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Author Topic: Amp situation critical Heath Dutton Film Handler Posts: 37 From: Montgomery, Alabama / United States of America Registered: Jul 2005 posted 08-10-2005 03:45 PM                     First off I'd like to send a huge "thank you" to everyone here, this forum has been the single best thing that has happened to my booth. I had less than two weeks of "training" with other projectionists before running a set of 16 projectors alone on weekends. Two years or so later I'd like to think I've surpassed those who taught me in a big way, and I have you guys and gals to thank! I am working in the first-ever-built of the "Rave Motion Pictures" theater chain. It is an all-stadium seating all-digital multiplex monster (I mean that it the nicest way ). We now have 19 theaters and counting. Our biggest selling point has always been that their presentation (on screen) is our foremost concern. Now on to the problem: The theater I work in is now 5 years old (the oldest of our chain), and our amps are dropping like flies. We have BGW Millenium series 2 and 3 on all houses, and about 11 of these amps have one channel (usually high) that is only functional most of time. Some of these amps have to be "tapped" every morning for them to work during the first show. On some of them I can never get both channels to work at the same time. Usually by the end of the day they have warmed up to the point that all but 3 or 4 are working completely (this tempts me to keep them on 24/7). In the past the company's answer to this has been to simply send off the amps to get repaired. This has turned out to be a very costly venture, as I have personally shipped off 12 amps in the past two years for repair. The turn around was usually 2 months and the last two amps sent out NEVER CAME BACK! Luckely one was our only spare. Unfortunately that means that one of our small auditoriums has a single amp delivering right and left sound (combined). We havn't had a single complaint, but I wouldn't dare watch a movie in there. I have also noticed that the amps that come back are usually the ones that die again in 6 months. One came back once that was completely non-functional after an hour of use (it could have been damaged in shipping, but it didn't appear to be). I've suggested that they stop this madness and start replacing the BGW amps, but I heard back that the complication would be that our amps have built in crossovers, and amps like that are rare and expensive. I find this rather confusing since the crossovers are only used for L/C/R and our speakers are all JBLs which came with built in crossovers. While changing speakers I noticed that the crossovers have been unscrewed and left laying by the speaker boxes in one of our large auditoriums so that the speakers could be wired directly to the amps. Why was this done? Are JBL crossovers unreliable or something? Why do we need amps with crossovers when we could put the JBL ones back in? I have heard QSC talked about alot in here, and I would like to have a game plan to suggest to management about overhauling our audio in the next budget. Note that I havn't checked all our L/C/R speakers to see if their crossovers are sitting by them like this, but I probably will soon. Since only L/C/R amps seem to have problems I would like to suggest replacing half of the theaters L/C/R BGW amps with QSC, and keep the ones we replace as tenative replacements for the other half over the next couple years. We have yet to have a surround amp go out, and only one sub amp has needed repair in the past two years, so I'm not too concerned with those. I need to convince corporate that we will be saving money in the long run by replacing these crappy amps. Do you agree? How long does an average QSC amp last before it starts having problems? Any thoughts? Suggestions? I'm eager to stop hitting amps in the morning... I have been told in the past that I should never use my real name or tell anything about my theater online (and in fact that conversation led me to this site), but honestly I think we have nothing to loose and all to gain by asking for help from the pros  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 08-10-2005 03:51 PM                     If the crossover is in the amp then the system is biamped as such there is no crossover in the speaker used This is the better way to design a system QSC offers crossover modules that are part of there amps in the DCA and ISA line I have never had much luck with BGW standing up well  |  IP: Logged Richard Fowler Film God Posts: 2392 From: Ft. Lauderdale, FL, USA Registered: Jun 2001 posted 08-10-2005 05:28 PM                     It was not unusual to ship in a system such as a JBL 4670D speaker with an internal passive crossover and convert it at the job-site for electronic crossover bi-amp operation. We had one cinema circuit order this way to give them an option for repairs and replacement in addition to new projects. Electronic crossovers sound better and offer superior protection to the speaker components, if properly chosen. QSC service and warantee is first rate....repair turnaround is quick......we have some units pumping away 20 years later  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 08-10-2005 07:12 PM                  Ummm... a 4670 is NOT worth bi-amping...  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 08-10-2005 08:35 PM                     I haven't had anything positive to say about BGW amps either. You get what you pay for. Sounds like whoever made the purchasing decisions on that building probably based their decision on what was the cheapest. (Probably a Strong projector package too.) Start buying QSC amplifiers. As was mentioned above, you can order them with crossovers built in, so that's a non-issue. Your idea is a good one though. Replace all of your stage speakers with QSC and hang onto those BGWs that are still functioning to use as surround and subwoofer amps as the other BGWs continue to fail. That's the most cost effective solution.  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 08-10-2005 11:09 PM                       Whatever is wrong with the BGW Amps, it had nothing to do with low cost. They have always been a bit higher cost then most others. The company was in real trouble when it was run by the family of Brian Gary Wachner for years and has been sold to a new group of investors.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 08-10-2005 11:16 PM                     Brad, You're starting to sound like a commercial for QSC lately! Sorry but lately I've been taking ALOT of QSC amps to the local repair facility over the last few months. In reality when you have as many of those and some start to get old you will find that they are in reality no more reliable than any other decent amp. Now granted the good BGW's are getting old and probably also starting to fail, but back when Brian G. Wachner ran BGW they actually produced the best built amps out there and as Sam says they were alot more expensive than anything out of QSC. BGW today is not even a shadow of what it once was but they also still build the BEST powered subwoofer available... just ask Phil.... There are alot of other amps out there, some alot better than QSC that I would also consider based on the needs of a given job. Mark  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 08-10-2005 11:27 PM                     That's ok Mark, no one can possibly beat your record for plugging AAIIs and such. QSC has been hands down the most reliable and best bang for the buck amplifier I have ever used, and as long as that holds up with the fantastic customer service they provide, I am going to keep plugging them. And again, no BGW amp have never performed truly well in my travels. I probably shouldn't have used the phrase "you get what you pay for" implying they are cheap. I've never sold or priced one because of their lousy performace record in existing installations. Generally speaking, lousy performance = cheaper product. Sorry for my error in that regard.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 08-10-2005 11:33 PM                     K Brad, Just wait till all those QSC's get to be 7 plus years old... they will keep you busy! Mark  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 08-10-2005 11:43 PM                     How are those CROWN amps compare to QSC's? I heard that CROWNS are close to those tube McINTOSH amps in quality. I'm still pluggin away with a wadful of those BGW's (both house amps and those powered SUBS) at our theatres. So far, they haven't pooped out - and being around 17yrs old. - thx Monte  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 08-11-2005 05:33 AM                     We've have MANY QSC amps that are 7+ years old...still plugging away. The number of amp repairs has truely be next to nil. The largest QSC failure we've had was the dreaded ribbon cable failure back shortly after the DCA line came out...QSC paid to have those all changed out too. BGWs have always dropped like flies everywhere I've seen them installed. Crown also has design issues...the marginally rate their products such that they age prematurely. They will drive a 1/2-watt resistor with .497 watts...it may take years of grind operation but it will fail. Crown makes some good sounding amps (depends on the model) but they just are not reliable in my book. I'm in the QSC camp here. So far, best bang for the buck of any amp I've laid my hands on for cinema application.  |  IP: Logged Alexander Alves Film Handler Posts: 33 From: Diwanman, Vasai, India Registered: May 2003 posted 08-11-2005 06:48 AM                     Well in India Crown amps give a lot of trouble esp. the CE series.In my opinion too the QSC's are value for money and Ive seen them work with heap full of dust and carbon ash on the PCB's  |  IP: Logged Steven J Hart Master Film Handler Posts: 282 From: WALES, ND, USA Registered: Mar 2004 posted 08-11-2005 07:53 AM                        We've got 6 Crown CE series amps in my single screen theater. They are about 3 years old and the 3 CE 2000's driving the stage speakers have failed in the same smoke-filled auditorium fashion (The amp rack is behind the screen). The amps that failed had crossover modules installed which led me to believe that the built in modules caused the amps to crap out. I hooked the passive crossovers back up on my JBL 4675C stage speakers, threw the Crown crossover modules in a box and am now running the amps for the stage speakers bridged. This was certainly not a great solution, but its better than dead stage speakers and a smokey auditorium. The amps all failed during the first 3 months of operation and I've been keeping my fingers crossed ever since. I've also got a couple CE's in use in a portable PA system. One of those also failed. I'm not impressed with this series of amps. Crown did next day ship replacement amps for each amp that failed  |  IP: Logged John Walsh Film God Posts: 2490 From: Connecticut, USA, Earth, Milky Way Registered: Oct 1999 posted 08-11-2005 08:19 AM                     Hi, Heath, and welcome to Film-Tech. I will give you my opinions, but remember these are just my own and there are several people here who do know more than I. I agree with most people (above) that BGW's are not that great, although I've never heard of that many problems. I don't know if your upper management allows it, but I would call BGW and describe what is happening (be prepared to give the serial numbers of the amps returned.) They may do something. You should ask your theater's service tech if he knows the history of this install to see if there are any weird, 'gotchas' like if the amps were purchased used, etc. You should ask him if it's OK for you to follow up on these issues because some techs get upset when someone else gets involved the equipment. It might also be a good time to see if you can get the design blueprints for the theater and verify the amps and speakers are large enough for each auditoriums. They may be too small for the size, and the amps are being overdriven. Also, it would be a good learning experience to go through the place and see if your calculations agree with what's there. If you read the "Blown Subwoofer" topic from about a month ago, Steve G wrote an excellent example of how to calculate the sub amp power needed vs. the auditoriums size and provided a Dolby guide in the manuals download. Your idea of swapping out amps is a good one. I have found QSC's to be very reliable; of the 300-350 I saw installed, there were (I think) two failures (not including the now-discontinued USA-series.) If rack space is a concern, the QSC DCA-series amps are only 2U, but are more expensive. A popular model is the DCA2422, which will cost you about $800 each. If rack space is not a concern, the ISA-series costs less, but uses a regular (non-switching) power supply, so is heavy. A cheaper alterative might be to purchase 'B' stock (used, scratched, demo product) from QSC; it has the same warranty as new, but avaiablity is very limited. Once you figure out how many amps you'd like to replace, contact a dealer. Your company probably has a dealer they like to work with, and you should go to that person first. Lastly, I applaud your honesty in using your real name and company, however your upper management may not be too happy to have someone listing problems at a location. For example, instead of stating that 11 auditoriums at the "XXX Theater" have sound problems, you might just say you are having a problem with a few BGW's and leave out any location details.  |  IP: Logged Wolff King Morrow Master Film Handler Posts: 490 From: Denton, TX, USA Registered: Feb 2004 posted 08-11-2005 08:50 AM                        Hi Heath, Actually I work the oldest Rave location at Hickory Creek Yours technically opened before we did (due to a delay), but our building is slightly older. I know exactly how you feel about the BGW situation. I have found the "warm-up" factor can be overcome by doing a morning check routine like this: Have your sound processor generate a pink noise for each of the speaker channels. You be able to hear right off the bat if the high frequency needs to be "popped". All I have to do is turn up the main volume slightly and the high frequency kicks in every time. Then its fine for the rest of the day. Consult your sound processor manual for the procedure, but you most likely have the same ones I do. If you don't have the manual for it, you can download the pdf file right here on film-tech. Hope this helps, and email me if you need more info. Ciao! [ 08-11-2005, 10:45 AM: Message edited by: Wolff King Morrow ]  |  IP: Logged

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