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MDAC first listen (part XX)

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Hi John,
I think the only time I've posted on this thread was to request to be put on the "original" list which I guess is at least 6 months ago, probably closer to a year!

Nevertheless would you add me in for the level 2 full upgrade?

(It'd be nice to think I could merge this along with a nice break in Prague but I'll see how things go in the meantime).

Best regards,

Dave
 
Due to the number of requests, I've developed a method to add a "Mickey Mouse" AV bypass option to the MDAC that will not effect the sound quality of the MDAC's outputs.

It would involve adding a pair of additional RCA connectors on the MDACs rear panel (these would be drilled by hand, while I'll try my very best - so please don't be disappointed if they are not 100% perfect).

When the MDAC is powered off, an internal pair of relays will route the AV input to the MDAC's outputs.

The RCA input bypass will work with both RCA and XLR outputs, but the XLR will be -6dB in level.

Messing about adding the RCA's and internal relays takes time - so I'd have to ask an extra GBP50 for the option on top of the upgrade cost...

Its a little Mickey mouse (added the RCA's to the MDAC's rear panel), but will not effect the MDAC's SQ :) and you have a simple AV bypass option.
 
DAVEDWACK said:
Hi John,
I think the only time I've posted on this thread was to request to be put on the "original" list which I guess is at least 6 months ago, probably closer to a year!

Nevertheless would you add me in for the level 2 full upgrade?

(It'd be nice to think I could merge this along with a nice break in Prague but I'll see how things go in the meantime).

Best regards,

Dave
Click to expand...

Hi Dave,

Added you to the list :) thank you :)

I guess as you asked a year ago :) just PM me when its convenient to have your unit updated.
 
JohnW said:
Due to the number of requests, I've developed a method to add a "Mickey Mouse" AV bypass option to the MDAC that will not effect the sound quality of the MDAC's outputs.
Click to expand...

Great news and timing! I like the out of the box thinking compared to adding more electronics or switches to the DAC's output (even though I'm still interested in the volume attenuator options for the MPAX, should it happen).

:)
 
jamjar784 said:
John

Maybe you could add what's the best way to ship the MDAC to you on the upgrade thread?

Thanks
Click to expand...

Sorry, I really cannot say! we ship via Czech Business post - so far (touching wood) with no problems.

We have had items sent to us via DHL, UPS and standard postal service, just insure the MDAc is sent via registered post /insured.
 
John, is there a dealer close to to you where I could purchase a new unit and have it upgraded vs shipping my unit? this would reduce shipping it one way. Have any extras sitting around the shop? :)
 
stellablues said:
John, is there a dealer close to to you where I could purchase a new unit and have it upgraded vs shipping my unit? this would reduce shipping it one way. Have any extras sitting around the shop? :)
Click to expand...

OK, I'll talk with Audiolab and see if I can purchase new units directly from them.

Black or Silver?
 
Hi John,

I'm a long time reader from Australia and would also be interested in buying a brand new fully modified black MDAC directly from you. I would use a virtual UK address service such as AlfaSent to ship it here. I've found the shipping weight to be roughly 4.6 kg's but cant find the dimensions of the actual box. If someone could give me those that would be great (gives me a better estimate for shipping costs).

Thanks, Curds
 
Hello John,

please, may you share some more measurement graphs before/after the upgrade?
What are new THD, SNR and Crosstalk values?

Many thanks in advance!
 
shaolin said:
Hello John,

please, may you share some more measurement graphs before/after the upgrade?
What are new THD, SNR and Crosstalk values?

Many thanks in advance!
Click to expand...

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).

Dynamic range is increased to over 129dB from 125dB Awtd.

FFT of a Modified MDAC reproducing a 1KHz -150dB test tone!!!! Mains related components can be seen at about the same level (that's the cluster peaks at -150dB and below on the very left hand corner of the FFT)...

https://dl.dropboxusercontent.com/u/86116171/-150dB Zoom FFT.jpg

FFT of a -60dB test tone (Modified unit), note the complete absence of any distortion components - this means that even at -60dB all harmonic distortion components are below the -165dB noise floor.

https://dl.dropboxusercontent.com/u/86116171/Modified -60dB Zoom FFT.jpg

Output impedance at 1KHz (Pre relay) is reduced from 0.19 Ohms to lessthen 0.00063 Ohms.

No change in Crosstalk as its defined by PCB design (IIRC its already around 130dB at 1KHz)!....

Analogue stage PSRR, Bandwidth and Slew rate have all been improved

Improvements in the DAC's PSU have reduced the modulation spurie on the DAC supply rails by up to x1000 lower noise components (I'll post FFT plots of a standard / Modified unit when I upgrade the next unit).

Apart from the lower noise on the DAC PSU supply's and the Dynamic range improvements there's little to see in the standard audio measurement - the MDAC's already very good :) !

Apart from these "technical" improvements - the upgrades are aimed at sonic improvement.

From a measurement perspective the standard MDAC is already up with the very best - the upgrades improve a host of "standard" audio measurements but this was a "secondary" side effect as the main focus has been on improving the Audio quality.
 
Thank you John,

excellent support/reply as always ;)
Can't wait for my turn for upgrade...:) I just hope that my ears damaged by so many parties can still catch all those improvements.. Wish I was younger again, would protect them more... :)
 
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