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MDAC First Listen (part 00100001)

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shaolin said:
Once you wrote: "THD is limited by the ESS DAC operated in voltage mode - so no change in THD as the ESS DAC is the limitation not the Analogue stages themselves (XLR 0.0008% THD).
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Jan,

The THD is now an order of magnitude lower due to the new circuit topology which eliminates the THD of the Array while still providing passive RF filtering.
 
jirij said:
John, do you have any kind of (time-based) roadmap? I know you wanted to have MDAC2 done by christmas 2014, has the development of the digital PCB started?

Just curious. :)

Thanks,
Jiri
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No I'm still designing the analogue PCB - the digital board can be autorouted, so will be much quicker.
 
JohnW said:
David,

I guess its your player as the MDAC cannot cause this issue.
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Thanks, John. I was guessing it was a Linn/JRiver (or finger trouble?) issue, but worth eliminating one out of four to start with. :)
When HD into the MDAC does work, it sounds so good - I can hardly wait for MDAC2 etc.
 
jirij said:
John, do you have any kind of (time-based) roadmap? I know you wanted to have MDAC2 done by christmas 2014, has the development of the digital PCB started?

Just curious. :)

Thanks,
Jiri
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:D

It's John time

Which is cool, because we'll get there in the end
And it's an interesting journey on the way

I'm enjoying the ride :)
 
JohnW said:
https://dl.dropboxusercontent.com/u/86116171/MDAC2 -60dB 132dBA DNR.jpg

Above is an FFT of the MDAC2's analogue stage attached to JariP :) Salvaged MDAC :D

Dynamic range 132.5dBA (Balanced) and THD 0.000087% 1KHz 0dB!

This Dynamic range result is close to my all time personal best - I believe the MDAC2 will have the highest Dynamic range performance in the industry (it will improve by a few more dB on the final PCB)... :)

There is a chance that the THD results will improve further once I have the complete design... although 0.000087% its amongst the very best already.

With the VFET AMPs, I'd really like to include internal gain scaling to maximise the dynamic range offered by the MDAC2 - the Tube noise looked good at about -120dB... (Which is good for a tube)...
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Thats pretty good(if i trust your numbers since the resulotion of the FFT isn't shown, i guess 2048) but it should only correspond to to approx 21 bits of audio resolution, this is why your scalable gain project is interesging. The only problem that i see with scalable
gain is that it could cause issues when classD amps(not lakewest) is used for the subwoofers.

with 132dBA dynamic range the noise should be at -7dBA(in an extremely silent room) when the maximum lodness of the system is 125 dB
 
Hey john, just curious with all the added features and different versions of mdac2 what will the firmware be like for stability/reliability. Will there be a phase of problem reporting that we will have to endure or do you think you will have it stable before shipment. Also will there be different firmwares for the various versions ?.

Danny.
 
Danny,

As with any new hardware / software there will be small bugs which we will resolve as soon as they are reported.

The initial software release will be very basic, with more features added each week - so there will be a constant cycle of bug reports / fixes...

It will take about 6 months for the software to be "complete" and stable... but the MDAC2 is such an advanced unit that I don't see there being a Final software release - more features will be constantly added.
 
@home,

The MDAC is still in the design process - we have no plans to mass manufacture the MDAC2. Only those who have funded the development of the MDAC2 (and Toy / Fusion owners) have secured there units - so there will be only a limited number of MDAC2s available.

I have no interest in mass manufactured designs - I'd rather design state of the art "hand built" custom designs - to the very best of my abilities, the MDAC2 and VFET amp project follow this ethos.

My experience of the mass produced "MDACs" leads be to believe its not possible to insure constancy - each production batch of MDAC's sounds different...

Due to the numbers involved with mass production, its not possible to listen individually to each unit and "approve" its sound quality.... so I'm no longer interested in "commodity" HiFi production...
 
JohnW said:
The SPDIF Optical output with A10 works - however it depends how the device connected to this output response to the SPDIF "Error" flag bit which is set to resolve the ESS Left channel locking bug. Most device ignore the error flag (work ok) - while some will Mute.

Why are you conecting the MDAC's digital output to a second DAC?
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Ok, so probably my second DAC mutes then. It's actually a DSP (Anti-Mode 2.0 Dual Core) with a DAC and a preamp. Due to equipment changes I now need a way to route all my digital sources to the DSP and I was planning to temporarily use my M-DAC for this. I suppose it's impossible since I need the features from the newest firmware versions.

My future plan is to route all the digital sources digitally via the DSP to the M-DAC and I'm thinking to use 8200CD as the switch (and as a CD player). Will the V12E (OLED) version of 8200CD also mute my DSP's DAC or is it only the modified M-DAC firmware which causes this?
 
anjora said:
I guess the L1 version will arrive before L2,L3
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The L1 to L3 versions will be built and released at the same time - I only plan a single SMD manufacturing run.

It will take time to build up the software feature set of the L2 / L3 units via downloadable updates.
 
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