2. amps-preamps
  3. 1243305832

Power consumption questions

When you plug an external multi-channel amp in to an audio-video receiver for increasing power output and overall performance, I'm assuming the power supply in the AVR shuts off automatically. Is that correct or does it stay on and work in conjunction with the new separate amp for driving the loudspeakers? Or does it get bypassed but stays on and used for powering the preamp processor?

If it does in fact get bypassed for driving the speakers, how could I then calculate how much of the rated power normally consumed by the AVR would be reduced (in watts) if just used as a preamp processor? I'm talking about Rotel equipment here and this information is not given in the owners manuals or specifications anywhere. In my case, the AVR has a rated power consumption of 450 watts and the multi-channel amp 800 watts.

The reason I'm asking this is that I only have a 15 amp 120VAC circuit available for my system and with the potential addition of this mulit-channel amp, I could be coming close to maxing out considering the other appliances that would be in use on that same circuit. Thanks in advance for the replies.
pdn
magfan
1,583 posts
 
Consider the purchase of a 'Kill-a-Watt'...an external, plug in power meter. It will give you Volts / Amps / Watts and other data, including hours and Watthours.

So, instead of reading back plates of equipment, you will be able to measure stuff and see. Even a hi power amp won't draw much current if not pressed. If pressed and the current capacity of the circuit is insufficient, you may see a voltage drop or sag.

Another measure is 'Power Factor', which for most gear is very near 1.0, meaning that current and voltage neither lead or lag one another. This is good.

The cost? I found 'em at Fry's, a local HUGE SoCal retailer for all of 20$. Other power measuring equipment has up to and including, a USB port to connect to your confuser. They are pricey and to me, vast overkill.

Let us know what you MEASURE.
jtwrace's avatar
jtwrace
443 posts
 
I like this: http://www.p3international.com/products/special/P4400/P4400-CE.html
magfan
1,583 posts
 
Yes....that's the killawatt...
I had only seen it 'internet', but when I spotted it at the local retailer, purchased it immediately. Pretty useful gadget and a great way to see just how much electricity you DO use.
pdn OP
438 posts
 
Thanks everyone. Great input. Looks like overall I can expect not to have problems and blowing the circuit breaker. I can not change the other devices that are powered in this same circuit (lights, TV, exercise machine, etc). But the draw should be well under the 15 amps. I just don't want to invest in this amp only to find out it's not going to work out. I'll look into this meter too.
pdn OP
438 posts
 
Follow up. I have the RMB-1075 now and so far so good. No problems with power but I do see the lights flicker for just a millisecond when I turn on the amp at times. Thanks again for all of your input and help.
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