"andy" wrote in message
oups.com...
As yet another owner of a Pioneer DV-575A I am curious about what the
above modifications will achieve and why?

**Output muting, via the use of BJTs has always been a sonic disaster, IME.
A relay contributes no distortion, whilst in the O/C mode. The output IC
used, whilst adequate, is hardly state of the art. Output ICs in 1983 (ie:
First generation) CD players were superior. In Philips derived machines,
that usually meant an NE5532/5534 chip. A fine chip, back then and still a
fine chip today. There are two, 220 Ohm resistors in series with each O/P
IC. These should be shorted (after replacing the ICs with a more suitable
device, of course). A 440 Ohm output impedance is pitifully high.
Additionally, it would be nice to organise a spilt rail power supply, for
the output IC. At present, it is powered by a single rail supply, thus a
large electrolytic coupling cap is required.

I suggest anyone who is interested, to compare the 575A to a decent,
contemporary CD (only) player, such as a Rotel RCD951 and report on any
differences.


--
Trevor Wilson
www.rageaudio.com.au