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NAD M33 Streaming Amplifier Review

pogo

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BluOS 3.14.31 is available.
Changes?
 

Ulmer

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BluOS 3.14.31 is available.
Changes?
Release notes are posted now to the Bluesound site:

BluOS 3.14.31. Released October 13, 2021.
  • Support for NAD M10v2 and C700.
  • Multi-language support on front panel of C700, M10, M10v2, M33, M50.2, T758v3i, T777v3i
    and T778.
  • Updates to Send Support Request.
 

pogo

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Does the distortion problem still exist after the BluOS update?
The changelog does not indicate an improvement in this area, but in the past not all changes were listed;)
 

Kaboo

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Does the distortion problem still exist after the BluOS update?
The changelog does not indicate an improvement in this area, but in the past not all changes were listed;)
Yes
 

Odradek

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still waiting for a ship to bring me one of these, very soon hopefully.

Anyway I was wondering, if I connect an external storage via the USB connection ao I can play my own files, can I access this storage via the network or in any way? So that I can update it for example if I add new files to my collection?

Has anyone tried this?
 

Ulmer

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still waiting for a ship to bring me one of these, very soon hopefully.

Anyway I was wondering, if I connect an external storage via the USB connection ao I can play my own files, can I access this storage via the network or in any way? So that I can update it for example if I add new files to my collection?

Has anyone tried this?
You can use BluOS to set up a network file share (on a computer or NAS) that contains your music files as a source. Then you can just keep adding files there and play them with the M33.

The M33 will not share out a file share on it's own. You'd have to update a directly connected USB drive the old fashioned way.
 

djn04

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I read that the new M10 V2 can decode Dolby digital and use wireless speakers for a 4.1 setup. Can the M33 do this? If not is the hardware compatible or would this have to be a V2 feature?
 

pogo

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Regarding surround option, the old M10 should also get a firmware update according to a German hifi magazine. Other Bluesound devices have also been made capable via an update. From a hardware point of view, a firmware upgrade for the M33 should also suffice.
 

Jone5

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I was considering replacing M10 with the M33 but after reading about the inter-sample clipping problem I began to hesitate, so to clarify that this issue is not present in M10 or am I just not hearing it? And yes, my system includes a subwoofer. Otherwise I would be looking elsewhere, but it seems that in this segment (streamer, decent/good amp modules, room correction, bass management) there is nowhere to look at.

So the workaround is to enable tone controls which introduce -6dB headroom, but has anyone found the preamp volume adjustment insufficient with very quiet tracks after this? I had some gain problems with M10 at least with dirac enabled (last 10 dB in the volume is reserved for dirac headroom) that I did not get the playback level I wanted. Related to this the new M10 V2 claims to have improved the gain structure "The M10 V2’s updated gain algorithms allow for higher output levels with inefficient speakers.". Strangely I think I noticed some change in the perceived volume with the M10 using same volume as earlier after some recent firmware update.
 

vanwalsum

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The M33 is better overall, more power, more control. The inter-sample clipping is not bothering me, never hear it. They must fix it in a future update.
 

pogo

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Strangely I think I noticed some change in the perceived volume with the M10 using same volume as earlier after some recent firmware update.
This may well be the case, gain changes after a f/w update have also been observed in the past:
Link

For me, this raises the question of how valid the reviews made in the past still are.
Has the M33 now become even better?
 

vanwalsum

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This may well be the case, gain changes after a f/w update have also been observed in the past:
Link

For me, this raises the question of how valid the reviews made in the past still are.
Has the M33 now become even better?
I don't think my M33 became better, i think Dirac Live do has some imporovements.
 

pogo

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In my opinion, the f/w version used for such complex devices must be stated in a review in the future. Measured values can look different with a different f/w influencing the sound reproduction (gain, distortion, ....).
 

deln78

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First post here.
I read through this thread *after* I bought my M33, and started wondering if I had made a terrible mistake.
However, all is good (no clipping or other issues), and I thought I'd share some impressions (and ask some questions).
I don't use subwoofers, and I only just tried Dirac Live (more on that below).

Price and availability
It looks like these are once again out of stock in some places, and prices have gone up even more! (Now at $5500 vs $5000 before).
There seems to be a lot of factory refurbished units around, and that's what I got. Mine was $4000 two weeks ago, they are now listed for $4400, so matching the same 10% price increase as the new units. I found this thing quite expensive even at the lower refurb price, and I probably would have gone with something else at the even higher price (and would not consider it at full retail).

Physical impressions
This thing is big! Larger than I thought, and quite an imposing presence. I would have preferred something smaller, but hey, it's not like there is tons of empty space inside. The unit is quite heavy, and feels very well built. The screen is very high resolution (I can't see individual pixels even up close), and I can read it from my listening position. Styling is... different. I can't quite decide if I like the looks of it or not, but that's subjective anyway.

Features
No USB input and no Chromecast is a bummer, but I use it almost exclusively for Spotify Connect anyway. I did some comparison with Tidal Connect and can't hear the difference so far... I'll probably upgrade to lossless Spotify when that is released anyway, for peace of mind.
I wish the screen could display more information, like bitrate, source (spotify vs tidal), etc. It only shows the album cover, artist, album and track. There is tons of room left on it for more information.

Dirac Live
This didn't make a dramatic difference. Maybe the bass is a bit less "boomy" and more controlled? I tried the NAD target curve, and the Harman curves (8dB and 10dB; the NAD curve is similar to the Harman 6dB curve, at least in the bass region, which is all my Dirac Live version can handle). I did not notice any difference in the highs and mids. I have to increase volume about 1.5dB when using DL to match the non-DL level. Speaking of volume, someone in this thread was worried about having enough volume headroom when using tone control which subtracts 6dB. I wouldn't worry about that. I usually play at -40 to -50dB; I went up to -20dB for a loud dance party. So there is tons of headroom, in my experience.
Here is my DL result:

Screen Shot 2021-11-05 at 4.16.43 PM.png


The most worrisome thing I discovered is the big dip in the 100-200Hz frequency range.
Is there any way to see the actual corrected curve after applying DL? Should I apply some other fixes before using DL, or is this ok? I assume this is the room, and not the speakers/amp, but who knows?
The speakers are a pair of KEF R7s bought at the same time. Here is the impulse response from DL for good measure (I don't yet know how to read this):
Screen Shot 2021-11-05 at 4.16.53 PM.png



Conclusion
I'm very happy with my setup overall. Happy to answer any questions.
 
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ex audiophile

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An FYI for those thinking of adding this beautiful subwoofer to your setup. I picked up a white KC62 to pair with an NAD M33, but sadly had to return it after seven days. There are a number of issues I experienced:
  • The KC62 won’t wake from sleep using the M33’s sub-out unless I increase the volumes to high levels. This is partially due to the M33’s low voltage output (max 1.1V) and the KC62’s wake threshold being too high (even their own KEF products struggle to wake the sub).
  • We all know about the inter sample clipping issue which rears it’s ugly head when using the subwoofer outputs. The temporary fix is to turn on tone controls and turn the volume up 10db to compensate.
  • There was a hum or ruffling sound from the subwoofer that would come and go. Changing the ground lift switch would sometimes fix the issue, only for it to reappear again randomly.
  • When using the M33’s pre-outs, there was an ENORMOUS pop from the subwoofer when it would come out of sleep. This would be a full excursion movement of the woofer cones. The first time it happened, I’m certain it shortened my life by a few years. I posted a video of it on the KEF owner’s forum on Facebook if you’d like to see the incredible excursion of the little woofers.
The KC62 is a marvel of mechanical engineering, but it feels like a beta product. I’ll definitely be looking at the V2 version of this subwoofer, when all the kinks are worked out.

As an aside, for those that dislike Dirac, I would think there has been some error in measurement or the filter creation process. The most recent version of Dirac has some bugs that result in the filter putting one channel out of phase. You can test this yourself if you’re getting funky outcomes from Dirac; just flip the wiring on one speaker and load Cheskey’s phase test single. You’ll know right away if you’re affected by the bug. While Dirac has confirmed this bug exists in 3.1.1, I’ve actually experienced this bug in previous versions as well, so it may be some interaction issue with the M33, or between Dirac and MacOS.

When Dirac is working correctly, it’s glorious, especially with the NAD curve which boosts the low end by 7-8db and gentles curves down at the high frequencies. I can never go back to listening to music without Dirac.
I had the same problem with my subs (JLA f112v2s). They would not wake up unless med/high volume selected. Ended up returning the M33, had to pay shipping and 15% restocking fee although this is clearly a defect in the design of the M33. So sub users caveat emptor.
I just purchased a Perlisten D15 sub and noticed in the app that the input sensitivity could be adjusted. Hallelujah!
 

jaymusic

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New BIOS upgrade today.. checking on the changes.

It's not listed in the BIOS changes log, but I can tell that something has been done to the Tone Controls. When engaged the sound no longer seems less sharp and no longer seems to lower the volume.
Maybe they have done something to fix the clipping issue that was apparent on some tracks too - will have to test later.
 
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Ulmer

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New BIOS upgrade today.. checking on the changes.

It's not listed in the BIOS changes log, but I can tell that something has been done to the Tone Controls. When engaged the sound no longer seems less sharp and no longer seems to lower the volume.
Maybe they have done something to fix the clipping issue that was apparent on some tracks too - will have to test later.

BluOS 3.16.1. Released November 23, 2021.
  • Support for Dolby Atmos on the SOUNDBAR+.
  • New audio settings and profiles for the SOUNDBAR+.
  • The addition of Tunify, a commercial music streaming service.
  • Roon improvements including a new icon.
 

jaymusic

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Checked the Lana Del Ray song 'For Free' with that line ending in 'walking green'.
The distortion is gone with the latest update as far as I can tell on limited testing.
This was streaming via Apple Music Airplay - no EQ applied. Tone Controls on but both Treble and Bass set to 0.
As mentioned before they have done something to Tone controls so it does not mess up the sound as it did before so it's all good leaving it enabled.
 
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fcracer

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I had the same problem with my subs (JLA f112v2s). They would not wake up unless med/high volume selected. Ended up returning the M33, had to pay shipping and 15% restocking fee although this is clearly a defect in the design of the M33. So sub users caveat emptor.
I just purchased a Perlisten D15 sub and noticed in the app that the input sensitivity could be adjusted. Hallelujah!
I wouldn’t say it’s a defect in the design. One of the biggest benefits of the M33 is that we don’t have to go through the hassle of matching components given each manufacturer has their own view of input and output voltages. This subwoofer issue just reminds that we need to pay attention to specs when buying equipment.

I hold myself accountable for not reading the output voltage spec and buying a subwoofer that requires nearly double the voltage the M33 produces just to wake up. As you noted, there are subwoofers available where the input voltage sensitivity and wake thresholds can be adjusted. I do however think that this is an area for improvement in NAD M33 mk2.
 
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