@barrista0611 well, a caveat with the D100 Mk2 and some other DACs with transformer-based analog output stages is that they will have a higher output impedance. So matching one with a passive preamp may be less than ideal if the preamp input impedance is too low or if there is a lot of fluctuation in the input impedance by frequency. Some passive preamps have changing input impedance by volume, while others do not.
But primarily a transformer-based output adds some warmth (i.e. distortion), usually to a slightly greater degree in the lower frequencies versus the mid-range or treble, without the negatives commonly associated with a NOS design like rolled-off treble or aliasing artifacts or the higher distortion associated with a tube design.
There’s decent set of measurements posted for the D100 Mk2 on the Neko Audio website, and many reviews can be found online.
Lumin and Linn also use output transformers in the analog output stage of their higher-end models.
But primarily a transformer-based output adds some warmth (i.e. distortion), usually to a slightly greater degree in the lower frequencies versus the mid-range or treble, without the negatives commonly associated with a NOS design like rolled-off treble or aliasing artifacts or the higher distortion associated with a tube design.
There’s decent set of measurements posted for the D100 Mk2 on the Neko Audio website, and many reviews can be found online.
Lumin and Linn also use output transformers in the analog output stage of their higher-end models.
