PMD100 HDCD, UltraAnalog DAC and Re-clocking

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RussT

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Joined 2004
#1
I am new to this forum. :>)
I purchased a PS Audio UltraLink DAC which uses NPC5803 D/F and UltraAnalog 20 bit DACs. Unit sounds real fine. I decided to try to update the '5803 to the PMD100 HDCD chip. What I did was remove the '5803 and replace with a 28 pin IC socket. I then made a daughterboard that plugged into the '5803 socket (I used a wire-wrap socket extending through the daughterboard to the '5803 socket). I then configured the PMD100 to mate correctly with the Yamaha YM3623B DIR and output correctly to the UA20400A 20 bit DACs. I used separate +5VDC lines for Vdd1 and Vdd2. I also used 100ohm buffer resistors in the data lines. I put the unit together and it worked flawlessly! I installed a nice blue LED on the front panel of the UltraLink and HDCD encoded discs light up as expected. The new detail, soundstage and resolution is extraordinary. I am now looking at re-clocking techniques that would work with this DAC. Perhaps utilising the Cirrus Logc DIR + PMD100? I do not know much about reclocking so any advise would be greatly appreciated. If it is helpful I can post theughterboard schematic. Thanks!
Russ :>)
 
#2
Hi Russ T.

I had an article published in Electronics World June 1997
concerning overcoming deficiencies of SPDIF.


These modifications are complex involving 74AC74
Flip Flops on transmission and reception of codes
Bitclock LRCK and Data. effectively bypassing SPDIF
altogether - pretty radical. There is no digital receiver
such as CS8412.

ie you then must view that Dac and transport as
a linked unit , there is no convienient single cable
to hook up.

More simply reclocking involves buying a crystal
as a spare from Sony or other manufacturer , just
source a schematic and quote the part number to them.
calculate frequency sampling ie 256fs is 11.286Mhz
384Fs is 16.934Mhz ie 44.1 Khz x fs

You have a few choices here , build a dedicated clock
driver or more easily.....
Source and study your oversampling ic pinout
Most Oversampling ic's allow a clock connection on two pins
and have a buffered output from this same ic.
feed this clock from the oversampling ic clock output to
clock input of a flip flop and whatever signal you wish to
reclock to the Data input of a flip flop.

There are also set and reset pins to
cater for ( read 74xx device data ) You then gain the clock
speed interpolation advantage as Q or inverted Q as an
output.

Cheers / Chris
 
#3
I just purchase a late series Ultralink II with HDCD decoding and am thinking about modifying the unit once I have had it for a while. (Still waiting for it to arrive.)
Any technical information on the Ultralink II beyond the usual wonderful but mindless raves found elsewhere would be helpful. I have had a Lambda Drive for years and have been very pleased with its performance.
Wondering if anyone out there has a data sheet for the UltraAnalog UA20400A Dac which I believe is used in this model.

If you have data sheets or other info shoot me an email at nospam.direct.heated@gmail.com remove nospam obviously

Thanks
 
#5
RussT said:
I am new to this forum. :>)
I purchased a PS Audio UltraLink DAC which uses NPC5803 D/F and UltraAnalog 20 bit DACs. Unit sounds real fine. I decided to try to update the '5803 to the PMD100 HDCD chip. What I did was remove the '5803 and replace with a 28 pin IC socket. I then made a daughterboard that plugged into the '5803 socket (I used a wire-wrap socket extending through the daughterboard to the '5803 socket). I then configured the PMD100 to mate correctly with the Yamaha YM3623B DIR and output correctly to the UA20400A 20 bit DACs. I used separate +5VDC lines for Vdd1 and Vdd2. I also used 100ohm buffer resistors in the data lines. I put the unit together and it worked flawlessly! I installed a nice blue LED on the front panel of the UltraLink and HDCD encoded discs light up as expected. The new detail, soundstage and resolution is extraordinary. I am now looking at re-clocking techniques that would work with this DAC. Perhaps utilising the Cirrus Logc DIR + PMD100? I do not know much about reclocking so any advise would be greatly appreciated. If it is helpful I can post theughterboard schematic. Thanks!
Russ :>)
Click to expand...


Hi

Look here for inspiration

http://www.tentlabs.com/Products/DIYDAC/DIYDAC.html

and here for a suggestion for a PLL

http://www.tentlabs.com/Products/DACUpgrade/DACUpgrade.html

cheers
 
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