How many ampheres do the 1095 & 1080 draw?

[UCLAman]

Anyone know how many ampheres the 1095 and 1080 are drawing? I looked in the manual and on the back of each amp. and still could not find it - unless I missed it. I ask cause I am in the process of upgrading the power cables. Its not over 15 amps for the 1095, is it? 8O

Thanks,

Rene

[RebelMan]

The 1095 will draw between 10 and 15 (20)* amperes and the 1080 up to 10 amperes.

*Theoretically

[Stev]

I dont think that is correct - by my calculations with the 1080 at 550 watts into 115v should be about 4.8 amps and into 230v about 2.4 amps. might be wrong ? - but think about it - if 550 watts can draw 12 amps how much is a 2400 watt portable heater going to draw ?

Steve

[RebelMan]

Your calculations are correct for a continuous load. However, given the dynamic nature of power amplifiers one shouldn't speculate "just enough". You'll notice I stated "up to" in my original comment.

[bigburner]

by my calculations with the 1080 at 550 watts into 115v should be about 4.8 amps and into 230v about 2.4 amps.

We must have gone to the same school Stev, because that's what I make it.

[Stev]

Yes 550 watts is the maximum the amp can draw - if it can peak at more than that whats the point of having a max wattage rating ? -550 is the peak

[csuzor]

I believe it is:
Power = Vrms x I = Vpeak / sqrt(2) x I
550W = 110v / 1.4 x I
so I = 7A

Having said that, I believe the instantaenous peak current could be larger, and I would estimate 50% more for peak current.

You can do the math for other power ratings.

[DrJRapp]

I dont think that is correct - by my calculations with the 1080 at 550 watts into 115v should be about 4.8 amps and into 230v about 2.4 amps. might be wrong ? - but think about it - if 550 watts can draw 12 amps how much is a 2400 watt portable heater going to draw ?

Steve

I think you are closer to the number than Rebeman, however, basing input on output you must take the efficiency of the amp into consideration. No amp is 100% efficient, so you need to put put more in than you'll get out. This varies by each design.

[csuzor]

I think you are closer to the number than Rebeman, however, basing input on output you must take the efficiency of the amp into consideration. No amp is 100% efficient, so you need to put put more in than you'll get out. This varies by each design.

Jerry, 550W is the input power rating on the 1080, and 800W on the 1075 and 1095. Seems like efficiency on the 1095 is well over 100%! (I doubt it can really deliver 5x200W, or its 800W input rating is incorrect).

I think Rebelman has the closest numbers, they are similar to the calculations based on input rating + 50% peak I mentioned.

[PewterTA]

800W is incorrect on the 1095.

1Kilowatt is correct input rating (and what is written on my 1095).

[UCLAman]

WOW - what a thread I started!

So in conclusion, the 1080 draws about 4.8 amps or so (max?) and the 1095 draws about 7 amps or so (max?) - depending on the configuration of the amp/speaker setup.

Did I get that right?

Regardless of configuration, its NOT OVER 15 amps. Right??? Hopefully I got this right.

[Stev]

I thought the original question was about current draw from the mains supply - so efficiency of the amp has no bearing on the current draw at all - does it ? Maybe I misunderstood are we talking about amps deliverd to the speakers ?

Steve

[RebelMan]

Regardless of configuration, its NOT OVER 15 amps. Right??? Hopefully I got this right.

As long as nothing else (of significance) is sharing the same circuit a 15A circuit should provide enough amperage to cover either device but it won't leave you with much headroom. The RB-1080 will draw the 4.8A that has been quoted and the RMB-1095 will draw 10.4A with a 115V source under their "published" power specifications. Until it has been confirmed that these values are correct and that they represent the maximum power the amplifier would draw I stand by my initial recommendation. Either way you should be fine.

[chrispy35]

Here's a thread from a while back with various members measuring actual current draw in their systems during normal usage. The results surprised many I think.

http://www.htguide.com/forum/showthread.php4?t=12538

Basically, the amps were not drawing anything near their rated power levels at more than reasonable listening levels.

Does anyone know how power amps are typically tested? Do they actually hook up a speaker to get the datasheet values or are they just running a resistive load bank? i.e. turning the amp into a heater.

[bigburner]

Wait, I've just checked brucek's posts and found this explanation. It appears that Stev and I haven't got it quite right.

Unless a device is purely resistive (i.e. a toaster), then power factor must be taken into consideration. If you plug an amplifier into a 120 volt circuit and it draws 3 amps, then the power in watts dissipated isn't 120 x 3 = 360 watts. The 360 watts is actually volt/amps (360 VA). The real power dissipated in watts is 120 x 3 x PF (power factor). Power factor is required to be considered as a result of the current lagging the voltage in a device that is not a pure resistance.

So for my amplifiers, the device shows 120 volts, 2.11 amps, 219 watts. If I multiply 120 x 2.11 = 253 VA. So the power factor is 0.87.

brucek's full post is #1 at http://www.htguide.com/forum/showthread.php4?t=12538