Non-Oversampling DAC

[tobias_svensk]

Anybode else built this one? And if so, how does it sound

I'm looking for a DAC to build and for this one I have many parts already.

/Tobias

[lucpes]

Well, I heard it about two weeks ago in the owner's system (Rockna preamp & monoblock amps, Dynaudio Contour 1.3 MKII, AudioQuest interconnects & speaker cables) and it sounded very nice (fast/detailed without being harsh and with well defined bass&midrange; maybe a a tad bit laid back in the upper treble range compared to what I'm used to but this is OK, vocals/instrument separation seemed more 'real' than in my system (Marantz CD94/passive atenuator/Randy Slone's OPTIMOS 200W monoblock amps/ Infinity RS II open baffle speakers). Too many different variables between the systems to draw a conclusion

I'll check how it fares against my Marantz CD94 next week

[Lupulroz]

The 1:1 upsampling is achieved by setting 1892's output sample freq. at 44,1 KHz - MCLK of 22.579 MHz (512xFs).

[till]

but this setting would not be called "bypassed" but resampled to same sampling frequency ?

rfbrw, is there any way to really bypass the reclocker?

[Lupulroz]

To bypass the ASRC of AD1892 you have to simply set this in chip's internal control registers, but the jitter will pass through...

[rfbrw]

Originally posted by till

rfbrw, is there any way to really bypass the reclocker?

Yes, with a microcontroller.

[lucpes]

Well, it's alive and kickin! Was in a hurry so for now some resistors are made up by two other values in series...

Using a Marantz CD94 as a transport the sound is great! I really think it outperforms the Marantz' analog out and that's not in a subtle manner. I won't comment with traditional "fuzzylicious bass, buttery mids or sweet and tender highs" terms

[lucpes]

Took some measurements for fun using a M-Audio Revolution PC soundcard, these seem almost too good to be true, except for the frequency response - non-OS DAC though; also, the freq test is limited to 44.1/2kHz so I couldn't catch any digital images due to non-os...

Of course, this particular soundcard's line in is not the best in the league so the DAC's standalone performance should be better (if that's possible)...

[Bernhard]

...the dynamics picture, does it show a low level (-67dB) 1 kHz sine ?

[Terry Demol]

Originally posted by lucpes
Took some measurements for fun using a M-Audio Revolution PC soundcard, these seem almost too good to be true, except for the frequency response - non-OS DAC though; also, the freq test is limited to 44.1/2kHz so I couldn't catch any digital images due to non-os...

Of course, this particular soundcard's line in is not the best in the league so the DAC's standalone performance should be better (if that's possible)...

The AD1892 will impose a digital brickwall filter even when
resampling at 1:1, such is the nature of how ASRC's work.

The idea of 0 x OS is to get rid of brickwall filter.

Cheers,

Terry