Ultra Analog D20400 datasheet?

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SergeySVS

Member
Joined 2012
Hi everyone,

I have D20400 and found some issue in data conversion.
Output signal (sinus pk-to-pk) is shifted to -2.5V and take only half range (from 0 to -5V)
It looks like MSB is jammed.
The input signals go from PMD100 and coreespond to datasheet.
BUT. Some times (very rare), DAC jumps to normal operation (+-5V max, zero offset)

So, the questions are:
Does anybody have FULL datasheet for D20400?
Does abybody have some contacts to designers of this DAC?
Has anybody found the same issue, and how to fix it (power supply Power-Up sequence, another input data mode, etc)?

Thanks,
Sergey.
 
J

jadis36r

Member
Joined 2014
MASDAC

Hello at all
I have just a question :
i open my second hand Metaxas MASDAC III rev3 and i see that the UltraAnalog 20400 ( UA D20400) module is directly connected to 2 news RCA outputs.
(Original RCA outputs don't work.)
Sound very good and transparent...
but does I need at minimum any good capacitor in serie on each positive red wire to protect Preamp and amp ?
Please what do you think of that ?
Your advices ?
Thanks in advance for answer
Phil
 

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N

NATDBERG

Member
Joined 2006
SergeySVS said:
Hi everyone,

I have D20400 and found some issue in data conversion.
Output signal (sinus pk-to-pk) is shifted to -2.5V and take only half range (from 0 to -5V)
It looks like MSB is jammed.
The input signals go from PMD100 and coreespond to datasheet.
BUT. Some times (very rare), DAC jumps to normal operation (+-5V max, zero offset)

So, the questions are:
Does anybody have FULL datasheet for D20400?
Does abybody have some contacts to designers of this DAC?
Has anybody found the same issue, and how to fix it (power supply Power-Up sequence, another input data mode, etc)?

Thanks,
Sergey.
Click to expand...

I'm pretty sure Dan Lavry was the designer for this DAC chip .. I've seen he at least used to post on www.gearslutz.com so it's possible he might be able to answer, or I may have it wrong or he may not want to..

I realise this post is two years old though!
 
N

NATDBERG

Member
Joined 2006
jadis36r said:
Hello at all
I have just a question :
i open my second hand Metaxas MASDAC III rev3 and i see that the UltraAnalog 20400 ( UA D20400) module is directly connected to 2 news RCA outputs.
(Original RCA outputs don't work.)
Sound very good and transparent...
but does I need at minimum any good capacitor in serie on each positive red wire to protect Preamp and amp ?
Please what do you think of that ?
Your advices ?
Thanks in advance for answer
Phil
Click to expand...

It depends what your preamp has on it's inputs perhaps? Many pre-amps do have capacitors on inputs to block DC anyway so they are not necessary on the output of the DAC .

Maybe, as it is connected directly to the DAC, there is less chance of DC on the output through a fault than if it were connected to an output stage? I'm not qualified to give you proper info on that though, only come up with the idea :)

Then again, try putting some good caps on the outputs and try to tell the difference - some would say that you can't.
 
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S

sumotan

Member
Joined 2013
This dac has a build in op amp with full scale v-out
Of 5 volts but the current is so small only 1ma. This
would require a very hi input impedance of the preamp
side & it will also be very cable sensitive. Ideal is to add
a buffer which when done properly will add better
performance

Cheers
 
J

jadis36r

Member
Joined 2014
sumotan said:
This dac has a build in op amp with full scale v-out
Of 5 volts but the current is so small only 1ma. This
would require a very hi input impedance of the preamp
side & it will also be very cable sensitive. Ideal is to add
a buffer which when done properly will add better
performance

Cheers
Click to expand...

Thanks for answers...

please could you help me to upgrade my Metaxas Masdac III rev3
witch include LT1016 - Apogee C768 clock - NPC SM5803APT - UA20400 and 5532.......

Cordially
 

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tiefbassuebertr

tiefbassuebertr

Member
Joined 2005
tiefbassuebertragung.de
tiefbassuebertr said:
Thank you.
About
Fejhallgatók és hozzávaló er?sít?k
and
DAC2????????? - ????????? - Yahoo!?????
are to read more informations - unfortunately not in english.
I am still looking for an internal schematic diagram.
Click to expand...
Both URLs are death in the meantime.
The first URL is still available under
Fejhallgatok es hozzavalo erősitők
Under post #24742 there is to read:
"This is the Ultra Analog DAC hybrid module, and I've looked at what the case actually contains.
The main part of the module is a MCU chip M72H035 manufactured by OKI (Japan), and an AD844 (2kV / us, 60MHz) operational amplifier works on the analogue output stages."
Where is to find a datasheet from the M72H035 ?
And who had overtaken Ultra Analog ?
Maybe there I can order the circuit diagram of these modul.
This URL don't provide the wanted information:
Ultra Analog, The Ghost Company
Thank you for advices.
 
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tiefbassuebertr

tiefbassuebertr

Member
Joined 2005
tiefbassuebertragung.de
NATDBERG said:
Does the URL still work? Didn't appear to work for me.

Although, someone emailed me the datasheet a while ago so perhaps I'll have to upload it somewhere for all to grab.

Wadia bought out UltraAnalog and I think, so the general opinion goes, burried them.. and so denying their competitors access to this wonderful DAC (it's not chip as such - it's a DAC unit with several chips inside, the actual DAC being made by OKI for the designer).

Still, it's a 20-bit dac and so obsolete in production terms anyway.. The original designer of the DAC - can't remember his name - is still around and producing DACs under the Lavry brand.

I have a Manley / Lavardin DAC with this unit in (actually UltraAnalog produced a custom unit for Manley but have never found out what's different about it..) and would love to modify it to the max.

Interestingly, the datasheet says is can handle up to around 350KHz sampling rate - so I'm wondering if it can be coupled with a modern receiver chip and still do excellent service to 96/24 recordings ..

P.S. If you want to play around with the DA20400 and can find a Manley Junior or Lavardin 20 bit DAC then grab it! The layout is so nicely sparse and simple that it should be a dream to work on.
Click to expand...
This is Mr. Dan Lavry from this company:
Lavry Engineering

More URLs:
Analog Digital Wandler / Digital Analog Wandler - Converter
Dan Lavry: Behind The Gear with Lavry Engineering | Tape Op Magazine | Longform candid interviews with music producers and audio engineers covering mixing, mastering, recording and music production.
Mono and Stereo High-End Audio Magazine: Interview with Dan Lavry of Lavry Engineering
The Lavry DA11: For your ears only | Headphone Reviews and Discussion - Head-Fi.org
https://www.headfonia.com/lavry-da11-review/
https://www.soundonsound.com/reviews/lavry-engineering-ad11
 
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tiefbassuebertr

tiefbassuebertr

Member
Joined 2005
tiefbassuebertragung.de

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tiefbassuebertr

tiefbassuebertr

Member
Joined 2005
tiefbassuebertragung.de
D20400 clone with genuine Parts

there seem to be real replicas of D20400, because according to the attached images there are no potting residues on both PCB sides.
Thus there are also actually be a circuit diagram present.
 

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N

NATDBERG

Member
Joined 2006
I think it is one that has had the potting removed - can see the odd scratch and some chipping to some edges. Depends how much the potting sticks I guess.

I have an Anagram/Edel S2 upsampling chip in a box waiting for me to make a DAC with and a couple of D20400 Audio synthesis DSM DACs waiting for me to butcher a little for the build..

The Edel S2 outputs 384KHz (variable upsampling to achieve the constant sample rate output) - generally speaking, it should be easy to connect the two shouldn't it? No need for circuitry between them? I think for example the S2 can output 2s complement.

(I'm a newbie really, can fix things ok but designing I need to paint by numbers).
 
J

Jon Lord

Member
Joined 2005
Hello NATDBERG,

please be aware, that the DSM DAC contains D20400, not D20400A, but the datasheets and application note (once) available here describe the D20400 anyhow.

For your design the TDA1541A (I2S) compatibility mode should be the way to go.

So far I identified three different versions of the UA DAC module:

1) D20400 (used in very early equipment, rather inferior regarding measured performance, but sounding quite good)
2) D20400A (This one was used by almost every OEM, sounding really great)
3) "Naked" D20400A without I/V converter (Lets call it D20400N), as used in the Sonic Frontiers Processor 3 and Spectral SDR-2000 DAC, which implemented external I/V converters.

I just found out, that one spare Sonic Frontiers "D20400A" I bought a few years ago is unfortunately number 3). This is not good news, since in my SFD-2 MKII just recently a D20400A module died :cannotbe:

Now I can decide, if I want to butcher my Parasound D/AC-2000 :whazzat:
 
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