Not the salesman.  Audio salesmen are driven by three things - Commission, margin, and rate of return - In that order.Honesty is about 40th on the list. 

The Sonos Amp is more powerful, it is indeed 125 watts .

https://www.sonos.com/en-us/newsroom/sonos-unveils-all-new-sonos-amp

Never trust a sales person. More often than not, they’re going to try to sell you the product that has the greatest profit margin for the store, or the one that gets them the greatest profit share from the sale.

Do your own research, which you’re doing. :)

The problem is that sometimes it isn’t as simple as “this one has X, the other has Y, so X is greater than Y, it must be better”. 

Fortunately, if you purchase directly from Sonos, you get a limited time return policy. So you would have the opportunity to test the Amp in your own home. 

There’s also advantages such as what kind of equipment you have in your home. Sonos (and Bluesound, from what I am aware) are both part of integrated systems, so you may be better off in the long run fitting one or the other in your home, due to the fact that you already have invested in either one.

But on the surface, I’d suggest The Sonos Amp’s 125 watts, rms, is more than Bluesound’s 80W rms. But you’re asking this question on a Sonos forum, where opinions may be skewed. You may want to find a non-partisan place to get a more balanced opinion. 

For what it’s worth, when I look at Sonos’ sales page, under Features and Specs, the first item says: Class-D digital amplifier. 125W/Ch at 8 ohms. Not sure how much clearer you need that. 

Edit: I type too slowly :)

Reputable brands such as Sonos - or even Bluesound - will never lie when it comes to published spec as the quoted - lies here are easy to nail down. Of course one needs to know how to read a spec because the ohms numbers and the distortion numbers in the spec are also needed to get an apples to apples comparison of two sets of amp specs, but in this particular case, the Sonos amp is indeed more powerful. That said, doubling of power yields about 20% higher sound levels, so keep that in mind as well.

But where sound quality claims are concerned, believe no maker’s flowery language. Test for yourself, preferably at home, and trust your ears. This is needed not so much for amps, but for speakers or kit that includes speakers.

Thank you for your time answering but Sonos only mentions that Amp is 125Watt/ch but no info if it´s rms or peak power. 

I agree; that IS a miss in the official spec which just says 125W into 8 ohms, but I am sure based on many reviews that it is 125 WPC rms. If it was peak power, the equivalent would be anything between 1000 to 2000 watts depending on what calculator is being used and the mood of the user and Sonos would not have quoted such a puny number as 125.

And @Corry P should confirm here - as Sonos employee - that the 125 per channel into 8 ohms is indeed rms. As is the 250 into 4 ohms.

Confirmed. 125 W per channel RMS at 8 Ohm.

Introducing Sonos Amp | Sonos Community

Physical Specs Amp comes in Matte black with black and silver banana plugs all in a standard rack fit size. The dimensions are 8.54 x 8.54 x 2.52 in. (217 mm (w) x 217 mm (d) x 64 mm (h)) and it weighs 4.6 lbs. (2.1 kg). Custom banana plugs that accept 10 - 18 AWG speaker wire and the Class-D digital amplifier sends a maximum of 125W per channel at 8 Ohms.
 

It says max not RMS.

I´m no expert but I don´t think it´s the same

Of course it isn't peak as the audio industry understands peak power. All that link means is the rms power delivered of 125 W is with the volume slider to the maximum.

The amp delivers 125 wpc rms into 8 ohms as Sonos has now confirmed just for you in this thread.

Or, trust a dB meter. Get both amps, and run both with the same music at max volume into your speakers, assuming they can handle that power without burning out. Then, let the dB meter tell you which amp delivers more dB.

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.

NAD amplifiers have a reputation for “soft clipping”, but they annoy me.

If an amplifier is overdriven it usually misbehaves either by obvious shutdown or gross distortion. If you watch the output using an oscilloscope it is obvious that the tops and bottoms of the waveform have reached a limit and are simply straight horizontal lines. This is known as “clipping”. Amplifiers such as NAD speak about “soft clipping”. This implies that some compression starts at about 70% of maximum power, avoiding hard clipping. If you watch this on an analyzer you can clearly observe an increase in distortion and reduction of dynamics as the compression kicks in. There are obvious tradeoff’s with this technique. While gross distortion is avoided when the the amplifier is operating near (and potentially above) the limit, there is usually excess distortion, resulting in a fatiguing sound for some listeners. If the amplifier would emit some sort of gross sound or shut down, it can communicate its situation with the user. An amplifier can also flash a warning light.

If the user habitually overdrives the unit, soft clipping can result in a more pleasant sound, but a more powerful amplifier or a user who can learn to back off a bit, will have superior results.

But this is more than doubling the 8-Ohm draw. What if the amplifier protection circuit shuts down hard at the 4-Ohm current? Even though rated at 4-Ohms, some amplifiers will tolerate short 2-Ohm excursions. AMP is in this class, CONNECT:AMP is not.

Hmm...news to me. I thought that the Amp will do better with a speaker that drops to 2 ohms because it has more grunt that the Connect Amp, not also because the Connect Amp will cut out.

In general: where does this characteristic show up in a typical amp spec? 

This sort of detail does not usually show up in a spec. You can infer a little by looking at the 4-Ohm/8-Ohm power ratio. In the case of CONNECT:AMP the protection circuit is very literal and quick responding.

There are two limits for a power amplifier, current and heat. If the current limit is exceeded, even briefly, the amplifier will fail catastrophically. If the amplifier has some excess current capacity, a brief higher current excursion will not cause dangerous overheating. The published ratings give the running forever limits.

Let’s look at this from a different angle. Say the output stage can safely deal with 10A, but the cooling, for various heatsink size, fan or no fan, etc, considerations, can only support 8A continuously. This amplifier will be rated for the 8A case, but an occasional 10A excursion is not a major issue.

Transistors are rated for a certain number of temperature cycles. A cycle begins at ambient, rises to the operating temperature, then returns to ambient. The deeper the cycle, the fewer the unit will tolerate. This is why leaving a unit running perpetually is not a big deal because this is a single cycle.

In the 10A/8A case above the occasional 10A excursions will simply widen that cycle a bit, but this is not a major issue for a relatively low number of cycles. A single 11A attempt will be the end of the line for that transistor.

Making it even more fun, while the power supply temp is directly related to the power being provided the output stages of an amplifier can actually run hotter at lower levels than at full power.

That is a big part of the industry grief over the RMS power specs as the 1/3 power pre-conditioning stage caused amps that had no problem reproducing much louder music to have cooling issues. I believe that was mostly a class B amp issue.

Something else to consider is the actual volume differences you get at the various power levels, often what looks like a big difference in Watts is pretty minor in dB. There are a lot of on-line calculators and charts to use in making your comparisons.