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

[slaweks]

The first reassuring message was at the end of August 2023.

 

[AlfaHolic]

The first reassuring message was at the end of August 2023.

Hmmmm. NAD must have really been working hard on implementing DLBC in that three year period between the release of the M33 in July 2020 and the reassuring message they sent you in August 2023 if they hadn’t been able to figure out during that three year period that the circuit design of the M33 didn’t allow for implementation of DLBC.

 

[pogo]

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.

You will always have additional latency due to the electronics of the active subs. There are very few exceptions. In addition, the subs must also be connected to the purely analog path.

 

[Paffi]

Hmmmm. NAD must have really been working hard on implementing DLBC in that three year period between the release of the M33 in July 2020 and the reassuring message they sent you in August 2023 if they hadn’t been able to figure out during that three year period that the circuit design of the M33 didn’t allow for implementation of DLBC.

It's always the same with NAD, you can't trust them. I just remember die promises made for the C658....

 

[vddobrev]

You will always have additional latency due to the electronics of the active subs. There are very few exceptions. In addition, the subs must also be connected to the purely analog path.

The latency is not from sub's electronics, but from BluOS processing, it seems it is approx. 500ms. Subs are plugged in sub out. What will be the pure analogue path for subs? Line out to line in of the subs? It will be full signal, and the subs will need to use their own high pass...

 

[vddobrev]

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!

I mainly listen to FLAC locally ripped CDs and digital downloads purchased from Qobuz. My files are on NAS, and I am using BluOS to stream them, mainly to the kitchen via Node X. In the living room I play CDs mainly on my Pioneer PD-50AE.
M66 is for stereo, primarily as a pre-amp: CD/SACD analogue out to M66 Line In.
I used T778 for stereo before I got M66. T778 lacks pure analogue mode (everything is converted to digital), and its DAC is less than stellar. Also the analogue output stage is not great.
When I got M66, the difference was night and day for stereo performance... but the other issues are driving me crazy.

 

[pogo]

The latency is not from sub's electronics, but from BluOS processing, it seems it is approx. 500ms. Subs are plugged in sub out. What will be the pure analogue path for subs? Line out to line in of the subs? It will be full signal, and the subs will need to use their own high pass...

At least 50ms for BluOS processing
Yes, line out to line in of the subs. The subs will need to use their own filtering, level and phase correction, ...

 

[vddobrev]

At least 50ms for BluOS processing
Yes, line out to line in of the subs. The subs will need to use their own filtering, level and phase correction, ...

Wait! If I say I have subwoofers in BluOS, then Line Out will be filtered... so I have to say no subs. Then, full signal to mains, and full signal to subs.

I kind of achieve this in my current config with which I am mostly happy with.
I am using hi-level input from amp speaker binding posts to Speakon connection on the subs.
Subs are Sonus Faber Gravis II - very similar to REL, and they are positioned in opposite sides of the room.
I adjusted sub level using Dirac (for the lack of better tool) - measured repeatedly and observed the curve/response, adjusted level and crossover on the subs repeatedly until the measured graph/curve looked nice.

Also I have LFE from T778 to subs, they have independent input and level control for movies duty.

The point is I wanted to use Dirac DLBC, but it screws up my soundstage, even if I adjust curtains to less than 500Hz. I tried 500, 350, 300, 300, 120, and it is always the same not satisfactory results, it kills the soundstage/voice of my Sonus Faber Sonetto V speakers. Most likely it is because of my open space plan - living room has open space to kitchen and to second floor, and is shaped as a circle of 9m diameter.

 

[Nocko!]

Wait! If I say I have subwoofers in BluOS, then Line Out will be filtered... so I have to say no subs. Then, full signal to mains, and full signal to subs.

I kind of achieve this in my current config with which I am mostly happy with.
I am using hi-level input from amp speaker binding posts to Speakon connection on the subs.
Subs are Sonus Faber Gravis II - very similar to REL, and they are positioned in opposite sides of the room.
I adjusted sub level using Dirac (for the lack of better tool) - measured repeatedly and observed the curve/response, adjusted level and crossover on the subs repeatedly until the measured graph/curve looked nice.

Also I have LFE from T778 to subs, they have independent input and level control for movies duty.

The point is I wanted to use Dirac DLBC, but it screws up my soundstage, even if I adjust curtains to less than 500Hz. I tried 500, 350, 300, 300, 120, and it is always the same not satisfactory results, it kills the soundstage/voice of my Sonus Faber Sonetto V speakers. Most likely it is because of my open space plan - living room has open space to kitchen and to second floor, and is shaped as a circle of 9m diameter.

Pardon me, I'm quite tired and perhaps I don't fully understand your setup, but I fear what you're trying won't work. I've attempted something similar. DLBC requires at least three separate channels: left, right, and at least one dedicated subwoofer channel to function correctly. Therefore, if some or all of your subwoofers are connected directly to power amplifiers, Dirac won't "see" them and won't be able to adjust them. I believe you're aware of this. Consequently, you must route one, two, or all subwoofers through your M66.

When using a digital input for stereo (!) listening and selecting a sufficiently low crossover frequency, you can achieve excellent results. However, this setup breaks down when you attempt to feed the M66 with the front channels from your T778. In this scenario, you must use an analog input on the M66.
This leads to two options:
Using "analog direct" or utilizing an analog input and allowing DLBC to perform its optimization. Unfortunately, you'll consistently encounter a significant mismatch in the time domain. As you correctly noted in your previous posts, the subwoofers will be out of sync with the other speakers. Furthermore, due to the processing by BluOS and Dirac, an additional delay will be introduced to the front speakers, causing them to lose synchronization with the center and surround speakers. It took me weeks to fully comprehend this issue, which ultimately led to the end of my long journey with NAD-gear.

I hesitate to suggest a definitive solution for your setup, as I suspect you, like me, prioritize a clean and perfect stereo setup while also desiring a good surround setup for 20% to 30% of your usage. Again, please excuse me if this is all nonsensical; I didn't get enough sleep last night...(and Gemini was trying to help me out writing this).
Nocko!

P.S.: Another dump question - why do you use the analog input of the M66 for your CD/SACD-Player? Does it sound better or is this because of some copyright restrictions when listening to SACD?

 

[pogo]

Could it be that BC and ART have not yet been understood?
These features do not work optimally if you integrate a surround setup. Even if the other AVP/AVR can compensate for the BluOS latency of 50ms, a proper integration is not possible because the other surround channels are not processed by BC or ART.

 

[vddobrev]

Pardon me, I'm quite tired and perhaps I don't fully understand your setup, but I fear what you're trying won't work. I've attempted something similar. DLBC requires at least three separate channels: left, right, and at least one dedicated subwoofer channel to function correctly. Therefore, if some or all of your subwoofers are connected directly to power amplifiers, Dirac won't "see" them and won't be able to adjust them. I believe you're aware of this. Consequently, you must route one, two, or all subwoofers through your M66.

When using a digital input for stereo (!) listening and selecting a sufficiently low crossover frequency, you can achieve excellent results. However, this setup breaks down when you attempt to feed the M66 with the front channels from your T778. In this scenario, you must use an analog input on the M66.
This leads to two options:
Using "analog direct" or utilizing an analog input and allowing DLBC to perform its optimization. Unfortunately, you'll consistently encounter a significant mismatch in the time domain. As you correctly noted in your previous posts, the subwoofers will be out of sync with the other speakers. Furthermore, due to the processing by BluOS and Dirac, an additional delay will be introduced to the front speakers, causing them to lose synchronization with the center and surround speakers. It took me weeks to fully comprehend this issue, which ultimately led to the end of my long journey with NAD-gear.

I hesitate to suggest a definitive solution for your setup, as I suspect you, like me, prioritize a clean and perfect stereo setup while also desiring a good surround setup for 20% to 30% of your usage. Again, please excuse me if this is all nonsensical; I didn't get enough sleep last night...(and Gemini was trying to help me out writing this).
Nocko!

P.S.: Another dump question - why do you use the analog input of the M66 for your CD/SACD-Player? Does it sound better or is this because of some copyright restrictions when listening to SACD?

Just like you, I prioritize clean and perfect stereo, with some movie watching in multichannel.
Yes, you understood my setup completely, with one exception - current setup vs when I was trying to use DLBC.

When I was trying DLBC, I had the subs connected to Sub Out 1 and 2. Dirac saw them fine, and I did the measurements.
But I was not happy with the results, for all that was said previously.
With Dirac filter enabled, the soundstage was shifted to the left (as well as the bass) - as if I set the balance to the left on purpose.

That is why I did a different setup with the same equipment, where M66 does not control the subs, they are simply an extension to my mains, using the amp speaker posts, to hi-level input on the subs. I dialed the sub level and filters to blend with my mains.

T778 pre-out L/R is connected directly to the amp M27 with single ended, while M66 is connected to the same amp via XLR. I have a switch on the amp to select either XLR or RCA. When I want to watch a movie, I simply flip the switch on M27 to RCA.

I use the analogue input on M66 for my CD/SACD player for 2 reason:
1. I like the DAC of the CD/SACD player much better than the DAC in M66.
2. Playing SACD discs - only outputs on analogue out, it does not output digital.

 

[vddobrev]

Could it be that BC and ART have not yet been understood?
These features do not work optimally if you integrate a surround setup. Even if the other AVP/AVR can compensate for the BluOS latency of 50ms, a proper integration is not possible because the other surround channels are not processed by BC or ART.

One option is to have dedicated input for the AVP/AVR, where it will do a complete bypass of all processing. I read the manual and review of Anthem STR Preamp, and it seems it has dedicated bypass for HT - L/R as well as two subwoofers. This way, the AVP/AVR will control all processing and Dirac corrections for the L/R as well as the subs. Moreover, it will work even when the unit is in standby.

This is missing, sadly, in the NAD M66.

 

[Nocko!]

@pogo:
But the vddobrev's T778 or my M17V2 are also Dirac-enabled. Of course you could try to use them together. You just have to avoid to correct a channel that is already corrected by Dirac. And of course you should think twice which system to correct first.
But if you let a M66 do it's magic with DLBC and two full range speakers and two subs connected to it you get a first class stereo setup (unfortunately only soundwise).

After that you let Dirac in the T778 or M17V2 calibrate the surround / center channels and perhaps a large subwoofer. Then you have a few options: a) You simply don't correct the channels that are already governed by DLBC or b) you assume that Dirac won't touch the already corrected channels (this won't work, I think) or c) you switch off DLBC when using the homecinema bypass (that's not there) and let all channels be corrected by the T778 or M17.

Unfortunately the M66 kills all these ideas because a) at least my M17 couldn't compensate a delay of 50ms that is introduced by always (!) routing the signal through the BluOS module within the M66 and b) analog direct mode doesn't work as promised, because in analog direct mode subs and main speakers that are connected to the M66 are not in sync. As vddobrev already stated: You can't get a precise staging or a tight bass with analog direct or the latency introduced by the M66. The more I write the more I am sure that the M66 is crippled from the scratch...
Nocko!

 

[vddobrev]

@pogo:
But the vddobrev's T778 or my M17V2 are also Dirac-enabled. Of course you could try to use them together. You just have to avoid to correct a channel that is already corrected by Dirac. And of course you should think twice which system to correct first.
But if you let a M66 do it's magic with DLBC and two full range speakers and two subs connected to it you get a first class stereo setup (unfortunately only soundwise).

After that you let Dirac in the T778 or M17V2 calibrate the surround / center channels and perhaps a large subwoofer. Then you have a few options: a) You simply don't correct the channels that are already governed by DLBC or b) you assume that Dirac won't touch the already corrected channels (this won't work, I think) or c) you switch off DLBC when using the homecinema bypass (that's not there) and let all channels be corrected by the T778 or M17.

Unfortunately the M66 kills all these ideas because a) at least my M17 couldn't compensate a delay of 50ms that is introduced by always (!) routing the signal through the BluOS module within the M66 and b) analog direct mode doesn't work as promised, because in analog direct mode subs and main speakers that are connected to the M66 are not in sync. As vddobrev already stated: You can't get a precise staging or a tight bass with analog direct or the latency introduced by the M66. The more I write the more I am sure that the M66 is crippled from the scratch...
Nocko!

See my post above - Anthem STR Preamp has a dedicated bypass for L/R and 2 subs, so that the AVR can control all Dirac corrections. I consider this the correct implementation for proper HT Bypass. Sadly I will probably part with M66 soon, like you.

 

[Hear Here]

Press device selector 'MP' on the HTRM2 and then the preset #
RP is preset #0 on my HTRM2.

Thanks for the tip about using the HTRM2 to select a Favourite. It's taken me 5 years to realise this useful feature!

 

[Hear Here]

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

Are you certain about that? I don't ever remember mention of DLDB when I bought my M33 5 years ago. In fact I didn't think that DBLC had been released at that time. Please provide a NAD link from the release date of the M33 that even mentions DLBC. Thanks

 

[Hear Here]

Can those continually bitching about the NAD M66 please suggest an alternative streamer preamp that offers either better sound quality, or more features, or better value for money than the M66?

Despite the whinging here that needs a big pinch of salt to even digest, the M66 seems to have few if any rivals at anywhere near its price point. What other streamer preamp offers DLBC (for what that's worth) and does the basic job of delivering high quality music from internet-based sources, or one's own library, or from vinyl, etc better than the M66? Thanks from a potential M66 (or rival) buyer.

 

[Purité Audio]

Practically every streamer measured here has had audibly transparent sound quality from the Wiim Pro Plus upwards.
Choose the features you need.
Keith

 

[ex audiophile]

Can those continually bitching about the NAD M66 please suggest an alternative streamer preamp that offers either better sound quality, or more features, or better value for money than the M66?

Despite the whinging here that needs a big pinch of salt to even digest, the M66 seems to have few if any rivals at anywhere near its price point. What other streamer preamp offers DLBC (for what that's worth) and does the basic job of delivering high quality music from internet-based sources, or one's own library, or from vinyl, etc better than the M66? Thanks from a potential M66 (or rival) buyer.

I've owned the M66 and the Anthem STR preamp. I returned the M66; much prefer the STR because of the ease of use of ARC, with sub phase matching. Yes, you only get 2 sub outs and need a streamer (I use a Wiim pro as transport) but you still save quite a bit. The STR has been bug free with a really nice user interface and features like initial volume setting (lacking in the M66). Anthem support when needed has been very good, not sure about support for the M66. Just my two cents having used both.

 

[Hear Here]

I've owned the M66 and the Anthem STR preamp. I returned the M66; much prefer the STR because of the ease of use of ARC, with sub phase matching. Yes, you only get 2 sub outs and need a streamer (I use a Wiim pro as transport) but you still save quite a bit. The STR has been bug free with a really nice user interface and features like initial volume setting (lacking in the M66). Anthem support when needed has been very good, not sure about support for the M66. Just my two cents having used both.

Thanks. I wouldn't want 2 boxes and cables to achieve a streamer preamp, and presumably 2 remote or apps to control the pair in your system. I'm sure Anthem DSP is similar to Dirac Live and I've had experience of both - with Anthem in a Martin Logan speaker system I had for a few months. I'm not an advocate of any "room correction" DSP that requires the entire frequency range to pass the filter, even if only the bass is adjusted, although the ML speakers applied Anthem to just its bass amp. Any other suggestions for a single-box streamer preamp? I have a short-list but most are 2 to 5 times the price of the M66.