[21qz]

OK, found the cord/power source, but honestly i don't hear the difference? Still at about 80-85 volume using Tidal.
my headphones are plugged into the left channel in front panel, not even sure what the right side is for.
Also sample rate never seems to go past 96? I must be doing something wrong.

 

[WilliamLeonhart]

OK, found the cord/power source, but honestly i don't hear the difference? Still at about 80-85 volume using Tidal.
my headphones are plugged into the left channel in front panel, not even sure what the right side is for.
Also sample rate never seems to go past 96? I must be doing something wrong.

That’s ok. I didn’t hear the difference either

 

[eeagle]

OK, found the cord/power source, but honestly i don't hear the difference? Still at about 80-85 volume using Tidal.
my headphones are plugged into the left channel in front panel, not even sure what the right side is for.
Also sample rate never seems to go past 96? I must be doing something wrong.

Play with the menus as I recall you need to select U2=USB Audio Class 2 mode, and then you will be able to install the driver I mentioned in the last msg link which will allow higher bit rates along with higher power.

That driver link also has the manual download pdf which will explain how the left and right HP jacks differ.as well as how all the filters and menus work....as they said when I was in the military RTFM

"When headphones are connected to the right hand jack, the line output signal is muted"

USB Connector #2 - High Power Input
Use this power connection to operate the m9XX in High Power mode. This connector carries only
DC power and no USB data. Once the included low noise 2A USB power supply is plugged into this
input, the m9XX will enter High Power mode (indicated by “HP” on the 7-segment display).

 

[21qz]

i was over here thinking my sound would go from a 7.5 to an 8-8.25/10 smh ...
The real question is why my sample stays at 96??

 

[mandrake50]

OK, found the cord/power source, but honestly i don't hear the difference? Still at about 80-85 volume using Tidal.
my headphones are plugged into the left channel in front panel, not even sure what the right side is for.
Also sample rate never seems to go past 96? I must be doing something wrong.

This from the Grace published technical discussion for the M9xx:
http://www.gracedesign.com/support/whitepapers/m9XX_tech_discussion_Rev3.pdf

"The efficiency of the audio power supply allows the m9XX to operate with +/-9V DC power rails when

running on USB buss power, which results in available continuous power for the headphones exceeding
160mW per channel with both channels driven in to 32Ω headphones. One channel power in to 32Ω phones
is more than 500mW.
The m9XX automatically senses when the external 2A USB charger is connected to the high power DC input.
Once detected, the m9XX increases the DC power rails to +/-14.5V, which results in available continuous
power for the headphones exceeding 1000mW per channel with both channels driven in to 32Ω
headphones. One channel peak power in to 20Ω phones is more than 1600mW."

You will only use the extra power if your situation requires it. The availability should not change the sound. It also will not change the gain of the amp, so volume control levels will stay the same.
Your situation is still another example of unused power not making any difference. If you are using 150 mA, having 4 or 5 or 6 watts available is pretty meaningless.

The second headphone output is for when you might want to drive a second set of headphones...
From the user manual:
http://www.gracedesign.com/support/manuals/m9XX_Owners_Manual_RevE.pdf

"There are 2 ¼” headphone output jacks on the front, which are wired in parallel. The second jack on
the right is a switched type. If you have the line outputs connected to a power amp or powered
monitors, connecting headphones to this jack will automatically mute the line outputs, allowing
you to effectively ‘toggle’ between the headphone and speaker outputs."


Have you installed the correct driver? The unit operates in Class1 USB audio in windows without the correct driver installed.

"The m9XX can operate as a USB Audio Class 1 or Audio Class 2 device. In USB 1 mode the m9XX
supports driverless operation on Mac OS and Windows at sample rates up to 96kHz.
In Audio Class 2 mode the m9XX supports driverless operation on Mac OS at sample rates up to 384kHz. On
Windows, Audio Class 2 operation requires downloading and installing a free driver, which can be
found on our website – http://www.gracedesign.com/support/support.htm.

 

[CoFire]

This from the Grace published technical discussion for the M9xx:
http://www.gracedesign.com/support/whitepapers/m9XX_tech_discussion_Rev3.pdf

"The efficiency of the audio power supply allows the m9XX to operate with +/-9V DC power rails when

running on USB buss power, which results in available continuous power for the headphones exceeding
160mW per channel with both channels driven in to 32Ω headphones. One channel power in to 32Ω phones
is more than 500mW.
The m9XX automatically senses when the external 2A USB charger is connected to the high power DC input.
Once detected, the m9XX increases the DC power rails to +/-14.5V, which results in available continuous
power for the headphones exceeding 1000mW per channel with both channels driven in to 32Ω
headphones. One channel peak power in to 20Ω phones is more than 1600mW."

You will only use the extra power if your situation requires it. The availability should not change the sound. It also will not change the gain of the amp, so volume control levels will stay the same.
Your situation is still another example of unused power not making any difference. If you are using 150 mA, having 4 or 5 or 6 watts available is pretty meaningless.

The second headphone output is for when you might want to drive a second set of headphones...
From the user manual:
http://www.gracedesign.com/support/manuals/m9XX_Owners_Manual_RevE.pdf

"There are 2 ¼” headphone output jacks on the front, which are wired in parallel. The second jack on
the right is a switched type. If you have the line outputs connected to a power amp or powered
monitors, connecting headphones to this jack will automatically mute the line outputs, allowing
you to effectively ‘toggle’ between the headphone and speaker outputs."


Have you installed the correct driver? The unit operates in Class1 USB audio in windows without the correct driver installed.

"The m9XX can operate as a USB Audio Class 1 or Audio Class 2 device. In USB 1 mode the m9XX
supports driverless operation on Mac OS and Windows at sample rates up to 96kHz.
In Audio Class 2 mode the m9XX supports driverless operation on Mac OS at sample rates up to 384kHz. On
Windows, Audio Class 2 operation requires downloading and installing a free driver, which can be
found on our website – http://www.gracedesign.com/support/support.htm.

Great info! I like in particular the information on low vs high power operation. In past post, the info provided was that high power mode only kicked in if the volume pot went above 90 which apparently is not the case. In essence, the 2A/5V connection only worked for volume above 90. This never made sense to me. Happy this info is more clearly defined as it explains many of the observations from low to high power mode. I feel the transients benefit in high power but until now, figured it was just in my head given the previous low vs high power mode understanding.

Edit: I'm going to AB test this DAC against a Mimby using the THX AAA 789 for the amp section. Looking forward to the comparison. In my last runoff between the 2, I preferred the m9XX using the A100 as the amp. I think this next comparison will be more revealing.

 

[Martijn W]

My M900 just came in.

Haven't compared it to my Benchmark DAC2 HGC yet, but the sound quality of the M900 is definitely good when operating 'just' USB-powered by my macbook.

I like it right away!!

 

[Martijn W]

hmmmzz..

testing high power mode i heard a hum when i got off/on my chair (ground issue?) and also felt some static when i touched the top button. also when i operated it in usb powered mode after that..

i already called grace support and left a 'call me back message'... but weird crap. i'm not sure if it has something to do with my home power facility of with the m900..?!

..to be continued!!

 

[CaptainFantastic]

hmmmzz..

testing high power mode i heard a hum when i got off/on my chair (ground issue?) and also felt some static when i touched the top button. also when i operated it in usb powered mode after that..

i already called grace support and left a 'call me back message'... but weird ****. i'm not sure if it has something to do with my home power facility of with the m900..?!

A few months ago, when I got my m900, I contacted their customer support via e-mail regarding this static (their response time and knowledge were fantastic). Basically if you are connected to high power and then the phone, not the PC via USB, then the m900 is not grounded, as its own charger does not have a grounding pin. Therefore it is normal and safe for the case to "float", you will feel a very small vibrating feel when touching the volume dial. As soon as you connect it to the USB port, the vibration/static go away.

Note - one thing I would not do is have the m900 connected to the USB, then plug it in to the power outlet. I think when I did this, my USB port shut down preventively. It then came back to life after a day or two. There must have been some surge that passed through. Now I just take care to always have the m900 plugged in, then connect it to the PC via USB. Maybe it was just my setup, something particular to how I did things.

 

[Martijn W]

hmm... I think it has something to do with grounding.

The problem occurred sitting in a Charles & Eames DAR chair (fully plastic seat) and with my shoes on (rubber shoe soles).
I just took my shoes off and now the problem does not occur anymore. Also now I am back on high power mode..

I find it strange however.. should the grounded cable which powers my laptop not make connection to the ground?
The power cord is grounded and the wall connection too, i think. It is definitely the right connection only I have not checked the rear of the wall socket.. :/

 

[CaptainFantastic]

Yes, if connected to your laptop USB then you should be grounded in the setup you described. I am referring to where you go portable and you connect just to your phone.

 

[Martijn W]

That sounds like a situation in which I would use my Astell&Kern

I now start to wonder if my sockets are correctly grounded.
But i should mention that my other gear never gives me any grounding problems...

 

[baiyy1986]

I join the m9xx club 2 months ago, reason is simple, too much cord too much things on my desk, they look like mass.
But now I removed everything and this little small thing is fantastic!
Function wise it gives me everything I want.
I moved my modi multi-bit +vali2 to my office.
I am so impressed by it can power HD8000 without USB power cord. It is insane.
Sound wise, it is in the middle, not fast not soft, neither cold nor warm.
It is a clean and the reference sound.
Really love it.

 

[CoFire]

Chain 2 x 400i on Grace m9XX dac/amp, playing High Resolution Spotify, 400i #1 has Universe Pads, #2 has Eikon Pads

Universe Pads - more comfortable than Focus A pads (stock), gimbal still touches pad top for bigger heads but not to bad. I have the 400i just below the largest setting with these pads, seeing 1.5 if it existed. Bass has better impact than stock, great texture, good energy in the mids. A great pad, recommended.

Eikon Pads - more comfortable than Focus A pads (stock), gimbal interferes more with pads for bigger heads and may take a little extra manual adjustment squeezing them under the gimbal, but fits well. I have the 400i on the largest notched seeing with these pads. Bass in some songs feels like it has a tad more impact and in some songs, a tad more extension, but possible with a tad less texture. The mids and treble sound similar to Universe. The soundstage is a tad larger giving a subtle sense of more clarity but with a tad bass texture clarity.

I A/B'd these over many genres and is close. They both are better over stock and depending on the song, they edge each other out on preference but not a total easy decision to make. Sometimes you think you hear a clear distinction in the difference and after more A/Bing, you just get fatigued thinking you are hearing things. I could go with either happily.

I tried the HEX V2 right after on the same source and it beats the 400i on all fronts but for the price, the 400i is a hell of a headphone and VERY formidable.

I compared the 400i to the Ether 2 and it handles mids and treble better IMO, but I think the Ether 2 slays it on bass.

Songs used but all inclusive
Sleepyhead - Passion Pit
Mary Jane's Last Dance - Tom Petty
Dark Horse - Katy Perry
On My Level - Wiz Khalifa
Creep - Radiohead
Bullet Proof... I Wish I Was - Radiohead
Titanium - David Guetta
Crystallize - Lindsey Sterling
La Quiero A Morir - DLG

And a couple others.

Verdict - give up a little texture for a tad subbass, impact and soundstage OR give up a more intimate presentation and texture in bass for a tad subbass and impact. Though this isn't across the board, which leads me to believe, there might be something subtle going on.

The pic shows the Universe on top, Eikon on bottom. The Universe have slightly larger openings but are flatter and Eikon have smaller openings and are more angled. On the side by side pic, the Universe are on the left and Eikon on the right.

 

[CaptainFantastic]

A few months back I asked on this forum what would be a good case for the m900 and someone from Grace Design told me the Pelican 1060 would be a good fit. It's a perfect fit. Thanks.

Now I have another question and I hope someone from GD is reading. The other day I tried to plug my unit in (EU plug) and because I didn't hit the outlet at a perfect right angle, the two metal bars dislodged inside the unit and went in a bit. I opened the charger and repositioned it, but it still feels flimsy. On top of it, the USB that connects to the charger never went in correctly, it was always a bit wobbly (the issue is the charger, because I plugged the USB cable into another charger to try and it stays perfectly in).

My question: what is a safe replacement charger? Any 5 volt 2.0 amp will do? Any suggestions on amazon.de?

Thanks.

P.S. - absolutely love the m900, disappointed with the cheap charger, I didn't violently push it in at the wrong angle, it's just clearly a poorly made thing (not by GD obviously).