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MDAC First Listen (part 00101111)

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JohnW said:
x1 for Digital

x1 Positive Analogue Left

x1 Negative Analogue Left

x1 Positive Analogue Right

x1 Negative Analogue Right
Click to expand...

John, a while back, on the “V-PSU" thread you posted (No.22) a diagram of the MDAC power connections( with thanks to Renata for Photoshop efforts). This is what I, and probably everybody else, have used , at least with the Calex supplies. By my count this diagramshows 4x Digital +15v rails, and only one pair of +/- 15v Analogue rails.
Paul, I didn’t check this before my earlier post, and for some reason I thought I remembered only 3x D+. The above count means 5x Calyces ( I’ve been looking for an excuse to get that plural in!) and definitely NOT 4x. Sorry for the confusion.

Bob
 
t30,

Not at all, drop-out voltage according to the Spec sheet is 1.1V @500mA - I like to see atleast 2V with the 100mA or so seen by the MDAC Regs. With 15V you have 3volts headroom which is more then adequate :)
 
Or a pair of subs :D

Edit: I need to postpone my sub project. According to the ESL panel manufacturer the panels need 200 hours of burn in to reach their full bass potential.
 
misterdog said:
So did the 5 rail supply improve on the 1/2 rail ?
Click to expand...

Yes.
Went from stock then sent it to JohnW and had sovereign DC+ mods, so will only work with a 5 rail DC supply. I have a second bone stock MDac and the differences are substantial. Same (A08 from memory) software, better sound stage and separation, tighter midrange and just feels more musical.

PSU was put together mostly from my parts bin, 5x super teddy regs, CRCRC supply and a custom torroid to suit.
 
sam_cat said:
Yes.
Went from stock then sent it to JohnW and had sovereign DC+ mods, so will only work with a 5 rail DC supply. I have a second bone stock MDac and the differences are substantial. Same (A08 from memory) software, better sound stage and separation, tighter midrange and just feels more musical.

PSU was put together mostly from my parts bin, 5x super teddy regs, CRCRC supply and a custom torroid to suit.
Click to expand...

Yours looks neater than a row of Calyces..

We shall soon see.
 
Bob L said:
+2! It looks very professional Some of us just have to make do with n x Calyces.
Click to expand...

Some DIY bits n bobs (PCB's) from the DIY room on here, a case from ebay, a pillar drill and some wiring bits n bobs.. the rest is time. :)

But thank you, the looks pro comment is appreciated. :D
 
John, would 330mA on each of the four analogue rails and 660mA on the digital rail suffice to power the MDAC?
 
Hi John,
I would like to know the "Sovereign upgrade Kit" which you have provided this upgrade in year 2012. i would like to implement this upgrade on my unit by myself. I will appreciating your helps if you can pm me more detail of this Sovereign upgrade.
 
t30,

There was never a upgrade kit for the Toy / Fusion units (Apart for the Vishay bulk foil resistors which where a part of the upgrade) rather a very very tedious strip, modify and then rebuild process - actually looking at a RTRT's Toy unit returned for service I must have been completely crazy to undertake such an effort!

At the end of the day each unit need component optimisation and working with SMD and PCB modifications is sadly not for DIY, each PCB had close to say 50 - 60 Modifications.

I have a basement full of salvaged MDAC's which I need to turn back in cash once I've completed the FDAC - we will most likely add a small daughter PCB which contains various design upgrades - this is a more practical MDAC upgrade for the experienced DIY'er.
 
I was thinking about using a 7 wire cable (L+, L-, R+, R-, Digital+, 2x GND) with a 7 pin XLR connector on the PSU side (fixed on MDAC side).

Any idea on the required wire gauge? 0,25mm² or 0,34mm² should be possible.

Do I need to connect GND anywhere on the MDAC case?
 
Hello John,
After see carefully your posted 2 images in year 2012, I notice you have done some jumper wire, cutting trace and removed some diode on the Power Board. (& not forgotten some additional opamp which i have no ideal). i am experience in those "dirty job" and manage to do it myself here (SIN). Unless there are some bench test/programming require after mod. :)
 
fusion5 said:
I was thinking about using a 7 wire cable (L+, L-, R+, R-, Digital+, 2x GND) with a 7 pin XLR connector on the PSU side (fixed on MDAC side).

Any idea on the required wire gauge? 0,25mm² or 0,34mm² should be possible.

Do I need to connect GND anywhere on the MDAC case?
Click to expand...

No need for Ground (as in Earth Connection) to the MDAC Chassis as no Mains level voltage is present in the MDAC.

For the power cable, the thicker the better. You can see that the MiniDin Cable is not great so anything thicker is good news :)
 
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