NAD M66 - finally someone makes a decent 2-channel preamp!

[Nocko!]

Thanks for your detailed opinion on the M66. What do you mean by features that simply don't exist? I'm currently using the very similar M33 and I haven't found many features that I'd like but are missing.


I gather that the M66 has a rather less comprehensive remote than the one supplied with M33, M12, M32, M50.2 and maybe others. I use my remote often, though there are a few things such as changing source that need to be done from the front panel or the BluOS app.

I'm surprised you have issues with the app developed by Bluesound. It is very comprehensive and far better than any other "company" app that I've encountered and does 95% of what Roon can do, but without the need for extra hardware and subscription. It's available for multiple platforms including Kindle and Alexa, although I think they are not maintaining the last 2. Few other apps are good for all 4 common platforms and it is updated regularly - in fact often to my dismay as it's becomes rather cumbersome and bloated compared with the earliest versions where a single page (on Windows) covered all you ever needed! In fact it is so widely admired as a control app that several other companies have adopted it in place of their own apps or telling their owners to go for Roon - see https://bluos.io/partners/ It certainly won't be ditched in the foreseeable future.


Since the streamer element in its basic form is no more than a small board, I would never consider buying just a streamer that needs its own case, power supply, sockets, cables, etc if that small board could easily be installed into a DAC, preamp, or all-in-one. If it was to irreparably fail, or you wanted for some reason to use a stand-alone streamer in future, simply get one and plug it into a spare M66 socket.

I read your commentary with interest as I'm likely to go the M66 route, but I'm still not sure I've grasped exactly which features you think are missing or which don't do the job expected of them. I'd really like to know - or perhaps I could help you find these as I'm sure my experience with the M33 may help in solving your problems. Thanks

I owned the M66 from June to October 2024 and returned it to my dealer after some frustrating discussions with NAD about missing features.
By "missing features," I don’t mean things I simply wished for, but functions that were (and maybe still are?) explicitly described on NAD’s website and in the manual. The M66 was advertised as supporting control via TCP/IP and RS232, and NAD even referenced an API for this on the M66 product page. But none of it worked. After some back and forth with NAD support, they admitted that these options were not implemented.
I had used an M17V2 for years, controlling it via IP/TCP without issues. The M66 also has an RS232 port, but it simply doesn’t function. More details can be found here:
https://www.audiosciencereview.com/...-a-decent-2-channel-preamp.44630/post-2015142

Eventually, I gave up on the M66 (and NAD in general), sent it back, and bought something else. Now, I’m happy.

I don’t know the M33, but I suspect (just an assumption, not firsthand knowledge) that it is a much better construction than the M66. The M33 seems like a great amp with an added streaming option. In contrast, the M66 feels like a BluOS node with an attached preamp. It might measure well, but as a preamp—the core of a stereo setup—it’s not really usable.
The remote is the same cheap plastic one used for the BluOS nodes but wrapped in aluminium. In some situations, you can’t even turn the device on with it. You can switch sources via the IR remote, but only after setting up presets (see Pogo’s post).

When I tried the BluOS app, I simply didn’t like it. There was no proper way to sort albums, no option to display lyrics—features that matter to someone who truly cares about their music library. Take a look at the Lyrion Music Server and the Material Skin plugin screenshots to see what a good music server should offer. You can use an app, but you can also control everything from any browser (even your TV’s), making you independent of NAD/BluOS’s ideas. Just look at the Sonos disaster—we should have learned from that.

In general, it’s absurd to rely on an app to control a €6,000 device. But that’s not even my main issue. The real question is: How do you control your Blu-ray player, TV, or CD player with the BluOS app? Do you really want to juggle multiple apps, switching back and forth just to adjust volume or change a channel? This brings us back to the core problem: Without a reliable TCP/IP control (which NAD already had in nearly all its amps), a preamp makes no sense to me. But I get the impression that home automation isn’t a priority for many in this forum—something I’ll never understand. In my setup, I don’t use an infrared remote at all.

By the way: As far as I can tell, nearly half of BluOS’s "partners" are part of the Lenbrook Group. So, to simplify things—most of these partners are NAD. And while I don’t use Roon, from what I’ve seen, it is vastly superior to BluOS. Maybe someone else can confirm this.

I understand your point about using a separate streaming device. A streamer doesn’t need to be "high-end"—even a Raspberry Pi can handle the job. But with the M66, you’re buying a streamer that doesn’t meet my needs and, in my opinion, is far from "state of the art." There’s a huge touchscreen on the M66, yet you can’t search your music with it?
To wrap this up (before Amir kicks me out of here...):

• Sound-wise, the M66 is great if you use DLBC. DLBC is the only real reason to buy it.
• As a preamp, it’s flawed. NAD misleads customers about its features, and essential functions (home cinema bypass, display on/off control, power management, triggers, etc.) were missing or not working when I owned it.
• The BluOS server wasn’t the reason I returned the M66. I never planned to use it but was still disappointed by its poor integration and capabilities.

Maybe my expectations were just too high?
Nocko!

 

[Nocko!]

DSP is a fudge and it can usually be avoided.

I thought this, too.
Many years ago.
But I was totally wrong.
Even back then...
Nocko!

 

[Hear Here]

Nocko - I give up on this. Your rubbish Sonos and BluOS apps, but I'd suggest these are about the most comprehensive apps of all and in fact, I put off upgrading from a basic Sonos streamer until I found a streamer that offered as good a control app as the Sonos one. Eventually I discovered BluOS.

Why don't you organise your music collection in the way you probably organise your photos? I use basic Windows Cut & Paste to move my 1500 ripped CDs into main folders - Classical, World & Weird, Non-Classical, etc and each main section into Composer folders or Artist folder, etc. Dead easy to find any music I want to listen to and no need to fiddle around with metadata.

Why you want to use obscure methods to control a device that offers its own remote, touchscreen and multi-platform apps is somewhat bewildering. I've never heard of some things you mention - none is necessary to do what the M66 is designed for - to play music from any of the connected sources and provide access to streaming services, your Library, etc. BluOS allows easy access to music (for me usually by Folder or by Search), TuneIn radio, Paradise, TV, etc, including volume control and everything most users are more than happy with.

There is no misleading by NAD, although one feature does seriously disappoint me. If Subs are connected and Sub Outs are activated, the Main outputs are nobbled to the same XO as your subs - no good if you have full-range main speakers - and inexcusably, the Sub Outs are all mono, even if you say there are 2 of them (M33) or presumably 4 of them (M66). Earlier Master Series (including M32 and M12) allowed the Main out to retain the full frequency range while the subs were XO'd at between 40 and 200 Hz, or (for those with stand-mounts, etc) the Main outs could be given the same XO (or a different one if overlap is preferred) as the Subs. Now these short-fallings are making me look at alternatives, though all are very much more costly and lacking in useful features offered by NAD.

 

[Nocko!]

Nocko - I give up on this. Your rubbish Sonos and BluOS apps, but I'd suggest these are about the most comprehensive apps of all and in fact, I put off upgrading from a basic Sonos streamer until I found a streamer that offered as good a control app as the Sonos one. Eventually I discovered BluOS.

Why don't you organise your music collection in the way you probably organise your photos? I use basic Windows Cut & Paste to move my 1500 ripped CDs into main folders - Classical, World & Weird, Non-Classical, etc and each main section into Composer folders or Artist folder, etc. Dead easy to find any music I want to listen to and no need to fiddle around with metadata.

Why you want to use obscure methods to control a device that offers its own remote, touchscreen and multi-platform apps is somewhat bewildering. I've never heard of some things you mention - none is necessary to do what the M66 is designed for - to play music from any of the connected sources and provide access to streaming services, your Library, etc. BluOS allows easy access to music (for me usually by Folder or by Search), TuneIn radio, Paradise, TV, etc, including volume control and everything most users are more than happy with.

There is no misleading by NAD, although one feature does seriously disappoint me. If Subs are connected and Sub Outs are activated, the Main outputs are nobbled to the same XO as your subs - no good if you have full-range main speakers - and inexcusably, the Sub Outs are all mono, even if you say there are 2 of them (M33) or presumably 4 of them (M66). Earlier Master Series (including M32 and M12) allowed the Main out to retain the full frequency range while the subs were XO'd at between 40 and 200 Hz, or (for those with stand-mounts, etc) the Main outs could be given the same or a different XO from the Subs. Now these short-fallings are making me look at alternatives, though all at very much more costly and lacking in useful features offered by NAD.

Sorry, I don’t mean to offend anyone using Sonos or BluOS—please don’t misunderstand me. BluOS, for example, has the undeniable advantage that it doesn’t require an additional server.

But ever since I started ripping CDs—or now downloading them—I’ve been embedding all relevant information (title, album, genre, lyrics, artist, etc.) into the tags and expect my streamer to read those tags. That’s exactly what tags are for in the FLAC standard. These days, it’s not as much of a hassle anymore because downloads usually come with fairly well-structured tags. But I understand that sometimes people just don’t want to bother with it. For me it is part of the fun to listen to a new album while searching for the lyrics to the songs and re-tag them.

TCP/IP control is not “obscure” but a long-established standard. Just take a look at Crestron, Control4, and others that NAD refers to.

In this regard, I have no patience for NAD. The feature “RS232 control” is still explicitly advertised on their website, yet the RS232 interface is dead. That’s simply fraud, and ultimately the reason why the dealer had to take the device back. I’d bet that this “obscure” interface still works on the M33...

It’s essentially like NAD advertising a phono input that doesn’t actually exist. If you don’t use a turntable, you might not care. But it’s still a feature being advertised (even now!) that simply isn’t there.

I’ve already explained why I need the TCP/IP interface. How do you control the devices connected to the M66?

I’m not entirely sure, but the issue you correctly describe with the subwoofer outputs might have something to do with DLBC. Or perhaps it’s because almost every input seems to be processed through the BluOS module before reaching the preamp. But again, I’m not certain about this. In any case, you’ve described the problem quite accurately: The earlier Masters Series devices were better (in terms of technical design).

I’ve mentioned several times that, when properly configured, I found the M66’s sound—using DLBC and digital sources—to be excellent. But if someone asks me whether I can recommend the device in general, unfortunately, I still have to say NO.
Nocko!

 

[Hear Here]

For me it is part of the fun to listen to a new album while searching for the lyrics to the songs and re-tag them.

Have you tried using Shazam to identify the music playing and show the lyrics? A lot less trouble than digging out and copying the lyrics to the tagging. I've never heard of anyone doing that!

TCP/IP control is not “obscure” but a long-established standard. Just take a look at Crestron, Control4, and others that NAD refers to.

So probably superseded by all the much more comprehensive modern apps that are developed by the brands specifically to control their devices?

The feature “RS232 control” is still explicitly advertised on their website, yet the RS232 interface is dead.

What do you want to use that connection for? I've never had any use for it and understood it was more for dealer diagnosis checks if something goes wrong. However I see from the M33 there's some other crazy applications such as Lutron lighting control. Not anything to do with the purpose of the NAD - to play music!

It’s essentially like NAD advertising a phono input that doesn’t actually exist.

Yes it does - in fact 2 separate phono inputs with the M66 - MM and MC. Using the Settings menu you can elect to keep the analogue source as analogue from start to finish, or to use the ADC and DAC to take advantage of Dirac. The choices are yours - just about unique to NAD I suspect.

I’ve already explained why I need the TCP/IP interface. How do you control the devices connected to the M66?

I don't need any other sources connected to my M33 apart from my TV via Opt 1 or HDMI ARC. If I choose Opt, the TV remote controls the channel selection and the NAD remote (or app) controls the volume. If I choose HDMI ARC the TV remote controls both the channel selection and the volume. ARC is a PIA as you can't prevent the TV remote from interfering with the NAD if that's what you want! For this reason I use the less good quality Opt unless it's a TV concert when I use the better sound-quality HDMI.

But if someone asks me whether I can recommend the device in general, unfortunately, I still have to say NO.

You should really say it's fantastic for 99.9% of owners - everyone apart from the 0.1% that may expect it to do non-audio tricks

 

[vddobrev]

How to select the BluOS source on NAD M66 from the remote?
I know how to do a preset for an album/playlist, but I don't want it to start playing, just switch the source.
Using the touch screen on M66, there is source BluOS, and when selected it also starts playing whatever was played last.

 

[vddobrev]

I own M66 since July 2024, and now it is end of March 2025. Here are the unresolved todate issues that I reported to NAD/Blusound:

1. Display Brightness - it is very bright even if set to 0
2. Amplifier Standby - the default 15 minutes is too short, no option to change.
3. Amplifier Standby - when disabled, there is no way to turn off the M66, power off button on remote and the unit does not work.
4. Auto Sense - on sources other than BluOS, if M66 powers off by itself after 15 minutes of inactivity, then M66 does not wake up when that same source starts playing. It will wake up on other sources only. In addition, when it powers itself off, it will remain working and will be warm even on the next morning after being off overnight.
5. In Analogue Direct, the subwoofers (I have two) are not in sync with the main speakers.
6. In Analogue Direct, when enable Dirac filter, the sound level is increased way way too much, approximately 12dB.
7. SACD Player to M66 via analgue and digital. The digital input is about 6dB louder.
8. HT Bypass (or input with fixed volume) I have NAD T778 that is in the same room for surround. Main speakers are powered by NAD M27, and fed by M66 via XLR. I want to connect T778 out to M66 and set the input to fixed mode. This was available in previous M series, e.g. M12. NAD/Blusound support said this was in the works, but do not have a date. I know I can make a preset with the option "Use current volume" and will store the current volume, but it will be 0dB (100%). What if I then start playing BluOS - volume will be 100% if I forget to reduce it... and there is no option to set default volume for BluOS.
9. Trigger In - if I plug a 12V trigger in M66 from T778, then M66 only will work with T778 on. There is no other way to turn it on, even BluOS player disapears from the app. It is like M66 does not exist if T778 is off.

Well, this is my list. I am very close to give up on this unit and list it for sale.

EDIT: I forgot one
10. No option to have main speakers as Large together with subs. My main speakers are pretty flat to 40Hz, I would like to have them play full range and roll-off naturally, while also having output to the subs.

 

[pogo]

No option to have main speakers as Large together with subs.

Waiting for DLART

 

[Hoeksel]

Waiting for NAD, great advice .

 

[Nocko!]

So probably superseded by all the much more comprehensive modern apps that are developed by the brands specifically to control their devices?

Okay, I’m getting the impression that I need to justify myself here, so here’s a bit of technical rambling that probably won’t interest anyone. This post is only about TCP/IP control and home automation.

---- All "audiophiles" should probably skip this—it’s only tangentially related to the M66 ----

TCP/IP control is not "outdated"—it is THE standard for reliably controlling Hi-Fi devices, or any devices for that matter. In the past, this required an RS232 interface, but nowadays, control is typically handled via LAN/Wi-Fi. Simply put, it’s not about a connection or a plug but rather a protocol—essentially a simple programming language. NAD had integrated this protocol into practically all their devices, offering truly exemplary functionality.

For example, you could send the command "Main.Volume=-35" via an app to the amplifier, and the volume would immediately adjust to that level. The device would then send the updated value back to the sender (e.g., an app), which could process it further—displaying the number as a value or adjusting a virtual volume knob accordingly. You could also query these values without changing them, ensuring that when launching the app, you’d instantly see the current volume, input, and Dirac slot settings. This setup also allows for fine-tuning the sensitivity of volume control, setting a maximum volume limit, or programming the system to automatically adjust volume, Dirac slot, and display brightness when selecting a specific input. Also, when changing something at the device the new value is sent to the app, so that all is in sync.

I use an iOS app to control my entire system as much as possible—TV, projector, preamp, Blu-ray player, Fire TV, lighting, blinds, heating, IP cameras, and more fore about 15 years now. Almost all of these devices I own can be controlled via TCP/IP or HTTP commands over the network. Not a single device in my setup is controlled using an infrared remote. The few devices that only support IR are controlled through "gateways" that convert network commands into infrared signals. But this is merely a workaround for subpar or intentionally "locked down" devices, such as the Sky Q receiver. Also the power sockets for my amps and the other gadgets are controlled via TCP/IP or http-requests.

This protocol has been used by well-known companies like Crestron, RTI, and others for over 20 years—and will continue to be used in the future—for a reliable, professional device control solution that doesn’t depend on a manufacturer’s app, which could be abandoned at any time. This protocol will still work after NAD has vanished.

You may choose to ignore or not need this feature, but it is a standard and a function that NAD explicitly advertises for the M66. It was always included in previous models, yet it is missing in the M66. That’s why I felt completely misled.

And in case it was overlooked: After persistently questioning NAD about this, pointing out their own manual and support documents, they eventually responded that they would have to change the manual (!) rather than the device itself. I don’t want to deal with such practices, yet I still spent weeks experimenting with the M66—because with DLBC, it really did sound great. But without DLBC, the M66 was just an expensive, stylish preamp riddled with issues.

See also:

NAD M66 - finally someone makes a decent 2-channel preamp!

Thanks for your detailed opinion on the M66. What do you mean by features that simply don't exist? I'm currently using the very similar M33 and I haven't found many features that I'd like but are missing. I gather that the M66 has a rather less comprehensive remote than the one supplied with...

www.audiosciencereview.com

I completely agree with the points made there.

And if you also consider point 5 in the linked post by vddobrev, you pretty much have to conclude that the M66 is beyond saving from a technical standpoint. It still seems for that the BluOS module sits in front of the actual preamp—both for signal and control purposes—which is a catastrophic limitation, setting the M66 back by years compared to other (pre)amplifiers from NAD. That’s not something I want in my setup.
Nocko!

 

[Nocko!]

Yes it does - in fact 2 separate phono inputs with the M66 - MM and MC. Using the Settings menu you can elect to keep the analogue source as analogue from start to finish, or to use the ADC and DAC to take advantage of Dirac. The choices are yours - just about unique to NAD I suspect.

Sorry, I didn’t express myself clearly. Of course, I know that the M66 has phono inputs. But for me, the missing TCP/IP interface is just as bad as it would be for a vinyl enthusiast if the M66, despite being advertised otherwise, didn’t have a phono input. It was meant as a comparison…
Nocko!

 

[vddobrev]

NAD T778 can be completely controlled via browser, its all OSD Menu is exposed via http://<local IP address>/osd/#/ - this is missing in M66. Oh wait, M66 does not have OSD Menu, if it did, it would display it on TV connected to it's HDMI port... ans perhaps album art and info.
Some settings are availbe on the touch display, but most important Audio Settings are not there, only via app.

One more thing I forgot to add to my list:
11. There is no info whatsoever on the screen about the input signal, like bit rate, frequency, etc.

 

[Hoeksel]

I solved my M33 coil noise from the unit by turning up the volume.

I solved the BluOS issues with Tidal Connect.

I solved the M33 remote control brick with a Logitech programmable remote.

I had to do the same with my previous M32.

Several people, except Pogo, have to do this now still with the M66.

To my own surprise it seems my M33 will survive it's 5 year anniversary but never, ever, will I buy NAD again.

What a disaster of a brand it is.....

 

[AlfaHolic]

Waiting for NAD, great advice .

Speaking of which, I've now received confirmation from NAD Support that -- despite what NAD promised when it released the M33 -- there will be no update to the M33 to implement DLBC.

"Regrettably, the internal circuit layout of the NAD M33 does not accommodate all the necessary connections for DIRAC Live Bass Control support. Due to the hardware limitations of the M33, the DIRAC Live Bass Control functionality cannot be integrated, even with an MDC upgrade.
However, you may anticipate that many new and forthcoming NAD devices will support DIRAC Live Bass Control natively like the M66."

 

[pogo]

If this really comes from NAD support, it's a poor performance as DLBC already works with just a single sub.
DLART shouldn't be a problem either, and you don't even need a sub.

 

[Nocko!]

5. In Analogue Direct, the subwoofers (I have two) are not in sync with the main speakers.
6. In Analogue Direct, when enable Dirac filter, the sound level is increased way way too much, approximately 12dB.

If I remember well, I observed this with my M66, too. But how can this happen, if there is a "analogue direct" route within the preamp? The analogue signal shouldn't be touched in any way, regardless of the state of Dirac. Dirac only works in the digital domain and shouldn't interact with the "pure analogue" path... One more thing I didn't understood...
When I got my M66 I confronted my dealer at once with the faults of the M66 and he granted me to return it at any time - we have quite strict "consumer laws" here in Germany... Perhaps that's the way to go.

If I understand your system correctly you use a M66 for stereo listening and the T778 for surround listening in the same room?
I had nearly the same setup with a M17V2 processor as a "surround source" for the front channels routed through the M66. I never got it to work well. I don't know the T778, but looking at its age I think it is a far better construction than the M66. Have you thought about dumping the M66 and use the T778 instead? (I know, it is hard to think about a surround amp for critical stereo listening...)
Nocko!

 

[slaweks]

Speaking of which, I've now received confirmation from NAD Support that -- despite what NAD promised when it released the M33 -- there will be no update to the M33 to implement DLBC.

"Regrettably, the internal circuit layout of the NAD M33 does not accommodate all the necessary connections for DIRAC Live Bass Control support. Due to the hardware limitations of the M33, the DIRAC Live Bass Control functionality cannot be integrated, even with an MDC upgrade.
However, you may anticipate that many new and forthcoming NAD devices will support DIRAC Live Bass Control natively like the M66."

But NAD advertised the feature, as coming soon, since the beginning. Aren't they liable for false advertising claims?

 

[AlfaHolic]

But NAD advertised the feature, as coming soon, since the beginning. Aren't they liable for false advertising claims?

They should be. I’m in California which has a strong false advertising statute (Business and Professions Code Section 17200/17500). I’m going to file a lawsuit in small claims court and will let you know it goes. Maybe it is just me, but when a company fails to deliver a feature that it explicitly promised, I would rather receive an apology than a pitch to buy a “new and forthcoming device[].”

 

[slaweks]

I think I got two emails from NAD on the subject, one stating that

"
Please note that Dirac Live Bass Control is not available for the M33 yet (or any other NAD products).
Dirac Live Bass Control is being worked on by our Developers and Dirac Developers and is planned for release in the future. Unfortunately we in support are not privy to the Developer's timeline so we cannot provide you an estimated release date.

Rest assured that Dirac Live Bass Control will be released for the M33 in the future. "

 

[Nocko!]

I think I got two emails from NAD on the subject, one stating that

"
Please note that Dirac Live Bass Control is not available for the M33 yet (or any other NAD products).
Dirac Live Bass Control is being worked on by our Developers and Dirac Developers and is planned for release in the future. Unfortunately we in support are not privy to the Developer's timeline so we cannot provide you an estimated release date.

Rest assured that Dirac Live Bass Control will be released for the M33 in the future. "

Can you recall when you got the first message? Before or after the introduction of the M66 (about mid 2023)?
Nocko!