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MDAC first listen (part III)

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ok cool, i didn't know ifit was supposed to say 'passed' or not, i don't think it matters either way though, it sounds 'bit perfect' to my ears, although i guess its good to know your digital source isn't being interfered with in anyway before reaching the DAC

i fail to see (apart from new speakers) how what im hearing now could possibly sound better, its so clean but so smooth, i become really aware of the space behind & within the music, when the different layers have space between then the music can really take you into it
 
Well I finally got my M-DAC a few days ago. Initial impressions are reasonably positive but I'm having a few issues. I'm using it with a Gateway FX laptop running a 64 bit version of Windows 7 that I've used in my audio setup for the past couple of years. I've set up my sound properties as directed in the manual, disable all enhancements is checked and default format is set to 24 bit, 44100 Hz with both Exclusive Mode options checked.

When hooked up via USB using WASAPI in foobar with a buffer set to 500 ms and output data format as 24 bit the song will occasionally refuse to play, you can see the progress bar ticking back and forth but not progessing forward and no sound. Typically this seems to happen when clicking on a track or jumping forward in a track via the progress bar. Also, when running the 16 bit, 44100 hz bit perfect test it just hangs as described above.

Using WASAPI in XMPlay with output set to 24 bit, 44100 hz and buffer set to 0.750ms I don't seem to have any issues and it passed the bit perfect test.
Switching to ASIO4All solved the hanging issues in foobar but I didn't try the bit perfect test.

The second thing I noticed was clicks and squelches on audio tracks of videos. I first noticed it when I was reading a music blog that had some youtube music videos embedded in the page. I noticed the occasional click or pop but chalked it up to poor quality vids but then I tried watching a couple of videos via Media Player Classic (64 bit) and also via VLC (32 bit). In both cases I got occasional clicks and squelches.

My laptop has optical out via the headphone jack so I tried these videos using that without any issue. Switching to my HeadAmp Pico DAC there were no issues either. I also tried my wifes laptop via USB which only seemed to have a minor glitch at the start of one video. I thought this might be in the audio track itself but when I went back and listened again it wasn't there, otherwise though her laptop seemed fine so I tend to think that wasn't necessarily related to the issues with my laptop.

I tried various things like changing options on the M-DAC, different USB ports and unplugging everything from the laptop. At first I thought unplugging my USB Hub solved the issue, I watched one show which previously exhibited issues from start to finish without any problems but then later I tried the first video I had tried watching which had issues and it was the same as it had been with clicks and squelches evident from the beginning (this is the same video that clicked once on my wifes laptop). Then oddly when I went back and tried the video I watched without problems it now also had the clicks and squelches it originally had. I haven't had much time to experiment further but it seems like the first video might trigger the problem or make it worse.

I can use the Optical output, it did test bit pefect, but it does cut off the first second or so of a track when you jump to it in a playlist which is only minor but still a bit of an annoyance. I am a bit concerned about the quality using optical, I've always been under the impression it wasn't the best option. I'm also concerned about the USB performance, I've never had any real issues before and still don't with my Pico DAC.

Does anyone have any thoughts or suggestions?
 
elnero - try disabling Lsb Restore from within the M-DAC's menu
Hi Dominik, thanks for the reply. I tried that previously and the sound went crazy but on your suggestion I tried it again just now, the sound didn't go crazy this time, unfortunately it didn't help with the problem though.
 
John, is there any way to hook up some quality vishay nudes/caddocks to the rca and/or xlr outputs for fixed variable attenuation without causing any impedance mismatch/misc problems? Or using a good TKD pot? Is that possible? Stock gain is too high for me to use a low-enough digital attenuation so as not to impact sound quality..

I know that there are some commercial in-line attenuators being sold but being the skeptic i am, don't trust what's going inside those pieces. All i need is the analog attenuation to run DAC direct in to power amp. Have no need (or rather, can't afford) for the extra PSU frills in the MPAX

Ideally, you would want the MDAC to drive the audio cable directly, and have the attenuators at the "amplifier" end of the Cable.

What level of attenuation do you need? do you have some resistors laying around? (and are you using RCA or Balanced connection)?
 
Well I finally got my M-DAC a few days ago. Initial impressions are reasonably positive but I'm having a few issues. I'm using it with a Gateway FX laptop running a 64 bit version of Windows 7 that I've used in my audio setup for the past couple of years. I've set up my sound properties as directed in the manual, disable all enhancements is checked and default format is set to 24 bit, 44100 Hz with both Exclusive Mode options checked.

When hooked up via USB using WASAPI in foobar with a buffer set to 500 ms and output data format as 24 bit the song will occasionally refuse to play, you can see the progress bar ticking back and forth but not progessing forward and no sound. Typically this seems to happen when clicking on a track or jumping forward in a track via the progress bar. Also, when running the 16 bit, 44100 hz bit perfect test it just hangs as described above.

Using WASAPI in XMPlay with output set to 24 bit, 44100 hz and buffer set to 0.750ms I don't seem to have any issues and it passed the bit perfect test.
Switching to ASIO4All solved the hanging issues in foobar but I didn't try the bit perfect test.

The second thing I noticed was clicks and squelches on audio tracks of videos. I first noticed it when I was reading a music blog that had some youtube music videos embedded in the page. I noticed the occasional click or pop but chalked it up to poor quality vids but then I tried watching a couple of videos via Media Player Classic (64 bit) and also via VLC (32 bit). In both cases I got occasional clicks and squelches.

My laptop has optical out via the headphone jack so I tried these videos using that without any issue. Switching to my HeadAmp Pico DAC there were no issues either. I also tried my wifes laptop via USB which only seemed to have a minor glitch at the start of one video. I thought this might be in the audio track itself but when I went back and listened again it wasn't there, otherwise though her laptop seemed fine so I tend to think that wasn't necessarily related to the issues with my laptop.

I tried various things like changing options on the M-DAC, different USB ports and unplugging everything from the laptop. At first I thought unplugging my USB Hub solved the issue, I watched one show which previously exhibited issues from start to finish without any problems but then later I tried the first video I had tried watching which had issues and it was the same as it had been with clicks and squelches evident from the beginning (this is the same video that clicked once on my wifes laptop). Then oddly when I went back and tried the video I watched without problems it now also had the clicks and squelches it originally had. I haven't had much time to experiment further but it seems like the first video might trigger the problem or make it worse.

I can use the Optical output, it did test bit pefect, but it does cut off the first second or so of a track when you jump to it in a playlist which is only minor but still a bit of an annoyance. I am a bit concerned about the quality using optical, I've always been under the impression it wasn't the best option. I'm also concerned about the USB performance, I've never had any real issues before and still don't with my Pico DAC.

Does anyone have any thoughts or suggestions?

There are so many variables with computers & software that its very hard to diagnose the root cause of a issues like this.

I would say that we don't recommend using the MDAC on a Hub (At least on a hub that has heavy traffic - such as sharing with an external hard disk).

Is your issue only when your playing videos - i.e is "audio only" played back ok?

John
 
When hooked up via USB using WASAPI in foobar with a buffer set to 500 ms
When using Foobar via WASAPI into a USB port, you will probably need to drop the buffer size to <100mS to obtain stable playback.

If you are interested in videos and other such 'complications', I seriously suggest you look at J River Media Centre which is a far more comprehensive program than Foobar and, more important, professionally supported.
 
There are so many variables with computers & software that its very hard to diagnose the root cause of a issues like this.

I would say that we don't recommend using the MDAC on a Hub (At least on a hub that has heavy traffic - such as sharing with an external hard disk).

Is your issue only when your playing videos - i.e is "audio only" played back ok?

John
The DAC itself isn't plugged into the HUB, I have one USB port on the right side of the computer and 2 on the right side. I use the USB port on the right side for the DAC while one of the ports on the left is connected to the HUB which typically only has a mouse and tablet connected but allows me to use other devices like a flash drive more easily. As I noted though, the problem persisted even with everything unplugged and only the DAC plugged into the right side USB port (and I did try one of the left side ports as well).

The clicking and squelches only seem to be apparent on video via USB but audio playback via WASAPI in foobar does lock up for no apparent reason. I thought maybe that problem had worked itself out but as I was just listening to Bon Iver, when it started to play the second track it just stopped, I can skip to other tracks but nothing will play. When I switch to ASIO everything seems to work fine.
 
When using Foobar via WASAPI into a USB port, you will probably need to drop the buffer size to <100mS to obtain stable playback.

If you are interested in videos and other such 'complications', I seriously suggest you look at J River Media Centre which is a far more comprehensive program than Foobar and, more important, professionally supported.
I've never had issues with my current buffer size when using any other USB DAC's I've owned or tried like my HeadAmp Pico, CEntrance DACmini, Headroom Ultra Mini DAC. I arrived at my current buffer size through trial and error but I'll certainly give a lower buffer size a try to see if it has any affect on the locking up issues but the clicking and squelches does not occur in foobar.

For video playback I'm using either Media Player Classic (64 bit) or VideoLAN VLC (32 bit), both are fairly robust dedicated video players. Also, I first heard the clicks in the audio watching a few music videos on YouTube.
 
Ideally, you would want the MDAC to drive the audio cable directly, and have the attenuators at the "amplifier" end of the Cable.

What level of attenuation do you need? do you have some resistors laying around? (and are you using RCA or Balanced connection)?
Ah, that makes perfect sense. Yes i do have some resistors lying around. I'm using both RCA and balanced. RCA for the active sub, balanced for the power amp.

About 20-30 dB, depending on the material. How should i hook up the resistors, and what values should i use? Thank you, John
 
Hi John, Once you get back from your epic road trip (did you factor in the fuel costs and danger element when you made that purchase? :eek: ) I just wondered if there was any ETA for when the SBT clock lock upgrade might be available? Really looking forward to hearing it!

Have a safe journey.
 
Hi John (or others who can help me),

I received my M-DAC a couple of days ago from the Canadian distributor.
Even with minimal burn-in, it's definitely a step up from my heavily modded Caiman in terms of sound quality.

There is one problem though. When I'm watching TV and running the audio from the cable box via optical (the only choice) the sound cuts out for about half a second every minute or two. As you can imagine, it's rather annoying. I've tried both optical inputs, and even used our other cable box, but the problem persists. This was never an issue with the Caiman.

I was wondering if any else has experienced this and what you might suggest as a solution, short of sending it back. I know from PFM forums that there have definitely been some QC issues with the first batch of MDACs, and would rather wait a bit if a replacement unit becomes necessary.

Any help would be most appreciated. Thanks. ;)

Bill
 
Hi John (or others who can help me),

I received my M-DAC a couple of days ago from the Canadian distributor.
Even with minimal burn-in, it's definitely a step up from my heavily modded Caiman in terms of sound quality.

There is one problem though. When I'm watching TV and running the audio from the cable box via optical (the only choice) the sound cuts out for about half a second every minute or two. As you can imagine, it's rather annoying. I've tried both optical inputs, and even used our other cable box, but the problem persists. This was never an issue with the Caiman.

I was wondering if any else has experienced this and what you might suggest as a solution, short of sending it back. I know from PFM forums that there have definitely been some QC issues with the first batch of MDACs, and would rather wait a bit if a replacement unit becomes necessary.

Any help would be most appreciated. Thanks. ;)

Bill

I'm pretty sure I read that this problem (with less than highest quality optical sources) is going to be rectified with the latest firmware update (please correct me if I've gotten that wrong folks!).

I should be getting mine in another week - fingers crossed!

- John
 
Hi John (or others who can help me),
...
There is one problem though. When I'm watching TV and running the audio from the cable box via optical (the only choice) the sound cuts out for about half a second every minute or two. As you can imagine, it's rather annoying. I've tried both optical inputs, and even used our other cable box, but the problem persists. This was never an issue with the Caiman.

I was wondering if any else has experienced this and what you might suggest as a solution, short of sending it back. I know from PFM forums that there have definitely been some QC issues with the first batch of MDACs, and would rather wait a bit if a replacement unit becomes necessary.

Any help would be most appreciated. Thanks. ;)

Bill

I'm pretty sure I read that this problem (with less than highest quality optical sources) is going to be rectified with the latest firmware update (please correct me if I've gotten that wrong folks!).

I should be getting mine in another week - fingers crossed!

- John

Hi wpope,

Like quad2fan mentioned, this is one of the items due to addressed in the forthcoming firmware release.

I would not consider it as QC issue, it is just about how the SPDIF receiver is configured currently to produce best jitter performance. Sources with sudden and large enough phase jumps need a different kind of trade off here. I've understood that this is going to be selectable in the future SW.

My DVB-T (terrestrial) box provides reasonably good SPDIF output so that drop outs are seldom enough not to be an issue. It is very nice indeed to enjoy the soundscape of TV material over a decent audio system. Sometimes it is quite amazing how much effort those folks - for whom visual world is the main thing - put into the sound!
 
Hi John (or others who can help me),

I received my M-DAC a couple of days ago from the Canadian distributor.
Even with minimal burn-in, it's definitely a step up from my heavily modded Caiman in terms of sound quality.

There is one problem though. When I'm watching TV and running the audio from the cable box via optical (the only choice) the sound cuts out for about half a second every minute or two. As you can imagine, it's rather annoying. I've tried both optical inputs, and even used our other cable box, but the problem persists. This was never an issue with the Caiman.

I was wondering if any else has experienced this and what you might suggest as a solution, short of sending it back. I know from PFM forums that there have definitely been some QC issues with the first batch of MDACs, and would rather wait a bit if a replacement unit becomes necessary.

Any help would be most appreciated. Thanks. ;)

Bill

Have you tried running optical from the TV instead?

I found this greatly reduced the dropouts opposed to using optical direct from my V+ box for some reason

A question for Dominik: when is it planned the fw to be released?

Id really also like to know if a 'screen off' will be available rather than just dim?

Thanks
 
I got mine on Wednesday, I'm very impressed so far. With regard to the fw, how do we get it installed? Probably a stupid question... But there it is.
Also can anyone tell me about the matching upcoming power amp? Is there only one, or a choice? And what's the predicted price?

Cheers
 
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