MDAC first listen (part IV)

[JohnW]

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

Hi Alan,

Sorry I missed your post earlier.

ATM we have no plans to offer a PSU only M_PAX.

The main cost in the M-PAX is the casework, and PSU sections, the additional analogue circuits might only add say 15% to 20% of the M-PAX cost, so its not beneficial for us to pay the manufacturing, certification and administration costs for two related but differing units.

John

 

[JohnW]

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!! - So, can you give me a final recommendation here...?

Thanks again mate!

Hi Vin,

Both options will work without damage to the MDAC - so what ever sounds the best - there is ZERO harm in trying both options

If you really want a definitive answer (not based upon SQ but 100% sure to work ok) I'd say the 17V option as this will allow for mains droop and ripple voltage headroom within the MDAC.

BUT there can be no harm done in listening to both options

John

 

[VinBob]

Hi Vin,

Both options will work without damage to the MDAC - so what ever sounds the best - there is ZERO harm in trying both options

If you really want a definitive answer (not based upon SQ but 100% sure to work ok) I'd say the 17V option as this will allow for mains droop and ripple voltage headroom within the MDAC.

BUT there can be no harm done in listening to both options

John

OK - Thanks for the recommendation John - I'll go with the 230v Transformer then which gives the 17.4/5v which is close to what you were seeing in Vegas and more in line with the UK voltage given the additional 10v output. I will use it sparingly though until I can get one of your M-PAX units in late April!

BTW, any ideas on why the US 110v PSU you kindly sent did not work out and is giving a much higher voltage? Is there any chance I can get a good working 110v version from IAG and avoid the transformers altogether while I wait for the M-PAX?

Cheers,
Vin.

 

[Dawg]

Hi Alan,

Sorry I missed your post earlier.

ATM we have no plans to offer a PSU only M_PAX.

The main cost in the M-PAX is the casework, and PSU sections, the additional analogue circuits might only add say 15% to 20% of the M-PAX cost, so its not beneficial for us to pay the manufacturing, certification and administration costs for two related but differing units.

John

Cheers John, could you please put me down for an m-pax with pcb for mdac then. I would also really like to use my squeezebox duet with clock lock as mentioned in my earlyer post, is there any chance of an option? I would be glad to send it for evaluation, I am sure a lot of people would benifit from a module for the receiver, i am more than happy to fit it myself as i am sure many others would be.

Alan

 

[JohnW]

OK - Thanks for the recommendation John - I'll go with the 230v Transformer then which gives the 17.4/5v which is close to what you were seeing in Vegas and more in line with the UK voltage given the additional 10v output. I will use it sparingly though until I can get one of your M-PAX units in late April!

BTW, any ideas on why the US 110v PSU you kindly sent did not work out and is giving a much higher voltage? Is there any chance I can get a good working 110v version from IAG and avoid the transformers altogether while I wait for the M-PAX?

Cheers,
Vin.

Hi Vin,

I have NO idea about IAG and US versions of the transformer - They certainly did not pass any 110V versions to Dom or myself for approval while we where still at IAG - it be interesting to to know what the Voltage level of the US unit is... I'd hope they are correct.

John

 

[JohnW]

Cheers John, could you please put me down for an m-pax with pcb for mdac then. I would also really like to use my squeezebox duet with clock lock as mentioned in my earlyer post, is there any chance of an option? I would be glad to send it for evaluation, I am sure a lot of people would benifit from a module for the receiver, i am more than happy to fit it myself as i am sure many others would be.

Alan

Hi Alan,

I'd steer you to the a SB Touch with Async USB connection using Adrian's software patch

What does the Duet do over the SBT (A genuine question as I'm not well informed about the world of streaming products)?

John

 

[PhilCTTE]

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

Thanks for the reply its appreciated. (learning curve)

Sorry, all this internet resource tredging is taking its toll . Plus the late night bottle feeds .

I seem to have forgotten the previous information gathered from this thread and confused myself by reading the many posts on computeraudiophile.

Specifically the care taken by CA enthusiasts on their choice of exotic USB cables and expensive PSU's. Which I have neither currently.

Its system specific I guess, if you haven't galvanically isolated the DAC or you are relying on the source clock with spdif and not clock locking the signal.
Then ensuring a clean power supply and shielding can make a difference?.

In our case the only reason for a clean environment source wise, is when its fed back into the mains and corrupts other components, as you mention.

So is it not worth while going for a low powered mini-itx with fewer options no wifi, no fancy graphics interfaces etc, on a board which boasts low emi and rfi emissions (such as the gigabyte atom based ones)?. And also paying attention to using an external linear PSU and the power rails to minimise this?.

Well I guess you've answered this issue if adding an RF filter totally removes this risk of polluting the rest of your system. By using common RF filter / mains conditioner found on some common mains distribution blocks from Isotek / Belkin / Oulson etc

If this is so then will any of the commonly found filters work ?

Like these one's for instance

http://www.amazon.co.uk/dp/B000PS5700/?tag=pinkfishmedia-21

http://www.amazon.co.uk/dp/B0002AG9SA/?tag=pinkfishmedia-21

 

[VinBob]

Hi Vin,

I have NO idea about IAG and US versions of the transformer - They certainly did not pass any 110V versions to Dom or myself for approval while we where still at IAG - it be interesting to to know what the Voltage level of the US unit is... I'd hope they are correct.

John

Well, the US unit that you kindly sent over seems to be reading 21v - so either it got faulty during shipping as you said it was showing 17v in Vegas, or they have it badly wrong which someone ought to make them aware as they will have a lot of North American M-DAC's going bad...!

 

[mcoteca]

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

Hi John,
is this true for Canada as well? I thought I was on your pre-order M-PAX list as I put in my request on a previous thread a long while ago. I can provide a UK address if required, but I would much prefer shipping directly to Canada.
Please advise if I'm on your pre-order list.
Cheers,
Martin

 

[travelfotografe]

Hi John,

I do hope that you will reconsider doing a clock-lock mode for the SB Touch. I have even bought an extra toslink cable (nothing fancy and not expensive) in anticipation for the mod! ;-)

Best,
Leon

I'd steer you to the a SB Touch with Async USB connection using Adrian's software patch

 

[scubaboy]

Hi John, when you have a moment could you outline exactly what the M-TRANS will be? Also, what is the M-ITX? I must have missed the info on it buried in this epic thread!

kr steven.

 

[Dawg]

Hi Alan,

I'd steer you to the a SB Touch with Async USB connection using Adrian's software patch

What does the Duet do over the SBT (A genuine question as I'm not well informed about the world of streaming products)?

John

John, please see my 2 posts here, bottom of page http://www.pinkfishmedia.net/forum/showthread.php?t=114068&page=25

Basically had both, sold touch for reasons above and ive invested in the receiver, ive bought all the parts to build a nice power supply, http://www.audioasylum.com/cgi/t.mpl?f=pcaudio&m=42853 and Ive also bought a really nice case from hifi 2000 to put it all in. I would really like to use what i have, i love the squeezebox remote that comes with the duet/receiver and i have a htpc which will serve usb audio duties.
I would just like to get the best out of the receiver.

Alan

 

[strocky]

Hi Alan,

I'd steer you to the a SB Touch with Async USB connection using Adrian's software patch

What does the Duet do over the SBT (A genuine question as I'm not well informed about the world of streaming products)?

John

The DAC in the Duet is inferior to the Touch (moot point when running through the MDAC), however the Duet CAN'T decode 24/96 and is a discontinued product with an even smaller user base than the Touch

The Duets main selling point is it's very small form factor and the fancy remote it came with

 

[uwe061]

Hi John,
thanks for the quick answer! I wrote you a PM, but your mailbox is full..
Best,
Uwe

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

 

[JTC]

FAO: JohnW:

Just wanted to find out when you think you'll be up my neck of the woods. Previously you suggested you'd be up here sometime at the end of February and I wanted to see if that's changed. PM if you want to take this offline.

Ta.

 

[beerboy]

Hi John,
Recently acquired the MDAC, and love it so much. By the way, just one quick question: is the balance out of the Mdac Pin assignment follows the general pattern i.e.
1 = ground 2= positive and 3 = negative?
Thank you.

 

[loris.p]

Hi Jonh,
still waiting for something......anything......

loris
italy

 

[ChrisPa]

Its system specific I guess, if you haven't galvanically isolated the DAC or you are relying on the source clock with spdif and not clock locking the signal. Then ensuring a clean power supply and shielding can make a difference?.

Yes, possibly

In our case the only reason for a clean environment source wise, is when its fed back into the mains and corrupts other components, as you mention.

Not necessarily just the mains (see below)

So is it not worth while going for a low powered mini-itx with fewer options no wifi, no fancy graphics interfaces etc, on a board which boasts low emi and rfi emissions (such as the gigabyte atom based ones)?. And also paying attention to using an external linear PSU and the power rails to minimise this?.

Lower powered
- the argument may be that any noise artefacts the psu is putting out are at a lower absolute level because the power demands are at a lower level
However the voltages being created for the supplies are the same levels whatever the power, so it's a big maybe
Only some proper emc measurements would give the answer and it will be component dependent

No WiFi
- WiFi is inherently a source of RF noise - that's what wifi is: an rf signal
So if the nearby equipment is sensitive to external RF noise, it's a good idea to remove a local source
Only use wifi if you need it. You could always try running the PC wired vs. wireless (disable the wireless adapter within the OS - or better still turn off or remove the hardware) and see if you can hear a difference
Your mileage will vary

Low emi and rfi
- yes that's the underlying objective
whether a board which proclaims low emi and rfi is actually any better than a 'standard' mini itx board is open to question - they all have to (should) meet emc directives
again would require proper emc measurement

Linear PSU
There are a lot of misconceptions around about linear psus vs switch mode psus - the devil is in the detail
There is no doubt that the switching nature of a switch mode supply has the higher likelihood to generate emi and noise on the output or back into the mains, but it all depends on how (well) it's been implemented.

Hypex swear by the low levels of emi produced by their class D amps (and their SMPSs) see http://www.hypex.nl/docs/appnotes/EMI_appnote.pdf. If implemented properly there should be no inherent reason why a linear supply will be better than an SMPS


However...
a 'standard' mini-itx pc won't necessarily be any worse than one implemented with the above measures

Overall my recommended two prime measures, whatever the PC, would be
- usb isloation
- mains filter between PC & hifi

 

[kryptonian]

John,

Is there an official way to pre-order a CDQ upgrade?

I definitely want to be part of this - and would help to miss out. Ditto for the M-Amp.

I tried sending a PM, but you are too popular and your inbox is full.


Thanks,


Richard

 

[PhilCTTE]

Yes, possibly

Not necessarily just the mains (see below)


Lower powered
- the argument may be that any noise artefacts the psu is putting out are at a lower absolute level because the power demands are at a lower level
However the voltages being created for the supplies are the same levels whatever the power, so it's a big maybe
Only some proper emc measurements would give the answer and it will be component dependent

No WiFi
- WiFi is inherently a source of RF noise - that's what wifi is: an rf signal
So if the nearby equipment is sensitive to external RF noise, it's a good idea to remove a local source
Only use wifi if you need it. You could always try running the PC wired vs. wireless (disable the wireless adapter within the OS - or better still turn off or remove the hardware) and see if you can hear a difference
Your mileage will vary

Low emi and rfi
- yes that's the underlying objective
whether a board which proclaims low emi and rfi is actually any better than a 'standard' mini itx board is open to question - they all have to (should) meet emc directives
again would require proper emc measurement

Linear PSU
There are a lot of misconceptions around about linear psus vs switch mode psus - the devil is in the detail
There is no doubt that the switching nature of a switch mode supply has the higher likelihood to generate emi and noise on the output or back into the mains, but it all depends on how (well) it's been implemented.

Hypex swear by the low levels of emi produced by their class D amps (and their SMPSs) see http://www.hypex.nl/docs/appnotes/EMI_appnote.pdf. If implemented properly there should be no inherent reason why a linear supply will be better than an SMPS


However...
a 'standard' mini-itx pc won't necessarily be any worse than one implemented with the above measures

Overall my recommended two prime measures, whatever the PC, would be
- usb isloation
- mains filter between PC & hifi

Thanks Chris ,

My area is software, strictly plug and play when it comes to hardware.

The specs on some of these mini-itx boards are not that clear when it comes down to these measurements (EMI/RFI). And I'm in no position to understand them in respect to whether they make an audible difference in this implementation. After all audio is not their main market, hopefully this will change. Some like the Jetway boards seem to be geared towards industrial implementations in harsh environments. The same one which is used in the CAPS II build on CA forum. This board was rubbished, to an extent by ItemAudio(early on in this thread), who has done extensive research in mini-itx board selection, stating the power implementation was poor from the DC jack. I believe the gigabyte board was recommended on ItemAudios FAQ section.

http://www.gigabyte.com/products/product-page.aspx?pid=3549#ov

As I mentioned earlier which may have got lost in the many many posts on here Bryston use the Alix board with a bespoked Juli@ audio card. £1300 pounds worth of kit !.

I guess Johns time on this will be pretty well limited in board selection as he seems to have many projects on the go. And it was only after some badgering by me that this has come about. Can’t hurt in knowledgeable folks like yourself Chris in throwing a few ideas his way.

He has explained that the main costs are to do with the tooling of the casework. Ok if a few hundred of us put down a pre-order list, and I’m sure from posts on here and AVF there will be a fair few. The spec of this M-ITX exceeds all others in a £500 price bracket. If you are after an audio streamer and not multi room that is.

What if this combo M-DAC M-PAX & M-TRNS (guessing in the region of £1400 - £1500, derived from £600 + £350 + £400 plus software windows 7 and Jriver for example £120 ) beats all the competition upto Linn Akurate (£3500) and Bryston BDA/BDP (£3500) for less than half the price?. Perfect solution don’t you think ?

Overall my recommended two prime measures, whatever the PC, would be
- usb isloation
- mains filter between PC & hifi

In regards to USB isolation - with the optical 192khz convertor this ensures that, does it not ?.

Mains filtering - I have no idea what products would be best. So would look for some guidance here please.
Foolishly I always looked at the mains distribution blocks with filtering built in as an incoming filter , never considered that it stops RF being fed back into mains. Showing my niavety!
With these blocks is each socket filtered or is there a single filter for all ?

Thanks again for your valued input here .