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MDAC first listen (part XIV)

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Trojka said:
What does the isolator do? (oh, there's non powered hub in between in my setup as well)
Click to expand...

...err probably cures my OCD ;)

I originally put it there in an attempt to cure an annoying 'click', which turned out to be a synchronisation issue between an SBTouch, and an SBReceiver.

That's been cured by replacing the Receiver with a second hand Touch.

I bought the 'Danish' one, there's a few references to it earlier in the thread...if there's an improvement it's marginal, but as I now have it I might as well use it. :)
 
hluga said:
if you restart the mdac with music playing the player must switch to another output and then eventually come back to mdac when usb recognition has been achieved (i.e. when the drivers are ok and the device registered as a coreaudio component)
Click to expand...

I think it will take a true expert (? Dominik) in the art of USB audio to answer whether or not it is a realistic expectation that a USB audio stream is expected to survive the upheaval of a receiving device (MDAC) stopping then restarting.
 
JohnW said:
Don't worry, I'm designing this as a Christmas gift too myself! - I'm even more excited by the design as the days go by, as speaking with Dom we have come up with more tricks to improve performance :)
Click to expand...

Hi John,
That's great, thanks for putting my mind at rest - please keep me on the list in that case :D:D

The prospect of hearing what you can do with an unconstrained design like TDAC has got me drooling a bit, although when I think about my existing power amp I realise that it might be a case of pearls before swine at the moment - so there'll hopefully be more to unlock when the MAMP comes along.

I'd also be one of those who'd appreciate an analogue input if it's doable without you overrunning on your christmas prezzie :)

Even then, it's still possible I might go down the road of MDAC/MPAX as an "every-day" system, if only for the convenience of the AV bypass. I certainly wouldn't expect you to pollute your statement design with one of those!

edit:
fusion5 - just seen you post. So i'm not the only one needing the HT bypass then :)
 
I've had my M-DAC for some time now, and I'd performed a bit perfect test via my laptop when I first got it, however my normal mode of listening is via an SBTouch, playing FLAC from a QNAP server...

I thought I'd test out the 'Bit Perfect' test using the entire setup, and in the way I normally listen...

So I created a mini album 'M-DAC Bit Perfect Test' with a nice little M-DAC album cover, with the following tracks (FYI I created the FLAC versions using dBpoweramp);

1. 16*44.1 WAV test.wav
2. 24*96 WAV test.wav
3. 16*44.1 FLAC test.flac
4. 24*96 FLAC test.flac

And then rebuild my SB catalogue...

FYI I'm using A0.5 on the M-DAC, EDO 7 on the SBTouch (connected via USB/USB hub/USB galvanic isolator), and LMS 7.7.2 on a QNAP TS-119

And hurrah! it passed each time :)

Interestingly enough the CPU on my server went through the roof (about 50% cpu) when I was testing the WAV, presumably it must be transcoding on the server, whereas when playing the FLAC tests it was back down to its normal 5%, with the transcoding occurring at the Touch end.

So there's a couple of urban myths dispelled, if FLAC from an SB server transmitted by wi-fi to an SBTouch can produce a 'bit perfect' test at the M-DAC for both 16*44.1 & 24*96 there can't be much (or anything for that matter) wrong with that architecture.

Therefore not much wrong with FLAC and Wi-Fi then, less bandwidth, less storage, less cables, and 'bit perfect'...cue smug face! :)
 
:D

Nice. Only difference between your setup and mine is the addition of the USB isolator and the use of WIFI (and I'm using a QNAP TS-219+, I needed more power because of my 2500+ cd collection in FLAC).
 
Trojka said:
:D

Nice. Only difference between your setup and mine is the addition of the USB isolator and the use of WIFI (and I'm using a QNAP TS-219+, I needed more power because of my 2500+ cd collection in FLAC).
Click to expand...

I have about the same library size, I think the ts-119 is 1.2ghz, since moving to 7.7.2 it runs like a 'greased weasel'...4 mins for a delta rebuild, and 45 mins for a full rebuild...so happy days!

On 7.3.3 those figures were 45mins and 5 hours respectively!!!

It's the adoption of the embedded SQLite DB that's done the trick, no more cross application calls to MySQL :D
 
I tried it first with a TS-119, but my NAS is being used quite extensively: my wife streams video's from it to 'the gym', while I listen to some music downstairs (let's say in 24/96 format) and an online musical collaborator grabs the bass parts I did for his song last night from my FTP server. The TS-219 seems to cope with all this a little bit better. :D Although a library scan at the same time, is still too much for the poor little server.

What I really love about the Squeezebox and its software (and I have discovered this recently) is that I can connect to my library at work via Squeezeplayer and OpenVPN for Android. Listening to everything in FLAC on my Galaxy SII. Brilliant. Sound quality isn't great, but once I finally get my laptop from work I'm thinking about buying a Dragonfly or something and install Softsqueeze and OpenVPN.
 
jonathanmueller said:
No, I own a bunch of DACs and none has these problems.
Click to expand...

Jonathan,

We still believe that you maybe experiencing a filter load issue, should you try using the unit with Fast or Slow filters and see if the issue occurs (Power cycle with Fast or Slow filters selected)?

John
 
JohnW said:
Jonathan,

We still believe that you maybe experiencing a filter load issue, should you try using the unit with Fast or Slow filters and see if the issue occurs (Power cycle with Fast or Slow filters selected)?

John
Click to expand...

John,

changing the filters doesn't change anything.
It's not a problem just on my side as at least 3 others here have reported that issue:
Turning on the M-DAC with music playing will set the volume to -80 dB, the frequency to 96 kHz. The peak meter will work but no signals from the M-DAC.
 
jonathanmueller said:
John,

changing the filters doesn't change anything.
It's not a problem just on my side as at least 3 others here have reported that issue:
Turning on the M-DAC with music playing will set the volume to -80 dB, the frequency to 96 kHz. The peak meter will work but no signals from the M-DAC.
Click to expand...

John's said he'd thinks it might be a problem with the way the software within the mdac loads the code for the filters.

He hasn't asked you to simply change filters, he's explicitly asked you to power cycle the DAC with specific filters selected, and then to report back on the results.

You have a model which seems to be exposing the problems, so he's adding you to do some specific tests so he can use those results as part of the diagnosis
 
ChrisPa said:
He hasn't asked you to simply change filters, he's explicitly asked you to power cycle the DAC with specific filters selected, and then to report back on the results.
Click to expand...

Ok, sorry. Didn't quite get his points.

I did the following for every filter:
Select the filter and reboot the device.

Every filter made the volume jump to -80 dB.
Sometimes it showed this message: "Flushing buffer (3)"
Sometimes the frequency was set from 48 kHz to 96 kHz.

I also tried switching the inputs.
1.) Start music
2.) Power off, then power on the M-DAC
3.) Peak meter is moving but no sound
4.) Switch from USB to OPT2
5.) Peak meter stops moving
6.) Switch back to USB input
7.) Peak meter is not moving
8.) Then, sometimes after switching back to USB it displays the message "Flushing buffer (3)".
 
jonathanmueller said:
Ok, sorry. Didn't quite get his points.

I did the following for every filter:
Select the filter and reboot the device.

Every filter made the volume jump to -80 dB.
Sometimes it showed this message: "Flushing buffer (3)"
Sometimes the frequency was set from 48 kHz to 96 kHz.

I also tried switching the inputs.
1.) Start music
2.) Power off, then power on the M-DAC
3.) Peak meter is moving but no sound
4.) Switch from USB to OPT2
5.) Peak meter stops moving
6.) Switch back to USB input
7.) Peak meter is not moving
8.) Then, sometimes after switching back to USB it displays the message "Flushing buffer (3)".
Click to expand...
Just being curious, what would happen if you unplug the DAC, turn off the player, then plug the DAC, and restart the player? When I have a problem with my portable DAC, I try this and sometimes it works.:)
 
jonathanmueller said:
Ok, sorry. Didn't quite get his points.

I did the following for every filter:
Select the filter and reboot the device.

Every filter made the volume jump to -80 dB.
Sometimes it showed this message: "Flushing buffer (3)"
Sometimes the frequency was set from 48 kHz to 96 kHz.

I also tried switching the inputs.
1.) Start music
2.) Power off, then power on the M-DAC
3.) Peak meter is moving but no sound
4.) Switch from USB to OPT2
5.) Peak meter stops moving
6.) Switch back to USB input
7.) Peak meter is not moving
8.) Then, sometimes after switching back to USB it displays the message "Flushing buffer (3)".
Click to expand...

To help me better understand the issue, Pls. follow these steps:

1. Select Fast Filter

2. Set Level to say -40dB

2. Power Off

3. wait 10 seconds

4. Power On

Is the Level still "-40dB" upon power-up?

Is the "Fast Filter" Selected upon power up?

Do you still have the issue?

If the MDAC has not recalled the Volume level set before power off (in this case -40dB as requested in Step 2) and / or the selected "Fast" Filter then I'm sorry YOUR UNIT HAS A HARDWARE ISSUE - I cannot stress this in any other way.

Hopefully this will not be the case and the MDAC will correctly recall the selected Fast Filter and recall the Volume level set before power-off.

An instantaneous "Buffer-Flush" message on first enumeration of the USB port is normal while the buffer's correctly align themselves...

John
 
jonathanmueller said:
John,

changing the filters doesn't change anything.
It's not a problem just on my side as at least 3 others here have reported that issue:
Turning on the M-DAC with music playing will set the volume to -80 dB, the frequency to 96 kHz. The peak meter will work but no signals from the M-DAC.
Click to expand...

Pray pardon the 'tard question...but why do you start the music BEFORE the dac is on and ready? :confused::confused:
 
Hi John,

So, I've definitely settled on A08 at 180 degrees phase and OT XD filter. It seems to favour the ProAcs a friend has lent me for a while too. It sounds more focused, with tighter, more defined bass than it did with the shipped firmware.

I know you're busy on millions of other very exciting projects at the moment too (still looking forward to the MPAX!) - but do you know when you and Dominic will get around to looking into source renaming?

For me, that would be the icing on the cake!

Cheers,

Ben
 
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