MDAC first listen (part XVII)
- Thread starter Sebbyp
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fusion5
on the dark side of hifi...
24/192 requires USB 2.0
I very much prefer A.08 on Windows 8 Pro.
But it's not entirely OS dependent as A.08 largely became my favorite M-DAC FW after improving the mains power filtration to my entire system using a PS Audio P5 PowerPlant, and also upgrading the M-DAC's PSU to the McRU unit.
Prior to the above I preferred v.90 and to a slightly lesser degree v.99
LittleToast
pfm Member
Hi John,
My 16 bit AAC files ripped from cd are playing as 24 bit by mdac. I am using an ipad 3 connected to the mdac via usb. How do I make the mdac see the files as 16 bit?
Thank you very much.
My 16 bit AAC files ripped from cd are playing as 24 bit by mdac. I am using an ipad 3 connected to the mdac via usb. How do I make the mdac see the files as 16 bit?
Thank you very much.
The external DC PSU I am building has been tested and is ready to be connected to my M-DAC. I have the following DC rails set at +/- 16V with 300mA current capability. I can adjust both independently on each rail.
+15V Analog: set to +16V
-15V Analog: set to -16V
+15V Digital: set to +16V
Ground: Analog and Digital grounds tied together
I'm using an off-the-shelf 9-pin DIN cable assembly. I double checked the pin-out against the M-DAC PSU pin-out that John has shown here:
http://www.pinkfishmedia.net/forum/showpost.php?p=1704807&postcount=22
I also did some AC measurements on the M-DAC wall wart rails and get this unexpected result: voltage difference between pair 6, 9 and pair 3, 7 is 30V whereas between 6 and 9 it is 0V and same thing between 3 and 7 (also 0V). All 4 pins are referenced as +15V Digital. I guess pair 3, 7 is 180deg out of phase, correct?
John, Gh0st and sam_cat, any last minute advice before I power up the M-DAC? Gulp !
Cheers,
Martin
+15V Analog: set to +16V
-15V Analog: set to -16V
+15V Digital: set to +16V
Ground: Analog and Digital grounds tied together
I'm using an off-the-shelf 9-pin DIN cable assembly. I double checked the pin-out against the M-DAC PSU pin-out that John has shown here:
http://www.pinkfishmedia.net/forum/showpost.php?p=1704807&postcount=22
I also did some AC measurements on the M-DAC wall wart rails and get this unexpected result: voltage difference between pair 6, 9 and pair 3, 7 is 30V whereas between 6 and 9 it is 0V and same thing between 3 and 7 (also 0V). All 4 pins are referenced as +15V Digital. I guess pair 3, 7 is 180deg out of phase, correct?
John, Gh0st and sam_cat, any last minute advice before I power up the M-DAC? Gulp !
Cheers,
Martin
Here's a picture of the little beast.
https://plus.google.com/photos/116275103191426331121/albums/5835353298895620801?authkey=CKCaovSqv5WslQE
BTW, junior members do not have rights to insert attachments. Is there a way to change that?
https://plus.google.com/photos/116275103191426331121/albums/5835353298895620801?authkey=CKCaovSqv5WslQE
BTW, junior members do not have rights to insert attachments. Is there a way to change that?
DANOFDANGER
pfm Member
Is a high quality usb cable important even though the system is asynchronous ?. I couldn't understand how it could make a difference given that the conductors speed would not change enough or at all to affect how the asynchronous clocks would interact with it.
Brings me to why is there a distance limitation, does the longer cable actually induce more jitter or suffer from power loss ?.
Brings me to why is there a distance limitation, does the longer cable actually induce more jitter or suffer from power loss ?.
I've seen in other forums that bad designed/long usb cables are subjected to interference and hence data loss, and in the external dac's case will not be error corrected as in ordinary computer peripherals such as printer, therefore is the edge of using better cable for dac.
DANOFDANGER
pfm Member
I've seen in other forums that bad designed/long usb cables are subjected to interference and hence data loss, and in the external dac's case will not be error corrected as in ordinary computer peripherals such as printer, therefore is the edge of using better cable for dac.
How can interference cause error when the medium is in pcm, wouldn't the interference have to be that bad that the signal would have to be halted or prevent some of the encoded signal from reaching its destination. Which is why the data could not be corrected ?.
Wouldn't it have to be truely severe in order to have a impact of that kind ?.
JohnW
pfm member
Hi Martin,
The connection details you linked to are correct - the digital connections are paralleled - that's why you are reading 0V between them - measuring to the Mini Din outer shell and you will measure about 15V AC on each "Live" conductor - and 0V on each Ground connection...
Nice work, just need case now. Is your unit sov ? If so could you tell us the improvments ? Do you start from standard psu kits or make the design by yourself ?
has anyone tried the m-dac with the pre switched off and used it as a dac only into a quality pre-amp?
I've had the m-dac powered up constantly since boxing day and find it detailed but a bit laid back and unexciting.
my power amp and speakers have been used with various pre-amps and cd players in the past and gave great results.
I've had the m-dac powered up constantly since boxing day and find it detailed but a bit laid back and unexciting.
my power amp and speakers have been used with various pre-amps and cd players in the past and gave great results.
finesensations
pfm Member
AFAIK, you can't actually 'switch off' the 'pre amp'.
Fixed output level mode (0dB) offers the same SQ as setting the volume control to 0dB.
Suggest you try the various Firmware versions and Filters to fine tune the SQ to your preference.
Were there the tiniest of delays between the channels, good solid imaging would not be possible.
Take, for instance, a Red Book (CD) data stream of a mono disc - I cite Red Book because the data is always stereo, even if the content of the two channels is identical i.e. mono. If there was the tiniest inter-channel delay, the image stability of such a disc would be severely compromised.
This is generally correct because the AAC decoder will calculate as deeply as it is able - silly as this may seem when dealing with a compressed format. Don't worry about it.
Hi Plutox
I don't see how this is related to my post. I wasn't asking what the effect of a delay would be, I was asking for the evidence of a delay
Thank you for the encouragement, hluga.
My M-DAC is standard. If John offers a DIY kit in the future, I would be interested in sovereigning it. Adding another bipolar rail to my project wouldn't be a problem. Will need a bigger enclosure than the 7x9 in case I currently have in mind, though
I use Twisted Pear Audio Placid HD PSU kits. All in all, the project should cost me around $US300 (including the case)
John, thanks for your answer. I guess the next step is to let the thing rip into the M-DAC: short high anxiety moment ahead.
Martin
sam_cat
C'est Crounchifique!
Good work.
On first power on hold the Mdac knob in and check voltages that way.. Do it now on standard psu then compare.. Gives you some idea if something is wildly out.
And let ilus know how much of a step you feel it makes when you brave switching it on....
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