[roscoeiii]

I'm not clear on where folks are getting the amount of power consumption these XLS amps are drawing. Salis, where did you get that 300w figure for the XLS. And which model is that?

One reason I ask is that I had been planning to keep them plugged into my Equitech 2Q balanced power conditioner. But are the bridged monos going to be too demanding in their power requirements for the 2Q? The load capacity (from its big ole toroid) is 2 kVA. Any other specs on the 2Q or XLS I need to be looking into?

Not that I think I will get close to using the XLS 2000 at full power...

[*Scotty*]

http://www.crownaudio.com/media/wysiwyg//XLS/XLSDrivecore_powerdraw_thermal_keh.pdf
Scotty

[Folsom]

The PFC section in the XLS has reservoir capacitors that allow it to run higher peak wattage.

The wattage that ranges in 200w area is on the back of the amp itself, printed next to IEC socket.

Maybe I'm wrong but I'd call the heatsink insufficient for continuous 200+ watt burning.

This isn't that important unless you like to run bass sine waves through your system, or the XLS would be on the cusp of enough power. I'd practice wanting some headroom with it.

[roscoeiii]

http://www.crownaudio.com/media/wysiwyg//XLS/XLSDrivecore_powerdraw_thermal_keh.pdf
Scotty

OK, but I am not sure how to interpret that document. Wattage given is just the power dissipated as heat, and the only other info that isn't related to power dissipated as heat is given in amps.

So I'm looking at 9.13 amps at 1/3 peak power with pink noise into 4 ohms. When run as a stereo amp. How is that info useful to me? Or how can it be made useful.

Unfortunately, bridged mono data isn't given.

[roscoeiii]

The PFC section in the XLS has reservoir capacitors that allow it to run higher peak wattage.

The wattage that ranges in 200w area is on the back of the amp itself, printed next to IEC socket.

Maybe I'm wrong but I'd call the heatsink insufficient for continuous 200+ watt burning.

This isn't that important unless you like to run bass sine waves through your system, or the XLS would be on the cusp of enough power. I'd practice wanting some headroom with it.

But bass sine waves are all that I want to listen to!!! 

[a.wayne]

All about that Bass, that bass, no treble ...... 


https://www.youtube.com/watch?v=lc9MzCcmNCU

[a.wayne]

OK, but I am not sure how to interpret that document. Wattage given is just the power dissipated as heat, and the only other info that isn't related to power dissipated as heat is given in amps.

So I'm looking at 9.13 amps at 1/3 peak power with pink noise into 4 ohms. When run as a stereo amp. How is that info useful to me? Or how can it be made useful.

Unfortunately, bridged mono data isn't given.

What i'm seeing here http://www.parts-express.com/crown-xti-1002-xti-2-series-power-amplifier--245-405

look at rear pic , Wall draw is 1K plus ..........................   

[JohanH]

So I'm looking at 9.13 amps at 1/3 peak power with pink noise into 4 ohms. When run as a stereo amp. How is that info useful to me?

I don't know
Maybe multiply with voltage and calculate amount of watts it consumes?

[*Scotty*]

Subtract the power wasted as heat from the amperage draw for specific load times the AC line voltage. From ohms law, Amps x volts = Total watts.
In the case I mentioned the wall voltage was 120volts, the amperage draw at 2ohms was 14.2 amps. Therefore 120v.X 14.2 = 1704 watts. Then the power dissipated as heat, 227 watts is subtracted from the total power 1704 watts, which yields the net power delivered to the load. The pink noise test signal represents a continuous power output condition rather than instantaneous peak power delivered. This would be an RMS power delivery situation under severe clipping into the load. The clipping could be equal to THD of 10%, which is ridiculous but seems to be a commonly used specification, even if worthless.
 I suspect that if clipping was specified as equal to 1% the continuous power output would be considerably lower. The 1/8 Power Pink Noise test may reflect something like a 1% clipping condition but who knows. The amperage draw from the wall in this situation into 2ohms is less than half that of the severe clipping condition. These may not exactly be the power houses that they are billed to be.
Scotty

[DaveC113]

I'm pretty sure the power ratings are given at .5% THD according to Crown's specs... and I believe I saw that Harmon guarantees the power output to meet spec, it's just a question of exactly how the testing is conducted.

[rodge827]

it's just a question of exactly how the testing is conducted.

Do you mean there is ambiguity in audio measurements? 

Never! 

[Russell Dawkins]

OK, but I am not sure how to interpret that document. Wattage given is just the power dissipated as heat, and the only other info that isn't related to power dissipated as heat is given in amps.
So I'm looking at 9.13 amps at 1/3 peak power with pink noise into 4 ohms. When run as a stereo amp. How is that info useful to me? Or how can it be made useful.
Unfortunately, bridged mono data isn't given.

It's about current draw and heat dissipation - needed to determine circuit breaker and ventilation requirements. The 1/3 power rating is to show conditions at maximum possible draw - not a condition you would ever operate intentionally under ("heavy clipping") but it is possible to draw that much. The absolute maximum draw in normal operation would be the rating just above that: 1/8th power ("just at clip"). Since we're talking average program material, with 1/8th power we would be hitting clip on peaks, typically, so we're peaking at 650 w, averaging 81 watts (that's a screaming average power!) and at the same time drawing 4.32 peak amps from the wall. That's 518 watts draw, peak. Under typical listening conditions in the home, you wouldn't be drawing as much as 5 average watts, even playing loud, into the typical speaker. The useful figure is the 0.7 amps it draws when awake but at idle. That's 84 watts with 31 watts dissipated as heat. That's what you will be drawing at any sane listening level (up to 13 watts, RMS or average).

What i'm seeing here http://www.parts-express.com/crown-xti-1002-xti-2-series-power-amplifier--245-405
look at rear pic , Wall draw is 1K plus ..........................   

Again, that's in heavy clipping - you would never intentionally go or stay there. It's to know the maximum possible draw from the wall, so you won't blow a critical (like the one feeding the lights at the bar) circuit breaker if you do something stupid, like short the outputs with a 4 gauge jumper cable.

[roscoeiii]

Many thanks for all the clarification folks!

[Russell Dawkins]

"....These may not exactly be the power houses that they are billed to be.
Scotty

Yet, according to reviews by working sound pros, they are.
How about this review comment from a PA "engineer,designer, fabricator and installer":
"This amp is now powering a Triple 18 sub on one side and 4 satellites on the other at 2 ohms and can ROCK a small club to pieces! The clarity is stunning and the power is endless."
I've seen many similar comments in the pro audio forums
Sounds pretty power house-like to me, especially considering domestic acoustic power needs!

[jimdgoulding]

For those of you who don't know, Russell Dawkins is a recording engineer par excellence.  That's coming from a listener par excellence.  This is a fine example of a live concert- music from 4 players/composers- with terrific playing with intimacy and transparency to the stage and hall:



Think you should see for yourself and the music is plenty special.  PM the man.

[roscoeiii]

Yet, according to reviews by working sound pros, they are.
How about this review comment from a PA "engineer,designer, fabricator and installer":
"This amp is now powering a Triple 18 sub on one side and 4 satellites on the other at 2 ohms and can ROCK a small club to pieces! The clarity is stunning and the power is endless."
I've seen many similar comments in the pro audio forums
Sounds pretty power house-like to me, especially considering domestic acoustic power needs!

Yes, these are designed for power needs well beyond home audio system demands.

And in light of the draw they'd have in a home system and their prodigious power output capabilities, does it make sense from a gear protection POV to activate the protection circuitry. IIRC they are said to sound best without it turned on. But I'd also like to make sure my drivers have a long, long life...

[Russell Dawkins]

I would think that, again, in terms of typical - even loud - domestic use, it wouldn't make any difference in terms of speaker protection. All the limiter is doing is preventing the amp from going into heavy clipping and sending those nasties down the line. I think heavy clipping on this amp would occur at a power point well beyond that at which the typical 2" voice coil on a typical 8-10"woofer had become incandescent. In other words, even with the limiter engaged you would fry your speakers before the amp broke a sweat.
I remember Bob Smith (of SPTech/Aether) saying that his speakers' woofer was so clean the voice coil would fry before you heard any signs of distress. Many speakers will signal their distress before damage is done, but these days, with ultra long excursion woofers being quite common and their design preventing voice coil bottoming as an early warning sound, many speakers will fry before they cry.

So...caution is called for. Don't plug/unplug interconnects nor drop the needle in the groove at max gain!

Thanks for the mention, Jim.

[roscoeiii]

Many thanks Russell!

[*Scotty*]

If you need to protect your loudspeakers from excess power, an appropriately sized inline fuse would be easy to implement.
Scotty

[roscoeiii]

Oh man, just put on some James Blake to give the set-up a solid bass test.  Now that is some impact and bass