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Power Amp - Power
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Author:  jamkaraoke [ Mon Mar 20, 2006 11:00 am ]
Post subject:  Power Amp - Power
Worked a double shift on Saturday due to a St Pat day party.
Had my system working non stop from 4:00pm until 1:30 AM

I noticed (or maybe just imagined) that  about 11:30pm - I needed to push the sliders on the volume a little bit higher.  Hence my question

Will amps lose some power when HOT?
Author:  EElvis [ Mon Mar 20, 2006 11:24 am ]
Post subject:  Re: Power Amp - Power
Possible, I supposed. But in reality it was probably that you had more people in the room and the sound absorpsion was higher. Making you have to turn it up to keep the same status quo.
Author:  Kellyoke [ Mon Mar 20, 2006 11:45 am ]
Post subject:  Re: Power Amp - Power
I use powered Mackies and often I find the same thing.  Volume settings that work great at 9:00p.m.  quite often have to be raised a little by 11:00.  More people will quickly absorb the sound.  I run my speakers at 50% and then will boost from the main a little.

Kelly
Author:  jamkaraoke [ Mon Mar 20, 2006 11:48 am ]
Post subject:  Re: Power Amp - Power
Dr.

Thats the funny thing..There were actually less people in the place at 11:00pm then at 6:00pm.  The place was jampacked in the afternoon..could it be that the sound was "blocked" by the wall of people and it just SEEMED louder.
Then again it could have been the 6 beers I drank too.....LOL
Author:  karyoker [ Mon Mar 20, 2006 12:09 pm ]
Post subject:  Re: Power Amp - Power
The beta or gain of any transistor depends on many factors.. max ratings, bias, voltage, impedances all of which are  affected by temp.   The number one enemy of any solid state component is thermal runaway which is totally destructive .  A good habit to get into is periodically feel the heat sink and have an idea how hot it should run especially if you are doing outside gigs during the day.. A fan blowing across the heat sink will do wonders.
Author:  twansenne [ Mon Mar 20, 2006 12:49 pm ]
Post subject:  Re: Power Amp - Power
It also could have been your EARS.  Ever notice whenn watching TV, and you go into the kitchen to make a snack, and the come back to the TV 5 minutes later, and your think to yourself "Damn, that is loud"  OR when you come home from a gig and your ears a ringing, and you have to turn the TV up lound, then the next day, you notice that the TV was WAY TOO LOUD.

Playing from 4:30-1:30, your ears probably took some abuse.
Author:  jamkaraoke [ Mon Mar 20, 2006 12:54 pm ]
Post subject:  Re: Power Amp - Power
karyoker @ Mon Mar 20, 2006 3:09 pm wrote:
The beta or gain of any transistor depends on many factors.. max ratings, bias, voltage, impedances all of which are  affected by temp.   The number one enemy of any solid state component is thermal runaway which is totally destructive .  A good habit to get into is periodically feel the heat sink and have an idea how hot it should run especially if you are doing outside gigs during the day.. A fan blowing across the heat sink will do wonders.


So what you are saying is.....YES?   an amp can lose some power when running very hot???
Author:  jamkaraoke [ Mon Mar 20, 2006 12:56 pm ]
Post subject:  Re: Power Amp - Power
twansenne

You may be on to something ..like I said ..it could have been my imagination or just shear exhaustion by that time
Author:  twansenne [ Mon Mar 20, 2006 1:04 pm ]
Post subject:  Re: Power Amp - Power
JAMKARAOKE @ Mon Mar 20, 2006 2:56 pm wrote:
twansenne

You may be on to something ..like I said ..it could have been my imagination or just shear exhaustion by that time


One way to checkis to carry a decible meter.  At the begining of the night I set the sound level, and a specific spot (near the bar), so the bartenders don't have to yell.  Then perodically throught the night I double check the sound level, and adjust accordinly.
Author:  karyoker [ Mon Mar 20, 2006 1:28 pm ]
Post subject:  Re: Power Amp - Power
Quote:
So what you are saying is.....YES?   an amp can lose some power when running very hot???


Agood analogy would be the light bulb.  A lot of the energy is wasted in heat. Efficiency of mechanical or electronic devices is best when at the center of the temperature operating curve.  A detectable change in volume would take a large temp change unless it is already running in the upper region of tolerance in which case it needs cooling.  An easy way to tell is fan the heat sink and see if the volume varies. So it is possible not probable unless the room temp is high too.
Author:  lyquiddye [ Thu Mar 23, 2006 12:59 pm ]
Post subject:  Re: Power Amp - Power
If you are running you amp hot I would suggest it is time for a bigger amp.

I used to push my amps and speakers very hard and I have had amps overhead and shut down on me.

Since I have switched to QSC PLX3402 amps. 700watts at 8 Ohms Stereo. I never have to push the amp. After 4 to 5 hours it is still room tempature.

Now it gets hot when I'm pushing 2 4 ohm subs all night with the clip flashing on the hard bass hits, but they still are not hot after all the abuse.

Better amps, better design will produce better quality.

What are you using??
Author:  TTowntenor [ Thu Mar 23, 2006 1:55 pm ]
Post subject:  Re: Power Amp - Power
lyquiddye @ Thu Mar 23, 2006 12:59 pm wrote:
Better amps, better design will produce better quality.

What are you using??


Oh come now, you mean a $300 Behringer amp isn't as good as the PLX series?  Aren't all electronics created equal, you know cheap don't mean bad.....or does it?  Hmmmm.
Author:  jamkaraoke [ Thu Mar 23, 2006 2:16 pm ]
Post subject:  Re: Power Amp - Power
Lyq,

The power Amp I was using that night was a Peavey PV1200
Normally never had a problem , and even that night there was no problem with the amp functioning non stop. It just SEEMED like a power loss. ?
Author:  lyquiddye [ Thu Mar 23, 2006 3:19 pm ]
Post subject:  Re: Power Amp - Power
Peavey has always made very solid power amplifers. Not many will list them on the top of their list, but I have owned 3 and use a them in 2 of my different bar setups.

The PV 1200 has been dropped for the 1500. The line is been around since the early 80's and the technology has not changed. It's a heavy in weight amp and does a great job.

The one Bar I used to work had a 2400 now it is a very old model and after 2 to 3 hours of continiously pusing the amp as hard as I could without cliping. I noticed that I would lose some volume loss after a few hours. It's all because of not having enough head room. If I had 2 amps at that bar I would have more head room and the same amp would work just fine.

I begin to question what speakers you are using?

270 watts at 8ohms is a little light on power. I would tend to believe in a bar setting it gets quite loud and you tend to push your levels.

In the past I have done gigs that lasted for long periods of time I have switched from 1 amp to another after 4 hours.
Author:  jamkaraoke [ Fri Mar 24, 2006 5:51 am ]
Post subject:  Re: Power Amp - Power
Speakers that night were Peavey SP5G's  which is the set I have used with the amp for the last 5 years.  ( also have used a set of Yam's and Peavey PR12 also )
Needless to say for the jobs I've done in the past the AMP and Speakers always worked flawlessy.   But I don't ever recall working them 9 hours straight before...basically that is why I asked the  question regarding the PERCEIVED power loss.   Like I said it could have been my imagination.  I checked the amp all night and although WARM it never felt too hot and the fans were working .

So I'll ask the same question a little differantly

HAs anyone experianced power loss when runnoing their systems for LONG CONTINOUS HOURS????---
Author:  jamkaraoke [ Thu Mar 30, 2006 8:01 am ]
Post subject:  Re: Power Amp - Power
I didn't notice any power loss last weekend but did notice --
That the bar I'm working at now has one of these BIG GOLF VIDEO machines
plugged into the same set of sockets that  I use.

Now let me explain ... There are 4 sockets - The TV is plugged into 1
The other DJ's powered Mixer is plugged into another ( He leaves his stuff set up )
The there are 2 power strips into the other 2 sockets. In those are plugged the neon window lights, another smaller table video game , the ATM machine and then I plug my case into it also ( mixer /power amp / player / laptop / extrenal hardrive) and on occasion wirelss mics.  NOT TO MENTION this new large video game.

I'm not an electrician but I do know these is not safe ...But could this also have anything to do with a slight power loss to my power AMP a few weeks ago???
Author:  timberlea [ Thu Mar 30, 2006 9:21 am ]
Post subject:  Re: Power Amp - Power
What needs to be done is to ascertain if they are on separate circuits.  You can have a recepticle with two outlets on separate circuits or the same or many separate outlets on the same circuit.  If the recepticles you use are on the same ciruits, then tell the manager about it and the dangers.  Ake him to consult an electrician if he doesn't believe you.  If he does find this is a problem and changes things to separate circuits, then you should find any problem resolved.
Author:  Lonman [ Thu Mar 30, 2006 9:34 am ]
Post subject:  Re: Power Amp - Power
JAMKARAOKE @ Thu Mar 30, 2006 8:01 am wrote:
I didn't notice any power loss last weekend but did notice --
That the bar I'm working at now has one of these BIG GOLF VIDEO machines
plugged into the same set of sockets that  I use.

Now let me explain ... There are 4 sockets - The TV is plugged into 1
The other DJ's powered Mixer is plugged into another ( He leaves his stuff set up )
The there are 2 power strips into the other 2 sockets. In those are plugged the neon window lights, another smaller table video game , the ATM machine and then I plug my case into it also ( mixer /power amp / player / laptop / extrenal hardrive) and on occasion wirelss mics.  NOT TO MENTION this new large video game.

I'm not an electrician but I do know these is not safe ...But could this also have anything to do with a slight power loss to my power AMP a few weeks ago???


It could be leading to your "power loss" if the circuit is overloaded.  I just got out of the same situation - kind of.  I had my entire system plugged into 1 line of outlets.  I would notice the littlelight on my mixer dim with the beat the louder it got throughout the evening.  We had a couple nights where it would actually trip the breaker.  They just gave me a dedicated circuit for my amps this week - now no problems, no dimming.
Author:  karyoker [ Thu Mar 30, 2006 10:57 am ]
Post subject:  Re: Power Amp - Power
When we first started putting Valley dart boards in bars everybody was having problems. The logic circuits are working with 5 volt or less signals.  The cricket display o top was suseptible to the slightest amount of interference. The power suppy was inadequate so I started putting a higher amp voltage regulator which supplied the cricket board. I was a big hero with Valley for a week or two..
 Bars are the worst enviroment for sensitive electronic stuff.  They have big cooler motors that put induvtive surges into the lines when they start up. You might have 40 dozen little neon signs that dont help.  A big neon sign on the roof can totally destroy stuff. Microwave ovens, neon lights, poor wiring in older bars with missing grounds and other stuff I cant think of are all culprits . And believe me I have fought them all...
 All gear should be powered by a power conditioned strip with overload and spike or surge protection. Unless I have been in a place before I do like to run everything from my source. The first thing in setting up in a new venue is finding out where the circuit breaker box is and get a general idea of the wiring of the place and which breaker you will be on.  The next is checking out the outlet recepticals with a cheap tester availible at the shack. With the overall gain structure used and everything and no input to the mixer there should be a minimum amount of noise coming out of the mains.. If there is a violent electrical storm out side I shut down and unplug everything. At one time I shut down a tv station for over 30 minutes.

All interference and related problems can be solved...eventually..
Author:  EElvis [ Thu Mar 30, 2006 11:10 am ]
Post subject:  Re: Power Amp - Power
There is also the possibility of Power problems here.  At home, I have a Furman power conditioner with led voltage and amps readout on it.  I notice the voltage in the house Varies greatly over a matter of hours. going fom 110 to 127 volts.  That ia roughly a 10% change. If you have the voltage change through out the night you will be adjusting the volume.
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