DAC AD1862: Almost THT, I2S input, NOS, R-2R

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#9,401
A question for the group. How difficult would it be to modify Miro's CPLD code that converts I2S to PCM so that it went directly from SP/DIF to PCM?

I have the devices and the programmer and am planning to attempt to learn Miro's CPLD approach.
 
#9,403
Tam Lin said:
Early in my programming career I worked for a start-up that made IBM compatible mainframes. The chief engineer there liked riddles. For example, "When is a clock not a clock?" "When is passes through combinatorial logic." The idea being, the logic gates destroy the integrity of the clock.

In addition to damaging the clock signal, Stop-Clock introduces significant Fs noise into the system.
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For the AD1862, conversion is triggered by wordclock, not bitclock. After the combinatorial logic you reclock the wordclock.
(I think the designers of the PMD100 digital filter knew what they were doing, they chose to implement the stopped clock conversion).
 
#9,404
#9,405
@hirscwi, do you really have to ask? Is BCK an important clock your the system? Yes. Is a multiplexer combinatorial logic? Yes.

But that's beside the point, because the clock had already gone through many logic gates during the creation of the I2S signal. I2S is the worst digital transport protocol ever foisted upon ignorant audiophiles.
 
#9,407
Tam Lin said:
@hirscwi, do you really have to ask? Is BCK an important clock your the system? Yes. Is a multiplexer combinatorial logic? Yes.

But that's beside the point, because the clock had already gone through many logic gates during the creation of the I2S signal. I2S is the worst digital transport protocol ever foisted upon ignorant audiophiles.
Click to expand...
Thanks for your answer. It makes sense to me. But is there a good way to have multiple inputs to the DAC, given that I2S is a protocol that's in common use?
 
#9,410
Vunce said:
That looks like a Musical Fidelity X-10D Buffer clone board.
If it is, no voltage gain in that circuit.
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The power supply is a clone of the X-10D, but the schematic is not, it is different. Neither is worth it for this DAC.
 

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#9,414
I soldered an opa1611 with flux.
It's not working properly as the flux goes under the chip and made bad contact when it's heating up. For 10-20 seconds everything works fine after the problem starts.
An other one I soldered without flux works without a problem.
Beter have good solder then using flux I guess
 
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