Grimm Audio MU1 and MU2 Music Players

[FredM]

2 hours ago, The Computer Audiophile said:

Done.

Thanks, much appreciated 👍

[Eelco Grimm]

FYI, we just tested the latest Roon version and it is (still) bit transparent, as long as you turn off all processing.

 

Please note that in very rare cases the memory of our FPGA can get partly corrupted (it is a bug of the Xylinx hardware). You may hear that as a lower SQ than you're used to. The only way to solve this is to turn off the MU1 (or MU2), disconnect the power cord, reconnect it after a few seconds and turn the unit on again. This is a hard reset, the FPGA memory is then reloaded. We are working on an intermediate firmware release that both solves this problem and (to be sure) adds an automated test to frequently test if the problem exists. Until then, whenever you have the feeling that something is wrong, it never hurts to follow the unplug procedure.

[stevebythebay]

1 hour ago, Eelco Grimm said:

FYI, we just tested the latest Roon version and it is (still) bit transparent, as long as you turn off all processing.

 

Please note that in very rare cases the memory of our FPGA can get partly corrupted (it is a bug of the Xylinx hardware). You may hear that as a lower SQ than you're used to. The only way to solve this is to turn off the MU1 (or MU2), disconnect the power cord, reconnect it after a few seconds and turn the unit on again. This is a hard reset, the FPGA memory is then reloaded. We are working on an intermediate firmware release that both solves this problem and (to be sure) adds an automated test to frequently test if the problem exists. Until then, whenever you have the feeling that something is wrong, it never hurts to follow the unplug procedure.

At least it's not subject to Starbleed, I assume. Coding for FPGAs has always been a challenge.  Fixing without introducing new problems is one.  And I'm guessing the problem can arise independent of how a user configures their MUx unit, right?

[Eelco Grimm]

@stevebythebayYes, this is totally independent of any user settings and it has nothing to do with Starbleed. It is an obscure hardware bug of the FPGA that popped up a few times now. Like I wrote, we have solved it in the upcoming update, the workaround is to do an unplug procedure. 

[kaka]

The MU1 talked to the dac via AES or spdif, so it downsampled to 24/192 as that was the limit of those connections.

I haven't seen mention of what the MU2 does playing from the internal SSD, with the dac included AES or spdif cease to be the limitation.

 

The hardware PDF says

 

Clock specifications:
• Internal intrinsic clock jitter < 0.6 ps RMS (> 10 Hz).
• Can slave to 44.1 kHz and 48 kHz based digital sources of 1FS, 2FS and 4F

 

Do things still top out at 192?

[Low325]

Well then, let me just go and gracefully shut down my lovely MU1, unplug for a few and get it started up again. 🙂 ahhhh - what a beautiful piece. 

[Eelco Grimm]

@kakaThe MU2 internal intermediate rate is 8FS @ many bits. 

[stevebythebay]

On 11/20/2023 at 5:01 PM, kennyb123 said:

I would say that it’s better.  It’s like a reduced functionality version of JPlay that contains only the functionality needed to find and scan libraries, browse your library to play something, and then control playback.  It could be just enough for many users.  

If I'd want to give Squeeze a try, what app and server are required.  As an Apple guy and using Synology are there server and clients available to make this work?

[stevebythebay]

On 11/17/2023 at 6:15 AM, Low325 said:

Did you ever do a comparison between norms stuff and the AUVA? I have Norm’s footers too but underneath my speakers stands. 

Got back home from the recent Thanksgiving holiday celebration to find a box of AUVA’s at my door and set about testing.  I followed Hans’s approach in positioning the 4 of them under the MU1 stradling both the bottom and sides of the base and exterior frame.  Seems both of these surfaces are prone to airborne sound that needs to be absorbed by the AUVA. 
 

I removed a ground cable I'd connected from one of the MU1's side screws to my Shunyata Altaira.  I'd not found this connection noticeably helpful in reducing any "noise" in the system. Once again, the MU1 seems immune to applying such tweaks with any real benefit, at least along these lines.  Also, the cable itself, due to its necessarily heavy design and position, rested on the rack surface.  That tells me any rack base vibration would find its way into the MU1.  Not a positive outcome.  
 

I was quite surprised at the positive sonic benefits of these isolators.  Everything everyone has noted proves true.  Even if my HRS rack is doing a great job of preventing the vast majority of vibrations from entering the MU1, there's a substantial amount of non-structural, post-sonic transfer from the walls and floor and ceiling after the speaker has effectively stopped, amplifying frequencies and causing time delayed smearing.  Structural materials are denser than air and transfer the energy much faster than air, allowing the energy to arrive before the direct sound from the loudspeakers, causing pre-direct time smearing.

 

All of this seems of particular importance in how it affects the lower frequencies and then up the range.  I suspect harmonics are also impacted.  Net: the AUVAs prevent any disturbance in the MU1's digital clocking.  

[PYP]

17 minutes ago, stevebythebay said:

Got back home from the recent Thanksgiving holiday celebration to find a box of AUVA’s at my door and set about testing.  I followed Hans’s approach in positioning the 4 of them under the MU1 stradling both the bottom and sides of the base and exterior frame.  Seems both of these surfaces are prone to airborne sound that needs to be absorbed by the AUVA. 
 

I removed a ground cable I'd connected from one of the MU1's side screws to my Shunyata Altaira.  I'd not found this connection noticeably helpful in reducing any "noise" in the system. Once again, the MU1 seems immune to applying such tweaks with any real benefit, at least along these lines.  Also, the cable itself, due to its necessarily heavy design and position, rested on the rack surface.  That tells me any rack base vibration would find its way into the MU1.  Not a positive outcome.  
 

I was quite surprised at the positive sonic benefits of these isolators.  Everything everyone has noted proves true.  Even if my HRS rack is doing a great job of preventing the vast majority of vibrations from entering the MU1, there's a substantial amount of non-structural, post-sonic transfer from the walls and floor and ceiling after the speaker has effectively stopped, amplifying frequencies and causing time delayed smearing.  Structural materials are denser than air and transfer the energy much faster than air, allowing the energy to arrive before the direct sound from the loudspeakers, causing pre-direct time smearing.

 

All of this seems of particular importance in how it affects the lower frequencies and then up the range.  I suspect harmonics are also impacted.  Net: the AUVAs prevent any disturbance in the MU1's digital clocking.  

How long did they take to settle in?   I was surprised that in my setup initial settle in was about 8 hours and then there were further improvements for a week.  But my cabinet is not an audiophile rack and that may be a factor.   I have done some DIY vibration mitigation for the cabinet but as you say disturbances are coming from all directions.  I also had tried a grounding experiment and found no benefit.  

[Low325]

Thanks for the update @stevebythebay !

my AUVA EQ are supposed to be here soon. 
 

If things pan out I would like to trial the 50s or 70s underneath my speakers. 
 

Stack audio mentioned the EQs are height adjustable?  

[stevebythebay]

45 minutes ago, PYP said:

How long did they take to settle in?   I was surprised that in my setup initial settle in was about 8 hours and then there were further improvements for a week.  But my cabinet is not an audiophile rack and that may be a factor.   I have done some DIY vibration mitigation for the cabinet but as you say disturbances are coming from all directions.  I also had tried a grounding experiment and found no benefit.  

Well it didn't take long at all.  But I'll confess that in moving it around, trying to find the "sweet" spot, I likely disturbed things some.  I will leave it alone and see if it improves, as you indicated.  I think the soundstage, both width and depth do improve over time, even more than the immediate impact of focus and other attributes.

[stevebythebay]

1 hour ago, Low325 said:

Thanks for the update @stevebythebay !

my AUVA EQ are supposed to be here soon. 
 

If things pan out I would like to trial the 50s or 70s underneath my speakers. 
 

Stack audio mentioned the EQs are height adjustable?  

I'd ask your distributor about adjustments.  However, it seems from the website that's not an option for any of the AUVA Isolators.  And the ones for speakers must be chosen with care to match your speaker's threads.  Guess the spikes are removable if you're on hardwood floors vs. carpets.

 

Edit: found this -

Custom Silicone Absorber 

Unlike loudspeakers that should be positioned precisely and held rigidly, Hi-Fi electronics benefit from being de-coupled from the stand or shelf that they are setting on. By their nature, compliant solutions absorb vibration by movement.

Our Custom Silicone Absorber is specifically formulated and modeled to absorb high levels of external vibration that can be transmitted up through Hi-Fi racks, effectively de-coupling the Hi-Fi equipment. The CSA is height adjustable and comes in 3 versions to work optimally with different weights of partnering equipment.

 

I didn't find anything that points to how the adjustment is done, however.

[Low325]

Yeah it was someone at stack audio that i was in touch with via email. He said the included manual will provide instructions.  Hopefully I’ll have mine soon. I’m actually using oreas under the MU1.  But as PYP mentioned earlier, my rack isn’t an aduiophile rack either. So perhaps there are still other airborne entities that resonate into the space and the structure the mu1 sits on. I have the worst kind. It’s basically a cavity I have my MU1 inside of. 

[stevebythebay]

6 minutes ago, Low325 said:

Yeah it was someone at stack audio that i was in touch with via email. He said the included manual will provide instructions.  Hopefully I’ll have mine soon. I’m actually using oreas under the MU1.  But as PYP mentioned earlier, my rack isn’t an aduiophile rack either. So perhaps there are still other airborne entities that resonate into the space and the structure the mu1 sits on. I have the worst kind. It’s basically a cavity I have my MU1 inside of. 

I got a two page document.  The second states:

 

"6. Level adjustments (if applicable)" If your HiFi equipment appears to tilt of be unstable once you have positioned it; adjust using the CSA insert.  Each CSA insert has a small margin of height adjustment (2 mm); loosen by a maximum of two counter-clockwise turns."

 

Good luck!!!

[Low325]

Yah they didn’t go into too much detail. So I expected it to just be minuscule lol! Thanks for confirming!

[kennyb123]

4 hours ago, stevebythebay said:

If I'd want to give Squeeze a try, what app and server are required.  As an Apple guy and using Synology are there server and clients available to make this work?

LMS and Squeezlite are available to run on a number of operating systems.  I’ve yet to roll my own as I’ve had the combo available to me on a number of the servers I’ve owned.

 

Start here maybe.  Also I would strongly recommend this skin.  I was fortunate to have this as the default on Antipodes.

[stevebythebay]

1 hour ago, kennyb123 said:

LMS and Squeezlite are available to run on a number of operating systems.  I’ve yet to roll my own as I’ve had the combo available to me on a number of the servers I’ve owned.

 

Start here maybe.  Also I would strongly recommend this skin.  I was fortunate to have this as the default on Antipodes.

Seems LMS on the Synology is no longer supported (latest version of the DSM software).  That leaves setting up a separate server.  So, a small Intel NUC with Linux, I suppose (slim server) wired to my switch, right.  And using SqueezePad on an iPad looks to be the client, right?

[kennyb123]

1 hour ago, stevebythebay said:

And using SqueezePad on an iPad looks to be the client, right?

I prefer the Material skin for the web browser interface but Squeezepad or iPeng would do the trick.

[stefano_mbp]

3 hours ago, stevebythebay said:

So, a small Intel NUC with Linux,

In this case I suggest to try Daphile

Daphile is an optimized version of LMS and Squeezelite with it’s own os.

Daphile is simpler to install and runs on a dedicated pc, you can run it:

• as integrated LMS and Squeezelite 
• as Daphile server and Daphile client (Squeezelite) on separate pc
• as Daphile server and Squeezelite client (SOtM sms200 or Holo Red for example)
• all LMS plugins (Material Skin included) are available

It can boot from a usb key or from the internal hdd/ssd.

 

[playtron]

SAMSUNG just bought ROON: https://news.harman.com/releases/harman-acquires-roon-a-popular-multi-device-multi-room-audio-technology-platform

[Vincent des Champs]

40 minutes ago, playtron said:

SAMSUNG just bought ROON: https://news.harman.com/releases/harman-acquires-roon-a-popular-multi-device-multi-room-audio-technology-platform

 

[FredM]

Here you go 😀

 

 

[PYP]

On 11/30/2023 at 5:40 AM, Eelco Grimm said:

The MU2 internal intermediate rate is 8FS 

Is that possible for the MU1?  

[FredM]

1 hour ago, PYP said:

Is that possible for the MU1?  

Most likely that won’t be possible. The MU1 player has digital outputs. To carry the all important clock signal to an external DAC, the rate has to be limited to 4fs: which is the max supported by the regular digital cables/interface. A benefit of the MU2 is that streamer and DAC are in one device, opening up possibilities to internally use higher rates (my 2 cents, happy to be corrected).