Grimm Audio MU1 and MU2 Music Players

[Evo1668]

Dutch & Dutch 8c and 2FS sampling.  A SMSL Sanskrit Mkll and 4FS for headphone listening 

[skatbelt]

7 hours ago, The Computer Audiophile said:

Which DACs are you guys using with the MU1? I have a handful on hand here and I'm trying to find the best match.

 

Edit: Are you guys using the MU1 internal upsampling?

 

Chord DAVE with MU1 set to 2FS upsampling was a sweet spot in my system. 4FS sounded somewhat artificial and 'larger than life' if you know what I mean.

 

The upsampling algorithm makes the MU1 special. With no upsampling, MU1/Roon was on par with a dCS Network Bridge/Mosaic.

[The Computer Audiophile]

I’m trying to determine the best settings, given that most DACs internally upsample. The double upsampling is interesting. 

[Analog Audio of Minnesota]

for what its worth, I always get rave reviews on customers who use ladder style DAC's. NOS on some of them is very special. I am experimenting with the Sonnet Pasithea right now and quite taken by the performance. I have run a Nagra Tube DAC, T+A 200 DAC, Bricasti M3 and now a T+A HV DAC in my main audition room and each has reacted differently to the MU1 but each is noticeably better with the MU1 feeding it the data stream.

 

 

 

 

[PYP]

got curious about the difference between oversampling and upsampling:

 

https://www.audioholics.com/audio-technologies/upsampling-vs-oversampling-for-digital-audio

 

Basics of Sampling - Oversampling and Upsampling 

To start with, we must review the system as a whole and look at the terminology. Two main parts of the whole system we are going to consider are upsampling and oversampling. In the purely mathematical context, they are similar operations. When practically implemented though, oversampling refers to using a higher sampling rate than needed to run the A/D or D/A converter thus increasing the rate of the signal. Upsampling is on the other hand a rate conversion from one rate to another arbitrary rate. Oversampling in the ADC has been around for quite a bit of time, while upsampling of audio that results in a simple rate conversion is relatively newer. The figure below shows an example of oversampling. We assume that we can sufficiently sample the analog waveform at twice the bandwidth of the signal as to prevent any aliasing in each case. In one case we are sampling at some frequency, f s and in the other case we are at twice the same sampling rate. The resulting data samples are shown to the right in the figure. In both cases we have assumed that we are at twice the Nyquist rate for the signal to prevent any aliasing.

 

Figure 1 : Oversampling Operation 

 

[PYP]

1 hour ago, Analog Audio of Minnesota said:

for what its worth, I always get rave reviews on customers who use ladder style DAC's. NOS on some of them is very special. I am experimenting with the Sonnet Pasithea right now and quite taken by the performance. I have run a Nagra Tube DAC, T+A 200 DAC, Bricasti M3 and now a T+A HV DAC in my main audition room and each has reacted differently to the MU1 but each is noticeably better with the MU1 feeding it the data stream.

 

 

 

 

has Grimm said whether the DAC in their MU2 will be a ladder style?  Just curious.  

[Analog Audio of Minnesota]

Just now, PYP said:

has Grimm said whether the DAC in their MU2 will be a ladder style?  Just curious.  

probably best to have Eelco reply directly, but given the existing FPGA system, it will be a system similar to the Mola Mola design. Again: ask Eelco for details. I don't want to give misleading information.

 

[pmorali]

2 hours ago, The Computer Audiophile said:

I’m trying to determine the best settings, given that most DACs internally upsample. The double upsampling is interesting. 

 

As you may have read or heard from Grimm Audio, they recommend minimizing up/downsampling in the DAC (use NOS mode), and use the dedicated FPGA in the MUI for up/downsampling...

[The Computer Audiophile]

7 minutes ago, pmorali said:

 

As you may have read or heard from Grimm Audio, they recommend minimizing up/downsampling in the DAC (use NOS mode), and use the dedicated FPGS in the MUI for up/downsampling...

This leaves very few DACs with which to use the MU1, in such a configuration. It also presupposes the technical ability of a ton of DACs is less than that of the MU1. That’s a bridge too far for me. 

[Analog Audio of Minnesota]

2 minutes ago, The Computer Audiophile said:

This leaves very few DACs with which to use the MU1 with, in such a configuration. It also presupposes the technical ability of a ton of DACs is less than that of the MU1. That’s a bridge too far for me. 

As I said in my previous post, I have found wonderful results from ladder dacs and especially those that have an NOS mode. With that said, I have enjoyed the MU1 with DAC's that aren't ladder DAC's or offer NOS. The Bricasti comes to mind in that case.

[The Computer Audiophile]

I’m trying to figure out if the MU1 is in a way similar to a dCS Upsampler, in that both upsample prior to the DAC. Or, if two different conversions operating very differently have pos/neg effects. 

[Nicholas Dong]

2小时前，skatbelt说：

 

MU1设置为2FS上采样的和弦DAVE是我系统中的一个甜点。如果你明白我的意思，4FS听起来有点人为，“比生命还大”。

 

上采样算法使MU1与众不同。由于没有上采样，MU1/Roon与dCS网络桥/马赛克相当。

I was fortunate enough to compare the MU1 and DCS bridges. Without upsampling, the MU1 is still more neutral, more transparent, and more detailed than the DCS bridge. The MU1 has better treble extension, clearer mids, and stronger bass.  , DCS treble is more rounded, mid-bass is thicker, with obvious coloring.

[Nicholas Dong]

I use MU1 with Merging hapi DAC. The DAC filter has slow and sharp. The filter closer to the nos mode should be slow? The slow roll-off mode seems to be more suitable for the upsampling of Mu1. Are there users who also use the Merging DAC?  ,thanks

[TheAttorney]

I use MU1 with 4FS to DAVE.

 

DAVE does its own upsampling (to 16FS if I remember correctly), but setting MU1 to 2FS is still very worth it. And 4FS is even more worth it  (this is where I differ from scatbelt).

 

And to complete the picture, putting the HMS MScaler (also up to 16FS)  between MU1 and DAVE was not helpful, as per my earlier posts.

[skatbelt]

8 hours ago, Nicholas Dong said:

I was fortunate enough to compare the MU1 and DCS bridges. Without upsampling, the MU1 is still more neutral, more transparent, and more detailed than the DCS bridge. The MU1 has better treble extension, clearer mids, and stronger bass.  , DCS treble is more rounded, mid-bass is thicker, with obvious coloring.

 

Not in my system. But only when the dCS Network Bridge was used with dCS's own music player (Mosaic). With Roon I agree with your observations. The MU1 is the first device that really makes Roon sound good.

[skatbelt]

56 minutes ago, TheAttorney said:

I use MU1 with 4FS to DAVE.

 

DAVE does its own upsampling (to 16FS if I remember correctly), but setting MU1 to 2FS is still very worth it. And 4FS is even more worth it  (this is where I differ from scatbelt).

 

And to complete the picture, putting the HMS MScaler (also up to 16FS)  between MU1 and DAVE was not helpful, as per my earlier posts.

 

It's a matter of taste I guess. Neutral versus a little euphoric.

[Nicholas Dong]

40分钟前，skatbelt说：

 

不在我的系统中。但只有当dCS网络桥与dCS自己的音乐播放器（马赛克）一起使用时。对于Roon，我同意你的观点。MU1是第一个真正让Roon听起来不错的设备。

The DCS bridge is indeed a very cost-effective device. I have been using it for two years. In fact, the sound will be drier with the mosaic, but the whole is also more hazy, especially the treble.

[skatbelt]

38 minutes ago, Nicholas Dong said:

The DCS bridge is indeed a very cost-effective device. I have been using it for two years. In fact, the sound will be drier with the mosaic, but the whole is also more hazy, especially the treble.

 

Nothing hazy in my treble.... 🙃 What do (and did) you have upstream of the MU1 and dCS NB? Based on the experiences of others the MU1 is not so sensitive to the quality of the incoming ethernet signal. The dCS NB is! A lot can be gained here. This of course also means kudos for the MU1 and shows that there are so many variables.

[Nicholas Dong]

6 hours ago, skatbelt said:

 

Nothing hazy in my treble.... 🙃 What do (and did) you have upstream of the MU1 and dCS NB? Based on the experiences of others the MU1 is not so sensitive to the quality of the incoming ethernet signal. The dCS NB is! A lot can be gained here. This of course also means kudos for the MU1 and shows that there are so many variables.

I used uptone JS2 to power the Openwrt soft router and Tp-link WDR5620 WiFI router in the network in front of the media player, and the optical access equipment was powered by Taiwan's EAhibrid DC-B1 lithium battery power supply, I did not use any network isolation devices and switches  ,The router in the computer room is directly connected to the MU1 or DCS bridge. In the same situation, the MU1 is much better, so I sold my DCS bridge. Indeed, as you said, the dCS bridge is very sensitive to the network environment, and  I am also very sensitive to Roon core. I used Antipodes S40+S60 as Roon Core with DCS bridge Roon Reday before, and I was not satisfied with the effect.

[The Computer Audiophile]

I've got a good handle on this now. 

 

Question 1: Do you guys change the MU1 upsampling setting (No, 2fs, 4fs) for different music, or leave it alone once you set it?

 

Question 2: Is anyone using convolution with the MU1?

[PYP]

12 minutes ago, The Computer Audiophile said:

I've got a good handle on this now. 

 

Question 1: Do you guys change the MU1 upsampling setting (No, 2fs, 4fs) for different music, or leave it alone once you set it?

 

Question 2: Is anyone using convolution with the MU1?

#1:  for me, it is set and forget (4fs)

#2:  have not tried.

#3:  hope you are having fun

[PYP]

6 hours ago, skatbelt said:

Based on the experiences of others the MU1 is not so sensitive to the quality of the incoming ethernet signal. 

I would say that the MU1 is not sensitive to incoming noise, however, upstream devices can change the sound.  In my setup, upstream ethernet noise cleaners moved me closer to the performance stage, so to speak.  That wasn't my preference, so I eventually removed them.  In other setups, of course, the effect might be different, but I assume that all devices leave a fingerprint on the sound.  

 

The MU1 does something unique in that it seems to elevate a given setup to a different realm of musical engagement.  It isn't about soundstage, details, etc. per se.  It weaves an elevated form of all of those into a whole that is so much more organic.  But, no need for me to explain that to folks who already have one in their setup.  🙂

[Mike123]

as a DAVE DAC owner, Ive found 4X to be a bit too overwhelming in midrange. 2X seems to be more immersive. Anyone else with DAVE thats experienced same?

[The Computer Audiophile]

17 hours ago, PYP said:

got curious about the difference between oversampling and upsampling:

 

https://www.audioholics.com/audio-technologies/upsampling-vs-oversampling-for-digital-audio

 

Basics of Sampling - Oversampling and Upsampling 

To start with, we must review the system as a whole and look at the terminology. Two main parts of the whole system we are going to consider are upsampling and oversampling. In the purely mathematical context, they are similar operations. When practically implemented though, oversampling refers to using a higher sampling rate than needed to run the A/D or D/A converter thus increasing the rate of the signal. Upsampling is on the other hand a rate conversion from one rate to another arbitrary rate. Oversampling in the ADC has been around for quite a bit of time, while upsampling of audio that results in a simple rate conversion is relatively newer. The figure below shows an example of oversampling. We assume that we can sufficiently sample the analog waveform at twice the bandwidth of the signal as to prevent any aliasing in each case. In one case we are sampling at some frequency, f s and in the other case we are at twice the same sampling rate. The resulting data samples are shown to the right in the figure. In both cases we have assumed that we are at twice the Nyquist rate for the signal to prevent any aliasing.

 

 

I'v been thinking about that paragraph above and don't think it's totally correct. In fact, I'm not sure there is a current and correct definition that delineates between up and over sampling. The MU1 calls its capability Oversampling (2fs and 4fs). But, this is nowhere near what's "needed" to run the D/A conversion (if sticking with the paragraph above). Almost all DACs will go much higher whether the users likes it or not. 

 

Perhaps a digital expert like @Miska could lend us a hand?

[Nicholas Dong]

What power cables do you use with Mu1?  I am using Vovox excelsus power cable for now. I have not tried other cables. What do you think is the most suitable power cable for MU1?  Eelco claims not to use HIFi cables, its 1 is that will damage the power jack, its 2 I think most power cables add clarity, and MU1 upsampling is doing the same thing, so is there a conflict between them  , what do you think?