Film-Tech Forum ARCHIVE: QSC DCA reliability

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Posted by Antonio Marcheselli (Member # 373) on 10-29-2003, 07:26 AM:

Hi everyone.

My theater has QSC DCA 1622 and 2422 in all screens. They sound very good but we had two fail (center channel of course!) during last 4 months.

Does this kind of amplifier has some reliability problem?

Bye
A

Posted by Gordon McLeod (Member # 33) on 10-29-2003, 09:37 AM:

I haven't had any failures of those amps yet

Posted by Greg Mueller (Member # 17) on 10-29-2003, 10:03 AM:

I love QSC amps
I bought my DCA 1622s as B stock units and they had been modified so the fan cooling is on Hi all the time. I think (but not sure) that they had a two speed or on/off arrangement originally. Maybe there was a problem with overheating?????

Posted by Antonio Marcheselli (Member # 373) on 10-29-2003, 11:15 AM:

Perhaps the fan was blown but I cannot check 78 amplifiers every day!! Does that amp has a termal protect? I noted that they don't have any fuse...

Bye
A

Posted by Matt Zeiner (Member # 1914) on 10-29-2003, 05:32 PM:

DCA amps have proven to be very reliable in our theatres. I had one go in the four years that we have been installing them, and that was a minor issue with a failed diode in the power supply. I hate the idea of switchers in general, but I can't fault these amps for being switchers. They work very reliably and sound very good. Anyone notice how much improved the filters in the new DCMs are? (a bit OT, I know) I don't know what they did, but the first batch I installed four years ago sounded like plastic. I just installed ten new ones in a theatre and they sounded like music...

Posted by Jean-Michel Grin (Member # 1360) on 10-30-2003, 01:31 PM:

Ciao Antonio !

In our new multiplex we installed all DCM monitors and DCA amplifiers series. No faillures with amplifiers, by luck, but the center channel on The DCA was mute ! The cure to correct this was to switch Off and On again the DCM.

I will back to mono [Big Grin]

Bye,

Posted by Michael Harlow (Member # 1353) on 10-30-2003, 04:30 PM:

I have QSC RMX1450 power amps in my cinema, no problems at all, although they are only 2 years old! Did have Peavey CS1000x amps and managed to blow two channels out of 4 amps. I also have QSC RMX2450 amps in a nightclub i have they are on 24/7 in their own air conditioned room, never had any problems....

Posted by Pete Naples (Member # 761) on 11-01-2003, 03:50 AM:

I've had quite a number of failures with those amps, however it is always at power on when brand new. A loud bang, a puff of smoke and it's all over! In fairness to QSC, their UK agent has replaced the faulty units in bery quick time, and the replacements have been trouble free.

Posted by Nic Margherio (Member # 273) on 11-01-2003, 09:58 AM:

Just over four years ago, when the DCA was still fairly new, I began to have problems with a couple of amps at a new install. I contacted QSC about the problem and I was told that there was an "unofficial" recall of all DCA amps manufactured prior to July of 1999. The reason for this was a faulty ribbon cable, manufactured by a supplier that they had since dumped. All 48 of our installed amps and three spares had to be replaced. QSC was very prompt and professional about taking care of this, but I think they certainly should have made us or our supplier aware of this potential problem before we had to call them.

That being said, we haven't had a single failure since and it is still my opinion that the DCA is the probably the best amp on the market.

One problem I have with the DCM monitor is the lack of digital input. The first thing that it does to the analog inputs is run them through an A/D converter. For DSP-based processors, it would be far better to output a bitstream to the DCM instead of going through unecessary (and signal degrading) D/A and A/D conversion.

[ 11-01-2003, 12:57 PM: Message edited by: Nic Margherio ]