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MDAC first listen (part VII)

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Krisposs12 said:
Hi John,

I just noticed something a little strange and hoped you might have some insight. When using a coax (*or* TOSlink, from the same socket with an adaptor) input from my STX soundcard which passes BTP tests with no problem, I noticed that quite often (but sometimes not) when stopping playing a file one or both of the level indicators on the M-DAC will stick at a certain random level. There will be no sound (at least none audible) even if the levels are stuck on high, but there will be a slight clicking/stepping sound when adjusting the volume in this state (which never occurs otherwise). Now the problem seems to be the STX outputting a constant signal of some kind; when unplugging the cable in this state (from the STX) the signal disappears and plugging it back in causes the situation to revert and the level indicators jump back to where they were before unplugging. Using the same cable on the same input from another coax source doesn't seem to have any issues which suggests it's the source. So:

(1) Do you have any (perhaps general) insight into what kind of situation could cause the constant input/stuck levels/subtle stepping noise when adjusting volume?

(2) Is this likely to be harmful to the M-DAC?

Many thanks again in advance,
Krisposs
Click to expand...

Hi Krisposs,

This is quite a worrying issue - caused by your source .

From your description, it would seem that the STX is holding (and repeating) the last Sample (instead of returning to Zero) - thus causing effectively a DC level at your MDAC output. This is indicated by the level meters they stay fixed at one level.

This will not damage your MDAC - but could damage your amplifier / speakers if there's no AC coupling / DC offset protection.

Suggest trying to find new software drivers / firmware for the STX - or contact them and explain the issue... (Good Luck)

John
 
StephenG said:
I've been lurking around this thread since I purchased the MDAC a couple of months ago. I've been listening to a lot of music since then and am happy for the lift in sound quality the MDAC has brought to my system - it's never sounded better! The MDAC is connected to my Win 7 64-bit laptop via USB playing (mainly) AIFF 16/44.1 files and a limited number of 24/96 flac files utilising J.River Media Center. I've updated the firmware to V0.96 and subsequently to V0.99.

I've noticed a possible 'bug' in my MDAC which the current firmware hasn't resolved, and I haven't read anyone else bring up this issue on this forum...

When I power up the MDAC, it shows 44.1 on the bottom of the display. When I fire up J.River Media player and attempt to play a 24/96 flac file, I do not get any sound. I have to subsequently play a 16/44.1 AIFF file to obtain sound. Only then, I can proceed to play the 24/96 flac file successfully. The same happens if I try to stream music using Spotify immediately upon power up...no sound, display reads 24/96 (which I'm sure it isn't!). It only plays fine AFTER I play a 16/44.1 file. :confused:

Is this normal? Has anyone else experienced this issue? John, I will be grateful if you could comment on this...by the way, I think the customer service you're providing is amazing! :)

Stephen
Click to expand...

Hi Stephen,

Try unplugging and re-plugging the MDAC USB cable - see if the system recycles the software drivers...'

Is this a new issue, or an issue since V0.90?

I tend to think its an odd software Bug on your PC... let us know if the unplugging and re-plugging the USB on the MDAC helps...
 
arthur said:
Now that is an excellent idea. My bet is Spendor. Just a guess :)

If that happens, might it be possible to build a cut off frequency for the speakers into the dacs and redirect to a sub?

Or do I not know what I'm talking about?
Click to expand...

Good idea - We could add a "Sub Out" on the "Active Cross Over Box" which might be internal to the MAMP's or an external unit...
 
Krisposs12 said:
Hi John,

I just noticed something a little strange and hoped you might have some insight. When using a coax (*or* TOSlink, from the same socket with an adaptor) input from my STX soundcard which passes BTP tests with no problem, I noticed that quite often (but sometimes not) when stopping playing a file one or both of the level indicators on the M-DAC will stick at a certain random level. There will be no sound (at least none audible) even if the levels are stuck on high, but there will be a slight clicking/stepping sound when adjusting the volume in this state (which never occurs otherwise). Now the problem seems to be the STX outputting a constant signal of some kind; when unplugging the cable in this state (from the STX) the signal disappears and plugging it back in causes the situation to revert and the level indicators jump back to where they were before unplugging. Using the same cable on the same input from another coax source doesn't seem to have any issues which suggests it's the source. So:

(1) Do you have any (perhaps general) insight into what kind of situation could cause the constant input/stuck levels/subtle stepping noise when adjusting volume?

(2) Is this likely to be harmful to the M-DAC?

Many thanks again in advance,
Krisposs
Click to expand...

Krisposs,

Could you give us your EXACT software versions for both Mainboard and Front panel MCU's (Press the Knob on Power up) - ie. "V0.99/V0.98"... This is the latest build BTW...
 
simonom said:
Hi John and Dominik,
FYI re. FW 0.99 update on a Mac not running OS Lion:
I have now tried 2 different virtual machines (Parallels and VMware Fusion with XP), Bootcamp (XP), and two different Macs (both running 10.6.8), but I cannot get the 0.99 .exe file, or any of the earlier versions, to run. No matter how many times I download and try to run it, I get the message: "the application configuration is incorrect. Reinstalling the application may fix this problem."
It's only greed that makes me want to update. Greed for what others are claiming gives better SQ.

Please: If anyone has successfully installed 0.99 or prior versions using Snow Leopard (10.6) or earlier, would they post or PM. Many thanks.

PS. running FW 0.90, using high-end Grado headphones, I struggle to hear a difference between the filters. The exceptions are Minimum Phase and Opt. Spectrum.
Click to expand...

simonom,

Some good news,

Dominik's now cracked the problem with updating via native MAC OS...

The soon to be release V1.0 will be compatible with updating via MAC...

So I'll tell Dominik that you will buy him a beer :p
 
JohnW said:
Dominik's now cracked the problem with updating via native MAC OS...

The soon to be release V1.0 will be compatible with updating via MAC...
Click to expand...

John, that's great news, thanks for letting us know.

Will v1.0 be bug fixes or will there be added functionality too?

Do you have any kind of roadmap for the Westlake version of the firmware?
 
JohnW said:
Krisposs,

Could you give us your EXACT software versions for both Mainboard and Front panel MCU's (Press the Knob on Power up) - ie. "V0.99/V0.98"... This is the latest build BTW...
Click to expand...

Hi John,

Thanks for your reply. The software versions are V0.99/V0.97 (I didn't realise the latter has been upgraded to 0.98)

Could my amp and speakers be damaged even though there's effectively no sound coming through? What about headphones?

Krisposs
 
Krisposs12 said:
Hi John,

Thanks for your reply. The software versions are V0.99/V0.97 (I didn't realise the latter has been upgraded to 0.98)

Could my amp and speakers be damaged even though there's effectively no sound coming through? What about headphones?

Krisposs
Click to expand...

Most likely your Amplifier will be AC coupled - thus your speakers will be protected - but there's nothing to protect your headphones.

I strongly suggest you don't continue using the source until you can resolve the situation...
 
JohnW said:
Most likely your Amplifier will be AC coupled - thus your speakers will be protected - but there's nothing to protect your headphones.

I strongly suggest you don't continue using the source until you can resolve the situation...
Click to expand...

Thanks John, I have contacted Asus but I doubt they'll be getting back to me anytime soon (or they'll give me the stock response and ask me to send it back to Amazon). In the meantime I'll avoid using it.

Am curious though - what kind of damage could it do to my headphones? I can't hear anything when it happens...

Krisposs
 
The soon to be release V1.0 will be compatible with updating via MAC...
So I'll tell Dominik that you will buy him a beer :p[/QUOTE]


Only one? :confused:
It's amazing what you two do.
 
Krisposs12 said:
Thanks John, I have contacted Asus but I doubt they'll be getting back to me anytime soon (or they'll give me the stock response and ask me to send it back to Amazon). In the meantime I'll avoid using it.

Am curious though - what kind of damage could it do to my headphones? I can't hear anything when it happens...

Krisposs
Click to expand...

You would not hear anything as its a "constant" DC value.... Depending upon the level of the "repeated" audio sample - you might hear a Pop once the audio is restarted...

Dom's looking it wither we can add software protection to prevent damage from "bad" input data (Held DC values) - but we have limited DSP power remaining... We might be able to tap into the Level meter routine - lets see...
 
JohnW said:
You would not hear anything as its a "constant" DC value.... Depending upon the level of the "repeated" audio sample - you might hear a Pop once the audio is restarted...

Dom's looking it wither we can add software protection to prevent damage from "bad" input data (Held DC values) - but we have limited DSP power remaining... We might be able to tap into the Level meter routine - lets see...
Click to expand...

Ah you mean the sudden "pop" might cause damage to the speakers/headphones... well that makes sense. I was wondering what damage an inaudible signal could possibly do. To be honest I do hear pops now and again but they are very low in volume.

In that case, just taking precautions to lower the volume or mute the M-DAC before stopping the play might avoid the problem for now? Am just thinking what I could do in the meantime to still make use of the STX even if it is an inconvenience. Apart from the obvious audible pop-related dangers, is there another inaudible reason for potential damage (i.e. more subtle signal related ones that might degrade electronics or something)? And would such damage be immediately obvious?

Many thanks
Krisposs
 
Krisposs12 said:
Ah you mean the sudden "pop" might cause damage to the speakers/headphones... well that makes sense. I was wondering what damage an inaudible signal could possibly do. To be honest I do hear pops now and again but they are very low in volume.

In that case, just taking precautions to lower the volume or mute the M-DAC before stopping the play might avoid the problem for now? Am just thinking what I could do in the meantime to still make use of the STX even if it is an inconvenience. Apart from the obvious audible pop-related dangers, is there another inaudible reason for potential damage (i.e. more subtle signal related ones that might degrade electronics or something)? And would such damage be immediately obvious?

Many thanks
Krisposs
Click to expand...

P.S. Sorry for all the questions - I am a little concerned about what damage I may have already caused by using the STX!
 
Krisposs12 said:
Ah you mean the sudden "pop" might cause damage to the speakers/headphones... well that makes sense. I was wondering what damage an inaudible signal could possibly do. To be honest I do hear pops now and again but they are very low in volume.

In that case, just taking precautions to lower the volume or mute the M-DAC before stopping the play might avoid the problem for now? Am just thinking what I could do in the meantime to still make use of the STX even if it is an inconvenience. Apart from the obvious audible pop-related dangers, is there another inaudible reason for potential damage (i.e. more subtle signal related ones that might degrade electronics or something)? And would such damage be immediately obvious?

Many thanks
Krisposs
Click to expand...

Under normal conditions Pops and click are normal and nothing to worry about (unavoidable with audio replay).

Damage "could" occur if the last sample was a high level (So a High level is "held" - so the Level meter was pegged say above -10dB).

Luckily, the MDAC's volume control will attenuate any DC on the input - I'm not sure what level you listen to with your headphones, but if the MDAC control was set below say -10db to -20dB then any DC from the held audio sample would be so low, I'd not worry about the potential of damage.

You would have to have a combination of a "High level" audio sample held (say above -10dB (-10dB to 0dB)) and the volume control set say above -10dB (-10dB to +3dB) before the potential of damage exists...

If your headphones work OK, then I'd not worry about any "Potential" damage...
 
JohnW said:
Under normal conditions Pops and click are normal and nothing to worry about (unavoidable with audio replay).

Damage "could" occur if the last sample was a high level (So a High level is "held" - so the Level meter was pegged say above -10dB).

Luckily, the MDAC's volume control will attenuate any DC on the input - I'm not sure what level you listen to with your headphones, but if the MDAC control was set below say -10db to -20dB then any DC from the held audio sample would be so low, I'd not worry about the potential of damage.

You would have to have a combination of a "High level" audio sample held (say above -10dB (-10dB to 0dB)) and the volume control set say above -10dB (-10dB to +3dB) before the potential of damage exists...

If your headphones work OK, then I'd not worry about any "Potential" damage...
Click to expand...

And that damage could occur at those volumes even without being able to hear anything through the speakers/headphones?
 
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