I've been listening to the analog output of an old Sony CDROM with a 1-bit DAC and comparing to OPUS 8741 with Metronome at 24/192. Using Sennheiser 580 and iBasso D2 headphone amp. Both the OPUS and CDROM are used single-ended.

Well, after listening to different CDs including some good recording chesky CDs, I am hard pressed to hear any differences (The Opus has probably a 3db higher volume because the sony DAC is spec'ed at 1.75V).

are 1-bit DACs "that good"? In some recordings, the 1-bit DAC seems smoother at the top end.

I can't find any difference in detail (No matter the attention I give to any small detail I hear the same detail on both DACs)
I can't find any difference in tonality (instruments sound exactly the same)
Soundstage (if there is such thing in a headphone) is exactly the same. Instruments don't "move" when switching sources.

So is it my hearing (which compared to other middle aged people I have a pretty good hearing) or is it possible that the 1-bit DAC is indeed a good DAC?

I am connecting the OPUS/Metronome to the PCM output of the CDROM controller chip (similar to I2S) and I am also using the analog output of the CDROM. I am using a little contraption I made to switch between the sources with a toggle switch, so this is an A/B test.

Here is a picture of the CDROM I hacked: http://picasaweb.google....QnD8&feat=directlink

How are you deriving your SE output from the Opus?

Edited by user Friday, February 6, 2009 5:29:15 AM(UTC)  | Reason: Not specified

Ok, I think this has a lot to do with your findings. You will gain significantly from utilizing a proper bal->se converter. Namely, cancellation of common-mode distortion. Additionally, you would benefit from filtering high frequency noise from the DAC's outputs.

FWIW: The Sony "1-bit" dacs are Delta-Sigma dacs with a marketing name.