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UltraAnalog D20400A

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A

apsietje

Member
Joined 2011
I'm searching for my DAC2 Threshold the DAC-chips UA D20400A ? Is there anyone thar can help with OEM-chips, replacements or have anyone the datasheet from that UltraAnalog? The T-DAC2 has 2 DAC-stages. Ist this unit a current or a voltage DAC?

A lot of thanks for help !!!
 
C

chrisautosound

Member
Joined 2008
pyramid-audio.com
D20400 replacement update

chrisautosound said:
I just finished a drop in replacement for the D20400 in the Levinson No35. like the No30.6, It uses two PCM1704K and OPA627.

At first I thought there was a data format problem since the output was very distorted. But the problem was the No35 bit clock driver IC sucked. The long BCLK trace to the DAC is about 8 pF and the original IC MCxxxx could only pull up 0.5 mA. So a poorly shaped 1 V p-p is all there is, but for the D20400 it worked. The replacement SN65XXX delivers a beautiful BCLK and all is good.

I got the idea from the Levinson No30.6 where they did just about the same thing but their board is NLA and was $800. I also used dual PCM1704K and OPA627. So it also measures and funtions almost exactly like the D20400 but I included a 2 pole LPF to reduce out of band noise. I still need to try it in our No30 and No30.5.

S/n 114 dB un-wtd 22-22kHz. Low 0.0020% distortion with 16 bit data.
Click to expand...


Yippee!
as of 08/17/2011 I also have a version that drops into the Levinson No30.5 with no other parts or changes. Thanks to the client that needed it done. He is now the first No30.5 customer in many years to have a successsful repair.

Although ANYONE that has opened the 30.5 knows that "drops in" really means hours of disassembly. and if you want the thing to last a long time recap it too, that only adds another day to the repair.

:joker:
 
N

NATDBERG

Member
Joined 2006
apsietje said:
I'm searching for my DAC2 Threshold the DAC-chips UA D20400A ? Is there anyone thar can help with OEM-chips, replacements or have anyone the datasheet from that UltraAnalog? The T-DAC2 has 2 DAC-stages. Ist this unit a current or a voltage DAC?

A lot of thanks for help !!!
Click to expand...

Hi Apsietje - Voltage output.

Uses some high frequency op amps (AD714? - from memory) before the output of the package I guess as part of I/V conversion.

You have to think of it as a package rather than a chip. Only a couple of custom chip in the actual unit - "custom CMOS IC, custom thin-film resistor networks" so they could be repaired in theory but delicate work and would rely on it being a common part that's broken.

I have the datasheet as a pdf.. will happily email it to anyone. PM me.

Alternatively I'll try to put in on a filesharing site like megaupload as it's too large for an attachment on here (500Kb) and I don't have Acrobat pro to split or crunch it.

Have a search around the web though as there are some photos around with the resin removed to reveal its innards.. Chinese hifi websites. Search DAX too.
 
abraxalito

abraxalito

Member
Joined 2007
I'm curious about that module - there's no spec sheet but they say the performance is equivalent to, or even better than the original. Which would be quite a feat as there was a fair degree of 'secret sauce' involved. It would be very interesting to learn who has developed this module for PCX, particularly as the price is only $250.
 
T

tonimxp

Member
Joined 2007
Sonic Frontiers sfcd1 PCB replacement ultra Analog D20400A with dual AD1862

Hello! This Is my solution for UA D20400A
It work fine and It give a very nice sound.
 

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