MDAC First Listen (part 00100110)

[JohnW]

Sorry to drag you off topic, but what do you think of this ACSS current mode connection which they seem to be pushing.

Its really not for me as a "Competitor" to comment in much detail on 3rd party designs.

I can say that the FFT show a 16K FFT Noise floor of -110dB which is less then 16 Bit dynamic range...

Just like the *Chinglish used on their website (The term "Chinglish" is commonly applied to ungrammatical or nonsensical English in Chinese contexts) I see a Hot Pot of "nonsensical" circuit blocks with a very heavy influence from the DIYForum.

For example their "Strong diamond difference output stages" is your typical uninspiring classical Diamond buffer circuit that plasters the DIYforum that with even a mediocre effort can be nicely improved.

I fully expect their ACSS to display the same level of "Unique" engineering prowess - I suspect it shares much in common with designs by the "Buffalo" crowd, which is not a bad thing.

Ok, now I feel really bad

*I guess most times my English is not much better and I certainly cannot speak Chinese!

 

[JohnW]

John, what's the position with M-DAC 2 firmware? Has it been specified, and what's the timescale for it being written?

I know nothing about programming embedded systems, but can't a functional specification only be written once the hardware has been nailed down?

Steve,

The first release Firmware will be little more then a "Get you going" build - lacking "polish", as we progress though the year the feature set will be rapidly expanded - with the Advance FPGA Modulators to came "Last" - it will take about a years development to fully optimise the modulators, but inbetween we will release many prototype builds for trial and feedback

The MDAC2 is as much a development platform as a product - so expect a steady stream of updates and expanded features - With both FPGA and DSP the possibilities (and Bugs) are endless

 

[ti33er]

Hi John

4th L2 payment paid:

Total £100.00 GBP

Many thanks for the good work thus far

 

[misterdog]

I see only "cosmetic engineering" without the "in depth" knowledge

I've always felt that this is a shame, as they are trying hard, but without sound engineering knowledge they can only fall back on the primary sense of "Vision".

which is precisely the 'science' I applied to the Plydac case

And am about to do so again with Acryldac case

I am happy to let others apply the science and pronounce judgement..

 

[therixonator]

Hi John,

I've paid the 4th payment (existing Toy owner). I'd like to go for the L3 option when the time comes. Thanks for all you're hard work on this project, I think we should club together and send you and Renata off on a nice trip at least 200 miles from a lab bench when this is all done!

James

 

[Rjpcardoso]

Hi John,
So count on one more just joined.. What else do I need to do at this moment apart from paying with paypal (which i already did)?

Thanks,
Ricardo

Ricardo,

Support at anytime is greatly appreciated

We have a "hard limit" of a maximum of 150 MDAC2's due to certain component (Crystal) that I have available. Taking into considerations potential Toy / Fusion owners "Officially" joining the project at this payment round, then we will be coming close to this limit.

A second aspect is that I don't really want to "Mass Produce" the MDAC2 - I'm a designer, and my lab is not set up as a "mass" production facility, although I have recently invested significant funds to install a small production / test bench.

The MDAC2 is a complex design - rather then using "Off the Shelf" integrated components such as Opamps, Regulators and Clock modules etc. each critical circuit section is a "Discrete" circuit design to optimise the circuits performance.

While discrete circuits offer the highest performance, this dramatically increases the PCB component count + design complexity resulting in a daunting task for anyone apart from the designer to understand the design and to be able to service / repair the unit, as such its not a design suitable for "Mass Production". With so many of the circuit sub-sections are "Novel" the design would be Alien to your average technician.

While I'll "happily" build say 150pcs - I have no intention to spend my life building MDAC2's... my skills are better served designing and not as a production engineer.

Basically, I hope only build as many units required to "cover" the development costs, so that I can design the best DAC I can within the MDAC chassie, and no more...

 

[JohnW]

Hi John,
So count on one more just joined.. What else do I need to do at this moment apart from paying with paypal (which i already did)?

Thanks,
Ricardo

Ricardo,

Nothing else to do at the moment, just reply to Renata's which should arrive shortly to confirm your details.

Thank you and welcome to the MDAC2 project

 

[JohnW]

Hi John,

I've paid the 4th payment (existing Toy owner). I'd like to go for the L3 option when the time comes. Thanks for all you're hard work on this project, I think we should club together and send you and Renata off on a nice trip at least 200 miles from a lab bench when this is all done!

James

James,

Thank you (and to everyone else whose paid)

200 Miles - Once I've complete these projects (MDAC2 / VFET amps) - maybe I'll start building our place in the mountains - the lab was just a trial run that's not 200 miles, but its stunning up there

 

[misterdog]

Different Mayor in charge up there ?

 

[Neil A]

Dear All,

Seeing as my MDAC (and probably MDAC2) will never go back in the Audiolab sleeve, I finally got off my ar&se and modified a cheapo case, that had nearly the right depth (the depth is non modifiable, due to the power button and phones socket being mounted on the boards, that are fixed to the back panel)

Cheapo case off Ebay :

http://www.ebay.co.uk/itm/Large-Project-Box-Enclosure-Case-with-Side-Panels-Vents-Ventilation-Openings-Z17-/251658409289?pt=LH_DefaultDomain_3&hash=item3a98029549

I chose this box as it has enough height to give room below and around the board (allowing future copper foil shield experiments) and room above the board to add digital board of MDAC2 (allowing experimentation of distance away from MDAC2 analogue board)

V1.0 using the front panel flush, outside the alignment grooves - (note that this shows up that panel has corners missing...not good!)

Top/front view.

Back view - note spacer to get depth to match the new module.

Bottom view, showing feet, screws to clamp case halves together.

Module mounted in bottom half of case.

Case halves.

Internal module. Side rails made from CD drawer I took a dislike to
Welded together with old soldering iron.

Bottom view.

Shows how the new back / front panels have to be threaded onto side rails before they are screwed onto MDAC front or back panels.

MDAC board / back panel assembly ready to slide into new side rails. A lot of careful experimentation needed with rail slides , so they don't foul components on board, when the board is slid in.

V1.1 - back panel spacer replaced with new outer matt black acrylic outer front panel.

V1.1 - New outer front panel.

V1.1 - back panel spacer replaced with new outer matt black acrylic front panel, to cover crappy front panel. I did this slightly oversize and squared up, to give a "rack mount" look.

Hope this gives some food for thought for the (cheapskate) NUDEDAC users


ATB
Neil

 

[JohnW]

Different Mayor in charge up there ?

Thankfully yes - and no "Personal" problems

 

[JohnW]

Dear All,

Seeing as my MDAC (and probably MDAC2) will never go back in the Audiolab sleeve, I finally got off my ar&se and modified a cheapo case, that had nearly the right depth (the depth is non modifiable, due to the power button and phones socket being mounted on the boards, that are fixed to the back panel)

Cheapo case off Ebay :

http://www.ebay.co.uk/itm/Large-Project-Box-Enclosure-Case-with-Side-Panels-Vents-Ventilation-Openings-Z17-/251658409289?pt=LH_DefaultDomain_3&hash=item3a98029549

I chose this box as it has enough height to give room below and around the board (allowing future copper foil shield experiments) and room above the board to add digital board of MDAC2 (allowing experimentation of distance away from MDAC2 analogue board)

V1.0 using the front panel flush, outside the alignment grooves - (note that this shows up that panel has corners missing...not good!)

Top/front view.

Back view - note spacer to get depth to match the new module.

Bottom view, showing feet, screws to clamp case halves together.

Module mounted in bottom half of case.

Case halves.

Internal module. Side rails made from CD drawer I took a dislike to
Welded together with old soldering iron.

Bottom view.

Shows how the new back / front panels have to be threaded onto side rails before they are screwed onto MDAC front or back panels.

MDAC board / back panel assembly ready to slide into new side rails. A lot of careful experimentation needed with rail slides , so they don't foul components on board, when the board is slid in.

V1.1 - back panel spacer replaced with new outer matt black acrylic outer front panel.

V1.1 - New outer front panel.

V1.1 - back panel spacer replaced with new outer matt black acrylic front panel, to cover crappy front panel. I did this slightly oversize and squared up, to give a "rack mount" look.

Hope this gives some food for thought for the (cheapskate) NUDEDAC users


ATB
Neil

Neil,

Wow, that was quick

I would have positioned the PCB in the centre of the chassis so that its away from any metallic surface the MDAC might be placed upon

 

[Neil A]

Neil,

Sorry to hear you are considering leaving the world of Analogue - I've still not heard a PCM Digital system that comes close, although I've heard "Pure" DSD based systems that are unbelievably transparent considering the "torturous" path the original analogue signal has been though.

I hate to suggest this, but the MDAC L3 digitise your analogue collection into say DSD128, then you can sell on your turntable if you still are in that frame of mind

Considering that we are talking about late summer / early autumn before we start shipping the first units, you might have time to gather the funds - sell the Goldfish or some such

I should have your dSC repaired by then

Also, there is more budget headroom on the L2 / L3 units, so they may come it the lower end of the budget... My only concern is cost of production here in Europe... but atleast being based in Czech Rep. we are close to the bottom of the European cost (salary) scales...

Oh alright then John!...To be honest experimenting with the digitize to DSD option is probably all I would use the ADC for. My semi-retired recording engineer has not got this option on his now, quite elderly SADiE workstation (but he has got the rather good Cedar De-click.) I really gave up the world of analogue many moons ago, most of the LP's I have to digitize are some obscure classical stuff, left by my father and father-in-law.
Yes I know good analogue can sound, I spent many happy hours listening to master tapes on ATC SCM 200A's in the control room of a now late lamented London Studio

 

[Neil A]

Neil,

Wow, that was quick

I would have positioned the PCB in the centre of the chassis so that its away from any metallic surface the MDAC might be placed upon

I thought a pile of books achieved that?

I suppose it it stays that way it will have to be permanently re-located away from the other electrical junk.
I have spent all day listening to it, for the first time with the MDAC I actually dozed off while listening, there was just too much "digital" sound to do this before.

 

[iansr]

Neil
Do you think it sounds the same in the plastic enclosure as it did nude?

 

[sq225917]

Once I'm done making Markus's phone stage I'll have nylon make a large acrylic case for my mdac. I think we can rustle up something mega looking with no metal apart from the current fascia panels.

 

[misterdog]

The same size case will also fit Paradise, and Hypex n-Core .

 

[Neil A]

Neil
Do you think it sounds the same in the plastic enclosure as it did nude?

Yes, no difference noted.

I spent most of yesterday listening to hi-res "test" stuff that I have been using since any changes to my system. Stuff featured included the hi-res download of The Enid - Invicta (Off their website, recent, very dynamic all analogue recording) and an SACD ISO (the family was blessed with the "right" PS3) off my dCS test SACD "The Spirit of Turtle" (roll on MDAC2, so I can listen direct in DSD 64/128) The difference in particularly these two recordings is staggering.
As I have mentioned, I found that the MDAC cased always sounded better cold (this was leaving pc/mcrw power supply/active ATC's on), now it is the other way round (as you would expect with digital equipment).
The other thing I noticed (well certainly the Mrs noticed it!) was that (as is usually the case with active ATC's,) the better the input, the louder you tend to listen!

 

[hluga]

Maybe one can try to make a custom 3D model which could be 3D printed ? This allows to make some supports and to deal with different rigidities between top and bottom.
If someone has all the measures i can try.

Best regards

 

[misterdog]

NEIL A,

I'm impressed, more so if the on/off switch does not rub.

Though what perplexes me is that your capacitors seem unfatigued, your serial no. B0254 is only 18 less than mine (B0272) and yet many of my capacitors are bulging/erupting.

Have you left your unit powered on permanently, or do you switch on/off?.