Leaving Amps on

I am wondering, in the case of which is best for the speaker, is it best to leave the amps on all the time, or shut them off between use. I know that turning them on and off causes heat expansion in voice coils leading to stretching; The main reason that pro audio setups that are permanent stay powered up all the time. But, is it really best? Can I also cause long term damage to the speaker by leaving it powered up with no signal being sent? I just recently read an article that said too much continuous power can burn the parts in the coil. Can anyone help? Thanks in Advanced! Sam
Turn your amps off, PLEASE! Never heard of voice-coil stretching due to turning amps on and off. How do you keep a pro sound system turned on when you're moving it into a trailer for a 400 mile ride to the next concert? Also, is your amplifier's DC offset so high? It should be zero. A properly functioning amplifier will have NO output even when turned on. A properly designed amplifier will have no output while being turned on (a protection circuit or a relay will see to that). If your amp doesn't have this protection circuit or a muting relay, buy another amp! As for your second question, of course delivering large amounts of continuous power to the voice coil (it's just a coil of extremely thin wire) will damage them. There are no other parts to damage, however, unless you own a speaker that has an accelerometer, like the Velodyne subwoofers. Leaving your amps on all the time should cause no damage, but why risk lightning strikes and run up your electric bill? Some pro setups leave the preamps on all the time, especially if they're computerized (like some discos and recording studios) but the amps are always turned off. The world's three premier discos turn their gear off every morning at 6 AM, and on again at 10:30 PM every day 365 days a year. You may ask them if you wish: http://www.extra-palla.com.mx/enigma/ http://www.extra-palla.com.mx/palladium/ - and http://www.babyo.com.mx/ If a recording studio runs twenty-four hours a day, then there may be no need for them to turn the monitor amps off. Otherwise, fear about voice coil stretching is just BS. Period.
Leave them on! Notice how the amp is warm/hot when left on? When the amp was designed, it was always evaluated after it had warmed up. It does sound different after it has warmed up (Not just the heatsinks but EVERYTHING). If it is a big solid state amp, this can take hours, or even days. But even the most powerful amps draw very little power, when left in idle, so don't worry about power consumption.
Hi, fotopres hit the nail on the head. amps often sound a little sweeter warmed up, but i just turn the amp on and come back a few minutes later to crank everything else up. late
I have some original adcom equipment GFA-1A amp and a GFP-1 preamp. I have had some cold solder joints repaired several times and noticed that when the amp warmed up my left channel would come back. Call it foolish but I have had the amp and preamp on constantly for about 5 years. No problems.
All eletrical gear, audio or otherwise, was designed to be used, ie: ON. All specifications are produced using samples that have been on for many hours in the lab, connected as they are to be used in the "real world". I have been at this for over 30 years, and have always left everything I own on all the time, and I have never had a problem. The only thing that could possibly happen is that there could be a "brown out" (ie: voltage drops below the norm momentarily), a spike (voltage increases above the norm momentarily) or it shuts down altogether. You will know from experience if you have lived in a particular place for a long time how reliable the electrical service is. The electrical utility which provides you with your "volts" also has over and under voltage limiters in place for this reason. They are not interested in frying Mrs. Jones as she irons her clothes, or blowing up every pizza oven in town just before the big game, the resulting lawsuits would be staggering, For really sensitive appliances like computers, you can buy surge suppresors (questionable) or UPC units (better bet). Most of the products I have seen over the years produced to deal with this "problem" over the years don't work, and most of the rheteric I have heard and read was designed just to scare you. Leave your gear on, you will be fine.
An idling, but "ON" power amp will not heat your voice coils. It has no output. Music signals WILL heat your voice coils and heat WILL cause them to expand. If you don't want your voice coils to expand, don't use them! However, since they're designed to operate with heat (up to a point) heat won't damage them at all. Leaving your amps on will not help or hurt your speakers. Electrical devices are all somewhat like light bulbs; leaving them on all the time results in the max. total operational hours (everything has a limit). Flipping them on and off rapidly results in early failure from heat cycling. Turning them on for use and off when not needed gives the greatest calender life. You choose what is most important.
I saw no harm when I left my amps on, but the brown-out is always a fear and may damage your speakers too. If you are using tubes, or class-A transistors the heat and the component wear is also something to consider. As a rule, I leave digital components and preamps on, but switch off the power amps.