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MDAC first listen (part XV)

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H

hluga

pfm Member
John I've got two questions regarding PSU. I imagine that i can build one on my own.

Is there some reqs in terms of amps for properly feeding the MDAC ?
Is there an advantage to go toroidal if the PSU is external from the unit and boxed in a shielded case ?

Br/
 
liszt said:
JohnW: Sorry for being absent from the forum, guess what, late on the BDAC design...

JohnW: The Modifications involves working on a 4 layer PCB and removing and replacing SMD components and Hand soldering onto IC legs of the ESS DAC, its really a horrid job, one I don't relish - tomorrow I work on Sam's and Hulga units...

JohnW: The modification is not something that I believe can be done without guidance and experience with SMD rework.

John, you have nothing to apologize for. Your continual presence and help on this forums is much appreciated and i'm definitely very grateful for your support. I feel quite sad not being able to get my mdac sovereign-ed


JohnW: Replacing the MDAC's external "Transformer" with a multi-rail DC input from a linear supply would be beneficial.

Very good to know!


JohnW: Even with an MDAC in standard from you can use with DC input, the "DC" modifications I perform are just to optimise the MDAC's internal PSU for use with external DC input - separating the power feed to the Left and Right channels and adding extra Ground returns.

Great news, so i can go ahead and build that 15v linear supply? Okay, i guess that's at least some consolation for me since i'm not able to get my mdac sovereign-ed :( :p
Click to expand...


Liszt, where are you located? I'm in Montreal, Canada and I too would be interested in building 15v linear supply without getting my MDAC sovereign-ed.

Martin
 
Question about Bitperfect test:

My OPPO-93 Disc Player passes the bitperfect tests if I play the bitperfect test files (both 16/44.1 and 24/96, in both FLAC and WAV formats) from DLNA or DVD-RW Data Disc via optical output to M-DAC.

However, if I burn the 16/44.1 WAV files to a CD-RW as an audio CD and play the CD in the OPPO-93 via optical output to M-DAC, the bitperfect test will briefly show "passing test" and then after less than a second, show "failed test".

Any suggestions why the audio CD path will fail the test? Is it because I am using a CD-RW instead of a CD-R? Anyone else has an OPPO-93 hooked up to an M-DAC and tried a bitperfect test from the audio CD path?
 
JohnW said:
Or solution is the use a high quality car slot loader with our own designed servo board -
As with consumer grade plastic wonders car loaders are not all the same, so we turned to our German brothers and piggy-backed on what the Germans do the very best – bureaucratic over engineering and over testing :) - we use a loader that meets and passes BOSCH GMBH internal QC standards :) roll on the fine German over engineering!
Click to expand...

So now you have no night scope in your boot, and no CD player in your dashboard. :)
 
Tonyb said:
Intermittent loss of output
Very interested to see the problem here being discussed between hluga and JW. I see jonathanmueller has also had a similar problem. It seems to be the same issue that I have and I am very interested to hear if it is resolvable or is it necessary to return the unit to Audiolab (a major hassle for me since I bought the unit in Derby but am living in Germany).
The problem I have is intermittent with lack of output (affecting RCAs and headphone), while the screen continues to work, the db meters on the screen respond to the music input signal. This occurs on more than 50% of power ups (cold MDAC), and is quickly apparent because -80db volume setting is also indicated. I have normally been able to overcome it by repeatedly powering off then on again using the power switch, when the unit boots properly it can either return the previous volume setting or starts off at -80. Cycling the headphone out relays has never helped. Normally once running it is fine but 3 times now the problem has actually interrupted playback when, with a loud crack, the output stops. After the most recent of these I was only able to recover the functioning by a hard reset using the power connection on the rear. Note, one of these events appeared to coincide with powering up my satellite receiver, by ir control, so I was wondering about power supply perturbations, but it has not been repeatable so maybe just a co-incidence.
I would very much like to hear if anyone has overcome this problem..
Click to expand...

Hi Tonyb,

I don't believe your issue is related to hluga's - hluga has an issue with the relays (as far as I'm aware it has not powered up at -80dB) - the oddity with your unit is powering up at -80dB, this indicates most likely a hardware issue.

By the sounds of it, jonathanmueller indicated a similar issue - we are out of the loop at IAG - and as such have not had a chance to diagnosis a multifunctional unit...

Which software versions are you using? - it might be worth trying an earlier or later software.

Try a different software build - due to an overdue deadline with the BDAC design I'm being ultra unreliable at the moment, maybe I could send you my own unit on a loan basis, and you send me your unit to Czech Rep, then when I have time I can find out what's going on (but its going to take time)...

Sorry once again for your issue,

John
 
travelfotografe said:
Question about Bitperfect test:

My OPPO-93 Disc Player passes the bitperfect tests if I play the bitperfect test files (both 16/44.1 and 24/96, in both FLAC and WAV formats) from DLNA or DVD-RW Data Disc via optical output to M-DAC.

However, if I burn the 16/44.1 WAV files to a CD-RW as an audio CD and play the CD in the OPPO-93 via optical output to M-DAC, the bitperfect test will briefly show "passing test" and then after less than a second, show "failed test".

Any suggestions why the audio CD path will fail the test? Is it because I am using a CD-RW instead of a CD-R? Anyone else has an OPPO-93 hooked up to an M-DAC and tried a bitperfect test from the audio CD path?
Click to expand...

I suspect your Oppo is experiencing read errors with the CDR-RW (due to the very low reflectivity of CDR RW), I suspect your Oppo would be much happier with a standard CDR.
 
liszt said:
John, you have nothing to apologize for. Your continual presence and help on this forums is much appreciated and i'm definitely very grateful for your support. I feel quite sad not being able to get my mdac sovereign-ed


Very good to know!


Great news, so i can go ahead and build that 15v linear supply? Okay, i guess that's at least some consolation for me since i'm not able to get my mdac sovereign-ed :( :p
Click to expand...

Best to build a multi-rail supply:

2x +/- 15.5Vdc 350mA (separated L/R analogue supply rails)

+15Vdc 350mA (Digital supply)

Maybe I can send you a "DC" modified PSU board for the MDAC (on an exchange basis) - if you can wait until after I've completed the BDAC and say the MPAX...

John
 
hluga said:
John I've got two questions regarding PSU. I imagine that i can build one on my own.

Is there some reqs in terms of amps for properly feeding the MDAC ?
Is there an advantage to go toroidal if the PSU is external from the unit and boxed in a shielded case ?

Br/
Click to expand...

Best to build a multi-rail supply (with a DC modified internal PSU PCB), I can send you one on an exchange basis:

2x +/- 15.5Vdc 350mA (separated L/R analogue supply rails)

+15Vdc 350mA (Digital supply)

No real advantage in using a toroidal if the PSU is situated away from the MDAC..
 
misterdog said:
So now you have no night scope in your boot, and no CD player in your dashboard. :)
Click to expand...

Wish me luck, I don't expect anything to come from it (due to the elapsed time if nothing else) - but I've asked to have a meeting with Austrian owner of our Mercedes main dealer - if nothing else I want to tell him directly to his face that his staff are steeling personal possessions from customers cars - its sickening, not to mention that they cause more problems then they solve when they "Service" our cars...

In 20 years of working in China, I've never had anything stolen, yet come back home to Czech and the Mercedes main dealer steals from your car!

John
 
arthur said:
Pleeeeaaaase no...
Well not yet perhaps. It might interfere with the bdac :eek:
Click to expand...

Arthur,

I might have a design right up your street - its basically the BDAC with a lower power version of our power amplifier technology in a single box under the LakeWest brand...

Its the next design I work on after the BDAC as I need a decent Amplifier... Power output will be around 50W +50W but using our MOSFET/ Bipolar ClassA technology.

Need to think of a name for this design..
 
JohnW said:
Arthur,

I might have a design right up your street - its basically the BDAC with a lower power version of our power amplifier technology in a single box under the LakeWest brand...

Its the next design I work on after the BDAC as I need a decent Amplifier... Power output will be around 50W +50W but using our MOSFET/ Bipolar ClassA technology.

Need to think of a name for this design..
Click to expand...

MOBiA, if you say it quickly it sounds like a Geordie saying "more beer", always a good call!.
 
JohnW said:
Arthur,

I might have a design right up your street - its basically the BDAC with a lower power version of our power amplifier technology in a single box under the LakeWest brand...

Its the next design I work on after the BDAC as I need a decent Amplifier... Power output will be around 50W +50W but using our MOSFET/ Bipolar ClassA technology.

Need to think of a name for this design..
Click to expand...

Now that IS a thought John.

In fact I imagine it would be mighty popular, especially amongst the music first people as opposed to box collectors.

Certainly, it would be perfect for me.

I assume you mean something like an awesome dac hardwired, as it were (?) straight into power amp circuits. Perhaps dual mono from input to output?

Yup, I'll have one. :)
 
arthur said:
Now that IS a thought John.

In fact I imagine it would be mighty popular, especially amongst the music first people as opposed to box collectors.

Certainly, it would be perfect for me.

I assume you mean something like an awesome dac hardwired, as it were (?) straight into power amp circuits. Perhaps dual mono from input to output?

Yup, I'll have one. :)
Click to expand...

Yes, something like that - fully balanced dual Mono design :)

Should be very very good quality - a simple all-in-one box so no need to mess about - HiFi in a box...
 
JohnW said:
Yes, something like that - fully balanced dual Mono design :)

Should be very very good quality - a simple all-in-one box so no need to mess about - HiFi in a box...
Click to expand...

That may well take off hugely John. There seems to be a market for such; Naim's offerings and such.

With a top class dac and class A amps then even die-hard anti computer audioists should begin to reconsider.
 
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