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Posted by Heath Dutton (Member # 3265) on 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
 

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Posted by Gordon McLeod (Member # 33) on 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
 

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Posted by Richard Fowler (Member # 893) on 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
 

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Posted by Phil Hill (Member # 371) on 08-10-2005, 07:12 PM:
 
Ummm... a 4670 is NOT worth bi-amping...
 

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Posted by Brad Miller (Member # 2) on 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.
 

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Posted by Sam D. Chavez (Member # 1841) on 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.
 

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Posted by Mark Gulbrandsen (Member # 72) on 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
 

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Posted by Brad Miller (Member # 2) on 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.
 

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Posted by Mark Gulbrandsen (Member # 72) on 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
 

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Posted by Monte L Fullmer (Member # 2797) on 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
 

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Posted by Steve Guttag (Member # 268) on 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.
 

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Posted by Alexander Alves (Member # 1746) on 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
 

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Posted by Steven J Hart (Member # 2340) on 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
 

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Posted by John Walsh (Member # 168) on 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.
 

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Posted by Wolff King Morrow (Member # 2226) on 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 ]
 

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Posted by Richard Fowler (Member # 893) on 08-11-2005, 02:56 PM:
 
Phil, 4670D I would not use in an "Iwerks" project but a 175 seat shoebox cinema they bi-amp nice at 630 or 800 HZ crossover point ....they where usually an improvement from a home made speaker or Music store unit with a 180 degree horn found in some international locations Crown CE amplifiers need to stay clean, and do not tolerate low voltage on power. How about Ashley amplifiers
 

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Posted by Heath Dutton (Member # 3265) on 08-11-2005, 03:01 PM:
 
Hey Wolff,

Unfortunately we have ultra-stereo analog processors, I have a feeling you fellas lucked out and got the digital package we are so jealous of. These processors use a pink-noise generator card, that we unfortunately do not have. I requested one once, but never received it. I do however try to use non-sync to achieve the same end, and it does work to a certain extent. But, some of these amps are a little too far gone, and others will have to have this process repeated a couple times a day to keep them "warm". Alternatively I have an old mini-disc player with pink noise on it, but it's a pain to wire it to an input every time I need pink noise.

I may be wrong but I have the feeling that our humidity situation may be causing the excessive amp failures. Our AC ducts over the booth were removed a while back and since then I've noticed condensation on everything from port-hole windows to projectors. It could also have to do with the AC turning the booth sub-zero at night, and the fact that our exit doors no longer have weather stripping to speak of. The last two hurricanes both left the booth with rust on every projector (mostly on the dowser and gate pins). Needless to say we use alot of liquid wd-40.

Everyone has been very helpful, and I will be checking the blueprints and looking into what QSC has to offer.
 

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Posted by Gordon McLeod (Member # 33) on 08-11-2005, 03:17 PM:
 
Many amps use ribbon cables or cables with amp/molex headers and if humidity is an issue then they can get corroded and make intermitent or poor contact
 

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Posted by Richard May (Member # 2627) on 08-11-2005, 03:19 PM:
 
I have been installing the Crown CE series for about 6 or 7 years now. They did have a problem early with some of the amps pretty much exploding into flames. Since they fixed that though, I have had no problems with them. I do like the QSC amps, but for the price I will continue to stay with the Crowns. They have been extremely reliable. Out of the 400-600 that I have installed, I can remember about 10 or so that failed.
 

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Posted by Mark Gulbrandsen (Member # 72) on 08-12-2005, 01:12 AM:
 
I like the 4670D's for smaller theatres not over 175 seats or there abouts and they sound even better bi-amped.

In reality I've had about the same lick with all the power amos in this area if you take the number of amps out there VS the number that have failed. The amps in this area with the least problems seem to be the Ashleys. I think if you were to take a poll from each manufacturer you'd find the same failure rate with each company that you would with a ordinary light bulb.

Mark
 

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Posted by Wolff King Morrow (Member # 2226) on 08-12-2005, 04:21 AM:
 
Heath, we have the DSP 60S sound processors, so I think you're right on that. Bummer... I thought I had it rough with a few grumpy amps and a couple of bad spares, but y'all have a serious headache to contend with.

BTW, I do have a very nice set of crown royals and a Dolby Digital setup on one of my screens, which has never even hinted at giving me any amp problems. I'm quite pleased with their performance and reliability in comparison.
 

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Posted by Frank Angel (Member # 248) on 08-12-2005, 05:39 AM:
 
Talk about reliabilty, we had four 70w Norleco Philips rack mounted tube amps in our small theatre. They were never turned off since 1970. They were only turned off recently because they had to be physically moved, but they still work. Norelco also made a sound mixing console and, believe it or not, an theatre electronic organ (four registers) that we had in our big house for a few decades.

BGWs burst into flames. Regularly. So do the older Crowns. Anyone ever hear of Phase Linear amps? It was a company made up of a bunch of MIT guys. It was the first amp I ever bought and it has been in use for like 30 years. One channel died only a month ago. You would think they could make components more reliable today than they were able to back then, but I guess that is just not the case.
 

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Posted by Mark Gulbrandsen (Member # 72) on 08-12-2005, 08:05 AM:
 

quote: Frank Angel

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Anyone ever hear of Phase Linear amps? It was a company made up of a bunch of MIT guys. It was the first amp I ever bought and it has been in use for like 30 years. One channel died only a month ago. You would think they could make components more reliable today than they were able to back then, but I guess that is just not the case.

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Actually I know the person behind the original Phase Linear amps, Bob Carver. It wasn't a "bunch" of MIT guys it was all him and just some assistants working for him. I worked in a Hi-Fi repair shop in the Chicago burbs for several years right after getting out of High School in the early 70's and repaired scads of them along with scads of Crown D-series amps. Phase Limears, mainly the 400 also took out many drivers in speakers when they blew. +/- 75 volts in the 400 and +/- 100 volys DC in the 700 and the fuses couldn't always act fast ehough to protect the speakers. I haven't seen a BGW flame out yet but I have seen a QSC shoot flames out its front! Phase Linears were not very reliable or very good sounding amps but they were among the first affordable high power home audio amps made.

Actually semiconductors ARE more reliable today but manufacturers skimp and sometimes don't use enough of them for maintaining a decent SOA, or enough heat sinking to peoperly dissipate the heat generated. The Phase Linear amps are a prime example of an amplifier thats drastically under heat sinked.

Some QSC's are also among the best examples of amplifiers without enough sinking in the 1200,1400 series and the USA series. Try running one though the standard FTC conditioning tests sometime......PHEW! Also keep in mind that the heatsinks can be and typically ARE the most expensive mechanical part of an amplifier that is properly designed, Krell amps are a good exapmple of amplifiers with alot of $$ tied up in just the heat sinks, but these amps also allow proper dissipation of the OP drvices without the use of any fan.

BTW: Bob Carver sold the Phase Linear name and later went on to found Carver Corporation.....

Mark
 

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Posted by Richard Fowler (Member # 893) on 08-12-2005, 09:46 AM:
 
I remember installing phase linear amplifiers in clubs and theme parks in the early 70's....my boss at the time, who is now retired on his patent royalties, designed cooling kits and low pass filters for the units....nothing was a problem for him, he would design some widget as a fix
 

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Posted by Mark Gulbrandsen (Member # 72) on 08-12-2005, 11:18 AM:
 
Its funny that you mention that Richard because any DC on the input of a Phase Linear usually mest instant destruction for both amp and speakers!! The low pass filter was definatly a needed thing....

Mark
 

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Posted by Sam D. Chavez (Member # 1841) on 08-12-2005, 01:22 PM:
 
Phase Linear = Flame Linear in this area.
 

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Posted by Richard Fowler (Member # 893) on 08-12-2005, 02:56 PM:
 
Smoke residue was easy to clean off the satin aluminum finish of the amplifiers
 

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Posted by Heath Dutton (Member # 3265) on 08-12-2005, 04:56 PM:
 
Wolff,

How did you get crowns on your Dolby Digital house?

About a year ago I was told that they were considering replacing one of our large house racks with all crown amps and using those as spares. Perhaps this is what happened at your theater? We have never (as long as I've been here) had more than one spare. Of course it's gone now, lost to shipping or theft (which I will never know).

The one good thing about our setup is that we have 2 Dolby Digital houses, one medium sized (2) and one large (16). This makes 2 my favorite house of course But unfortunately we have changed general managers twice since I heard last about the crowns, and apparently it never made it into the budget.
 

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Posted by Wolff King Morrow (Member # 2226) on 08-13-2005, 02:10 AM:
 
The crowns were "donated". In other words, the company gave a demo and never bothered to pick them back up. This was 3 years ago I believe.

BTW we also have 2 DD houses, both our largest screens.
 

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Posted by Andrew Duggan (Member # 1302) on 08-15-2005, 11:28 PM:
 
I've never had the chance to use any Crown amps in a projection situation, but I had the luck of having a CE1000 go up in smoke a few months ago at a club I work at, in mid show. It was awesome, and by "awesome", I of course mean "a complete nightmare". It's biased me more than a little bit towards the whole brand.

Still waiting for my QSCs to die on me though.
 

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Posted by Steven J Hart (Member # 2340) on 08-17-2005, 07:51 AM:
 
Heath, I wonder if the problem with your bgw amps could be as simple as dirty contacts on the speaker protection relays. This could explain why tapping on the chassis of the amp fixes the problem. I've run into this problem several times with other brands of amps.
Steve
 

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Posted by Mark Gulbrandsen (Member # 72) on 08-17-2005, 07:57 AM:
 
Dirty input level pots are also VERY common. Try running them up and down a few times and see if this clears it up. If dirty they will have to be cleaned tith some Pro Gold contact cleaner.

Mark
 

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Posted by Don Sneed (Member # 955) on 08-17-2005, 04:47 PM:
 
I think the problem is the cheap plastic pot BGW was using on their TMC-1 & 2 amps (these are the amps with built-in crossover), I think they get dirty & lose a channel, removing the small cover over those level pots & turning to full & totaly off several usually makes the amps work, or in Heath's case tapping on those pots or neat it makes the amp work again...it appears BGW went to after Brian died...that's too bad, BGW was one hell of an amp in their days...
 

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Posted by Mark Gulbrandsen (Member # 72) on 08-17-2005, 09:39 PM:
 

quote: Don Sneed

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it appears BGW went to after Brian died...that's too bad, BGW was one hell of an amp in their days...

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Actually Don, After Brian passed on his wife Barbra Wachner gave it a real good go and didn't allow any major compromise on the quality end of things. It was a difficult battle though for the company with the comming of the Taiwanese and Chinese amps. I also feel that the Millenneum amps were a part of the downfall of BGW, its a real poor design and real goofy output stage that couldn't use a floating ground. Had they come up with a better design they might very well still be going strong today. At least it doesn't appear that the M2200 subwoofer has been changed very much but I'd want to see the inside first to check for any made in China crap before I would sell any of them again. I was involved with Brian Wachner since BGW appeared in the Chinago area in 1973. He was truely a great engineer that would never compromise quality for price!! He really ought to be inducted into the Audio Hall Of Fame .

Mark
 

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Posted by Sam D. Chavez (Member # 1841) on 08-18-2005, 10:02 AM:
 
Not to speak too ill of the dead, but Brian was his own worst enemy in many ways despite being a brilliaint engineer.

I knew him well and when Dolby went into the racking business he was my first choice for Amps.

He raised the standard net price of the Amp we chose from $425 to $515 only three days after agreeing to hold the price a minimum of 120 days. I had already done my proposals to AMC/NCS and had to come back from my vacation and start all over again.

I had anticipated this move as this tactic was vintage Brian and took the precaution of visiting the QSC plant just in case.

We switched our order to QSC, the industry largely followed and that was the begining of the end of BGW as a major player.

Another piece of audio history.
 

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Posted by Mark Gulbrandsen (Member # 72) on 08-18-2005, 04:49 PM:
 

quote: Sam D. Chavez

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He raised the standard net price of the Amp we chose from $425 to $515 only three days after agreeing to hold the price a minimum of 120 days. I had already done my proposals to AMC/NCS and had to come back from my vacation and start all over again.

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quote: Gordon McLeod

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Yes isn't the BGW the amplifier of choice in the brand of Sound System tat shall not be named

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Oh, yea, that sound system... YOU call that a sound system.... I don't! They supposedly have a special amp all of their own but I never thought too much of that model amp anyway.... that amp is what REALLY brought BGW down.

Un Named
 

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Posted by Gordon McLeod (Member # 33) on 08-19-2005, 09:20 AM:
 
According to the BGW web site they are now owned by a new company and most of the models of amps are discontiunued including the Millenium serries that I believe are part of the un-named soundsystem
 

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Posted by Mark Gulbrandsen (Member # 72) on 08-20-2005, 08:33 AM:
 


Well, I could think of a few good names for it.....
 

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Posted by Gordon McLeod (Member # 33) on 08-20-2005, 10:54 AM:
 
I think it is 0004 SPH system
 

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