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

[MingChops]

And I think there is another misunderstanding here: DLBC always suggests a crossover at 70Hz

That is disappointing, very in fact. I know I was under the impression DLBC found the best crossover for your, tbh I thought that was the whole point or at least a huge value add it had over regular Dirac.
I just watched a vid and whilst it's not too onerous to 'test' changing crossovers in DLBC, as a workflow it's still an element of manual intervention on top of what I thought was a fully automated process. Also the changing of crossovers in DLBC is of course post-process and therefore based on simulation, for my levels of pedantry I would want to then ratify with REW sweeps to check that indeed the crossover changes are constructive and representative of the final result Dirac predicted.

At this point it's not actually much more effort to use REW and build the filter sets (assuming a device to apply them on, but there's a lot more of those and for a lot less money) - I now wonder if this is why miniDSP have seemingly not been arsed to adopt DLBC?

I've been patiently waiting to see what other 2ch DLBC devices come to market, but I think the DMP-A10 just suddenly got a whole lot more attractive. Or maybe if Anthem update the STR Pre, which can't be too long away, it's a fairly old device now and iirc was it wasn't quite as good as an AVM90 in terms of the version of genesis it ran (something about didn't do auto distances or crossovers or something?).

 

[Hear Here]

Then we could see where there are problems in the room and can discuss if it makes sense to enable subwoofers and / or DLBC.

I think something that is all too often overlooked - because of the misleading description "room correction DSP - is that any Dirac or other measurement system don't measure the room alone. They measure the sound that is delivered to where the microphone is placed. Therefore, take into account any room acoustic problems, but also, and maybe more important, the deficiencies in setting up the speakers, or the speakers themselves. Another factor, though rather less important, they take into account deficiencies in the amplifier.

I'm not a fan of "room correction DSP" after having used Dirac, RoomPerfect, MARS (Micromega's system) and Anthem within my own system. As I said earlier, I believe any full-range amp that includes DSP is likely to spoil the top-end a little and, for me this over-rides any shortcomings in the bass that DSP can resolve. In multi-speaker systems such as home theatre, DSP may well be necessary as the skills to set up several speakers manually is beyond most of us, but for 2-channel stereo, most systems should be able to achieve excellent results without resorting to DSP. If the system is bi- or tri-amped, the DSP can be applied only to the bass amp so won't harm the top end.

Also it seems to me as if a few here are still used to the far too boomy bass that most mighty speakers produce in a room. So it would be really interesting to see some measurements.

I'm sure you are right. Once people add a sub or two, they want to hear the benefit of their investment and often use a higher sub volume than is natural. And "boominess" seems often caused by an overlap around the XO frequencies that muddies these frequencies when 2 non-matched drivers, usually powered by different amps are delivering them. Precise timing that takes into account these factors and the distances between the driver and listener are important. I guess DLBC is designed to account for and adjust these factors - to a degree.

Until I get my M66, I'll be content to use my M33 without Dirac messing with the signal, as I don't find it adds more than it takes away from music enjoyment.

The soon-to-be-released Eversolo A10 has been suggested as an alternative to the M66. It has its own DSP and an even better DAC than the M66 - and is £$€1000 less costly! I'd be reluctant to abandon NAD's excellent Master Series and its BluOS user interface for a relatively unknown newcomer from the Far East, but if it does a better job, it may certainly be worth a home demo.

 

[Nocko!]

Ha... I am faster than Pogo! For the first time!
There is a new BluOS Upgrade out there. Unfortunately the M66 isn't mentioned again.

@Hear Here:
The term "room correction" might be misleading because you don't change the room. But shall we call it "room and speaker misconceptions and placement and amplifer and listening point correction"?
I know some of the correction systems you named in your post but didn't encountered real problems at the top-end of the frequency spectrum but this might be related to my age - at least meanwhile.
But you seem to have a nearly perfect listening room and setup when you prefer no correction over Dirac or ARC (Anthem) or Room Perfect. In such a "perfect room" / environment I would look for something else than a M66. Why pay for Dirac / DLBC and the separate sub outs if you are not going to use these features? I have lost track of your sources and might miss your point here, but there should be plenty of great pure analog preamplifiers or DACs with volume control in a pure digital chain. And why put a streamer into the preamp?
The streamer will be the first thing that will be outdated in a few years.
Nocko!

 

[pogo]

Ha... I am faster than Pogo!

Not really : Link
It makes little sense to list BluOS updates here that do not affect the M66, and there will be some in the future.

 

[Shhh]

When I first got my m66, pressing the EQ button on the remote would cycle through the different Dirac filters I have -- AND display the name of the filter. Now it just cycles through them, but DOESNT display the current filter ... I find this annoying. Has anyone else noticed this? Am I doing something wrong, if so what's the fix?

... Thanks

 

[pogo]

The M66 will probably be able to play DSD directly in the future: Link

The M66 will probably also receive MQA QRONO (d2a/dsd).
The Node Icon will only be the beginning.

 

[poxes]

When I first got my m66, pressing the EQ button on the remote would cycle through the different Dirac filters I have -- AND display the name of the filter. Now it just cycles through them, but DOESNT display the current filter ... I find this annoying. Has anyone else noticed this? Am I doing something wrong, if so what's the fix?

... Thanks

This is a bug, but if you toggle the power switch on the back of the M66, the names of the Dirac filters will update.

 

[Mike-48]

The M66 will probably also receive MQA QRONO (d2a/dsd).

Not a feature that attracts me. Dirac ART, on the other hand . . . .

 

[MingChops]

Took delivery of an M66 today - has any one else had a grounding issue?

Using balanced XLR out to the power amp I was getting a buzzing noise out the speakers, after much fudging around I established that the noise wasn’t there when the single ended RCA was also connected. Which made me think earthing.

Seeing that the M66 has an additional grounding terminal on the back, I removed the RCA’s and then connected an earth between that and a screw on the power amp’s chassis - sure enough the buzzing went in and out every time you made contact.

As my old pre amp (Schiit Freya S) did not create this problem, I am (being not technically minded) concerned there may be an issue with the M66?

The power amp in question is an Audiolab 8300XP. I have completely removed everything out the power strip and they are both connected back to the same wall socket. I have no other cables connected to the M66 or 8300XP.

Should this be considered ‘normal’ in as much as no the M66 is not defective? If so I presume I can just remove a chassis screw from the 8300XP and replace with a marginally longer one and wrap the wire around - it doesn’t feel very legit though so suggestions welcome!

 

[pogo]

Connect a trigger cable. Or make an additional connection via an RCA cable that only has the shielding connected.

 

[MingChops]

Connect a trigger cable. Or make an additional connection via an RCA cable that only has the shielding connected.

Thanks, I will certainly try the trigger. (Update: No the trigger didn't work)

Because the old Pre was fine - does it imply a potential issue with the NAD?

 

[danielsmi]

I do not have a ground loop hum on my M66. However on my PC setup I have an NAD D3045, bookshelf speakers and a REL mini subwoofer. It's a known issue with REL subs connected via Neutrik to a class D amp to often have a ground loop hum, I fixed mine by connecting an RCA cable between the NAD and the sub's LFE input. LFE input isn't active on the sub it's just there to cancel out the ground loop

 

[pogo]

Should this be considered ‘normal’ in as much as no the M66 is not defective?

Maybe the same: Link

 

[MingChops]

Maybe the same: Link

Yes certainly appears to be and I’ve learnt a little (only a little mind!) about why. The M66 (like the ICON) has a floating ground, as is suspected of my amp. As both have a floating grounds there’s no stable common reference, thus each has varying ground potentials - and the problem exists with XLR because the ground pin is not used as an earth reference. Whereas the reason in this scenario the single ended is fine, is because RCA’s share ground with their shield - and thus connecting RCA’s between the M66 and amp then physically creates a common stable ground reference between them.

It makes sense (even if maybe I haven’t eloquently explained it!) and I’m happy, with a simple earth added everything is dead silent:

I understand the ICON owners being a little more miffed though because they do not have the extra ground post like the M66 has, which means they are forced to use RCA in addition to the XLR’s to solve the issue (as per the Bluesound support link).

I think Bluesound should be offering ICON owners free or cost price some RCA cables as per your suggestion whereby they have no signal conductor, just a simple shield/ground only.