Sonos amp power

Not overly surprising, unfortunately. I’d expect that Sonos, like many other companies, is affected both by issues surrounding the pandemic, as well as the worldwide chip shortage. It probably means it would be difficult to find in retail stores, unless they’d ordered a big allotment before this situation occurred. 

tk1980,

With respect to your salesman: The earlier SONOS CONNECT:AMP was rated at 60W. Perhaps your salesman was confused.

I just looked at the POWERNODE specs and there is no mention of “RMS” in their power spec. In fact they gave two power specs. One is 80W and the other is 130W into 8-Ohms. Why would the same amplifier have two different power specs?

I suggest that you do some research on the “FTC Amplifier Power” rating and its history. Be mindful of your sources because there is a lot of misinformation out there.

These specs are typical of NAD, the source tech of Bluesound as far as basic audio equipment is concerned. The first is rms and the second is dynamic power which is a NAD invention.

If anyone wants to read more about this NAD invention see as one example:

https://www.diyaudio.com/forums/solid-state/255740-nad-power-ratings.html

Any apples to apples comparison with Sonos amp should be based on the 80W number - that is the rms one.

The Bluesound POWERNODE is 80W RMS at 8 Ohms continuous, the 130W figure is what the amp can supply for brief periods using the IHF rating… used more on mainland Europe, but as Kumar says mainly by NAD.

Edit.. these digital amps make ratings difficult.
 

Edit 2… the amount of current an amp produces is probably more useful for driving complex speaker.

The theory is that music is a series of peaks, with a fairly low average power level. Therefore the peak power handling of an amplifier is more important than the average power capability. In the 1970’s this was greatly abused and some manufacturers would shoot a very brief pulse through an amplifier and measure the power. This resulted in very cheap, inferior amplifiers touting very high power ratings compared to more expensive and competent amplifiers. In 1974 the FTC established a spec to specify how amplifiers would be tested for the purpose of publishing it’s specs.

There have been some modifications along the way and heated discussions disagreeing with some of the details, particularly the pre-conditioning requirement. The IHF method tilts more toward peak power.

Many people feel that all reasonable quality amplifiers sound the same, others disagree. As I mentioned earlier, setting up a valid test situation is very hard, because external conditions easily effect the human’s opinion. Very difficult to measure level differences will have a large effect. Humans tend to prefer the louder result. It’s relatively easy to measure (with the correct equipment) amplifier output at a single frequency, but if the output varies by frequency for some reason (such as tone controls) the output  level number does not track very well with the human’s opinion when listening to music. And, if the human has recently been subjected to loud noises, such as an encounter with an automobile or mass transit, their opinion may be different after some quiet time.

Amplifier and speaker ‘listening quality’ comparisons typically degenerate into a my dog is better than your dog sort of shouting match.

Not just these - throw in my Hi Res v your CD quality v his lossy AAC for such matches as well. But if one can’t do that what else is a equipment fan to do?!

Why? How would two amps, both accurately measured to be 50 wpc rms into 8 and 100 wpc rms into 4 ohms, produce different amounts of current?

PS: Having owned and tested NAD amps - one of 50 wpc rms does usually sound more powerful than many others of the same spec, and NAD claims it is because they do higher dynamic power output. I think instead that this impression is due to a different volume control architecture. A NAD amp will go louder earlier in the turning of the volume control knob, giving the appearance of being more powerful. 

kumar,

The magnitude of speaker impedance varies with frequency. We talk about the “nominal impedance” of a speaker, but the speaker load probably matches that number at one frequency only and could be lower at some frequencies. At the low points more current will be drawn. A loud transient at that low point could trigger the amplifier’s protection circuit and create an annoying audio or shut down event.

Even though it is widely believed that all respected amplifiers sound the same, amplifiers that support doubling of the power at 4-Ohms compared to the 8-Ohm spec tend to receive more praise when connected to certain speakers that have a low point. SONOS amplifiers have always scored well in this environment. AMP is particularly tolerant of speakers with an impedance dip.

With an ‘rms’ spec it is implied that the amplifier could operate indefinitely at that level, but the amplifier may be able to supply more power for brief intervals without creating some some sort of thermal overload or overcurrent failure event.

Which is why my question was for two amps being compared, both of which do this doubling of watts as impedance is halved. When both do double the watts, how can one be delivering more current than the other?

Also, the claim that all respected amps sound the same is correctly made for such that have the same measured spec - including such doubling. A 20 wpc rms amp that does not do this doubling is probably going to clip and not sound the same as a 100 wpc amp that doubles, when driving a speaker that drops impedance down to 2 ohms at times. Even when sound levels are the same.