the 4050HD is a huge advantage, the reason for the additional weight, and the reason the 4050 seems to have endless power. I have not seen the 4050 clip since I put it to use and the amp runs cool to the touch all day long. There is a reason for the HD as in 4050HD. It stands for heavy duty, and the 4050 lives up to it's claims, and my subs have never sounded better. As for the PL4.0, if all things are equal I would still buy the 4050 because it's still a production amplifier and warranties do count. Good luck. Smile


I repeat my caution about trying to impute performance from technology (dual power supplies?) .

In fact the 4050 is similar to 1850 in design philosophy where the rail voltages are backed off, to give more thermal capacity but at some reduced peak power. The 1850, uses a 2450 heat sink and device complement, but only puts out 1850 peak.  Likewise the 4050 is a 5050 heatsink/power stage, running at cooler rail voltages.




This is just good conservative engineering, and more a variance in design details than a different technology. The 4050 trades peak power, for more thermal capability than the very similar 5050 due to a simple spec change of transformer voltage. For hard flogging a 2 ohm load the 4050 won't beat the 5050 for how loud it gets short term, but it will win for how long it plays loud.    

JR



Fully agreed and well noted John. There are actually three power supplies. In the simplest terms each side of the amp has it's own well to draw water from. It's proven to me that the 4050 works far better than the 3602 under more adverse conditions and it makes more sense to me that I sacrifice some db for longevity. I talked to my speakers just now and they have told me they are happy with the 4050HD also. As a matter of fact my 722s are asking for one as well. It seems a pair of them want more power than a pair of RMX2450s. What's happening is that I have a fairly varied collection of QSC amps and swapping them to compare performance vs speaker type. The losers go to the pile.
Logged
The roar of the grease paint, the smell of the crowd.

John Roberts {JR}

  • Newbie
  • *
  • Offline Offline
  • Posts: 0
Re: QSC Amp Choice
« Reply #11 on: January 05, 2008, 06:33:05 pm »

Bob Leonard wrote on Sat, 05 January 2008 15:46




Fully agreed and well noted John. There are actually three power supplies. In the simplest terms each side of the amp has it's own well to draw water from. It's proven to me that the 4050 works far better than the 3602 under more adverse conditions and it makes more sense to me that I sacrifice some db for longevity. I talked to my speakers just now and they have told me they are happy with the 4050HD also. As a matter of fact my 722s are asking for one as well. It seems a pair of them want more power than a pair of RMX2450s. What's happening is that I have a fairly varied collection of QSC amps and swapping them to compare performance vs speaker type. The losers go to the pile.


All three sides?

Methinks you're talking about the three level class H power supply which is even more efficient than 2 level, which is better than old 1 level class AB. Again the 5050 also has the 3 level PS but won't hang at two ohms like the 4050 because of rail voltage tweak.

The 3602 could be a 2 rail amp so that would be a case of a higher technology (switching PS) front end connected to a less efficient technology back end power amp. In the margin the three rail class H will also pull more power from a limited  mains distro thanks to that improved efficiency.

So the 4050 is pretty high efficiency amplifier, with a conservative heat sink. Probably a good value, with plenty of thump.

JR






Logged
 https://www.resotune.com/


Tune it, or don't play it...
-----

Bob Leonard

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4669
Re: QSC Amp Choice
« Reply #12 on: January 06, 2008, 01:55:15 am »

John Roberts  {JR} wrote on Sat, 05 January 2008 18:33

Bob Leonard wrote on Sat, 05 January 2008 15:46




Fully agreed and well noted John. There are actually three power supplies. In the simplest terms each side of the amp has it's own well to draw water from. It's proven to me that the 4050 works far better than the 3602 under more adverse conditions and it makes more sense to me that I sacrifice some db for longevity. I talked to my speakers just now and they have told me they are happy with the 4050HD also. As a matter of fact my 722s are asking for one as well. It seems a pair of them want more power than a pair of RMX2450s. What's happening is that I have a fairly varied collection of QSC amps and swapping them to compare performance vs speaker type. The losers go to the pile.


All three sides?

Methinks you're talking about the three level class H power supply which is even more efficient than 2 level, which is better than old 1 level class AB. Again the 5050 also has the 3 level PS but won't hang at two ohms like the 4050 because of rail voltage tweak.

The 3602 could be a 2 rail amp so that would be a case of a higher technology (switching PS) front end connected to a less efficient technology back end power amp. In the margin the three rail class H will also pull more power from a limited  mains distro thanks to that improved efficiency.

So the 4050 is pretty high efficiency amplifier, with a conservative heat sink. Probably a good value, with plenty of thump.

JR










No, there are 3 power supplies. One for each side and one common to both sides. Not 3 sides silly.
Logged
The roar of the grease paint, the smell of the crowd.

John Roberts {JR}

  • Newbie
  • *
  • Offline Offline
  • Posts: 0
Re: QSC Amp Choice
« Reply #13 on: January 06, 2008, 10:34:16 am »

Bob Leonard wrote on Sun, 06 January 2008 00:55




No, there are 3 power supplies. One for each side and one common to both sides. Not 3 sides silly.


Not to continue harping on this, but...  

There is little if any practical benefit from two small power supplies vs. one big one. I can even argue that one big one is better. If we visualize what is going on in bridge mode one channel is drawing only from the plus rail(s) while the other channel only from the negative, and vice versa. Using a common PS means each channel can draw upon the full capacity of the whole amp's available current.

I suspect the supplies were split up for packaging reasons. Putting the rail capacitors right next to the output stages could reduce internal wiring losses, and the two could still be wired together, so they will share like one big one during peaks.  

I'm not trying to mystify amp design, technology can make a difference but IMO design execution is very important. The lads at QSC have plenty of practice and by now have pretty much figured out what works or not. Their different models are dialed in for different applications and pocketbooks.

JR

PS: Some audiophools will argue separate supplies improve crosstalk between channels but how do you measure crosstalk in bridge mode?
Logged
 https://www.resotune.com/


Tune it, or don't play it...
-----

Vinny D'Agostino

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 495
    • http://www.myspace.com/vinnydagostino
Re: QSC Amp Choice
« Reply #14 on: January 06, 2008, 10:40:57 am »

um, yeah......anyway, I like how the 4050HD sounds which too me is all that matters Rolling Eyes

Bob Lee (QSC)

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1788
Re: QSC Amp Choice
« Reply #15 on: January 07, 2008, 02:20:22 pm »

That is a correct read on the different amp models.

The RMX4050HD and RMX5050 do have two (not three) power supplies--a separate one for each channel. That is done primarily for packaging and manufacturing reasons.
Logged
Bob Lee
Applications Engineer, Tech Services Group QSC Audio
Secretary, Audio Engineering Society
www.linkedin.com/in/qscbob

"If it sounds good, it is good."
 -Duke Ellington

Chuck Nottle

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 63
Re: QSC Amp Choice
« Reply #16 on: January 07, 2008, 03:25:02 pm »

Thanks for your input JR, Bob(QSC) and Bob L.

You have put some of the amp weight mojo to rest, in my mind anyways.

Best Regards.
Logged

Bob Leonard

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4669
Re: QSC Amp Choice
« Reply #17 on: January 07, 2008, 05:12:34 pm »

Bob Lee (QSC) wrote on Mon, 07 January 2008 14:20

That is a correct read on the different amp models.

The RMX4050HD and RMX5050 do have two (not three) power supplies--a separate one for each channel. That is done primarily for packaging and manufacturing reasons.



Bob,
That sounds a little different from what I was told the last time we discussed the 4050. Now I'm confused (more).
Logged
The roar of the grease paint, the smell of the crowd.

BarryWillems

  • Full Member
  • ***
  • Offline Offline
  • Posts: 121
Re: QSC Amp Choice
« Reply #18 on: January 07, 2008, 07:59:11 pm »

I ran 2 QSC 3402's (bridged mono) to power 2 JBL SRX series double 18" boxes for 4 years in a previous rock band project. This sub setup had plenty of headroom and the big JBL's ate it all up with no problem. (I also ran 2 more 3402's bridged for the double-15 SRX tops and 1 2402 stereo for the 2 JBL horns). We did lots of outside gigs in Houston heat/humidity and Galveston Bay salty air. Despite the 4 ohm loads on the bridged 3402's (2 ohms to the amp), I never had any thermal trips or other problems. Of course, I don't believe in running any power amps with the clipping lights glued on, and we rarely saw them at all with this setup. The only occasional issue was lack of AC power at the venue for everything.

I don't think 1 3402 stereo would be enough for both sub boxes, but the new 3602's are only about a grand and 21 lbs each, so load up the rack and bridge away if your drivers are up to it.

I can't comment on the how this would compare to 1 4050 HD for subs, except to say 2 bridged 3602's ought to deliver considerably more power at considerably less weight. Might be a bit more $$ for 2 3602's vs. 1 4050HD however.
Logged

Walter Wright

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 313
Re: QSC Amp Choice
« Reply #19 on: January 13, 2008, 03:42:01 pm »

still eagerly waiting for the original question, which was comparing the roughly equally-rated pl.4 and the 4050.
Logged
Professional Guitar Repair Tech,
Semi-professional Sound Guy
Pages: 1 [2] 3  All   Go Up
 

Page created in 0.056 seconds with 16 queries.