Discrete Dual Differential DAC?

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#2
It's the first I've heard, at least in the audio realm.

I interpret "dual differential" as one per polarity per channel, or four DACs. Really all a DSD DAC is an RC filter, so this isn't a huge breakthrough.

The only discrete audio DAC I know of is a little dated by todays standards, and was of the one-DAC-per channel variety with S/H.
 
#3
Discrette DAC circuit can or can´t be better solution than integrated ciruit. It is more expensive way. longer traces, component selection, temperature stability are problem that must be solved.

Arcam, Spectral, Audio Syntesist allready go discrette. Ultra Analog and Anagram produced discrette DACs in big chips which are encapsulated discrette DACs.
 
#5
I believe the Pink Triangle Dacapo was the worlds first commercial 1 Bit Discrete Dual Differential DAC; I designed the original version in 1990 - 1991.

The EMM Labs DAC rate is claimed to be 128Fs – Even back in 1990 – 91 the Dacapo Discrete DAC’s operated at 3 times this rate @ 384Fs

Discrete Dual Differential DAC is old news. The latest Dacapo DAC (to be launched Q1 next year) has 16x "Discrete Dual Differential DAC's" per channel, making a total of 64 DAC elements per channel – 128 DAC’s per stereo unit!

JohnW
 
#7
JohnW said:
The latest Dacapo DAC (to be launched Q1 next year) has 16x "Discrete Dual Differential DAC's" per channel, making a total of 64 DAC elements per channel – 128 DAC’s per stereo unit!
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Hi John,

Could you define Q1 next year for as not familiar with this english term?

Also, have you received my mail sent thru diyaudio about S700 Isomagic service manual?

Ivo
 
#8
Hi Ivo,

"Q1" Means first quarter next year (which in reality is always toward the end of the quarter)...

Sorry - I do recall receiving a request recently for the Schematics for IsoMagic - however it was design more then 10 years ago - and I no longer have them to hand (many changes of PC and crashed HDD's since).

If I do stumble across them, I will forward to you.

John
 
#9
JohnW said:


Sorry - I do recall receiving a request recently for the Schematics for IsoMagic - however it was design more then 10 years ago - and I no longer have them to hand (many changes of PC and crashed HDD's since).

If I do stumble across them, I will forward to you.
Click to expand...

I know you don' have them John...but I was about to send you one (not the best copy, bur anyway), thanks to nice gay from Cambridge Audio (customer care manager).

And gays, if and when I get a clearance from John, I will upload a manual somewhere.

Ivo
 
#14
abzug said:

How much of an issues is glitch energy in this design?
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Glitch causes the same problem as jitter: it spoils the signal amplitude. The glitch has most effect on the MSB. A fast and precise S/H circuit could be the solution, but that part has not been worked out yet. I used the conventional op-amp output in the prototype without S/H, because I just wanted to test the concept of the digital and D/A part. The tube output on the circuit diagram is imaginary, all the other parts is actually working.

I think the "8 MSB trimming" idea could be used with a TDA1541A, as well. The current dividers are accessible at the ripple rejection capacitor pins... I need to check this.
 
#15
Dan Lavry has a discrete 24-bit R2R DAC which is recalibrated at every power-on. But modern sigma-delta DAC ICs outperform it. It seems to me ladders are obsolete tech. My question is, how to DIY sigma-delta... I know it's possible, because Bruno Putzeys has a discrete DSD A/D module.
 
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