Power requirements for Emotiva Amps

[rneill]

I am in the market for some amps and am trying to figure out the electricity requirements for the Emotivas but don't see it listed anywhere.  I don't want to go crazy and then not have enough amps at the wall to run them.  Is there a way to tell the draw of each model?

Thanks!

[jlafrenz]

Can't go wrong with a 20A circuit. I have all the stuff in my signature running on a 15A circuit.

[rneill]

Sweet thanks that is probably more draw than I will be running. If I go all out on amps for my speakers it will most likely be at the most two XPA-1L for fronts and probably an XPA-200 for my surrounds, I think an XPA-2 would be over kill on surrounds for me. I don't run a center currently and am not planing on adding one so four channels is enough. Thanks!

[Gary Cook]

Other than power amps audio gear doesn't really need a lot of watts and when it comes to power amps in a typical home environment they very rarely if ever run all channels at full power. So quoting maximum power consumption would be pretty much meaningless. Keeping in mind that the capacitors in the power supply handle the transient loudness. My rule of thumb for Class AB power amps is to take their quoted output in watts into 8 ohms and then halve it, so for example an XPA-5 at 200 watts x 5 channels / 2 = 500 watts drawn from the power circuit at the loudest I'm likely to drive it at.

This of course is not technically correct, there's its efficiency, power loss, sagg, etc. But as a rule of thumb it hasn't let me down so far.

Cheers
Gary

[rneill]

I should add the speakers I will be running will either be two Axiom M80 fronts OR two M3 Fronts with an ep175 sub depending on which sounds better and a pair of QS8s for surrounds.

Thanks for the help, that is exactly the kind of calculation I was looking to be able to do to get a rough idea of draw per amp 

[Dark Ranger]

It's difficult to quantify power draw for amplifiers beyond idle current. Wall socket power requirements will vary greatly based on source material, speaker sensitivity, and listening level (just to name a few). An amplifier has internal storage reserves (filter capacitance), so in some cases at lower volumes, power draw from the wall might not exceed the amp's idle current.

For example, my XPA-1L pulls about 1 ampere (at 120v) from the wall at idle in low-bias mode. I can play music at lower volumes and that 1 ampere current won't ever rise because the amplifier's internal power supply is loafing along. Crank up the volume, and suddenly the XPA-1L transformer needs to pull more current from the wall socket to recharge the storage capacitors and deal with the increased demand. The amplifier might say "power consumption: 1800 watts max," but it's not pulling that much from the wall 99% of the time.

So the answer to your question really is "it depends." If you enjoy spirited levels, have a larger room, hard to drive speakers, or dynamic source material etc., then your average current draw from the wall will be higher. A 15 amp dedicated circuit should be more than adequate for most folks, even with lots of powerful equipment (paging Porscheguy to the white courtesy phone). A dedicated 20 amp line is even better. If you can't get a dedicated line, then I recommend turning off anything else plugged into that circuit (if possible) while you're listening to music or watching a movie. That will reduce power consumption for non-essential devices.

Using a device like a Kill-A-Watt meter is helpful in measuring power consumption. Of course, you would already need to have the equipment in order to measure it.


EDIT: A bunch of other comments were posted while I was writing this. I see you're considering two XPA-1Ls. As a quick FYI, I can tell you that in low-bias mode (switch set to Class A/B) at idle, current draw is about 1 ampere at 120v for each XPA-1L as mentioned. If you're using high-bias mode (switch set to Class A) at idle, expect about 2.5 amperes at 120v for each XPA-1L. Idle current for the XPA-200 is around 0.3 amperes at 120v.

[rneill]

Yeah adding a dedicated circuit is kind of out of scope for this project. It's a brand new house with no basement or easy way to run it without tearing a wall up so what ever I buy needs to work within the power I have available. My speakers are fairly efficient and the room isn't that big, I used to run them off an Onkyo 5707's integrated amp with no problems until it died from the HDMI board failure like most of them... I have an XMC-1 on the way and am now looking for some amps to go with it.

Thanks!

[Gary Cook]

For completeness, I've tested the rule of thumb a few times over the years using a watt meter and it's very safe. I could divide by 3, even for party time, and still have headroom.

Cheers
Gary

[rneill]

Awesome Gary thanks. I think I should be fine, other than a couple lights that are using LED bulbs the only thing on the circuit is my entertainment center. I am going to verify this tonight but I am pretty sure this is the case.

Thanks again!

[seppo]

I had a very nice listening party with a few friends and plenty beer a few weeks ago. We played lots of 70's Genesis, Led Zeppelin, Metallica etc etc. Good times. I have SA-250 driving low sensitivity (85-86 db), low impedance (nominal 3 Ohm) up to 250 W rated Infinity RS-II's. We really cranked it up to way too loud levels, but the Emo and Infinity's kept on going nicely, with no audible distortion, just pure music. The APC H10 surge protector (rated 1kW), on the other hand, went to protection when playing Boston's Third Stage. The guitar riff on top of the organ finally was too much. I have all my 2-channel gear hooked up to the APC (see my signature below), but SA-250 is really the only relevant power hog.

In other words, per my experience, an amp rated at clean 400 wpc at 4 Ohm can be hooked up to standard wall outlet, and when played at extremely loud levels will draw over 1kW from the wall, and it will work fine.

[rneill]

Thanks Seppo. I have pretty much decided on the SA-250 at this point and the only other power hog I have is my ep175 although that doesn't use much at all and I probably won't even use it once I have a proper amp on my m80s. It is nice being able to kill the sub when the wife goes to bed though, otherwise I get bitched at about the bass from the m80s full range even at low volumes...

[Chris]

Mar 12, 2015 13:34:55 GMT -5 Gary Cook said:

Other than power amps audio gear doesn't really need a lot of watts and when it comes to power amps in a typical home environment they very rarely if ever run all channels at full power. So quoting maximum power consumption would be pretty much meaningless. Keeping in mind that the capacitors in the power supply handle the transient loudness. My rule of thumb for Class AB power amps is to take their quoted output in watts into 8 ohms and then halve it, so for example an XPA-5 at 200 watts x 5 channels / 2 = 500 watts drawn from the power circuit at the loudest I'm likely to drive it at.

This of course is not technically correct, there's its efficiency, power loss, sagg, etc. But as a rule of thumb it hasn't let me down so far.

Cheers
Gary

Its easy to figure out your draw. Either the kilowatt meter as recommended or simple math.

power = current * voltage

so 500W = I * 120V

or I = 500/120 = 4 Amps

Not that much if you have a 15A or 20A breaker your not likely to exceed it ever.

[Gary Cook]

Mar 31, 2015 12:33:17 GMT -5 Chris said:

Mar 12, 2015 13:34:55 GMT -5 Gary Cook said:

Other than power amps audio gear doesn't really need a lot of watts and when it comes to power amps in a typical home environment they very rarely if ever run all channels at full power. So quoting maximum power consumption would be pretty much meaningless. Keeping in mind that the capacitors in the power supply handle the transient loudness. My rule of thumb for Class AB power amps is to take their quoted output in watts into 8 ohms and then halve it, so for example an XPA-5 at 200 watts x 5 channels / 2 = 500 watts drawn from the power circuit at the loudest I'm likely to drive it at.

This of course is not technically correct, there's its efficiency, power loss, sagg, etc. But as a rule of thumb it hasn't let me down so far.

Its easy to figure out your draw. Either the kilowatt meter as recommended or simple math.
power = current * voltage
so 500W = I * 120V
or I = 500/120 = 4 Amps
Not that much if you have a 15A or 20A breaker your not likely to exceed it ever.

I apologise in advance if this come across as being difficult, it's not my intention.
What watts are being used in the calculation, the output watts or the power draw / input watts?
If it's output watts is it at 8 ohms or 4 ohms?
If the input watts aren't quoted in the specs then what efficiency % is used to calculate the input watts from the output watts?
An example perhaps, at 8 ohms an XPA-5 outputs 200 x 5 = 1000 watts.
But into 4 ohms it outputs 300 x 5 = 1500 watts.
If an XPA-5 has say 60% efficiency then it's 1500 watts output = 2500 watts input.
Using ohms law, 2500 watts / 120 volts = 21 amps.
That's assuming all 5 channels driven to their max.

That's why I have used the rule of thumb, take the output watts into 8 ohms and divide by 2. It has worked for me over the years, when compared to a wattmeter readings on my XPA-5 where I never see more than 3 amps (Australia is 240 volts nominal) even during party time.

Cheers
Gary