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Review and Measurements of SONOS Amp

MSNWatch

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I actually like the Sonos interface having used the system from the start. Currently have a pretty extensive system (mostly older stuff) but am very disappointed to see how mediocre this new amp measured. As we've seen in countless reviews here - it's not costly to get state of the art measurements. Even harder to understand or forgive given that Sonos has more resources than most and they come up with maybe 1 new product every 2-3 years or so.
 

JohnKay

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I actually like the Sonos interface having used the system from the start. Currently have a pretty extensive system (mostly older stuff) but am very disappointed to see how mediocre this new amp measured. As we've seen in countless reviews here - it's not costly to get state of the art measurements. Even harder to understand or forgive given that Sonos has more resources than most and they come up with maybe 1 new product every 2-3 years or so.

Agreed. I was a sonos customer from 2007 all the way to the present although I am in the process of migrating to other solutions. The sonos sound flavour changed over time ... or maybe my brain / ears changed over time... or both :). Anyhoo... the sonos amp is indeed a bit perplexing but it seems to me that the bad performance is mostly associated with the line in. If the amp were to be used exclusively for streaming then could we conclude it is fine?

Not that I justify the bad line in performance...
 

pjug

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For me the streaming performance is good enough. But still, I would like to see Sonos explain how they arrive at the 116dB SNR specification.
 

jsrtheta

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I hate those power cords, but they are fairly standard and were common 20 years ago, where they started to feel "cheap" compared to the 3 pins standard the world gets now. I still end up in situations where I need such a power cord and it is always a "where did I put those darned things?" moment. The only advantage they had (imho) was that they made clear they weren't actually grounded. It seems to be more of a cheap detail to make the device feel more refined and sophisticated...

And I have worse... (although I guess this must be someone's normal plug ;))

View attachment 22987

Pioneer and other manufacturers have used such removable, unpolarized power cords. I have seen at least two different types, leading me to think someone, sometime tried to get proprietary with their design. Frankly, I would have preferred a simple captive power cord to these options.

BTW, thrift shops are a great place to find these cords. Never hurts to have a couple on hand. I think I have three somewhere.
 

MSNWatch

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Over at the Sonos forum they say the numbers would be better if the line in level was increased from default setting on the Sonos app.
 
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amirm

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Over at the Sonos forum they say the numbers would be better if the line in level was increased from default setting on the Sonos app.
I raised it one notch for power vs THD graph.
 

JohnKay

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I had a look at the discussion over at the Sonos forum and it does not seem very constructive at all. Quite a bad vibe there.

A sidenote regarding the power cord socket: It looks to be identical to the one used by the Sonos Playbase / Play 5 gen II. I don't have the sonos amp of course so this needs to be confirmed. It looks that way though... if so then the socket does indeed accept standard power cables BUT... not all. The slight recess of the power inlet means that some standard power cables are a bit bulky and will not fit. I have had this exact situation with a Play 5 Gen II. I wanted to use a shorter power cable and had two old ones. One of them had a slightly bulky connector and did not fit. The other was fine.
 
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pjug

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I am wondering if you can check the switching frequency on an oscilloscope. I thought that the DDFA technology used a very high frequency so I would be very surprised if it is 98kHz. So maybe the 98 kHz peak has some other cause or else the analyzer measurement is disturbed by too much high frequency energy without the AES filter.
 

MZKM

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Speaking of volume control in the app, at least on Android, it has very coarse steps to control line in volume. I don't know how this is usable in practice. A single step would go from 6 to 12 watts of output or some such thing. The front panel controls seem to do the same thing (?).

I mean, is a 3dB difference that bad?
https://www.audiocheck.net/blindtests_level.php?lvl=3
 

D700

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I raised it one notch for power vs THD graph.
Amirm if you were to evaluate amplifier products solely on their performance with digital inputs, how would your ratings change? How would your opinion of this Sonos Amp change if there were no line ins...

I haven’t used a line in on anything since CDs arrived. I view them as nothing more than courtesy inputs ... but they seem to be the heart of most of your amplifier testing.
 

pjug

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Amirm if you were to evaluate amplifier products solely on their performance with digital inputs, how would your ratings change? How would your opinion of this Sonos Amp change if there were no line ins...

I haven’t used a line in on anything since CDs arrived. I view them as nothing more than courtesy inputs ... but they seem to be the heart of most of your amplifier testing.
I agree with you that the streaming performance is most important. On the other hand Sonos shows a turntable in a lot of the promotional photos so they are inviting this attention to the analog input.
 

D700

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I agree with you that the streaming performance is most important. On the other hand Sonos shows a turntable in a lot of the promotional photos so they are inviting this attention to the analog input.
Well, we could have an entirely different discussion about the number of people we think would buy a Sonos streaming amp to play vinyl...and of that small subset, what their expectations of quality might be of said vinyl...but that’s all off topic marketing. I’d bet the number of units sold that get connected to turntables is <1%.
 
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amirm

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I am wondering if you can check the switching frequency on an oscilloscope. I thought that the DDFA technology used a very high frequency so I would be very surprised if it is 98kHz. So maybe the 98 kHz peak has some other cause or else the analyzer measurement is disturbed by too much high frequency energy without the AES filter.
I tested it with the filter initially and it just attenuates it. I also went to 1 Mhz but didn't see any other frequencies of note.

Has anyone documented the sampling rate of the amp anywhere?
 
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amirm

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Amirm if you were to evaluate amplifier products solely on their performance with digital inputs, how would your ratings change? How would your opinion of this Sonos Amp change if there were no line ins...
It certainly is better with digital input. Unfortunately I cannot test its digital input beyond dashboard so hard to say for sure what the performance is.

While I am bothered by the low switching frequency, same issue with Lyngdorf didn't present problems in subjective listening. So I would say sure, for digital playback it is fine and the power amplifier would be an asset there.
 

pjug

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Has anyone documented the sampling rate of the amp anywhere?
I can't find anything specifically on the Sonos Amp (uses Qualcomm DDFA). Here are a couple documents on DDFA that give some mention, but I have no idea if this applies to the exact Sonos design.

http://www.goodwinshighend.com/manufacturers/nad/M2-white-paper-EU-Web.pdf
https://www.qualcomm.com/media/documents/files/csra6620-ddfa-controller-product-brief.pdf

from the CSRA6620 sheet:

1551813639633.png
 

D700

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It certainly is better with digital input. Unfortunately I cannot test its digital input beyond dashboard so hard to say for sure what the performance is.

While I am bothered by the low switching frequency, same issue with Lyngdorf didn't present problems in subjective listening. So I would say sure, for digital playback it is fine and the power amplifier would be an asset there.

Amirm, What equipment would you need to evaluate an amp via digital input? Do we need to hold a fundraiser?

I didn't see it mentioned, do you know if this Sonos Amp properly handles 24/32 bit files or is it still bound to 16 bit?
 

pjug

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I raised it one notch for power vs THD graph.

Why doesn't the power vs thd+n curve pass through approx -87dB at 5W? Are you sure that the posted graph is not for input level = 2, since curve passes through about -68bB at 5W, which agrees with the input level=2 measurement of SNR at 5W?
 
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amirm

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Why doesn't the power vs thd+n curve pass through approx -87dB at 5W? Are you sure that the posted graph is not for input level = 2, since curve passes through about -68bB at 5W, which agrees with the input level=2 measurement of SNR at 5W?
I am pretty sure input level is 3 as indicated on the graph:

index.php


Why should it jump to 87 dB at 5 watt?
 
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