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MDAC First Listen (part 00011110)

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JohnW said:
Sorry to hear about your issues (also sorry to hear your back in the UK from HK :p - the years I spent in HK was the best time of my life :) )

As MDAC2 is not likely to be shipped until July / Aug. I can repair you MDAC for free - but you would need to pay for the shipping to and from Czech Rep. (shipping from Czech Rep. to the UK is about GBP35).
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John, when my board is back with me in the UK, if it makes things easier I could send on your spare board, and chasefrench could send his board to you and you can then repair it for your spare? Just an idea...
 
JohnW and JTC,

Many Thanks, that is an incredibly kind offer. I will post back in the next few days when I hear Audiolab's evaluation. If it is just a faulty PSU, they said that would only be 40 GBP to replace, and so it would make more sense to just pay it, or buy one of the external linear supplies.

JohnW, I expect Hong Kong will also be the best years of my life, but alas I am a few months away from 30 and it was time to start growing up! Couldnt keep spending sunday nights in lang kwai fong!

I will almost certainly pledge the first two installments when I can get the funds toegther.

I will post back in soon if audiolab come back with an estimate over 100GBP

Rgds,
 
fred sonnen said:
hallo John

first, I like the idea of the 2 PCB (analogue / digital) solution.
But, I'm not sure if this mdac2 in small steps is a good idea.
everyone who is interested in mdac2 have at least a mdac. so, from this side no time pressure.
you expect the mdac2 at June 2014. so lets say July ;-). This is in front of the sommer holiday season. So, July or September is not that different.
I think most of the mdac2 user are interested in the final digital pcb. So the interim stage is a disposable article. Is that a good solution for our environment?

just my 2ct
F.S.
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+1
I'd wait for a full version MDAC2, if the TDAC is not coming out any time soon.
 
JohnW said:
Arthur,

I'd not recommend the UPS as its a High Frequency switcher (PWM) design, I'd avoid introducing anymore RF energy into your system. Your Adams being ClassD will not like an additional RF noise source via the mains supply.
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Damn...thanks a lot John. Saves me spending money on making my hifi worse :)
 
arthur said:
Damn...thanks a lot John. Saves me spending money on making my hifi worse :)
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You might want to think about getting a balanced power transformer. I have one and my entire hi fi system runs off it. It also has its own dedicated earth spike. ( Installed by a qualified electrician BTW). I can tell when it's raining when my hi fi is on without looking out of the window.
 
JohnW

Where do you think the MDAC2 will stack up sonically against the latest in DSD dacs when it arrives? Thinking specifically units in the ~$1500-3500 range: exasound, Auralic vega, benchmark dac2, ayre QB-9DSD, mytek 192-DSD, wyred 4sound, etc. Are you following the latest releases, reviews and tech?

I am already on the list for an MDAC2, so I'm not using this to make a purchasing decision but I wonder if I should front the money on something like the Vega now and then compare when the MDAC2 arrives and then sell the one which I love less?

Also what value do you place on the new wave of Femto type clocks in these units and how will the clock in the MDAC2 perform in comparison?

cheers,
 
stellablues,

I see the MDAC2 being a statement design - it will be the DAC that others will be judged against.

I'm very dubious about other manufactures claims of Femto clocks for several reasons.

1. No measurement details or Phase noise plots are provided to support there claims.

2. I'm not aware of any DAC manufacturer possessing the required equipment to perform these measurements (I'd be happy to be corrected).

3. Internal pictures of the DAC designs I've seen would lead me to the conclusion that even if the Clock in isolation could achieve fS jitter results (over a specified BW), due to poor PCB layout, PSU noise, Circuit design - the phase noise as seen by the DAC clock input will be far far worst.

MDAC's Master cloak has very good short term phase noise - under 1ps from say 100Hz to 20KHz... I dont recall the exact numbers - but certainly below the LF measurement capability of my US$250K Wavecrest measurement system.

MDAC2 will have a more advanced clock design that implements a LF noise cancellation circuit – whose performance I can only verify by simulations as its LF noise performance is below my equipments measurements limits. During development I can inject external stimuli to measure the circuit’s correction facture (Gain), thus proving the circuits effectiveness.
 
Hello everyone.

I have come here in a bit of desperation. I have searched through the MDAC first listen posts, and even though I see a lot of people with the same kind of problem I don't see a resolution to it anywhere.

My problem is with my MDAC, every once in a while it emits a popping/cracking sound. It is driving me to distraction.

I purchased an MDAC last year, only to have serious problems with it. The store where I obtained the MDAC were nice enough to replace it for me after much ado and the new one has been playing up intermittently ever since in different ways although this one worked enough to play music.

I probably should have taken this one back and just tried to get my money back but I didn't want to become a "problem customer". Also it sounds great aside from the popping noise. (You can hear it over the music)

I have tried just about everything I can think of, from different settings in the DAC itself to removing all the USB devices attached to my PC. In fact it does this when not connected to my PC at all, just with the DAC connected through either of my amps.

It does this whether connected via USB or coax or optical. I have tried different cables. Different USB (Always 2.0) ports. On different machines. I have also tried RCA and XLR outputs. Again it's the same.

I have tried different firmwares and am currently using the latest from John's wiki (Windows 7).

The only slight anomaly I can give you is that every once in a while there's two pops, right after each other maybe a second apart, then back to one for a while.

Finally got to the point where I just couldn't take it any more, I thought I would come and ask John or any other knowledgeable people :). Has anyone got any idea what this might be?

-Tim
 
Hi Tim,

The problem could be related to your playback software and some buffer settings. Can you give us some information on which software you are using?

Michael
 
fusion5 said:
Hi Tim,

The problem could be related to your playback software and some buffer settings. Can you give us some information on which software you are using?

Michael
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Well, the MDAC does it whether it's connected to my PC or not so I kind of figured it wasn't the software.

The software I use though is iTunes or more likely Foobar2000. The Buffer settings on Foobar have changed a bit trying to cure this problem to no effect, but I use 1k-1500 usually. I used to run it with ASIO but haven't done that for some time.

Other software I use are Cyberlink video player, VLC, Windows media player. I think that about covers it, aside from internet browsers and flash based things.

Thanks, but I don't know about that USB thingy. My MDAC is doing this when it's not even connected to my computer.
 
fusion5 said:
What's the big benefit? The power supply? To my knowledge the current MDAC design doesn't draw any power from the usb host.
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It doesn't which is why I dont use this card with a power supply, it just runs off the PCIE slot.

As far as I can tell, it shields the usb signal from interference caused by cooling fans, electromagnetic interference from the mobo and the psu. I noticed a blacker background with increased definition.

People often argue that because it is a digital signal, it isn't affected by interference. They don't realise that the digital signal is represented by changes in voltage travelling down the usb cable, which is essentially analogue and affected by interference
 
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