ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
This question concerns BL5 but would apply across the speaker range.
Each BL5 has 2 x 1000W and 2 x 250W amplifiers, for a total of 2500W (power ratings called "long term maximum" in service manual). Given a voltage of 240V that's a current requirement of about 10A (P = V x I). House wiring circuits in Australia are typically at 10A per line, so does that mean that I should have a dedicated 10A line (with associated circuit breaker at the fuse box) for each speaker, with nothing else on that circuit, to allow for maximum headroom for the speaker?
Confusingly the service manual also says that the "power consumption typical" is 15W, which would only be a current draw of well under 1A - this seems abnormally low. Perhaps this is the power consumption of the non-amplifier parts of the BL5?
Apart from house wiring considerations, I am wanting to insert surge protection for my speaker (power) wiring, so I need to know the current ratings required to size the surge protection appropriately. Any help to explain this requirement is appreciated
BV6-26, BV7-40, BL7.4, BL3, BL5, BS9000, BC1, ES1, Beo4, BeoPort
I had dedicated 20 amp lines put in to my stereo center, just to be safe. I did this back before I had any B&O, and I do not have the BL5s but now have the 9s.
Two things to consider, 1000 watts, or the total 2500, would be VERY loud, unless you were trying to implode a bowling ball at the listening position those will only be hit very briefly on short peaks, even then the average will be quite loud. Second, the BL5 uses Class D ICE Power amps, which are much more efficient than Class A or AB or B amps. I was doing some commercial sound work, and we were able to replace 2 channel Crown Class B amps with 8 channel Class D amps of the same output using less power from the outlets.
Jeff
I'm afraid I'm recovering from the BeoVirus.
Jeff:1000 watts, or the total 2500, would be VERY loud, unless you were trying to implode a bowling ball at the listening position those will only be hit very briefly on short peaks
True, but shouldn't the house wiring (and associated surge suppressor) be sized to account for the peak current draw? For example, a loud explosion while watching a film?
Beer_Baron:True, but shouldn't the house wiring (and associated surge suppressor) be sized to account for the peak current draw? For example, a loud explosion while watching a film?
The only time you'd be using anything remotely close to the peak power output of the speakers is in a single "impulse" of sound like the beat of a bass drum or the instantaneous bang of an explosion. The amplifier needs to be able to produce the high power outputs without distortion for only a very short burst (say <1/10 second) so the high power-handling figures are relevant. The energy for this short burst is provided by capacitors (like small electrical tanks) inside the speaker.
Peak current draw from the wall plug would happen when you plug in the speakers and the capacitors charge. (This is called "inrush current".) As long as they power up fine you should never have trouble with your house wiring.
-Alex
Edit: I decided to figure out peak electrical draw for the Beolab 5 by looking at B&O's fusing decision. Apparently the 220-240 VAC systems use a 5A fuse and the 100-120 VAC systems use a 10A fuse. This is the value at which the fuse blows, so it would NEVER reach this draw except in a fault condition. Exactly how much "overhead" there is in a fuse depends on the designer and intended use, but it's safe to say that with a 5A fuse you wouldn't expect to ever draw more than 4A in non-fault conditions. So two speakers could be expected to draw as much as 8A during heavy use. With the 10A circuit you mentioned for your home in Australia, you should be just fine with both speakers on the same circuit.
Edit2: Interesting discussion of this exact issue is at: http://archivedarchivedforum2.beoworld.org/forums/t/20750.aspx
Sources: 2x Beosound Moment • 4x Beosound Essence Mk II Speakers: 3x Beolab 8000 • 2x Beolab 6000 • 2x Beolab 3 • 3x Beolab 2 Integrated: 1x Beosound 2 • 1x Beosound Level • 4x BeoPlay M5 • 1x BeoPlay A6 Control: 16x* Essence Remote • 1x Beoremote Halo
* Yes, really! 🤦♂️
Thank you very much!
laseralex:Edit2: Interesting discussion of this exact issue is at: http://archivedarchivedforum2.beoworld.org/forums/t/20750.aspx
Wow, it's been more than 9 years... I didn't remember that thread at all! Since we probably have a lot of new members since then, it's worth noting that Dave Moulton (who sadly doesn't seem to visit us any more) is the guy behind the acousting lens principle and was heavily involved in the development of the BL5 - he should know!
And I had to look up "obstreperous" AGAIN!
--mika