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MDAC first listen (part IV)

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aloft said:
Hi there,

is there a thread / page where the MPAX can be ordered? Are there other tweaks available?

I just switched to MDAC from a Young since I wanted the convenience of driverless USB operation with my IPad. Soundwise, it's a close call.

Cheers, Matthias
Click to expand...

Hi mattias,

Not sure if you noticed but the MDAC remote handset will also control the iPad media player.

John
 
MartinFXDX said:
Well I borrowed a M-DAC for 4 days and compared it to my TAG DVD/AV32DP/Calliope setup. I used identical cables and the by-pass inputs with the M-DAC in "preamp disabled" mode.

In this way I was able to easily switch between the internal TAG DACs with their synch link to the DVD transport and the M-DAC

I found the differences between some of the filters quite noticeable. Optimal Transient XD was, at first a little like engaging the "Loudness" button on an old amp! Though to be fair, the effect did seem to be less pronounced as time went on. Maybe I got used to it or maybe the unit was still settling in. I found the best use of this filter to be with dull and lifeless masterings and in this role it worked very well.

Getting back to how it compared with my TAG setup I found that the Optimal Sectrum filter produced results very similar to the the TAG equipment using the synch link and better than digital sources without the synch link.

So, an impressive performance on the part of the M-DAC but one that didn't improve on what I already have as my non synch link digital sources are in the main AV ones. However the choice of filters would be useful for "correcting" poorly mastered CDs and for adding extra high quality digital inputs.
Click to expand...

Well I'm pretty much sold on the digital format now. My comparison between the MDAC and Tag DVD32R was from memory , glad to see the MDAC performance matches it. Depending on how long you have used the MDAC, 100 hours ish should do it, the performance does creep on you and smaller details in recordings you may not have noticed before suddenly jump out.

Hope your DVD player keeps going for a little longer.

Try and use the MDAC as a pre and see what you think . I've yet to do this as I bi-amp thru my AV pre and eagerly await the MPAX arrival to try out the bypass .
 
Hi John,

Is it possible you could switch my M-PAX order for an 8200CD upgrade instead please? I don't mind waiting.

On a side note, seeing as your basically throwing out the inside's of the 8200CD, is it possible to 'upgrade' to the 8200CDQ's internals at the same time (minus some of the analogue functions of the CDQ) ?

Thanks
 
Hi John hope all is well,

Quick question in regards the MTRANS or MSERV cd and mini-itx Async USB optical 192 , are you designing a PSU for it ? Perhaps as an upgrade path similar to the MDAC ?
 
PhilCTTE said:
Hi John hope all is well,

Quick question in regards the MTRANS or MSERV cd and mini-itx Async USB optical 192 , are you designing a PSU for it ? Perhaps as an upgrade path similar to the MDAC ?
Click to expand...

There will be no need for an upgrade PSU for the MTRANS - its PSU quality should not effect the sound quality of the MDAC when clock locked (same for the M-ITX).

John
 
JohnW said:
Hi Vin,

Both are OK - so what every sounds the best :)

The "dropout voltage" is around 14.5V, so 15V "regulated" should be OK.

The M-PAX will supply 15VDC to the M-DAC.

ETA 's about 2 months for first M-PAX units, I've just completed the "design and simulation" of the PSU section - if the the simulation results are to be believed then its certainly ultra high performance - I hope it equals a SQ benefit...

John
Click to expand...
Thanks John - not sure which sounds better at this point but I will go with the lower voltage based on the fact that the M-PAX will be providing the same voltage - would you agree?

One additional thought, it seems that the output voltage is closer to 17v when provided by a 230v feed and from what some others have kindly reported being around 16.8v or so. So I am a little confused as the power supplies are natively providing a higher voltage to what the M-PAX will be providing. Do you have any additional thoughts around this to share?
 
All down to the optical galvanic isolation ?
So basically once the digital data is sent from the processor via USB the bi directional method of verifying that all the data contains the right bits there no possible way of corruption ? Its a bit of a minefield when looking into all the exotic power supplies and cables for computers being promoted. Thanks for the guidance.

Regarding RF pollution is this sorted as well ?

Thanks
 
Hi VinBob,

The standard PSU supplied with the MDAC is unregulated AC - as the supply is unregulated and you need voltage headroom to maintain the "Dropout voltage" during low mains level.

The MDAC indicates an average voltage level - with the AC input from the standard MDAC AC supply there will be a significant Ripple voltage on the internal PSU. Due to this ripple (twice every mains cycle) the voltage will swing about the MDAC's average indicated level by about 1V to 2V.

With a regulated DC supply you do not need to worry about any ripple - and you can afford a lower input voltage which will reduce the heat dissipation within the M-DAC.

So the 15VAC from the standard MDAC supply will not be the same as the 15VDC from the M-PAX

John
 
Hi John

Loving the M-DAC i received last week, it really shines through my headphone setup :)

Could you add me to the waiting list for a M-Pax please ?

Cheers, Carl
 
Dear John,

please can you say what kind of usb receiver you will use in the 24/192 transport? Is it XMOS-based or proprietary code? Will it also improve the sq for 16/44 and 24/96 further?

I got my M-DAC ten days ago and after some days of non-stop-playing it's getting better and better. A lot of details, huge Soundstage, very good timing, deep bass, very "analog". I am really satisfied. I think this type of organic capacitors needs a lot of burn-in-time...

Thank you very much,
Uwe
 
Thanks John

Can you please again list all features which will be available on M-PAX and also the cost please.

Harry

JohnW said:
Hi Harry,

The M-PAX has a 115V/230V voltage selector - but it is officially for European sales only - you would need someone in Europe to ship the unit to you in the US.

John
Click to expand...
 
PhilCTTE said:
All down to the optical galvanic isolation ?
So basically once the digital data is sent from the processor via USB the bi directional method of verifying that all the data contains the right bits there no possible way of corruption ? Its a bit of a minefield when looking into all the exotic power supplies and cables for computers being promoted. Thanks for the guidance.

Regarding RF pollution is this sorted as well ?

Thanks
Click to expand...

The "raw" data should never be corrupted with any source (always the same 1's & 0's) but its the timing of the 1's & 0's that becomes important. Clock-locking the M-TRN or M-ITX removes any possibility of timing variations effecting the audio conversion process.

The M-TRN will inject very low levels of RF into the mains supply. However the M-ITX which uses a standard switching supply due to power demands of the PC system will inject significant RF garbage onto the AC mains - so a decent mains filter on the M-ITX PSU is recommended.

John
 
uwe061 said:
Dear John,

please can you say what kind of usb receiver you will use in the 24/192 transport? Is it XMOS-based or proprietary code? Will it also improve the sq for 16/44 and 24/96 further?

I got my M-DAC ten days ago and after some days of non-stop-playing it's getting better and better. A lot of details, huge Soundstage, very good timing, deep bass, very "analog". I am really satisfied. I think this type of organic capacitors needs a lot of burn-in-time...

Thank you very much,
Uwe
Click to expand...

Hi Uwe,

Yes, its quite interesting to hear how the MDAC "runs-in"... Its only conjurer on my side that its due to the Organic Caps - but they are the very first suspects on my list :) !

The XMOS is just a dumb peace of silicon - until programmed with software (firmware). We use the XMOS but with our own code stack.

The M-TRAN is galvanically isolated - so depending upon the system, it may result in improvement in SQ with 24/96 & 16/44.1 etc - depends if you hear any improvement with a USB isolator.

John
 
JohnW said:
Hi VinBob,

The standard PSU supplied with the MDAC is unregulated AC - as the supply is unregulated and you need voltage headroom to maintain the "Dropout voltage" during low mains level.

The MDAC indicates an average voltage level - with the AC input from the standard MDAC AC supply there will be a significant Ripple voltage on the internal PSU. Due to this ripple (twice every mains cycle) the voltage will swing about the MDAC's average indicated level by about 1V to 2V.

With a regulated DC supply you do not need to worry about any ripple - and you can afford a lower input voltage which will reduce the heat dissipation within the M-DAC.

So the 15VAC from the standard MDAC supply will not be the same as the 15VDC from the M-PAX

John
Click to expand...
Thanks John - I think I understand what you are saying but still a little fuzzy. So would you recommend I go with the lower 15v using the UK power supply from the regulated 220v transformer? I am just a little concerned about harming the MDAC (by not providing enough power) and really don't want to cause any issues to then have to deal with the whole wait and swap out process which has taken me 2 months.

Sorry for the repeated questions and appreciate your help/feedback here...

Thanks,
Vin.
 
John, I guess you missed my posts, any chance of just a psu upgrade? the pcb for the mdac and the HQ DC supply, I dont need any other options, just a nice power supply, if this isnt possible could you please let me know.
Many thanks

Alan
 
VinBob said:
Thanks John - I think I understand what you are saying but still a little fuzzy. So would you recommend I go with the lower 15v using the UK power supply from the regulated 220v transformer? I am just a little concerned about harming the MDAC (by not providing enough power) and really don't want to cause any issues to then have to deal with the whole wait and swap out process which has taken me 2 months.

Sorry for the repeated questions and appreciate your help/feedback here...

Thanks,
Vin.
Click to expand...

Hi Vin,

Unlike high voltage - you cannot permanently harm the MDAC with a lower voltage it might "play up" but will be ok once the correct operating voltage is restored.

The MDAC has voltage supply monitors that shut down the MCU's should the voltages get too low, but before this would happen you would see (hear) many odd effects.

So try both UK supply's and see which works best for you :)

John
 
JohnW said:
Hi Vin,

You cannot permanently harm the MDAC with a lower voltage it might "play up" but will be ok once the correct voltage is restored.

The MDAC has voltage supply monitors that shut down the MCU's should the voltages get too low, but before this would happen you would see (hear) many odd effects.

So try both UK supply's and see which works best for you :)

John
Click to expand...
Thanks John - Sorry if I did not explain correctly. I only have one UK supply but am using two different transformers. One is a lower 220v 'regulated' and one is a 230v brick non regulated. The 220v gives the 15.1v while the 230v gives the 17.5v (sometimes 17.4) - People seem to have reported voltage closer to 17v and you mentioned this is what you were seeing in Vegas. So I was looking for a recommendation on which one to go with that would also be safe to use. Sorry - I am being a pain now but given what I have gone through, I am now in paranoia mode and really want to be told what to do as I am worried I'll break it!! :confused: - So, can you give me a final recommendation here...?

Thanks again mate!
 
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