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Topic: The Amplifier You Install the Most

Phil Hill
I love my cootie bug

Posts: 7595
From: Hollywood, CA USA
Registered: Mar 2000

posted 06-25-2002 04:22 AM

After many failures and DOAs with Crown and JBL, I switched to QSC about 10 years ago when "brand recognition" was the most important thing to our "Marketing" department. It was not a pleasent political fight...so I just did it. Never have been sorry. I've used many 100's of QSC amps over the years with 99.9% reliability and great sound/performance. I think the DCA series is hands-down the best ever cinema amp.

>>> Phil

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Ron Lacheur
Jedi Master Film Handler

Posts: 650
From: British Columbia, Canada
Registered: Feb 2002

posted 06-25-2002 01:23 PM

aren't JBL amps manufactured by QSC?

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Richard Fowler
Film God

Posts: 2392
From: Ft. Lauderdale, FL, USA
Registered: Jun 2001

posted 06-25-2002 02:52 PM

JBL phased out their amplifier arm when their parent - Harmon - bought Crown last year.
Richard Fowler
TVP-Theatre & Video Products Inc. www.tvpmiami.com

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Ben Wales
Jedi Master Film Handler

Posts: 602
From: Southampton. England
Registered: Jul 99

posted 06-25-2002 06:30 PM

But for your concern, and others in Europe, all of our amps for countries running on 240V power are indeed capable of 240V—our European amps.

Gordon @ QSC

Are the European PSU rated for 240v 10% +/- ?, We have in the UK in some parts of the country high voltage as high as 250v in some citys

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John Gordon
Film Handler

Posts: 62
From: Earth
Registered: Jul 2000

posted 06-27-2002 12:52 PM

Scott N,
Features on the DCA:
Input connectors: XLR; ¼” TRS; terminal block (Euro connector); and our DataPort connector.
Output connectors: Speakon and safety-shrouded barrier strip, including monitor output.
Gain controls have a security cover that prevents the unwanted hands from playing with them. The RMX line has knobs on the front that cannot be locked out, which is not desirable.
And of course all seven models are THX approved.

Ron L,
Yes, at one point we manufactured amps for JBL, but no longer.

Regarding the 240V issue. We qualify all amps to withstand 25% high line for relatively brief periods without failing. Based on the 500V rating of the gate driver chip, the supply should briefly withstand about 47% high line. At this voltage the filter caps are 25% overstressed and will overheat fairly quickly.

btw, as for reliability, I've personnally installed over 1,000 DCAs (new and used) without a single failure.

------------------
John Gordon
QSC Audio Products, Inc.
1675 MacArthur Blvd.
Costa Mesa, CA 92626
(714) 957-7100
john_gordon@qscaudio.com http://www.qscaudio.com

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System Notices
Forum Watchdog / Soup Nazi

Posts: 215

Registered: Apr 2004

posted 06-02-2010 08:49 PM

It has been 2897 days since the last post.

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Mike Frese
Master Film Handler

Posts: 465
From: Holts Summit, MO
Registered: Jun 2007

posted 06-02-2010 08:49 PM

Are the QSC DCA's still one of the top choices? What about the QSC ISA's?

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Danial Simmonds
Expert Film Handler

Posts: 107
From: Kota Damansara, Selangor, Malaysia
Registered: Jan 2008

posted 06-02-2010 10:51 PM

Yup here im installing 11 screens 2 halls are using the DCA Amps the rest is using ISA amps due to budget...

DCA's are smaller, lighter easy to install... have installed more than hundreds of these amps all over the place :-) its a personal favorite.

Regards
Danial

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Demetris Thoupis
Phenomenal Film Handler

Posts: 1240
From: Aradippou, Larnaca, Cyprus
Registered: Apr 2001

posted 06-03-2010 06:06 AM

I believe this perception of QSC DCA amps as the best is just something that has been planted in our brains throughout the years. I do not say that QSC are not great. They are excellent and I used RMX series in a multiplex in 2001 and DCA in a multiplex in 2007 and so far not a single failure in either of these locations. I find though the overlove on the QSC to be something which cannot be explained. What really makes them the best? I can name a few other companies with better feature amplifiers like for example the Crown DSi Series. Not only they are excellent amps, budget friendly but they also incorporate very nice features like built in crossover network and some parametric eq minimizing the need for an external crossover network. I have not used these amps but I find this feature very interesting. Also the Crown XLS series are the most budget conservative amps. Still I am not saying that QSC are not excellent but I don't like the idea of everyone considering them the BEST because there are other excellent brands as well.
Demetris

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 06-03-2010 06:50 AM

Crown burned their bridges with NUMEROUS failures. Having built-in crossovers and other "features" in the amplifier also means those functions fail when the amp fails or have to be replaced when the amp is replaced...etc.

There ARE other amplifiers out there...even better ones than QSC... Lab Gruppen comes to mind but look at the QSC feature set, bang for the buck, form factor...and reliability and also support. They still sit VERY high on the list.

They have their ISA line for the budget conscious people that don't mind a HEAVY amp made in China that has higher distortion numbers and higher noise than the DCA line. The DCA line is also pretty decent on the electricity front too...no big surge at turn on...just cool clean power.

As for crossovers...rather than having them built in...they have them attach, if you desire (XC-3) and they will work on the ISA or DCA...need to swap an amp (I haven't) ...three screws, the crossover can move to the replacement without calibration.

Though I don't condone it...they have their DATAPORT for amazingly fast installation of the amp by most anybody. Simply plug a premade cable between their (or others now) monitor and the amp and you are wired for both input and speaker level MONITOR output. Even other amp companies, like Crown, copied them on that one.

Are there better amps (sounding, power...etc) yes...but when you put all of the factors of cost, reliability, performance, feature set, support....etc...they continue to simply be the best choice for the cinema market place.

Steve

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Stephen Furley
Film God

Posts: 3059
From: Coulsdon, Croydon, England
Registered: May 2002

posted 06-03-2010 11:09 AM

quote:
Are the European PSU rated for 240v 10% +/- ?, We have in the UK in some parts of the country high voltage as high as 250v in some citys

The highest you should see in the UK, phase to neutral is 230 V + 10% i.e. 253 V, close to the old limit of 240 V + 6%, i.e. 254.4 V. It's the lower limit which has been considerably lowered in recent years.

In our main building at work it's always below 230, sometimes well below, but we are overloaded. EDF are trying to find a route to get a new HV feeder into our substation at the moment. Phase 2 is always the worst, and phase 3 the best, or at least the least bad. Our load is also badly out of balance.

In another building which we have, just a few tens of metres away I'm seeing 247.2 V on one phase at the moment, and overnight I've been seeing over 253 V, I think 254.8 is the highest I've seen so far.

While we're talking of matters electrical, I wonder if anybody here can answer a question for me. As some of you may know, I collect lamps and lighting equipment. I have an unusual American lamp which I'd like to run up to see what the light from it is like. I have the correct ballast for it, tapped for 120, 208, 240 and 277 V, but of course, it's intended for 60 Hz. I can get 60 Hz. at various Voltages but only up to 200 VA, which isn't enough to run this lamp. Does anybody know what the effect of trying to run it with about 240 V 50 Hz into the 277 V tap would be? The lower frequency should increase the lamp current, it's a conventional magnetic ballast, but would the reduced Voltage bring the current down to a safe value? I only want to run it for a few minutes, but it's a metal halide lamp, so I'm inclined to be a bit cautious with it.

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Jonathan Althaus
Master Film Handler

Posts: 435
From: Bedford, TX
Registered: Dec 2008

posted 06-03-2010 11:41 AM

We've gone from the old style Peaveys to QSC and now Crowns. I hated the Peaveys, they always seemed to be needed to be replaced and compared to the QSC's and Crown's were insanely heavy. I like the Crowns a lot, slim, light, and give off a nice blue glow.

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Gordon Bachlund
Jedi Master Film Handler

Posts: 696
From: Monrovia, CA, USA
Registered: Aug 1999

posted 06-03-2010 12:42 PM

Stephen, since the 60 Hz ballast is magnetic, it will operate hotter at 50 Hz. However, since you plan to operate it for only short periods of time you should have no problems with 240V 50 Hz into the ballast's 240V winding.

When I worked overseas years ago I experienced shortened 60 Hz ballast life when wired to 50 Hz, but no catastrophic problems.

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Robert Minichino
Master Film Handler

Posts: 350
From: Haskell, NJ, USA
Registered: Dec 2005

posted 06-03-2010 12:58 PM

Since the ballast is working as an inductor and not a transformer (the ignition winding is a saturated high voltage tap, but that's unaffected), the current at 60Hz is the same as the current at 50Hz if you apply sqrt(50/60)=0.91 times the voltage. So 252V to the 277V tap should be perfectly safe. If it won't start with your line voltage into the 277V tap, you should be perfectly safe at the 240V tap for a short period of time. Make sure to use an appropriately-sized fuse.

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Stephen Furley
Film God

Posts: 3059
From: Coulsdon, Croydon, England
Registered: May 2002

posted 06-03-2010 03:41 PM

I ran it up, from a safe distance, and the lamp current was a bit high, but only by a few percent. The colour was rather poor by modern standards, with a rather nasty greenish tinge to it. It's a very early 2 kW metal halide lamp; metal halide technoogy has come a long way in recent years. The ballast is huge, and heavy.

Most lamp types will operate on simple inductive ballasts on 240 V over here. A few large ones run on 415 V across two phases for things like sports stadium lighting.

High-pressure mercury of any size will run on a simple ballast on 240 V, but 415 V ballasts are available for the largest sizes.

Low pressure sodium (SOX) lamps will work on an inductive ballast with a low-Voltage (~700 V) parallel ignitor; only the longest (180 W) ones need a leak transformer these days.

High pressure sodium Normally use a simple inductive ballast with a high-Voltage (2.4 - 5 kV) superimposed ignitor, and most metal halide lamps use the same gear as SON. Some older style probe start type metal halide lamps use a mercury ballast with a low Voltage ignitor.

Most fluorescent lamps tend to use high-frequency electronic gear these days.

Neon signs and cold cathode tubes use either transformers or electronic gear. We seldom see the sort of ballasts which are common over there. In most cases ours tend to be considerably cheaper.

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