Grimm Audio MU1 and MU2 Music Players

[Evo1668]

3 hours ago, Ronnie112 said:

Of course all depends on the circumstances and your power grid. In mine I have a nasty DC offset, which unfortunately makes transformers hum from time to time. Both in amps as in isolation transformers, so that doesn't do the trick for me. With the filters used so far I found some change for the MU1 and MU2, but not necessarily an improvement.

 

@PYP tried it yesterday without the Flux50 and into the Puritan 156 filter. Next to some additional blackness and ambient details I could hear the sonic fingerprint of the filter through the MU2. Which is not necessarily a good thing, since I find the filter to add some glare/edginess and artificiality which I don't really like so far. Maybe it needs to settle in or another power cable between wall outlet and filter, I don't know. So for now I'll keep the MU2 on its own dedicated power circuit (with nice fuses) with a Flux-50 killing some noise and EMI in the last inches.

 

Didn't try filters like Shunyata Denali or (the latest buzz here in NL) Sygnus. They will definitely yield good results, if it was not my DC offset upsetting things. 

 

Agree fully with the ethernet remark. Heard clear differences upgrading ethernet cables and switches, which is a good thing as you can further improve on an already excellent product.

Did you try the Ultimate cable with the 156.  There’s quite a few very positive reports using the Puritan Ultimate cable between the wall socket and the 156 and further improvements after a settling in period - sterile/artificial sounding being a common initial first observation by many.  

[Nicholas Dong]

This is what happened after updating the 5.5 firmware this time. Is this the same for everyone?

[bluebeat]

3 hours ago, Nicholas Dong said:

This is what happened after updating the 5.5 firmware this time. Is this the same for everyone?

From the change log regarding this update:

"2. Added lines to the startup and update dot animation, so the display will never turn black."

 

Looks the same on my MU1 when starting up or updating.

 

[Nicholas Dong]

Thank you so much

[Ronnie112]

7 hours ago, Evo1668 said:

Did you try the Ultimate cable with the 156.  There’s quite a few very positive reports using the Puritan Ultimate cable between the wall socket and the 156 and further improvements after a settling in period - sterile/artificial sounding being a common initial first observation by many.  

Yes tried the Ultimate cable first. Had the feeling the combo impacted dynamics, so tried a Furutech DPS4.1/50NCF as well as an AN Isis (very good value) so far. Restoring the most dynamics but not the natural flow I'm used to and edginess mentioned. As said, will give it some time, learned to not make any judgements on first impressions.

[Ronnie112]

On 12/20/2023 at 5:58 PM, bluebeat said:

For those of you who use a SR purple fuse in the MU1: in what direction did you put it in?

 

It's a bit tricky to place the fuse in the fuseholder of the MU1, you need to squeeze it in. Any tricks to do so without damaging the fuse's mantle?

 

Thanks!

2 tips:

1) make sure to wear thin gloves and push both ends at the same time gently in the holder.

2) Usually the side with the S goes on the Fase (hot) side of your inlet. Synergistic Research states the energy should flow from left 'S' to right 'R'). To simplify things, sometimes it sounds better the other way around. The direction that sound most detailed is the right one.

[bluebeat]

5 minutes ago, Ronnie112 said:

2 tips:

1) make sure to wear thin gloves and push both ends at the same time gently in the holder.

2) Usually the side with the S goes on the Fase (hot) side of your inlet and the R side on the Neutral. To simplify things, sometimes it sounds better the other way around. So let your ears decide which direction is best.

Thanks @Ronnie112

[FredM]

In addition to the Grimm MU2 video review from Alpha Audio, the written review is now online, with more in depth information on the Major DAC, pre amp, etc. The maximum rating is awarded, which was to be expected based on the ‘astonishing’ video review. (Both reviewers also picked the MU2 for their Best of 2023 - Top 5 list ).

 

https://www.alpha-audio.net/nl/review/grimm-audio-mu2-een-major-dac-herontwerp/

(in Dutch, the English version will probably be online shortly)

[PYP]

5 hours ago, FredM said:

In addition to the Grimm MU2 video review from Alpha Audio, the written review is now online, with more in depth information on the Major DAC, pre amp, etc. The maximum rating is awarded, which was to be expected based on the ‘astonishing’ video review. (Both reviewers also picked the MU2 for their Best of 2023 - Top 5 list ).

 

https://www.alpha-audio.net/nl/review/grimm-audio-mu2-een-major-dac-herontwerp/

(in Dutch, the English version will probably be online shortly)

Safari's translate to English worked fine.  Thanks for posting.  

[aangen]

I guess I am going to have to get one. It sounds so worth having! I’ll keep the MU1 as well. Or borrow it to the less fortunate. But that……

[TheAttorney]

13 hours ago, Ronnie112 said:

2 tips:

1) make sure to wear thin gloves and push both ends [of the fuse] at the same time gently in the holder.

The bigger issue is getting the SR fuse back out again. I used a small screwdriver to lever out the fuse from under the centre of its body - worked fine until I noticed that the SR's delicate lettering had been badly scratched (cosmetic only). Not sure there's a way to avoid this other than be extra careful - I can't remember if it's possible to lever out the fuse from the side of it's end caps.

[TheAttorney]

Very little reviews so far about MU2's headphone section, other than the suggestion that it won't be ideal for low efficiency headphones.

Having a great pre-amp section is a good start, but headphones will be more demanding.

[Vincent des Champs]

38 minutes ago, TheAttorney said:

The bigger issue is getting the SR fuse back out again. I used a small screwdriver to lever out the fuse from under the centre of its body - worked fine until I noticed that the SR's delicate lettering had been badly scratched (cosmetic only). Not sure there's a way to avoid this other than be extra careful - I can't remember if it's possible to lever out the fuse from the side of it's end caps.

Use a cotton swab instead!

[Eelco Grimm]

2 hours ago, TheAttorney said:

Very little reviews so far about MU2's headphone section, other than the suggestion that it won't be ideal for low efficiency headphones.

Having a great pre-amp section is a good start, but headphones will be more demanding.

In the MU2 hardware manual you can find "Headphone max output 40 mW in 30 Ohm, 55 mW in 600 Ohm.". That should drive most headphones 'adequately loud'. If you manage to find a super low sensitivity 80 dB/mW headphone with 30 Ohm impedance, it will still play at 98 dBSPL. All other headphones play louder. Please be careful and protect your hearing...

[TheAttorney]

1 hour ago, Eelco Grimm said:

That should drive most headphones 'adequately loud'. If you manage to find a super low sensitivity 80 dB/mW headphone with 30 Ohm impedance, it will still play at 98 dBSPL.

Maximum loudness isn't the real issue with driving headphones (as it happens I listen at very safe mid-70dB levels). Most integrated headphone sections, such as on my DAVE DAC, can drive just about any inefficient headphones to ear-splitting levels. But many DAVE owners still swear they get a better sound with a more powerful external amp. It's quality rather than quantity.

 

This remains to be seen (heard) with the MU2, something I'll get round to eventually - but I've yet to reconcile with MU2's lack of cross-feed, which is not important for many, but possibly a deal-breaker for me.

[stevebythebay]

Might be nice to find a dealer with both the MU2 and, say a dCS LINA for comparison 😉

[TheAttorney]

1 hour ago, stevebythebay said:

Might be nice to find a dealer with both the MU2 and, say a dCS LINA for comparison 😉

Naah, the Lina is a non-starter for my downsizing objectives. 3 boxes (if you include the super clock), 3 power cords, 3 fuses, etc, and it's not a full server (i.e. no internal disc afaik), so that's 4 boxes. And a power consumption much higher than MU2's. And then there's all the interconnect cables between those boxes - the horror!

 

So it's either an MU2, or I keep my MU1+DAVE, which I'm very happy with, but I'd still rather have 1 box than 2.

 

If I ever do consider an external amp for MU2, top of my wish list is the Zahl HM1, which has a very interesting cross-feed "sound stage" feature, plus tone controls.

[bluebeat]

8 hours ago, TheAttorney said:

The bigger issue is getting the SR fuse back out again. I used a small screwdriver to lever out the fuse from under the centre of its body - worked fine until I noticed that the SR's delicate lettering had been badly scratched (cosmetic only). Not sure there's a way to avoid this other than be extra careful - I can't remember if it's possible to lever out the fuse from the side of it's end caps.

 

Indeed. Damage to the fuse is the main reason why I asked for experiences regarding best direction, so I can minimise the chance that I have to take it out and put it in again several times. I know that I can hear the difference but would like to avoid to have to do that. In what direction did you place the fuse?

[FredM]

Here you go, Alpha Audio’s writen MU2 Review is now also available in English:

https://www.alpha-audio.net/review/grimm-audio-mu2-a-major-dac-redesign/


 

Another MU2 video: Hans Beekhuyzen explains why sells his MU1 & Dave DAC and replaces them with the Grimm MU2:

 

 

[stevebythebay]

2 hours ago, FredM said:

Here you go, Alpha Audio’s writen MU2 Review is now also available in English:

https://www.alpha-audio.net/review/grimm-audio-mu2-a-major-dac-redesign/


 

Another MU2 video: Hans Beekhuyzen explains why sells his MU1 & Dave DAC and replaces them with the Grimm MU2:

 

 

Surprised in the documented review that although the Pass preamp is listed, as: Pass Labs XP-12 (compare), they never discuss any testing of the MU2 for scenarios involving direct to amp vs via using the preamp.  Or did I miss something?

[matthias]

1 hour ago, stevebythebay said:

Surprised in the documented review that although the Pass preamp is listed, as: Pass Labs XP-12 (compare), they never discuss any testing of the MU2 for scenarios involving direct to amp vs via using the preamp.  Or did I miss something?

They mentioned in the YT that the preamp in the MU2 was superior to the Pass.

[TheAttorney]

15 hours ago, bluebeat said:

 In what direction did you place the fuse?

When standing in front of MU1, looking down at the fuse holder, my SR Orange goes from right to left (i.e. S nearer the back centre of MU1, and R nearer the edge). However YMMV as SR's print direction is not a 100% reliable indication of what sounds best.

 

The fuse holder holds two fuses. The one nearest MU1's back edge is a spare. The one towards MU1's centre is the active one. 

 

Whilst I had the fuse tray open, I checked that there is indeed enough space to the side of the fuse holder to lever out the fuse from the side with a small screwdriver, so that's a good way of removing the fuse without scratching its delicate printing.

[FredM]

A bit of topic, Listening Matters (a Dutch Grimm dealer) will move to another location. Quite some products are on sale, including…. a demo Grimm LS1be set (which is very rarely offered as a demo/used product).
 

The LS1be in HiMac is the top of the line speaker system from Grimm and an excellent partner with the MU1 player. Via the proprietary connection a seamless integrated is created, designed as one. (Of course other digital or analogue sources can also be connected with the LS1be). I’ve shared my experience with the LS1be earlier in this topic, the LS1be is also mentioned in this weeks Alpha Audio’s MU2 review.

 

For those who are interested, have a look here for the LS1be demo offer.

(I’m not related in any shape or form, given the MU1 owners in this topics, it might be interesting)

 

 

[stevebythebay]

On 12/22/2023 at 5:00 PM, matthias said:

They mentioned in the YT that the preamp in the MU2 was superior to the Pass.

I wonder how they would have "compared" the preamp in the MU2 to the Pass.  The MU2 manuals suggest, at least in my reading, that the preamp is in line, and there are no separate analog outputs, or seemingly any means of defeating the preamp function.  
 

I suppose, all other things being equal (and they're not), they could compare an MU1 into the Pass preamp versus the MU2.  That would then seem a reasonable comparison, though you'd not be able to extricate the DAC in the mix.  
 

And an even more "interesting" situation presents itself when faced with using the MU2 with an integrated amp, unless the integrated offers the ability to cleanly "defeat" or "bypass" its preamp function.  

 

Seems the MU2 will need to find a home for either building a fine music playback core of function, adding amp to taste, or perhaps downsizing an existing system. 

[Ronnie112]

1 hour ago, stevebythebay said:

I wonder how they would have "compared" 

 

And an even more "interesting" situation presents itself when faced with using the MU2 with an integrated amp, unless the integrated offers the ability to cleanly "defeat" or "bypass" its preamp function.  

 

I have that integrated amp with a bypass switch and can attest  the pre amp function of the MU2 is clearly outperforming. The MU2 on full throttle bypassed its attenuator (as far a I know) and I've compared bypassing the MU2, combining both attenuators and bypassing the SPEC pre amp, which was clearly offering the best performance. With the MU1 it was the opposite and preferred the pre amp of the SPEC (over the MU1&Sonnet Pasithea). Just my opinion, but hope it answers your questions.