"Stewart Pinkerton" wrote in message
...
On Fri, 01 Apr 2005 00:04:38 GMT, "Trevor Wilson"
wrote:


"Keith G" wrote in message
...

"Trevor Wilson" wrote in message
...

"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.

All well and good Trevor, but like Andy says: 'why'...???

**Because Lord Pinkerton could do the job for almost no cost. The benefits
are tangible. For those not capable of doing the job, I feel it is
probably
a toss-up as to if the value is there.

You claim that the benefits are tangible, I suggest that they are
almost certainly only theoretical.

**As is your right to do.


Don't see the point of buying a perfectly adequate budget player in the
first place and then spending *more* money on it.....???

**Me either. Still, I modded my own budget players. The cost was a little
time and some cheap chips and some relays I had lying around. The results
were worthwhile, in two out of the three instances. The bedroom system is
really too crappy to bother modding any player. The other rooms have quite
decent systems.

You did of course do this with two identical players, and compared
'before and after' sound quality?

**Yep. And so did two clients. I supplied one client with two, identical
players (budget, DVD-A). One modded, the other stock standard. Only I knew
which serial numbered unit had been altered. He reported the modded one as
sounding better.


My basic benchmark is that, since my 'off the shelf' Pioneer DV 575A
sounds identical to a 'high end' Meridian 588, it's vanishingly
unlikely that replacing a few parts inside the Pioneer willl make any
audible difference - except possibly for the worse!

**Nope. There is zero chance it will sound worse. There is a high
probability it will sound better.


--
Trevor Wilson
www.rageaudio.com.au