On Oct 8, 9:50 am, wrote:
Hi,

I recently picked up an old Musical Fidelity X-DAC at an audio sale.
It seems to be a slight improvement on my Quad CD66, little wider
sound stage, fractionally more precise instrument positioning.

The most kely audible change when you try a different DAC, is that its
output is at a higher or lower level than its predecessor.

Many people like to think that they can reliably distinguish changes
in level as being a change of loudness, but 30 years of blind tests
say otherwise.

However, what did surprise me was that some mono recordings seem to
have this 'widened sound stage'. Is this possible?

When you are limited to subjective perceptions like "widened sound
stage", all things are possible.

Perceptions are based on memory, expectations, and the current
listening experience. IOW, all other things being equal, about 2/3 of
what you base your perceptions on is irrelevant to the current
listening experience.

Can a DAC do this
or is there some DSP or analogue tweak being used to artificially
'improve' the apparent sound stage?

Yes. Historically X-DACs have been graced with tubes. Tubes are often
used as EFX devices.


BTW - Can someone point me to a not too technical article(s) on how
DACs work and why it is that one DAC can sound 'better' than another?

YOu might do better to read up on X-DACs since they are composite
devices.

For example:

http://www.stereophile.com/digitalprocessors/1204mf/