"Arny Krueger" wrote in message
...
"Trevor Wilson" wrote in message
.. .
**Quite a bit, but Bassett is wrong (no surprise there) about the DAC
being the major part of the problem. I've worked on quite a number of
cheap DVD players and have been surprised about the poor quality analogue
ICs used in the output stages. Most use 4558 class chips. These date back
to the late 1970s and are not even as good as the chips used in the first
generation CD players. Early CD players almost universally used
LM833/5532 class chips (which are still quite respectable today). The
other major problem I've found with cheap DVD players is their use of
transistor muting, in stead of relay muting. If relays are substituted
and output chips replaced with something more modern (I rather like the
AD825), the sound improvement is quite substantial. Unfortunately, it is
difficult to persuade people to part with nearly 10 times the original
price of the DVD player for an upgrade. In any case, most DVD players are
used with HT receivers, which renders such mods a moot issue.
Trevor is being quite paranoid on both counts. The sonic and measured
performance of low-cost DVD players with the design features that Trevor
decries is actually quite good.
**It would seem so. It is a pity that they sound like crap.
For example, the 5532 chip is a wonderful chip, but is not required for
equipment that drives consumer impedances (10K and up) with relatively low
voltages (always less than 2.5 vrms). The muting transistors have been
long used in all kinds of equipment with good results at these signal and
impedance levels.
**Indeed they have. However, decent equipment always use relay muting.
Transistor muting seems to introduce audible problems that (cheap) relays do
not. Don't forget: We're only talking about $3.00 relays here.
The 4558 that Trevor decries is even widely used in professional gear that
is highly regarded.
**No, it is not. It was so highly regarded, why did Philips choose the 5532
and Sony the LM833 for their first generation CD players? After all, the
4558 was MUCH cheaper back in 1983. Any ideas?
--
Trevor Wilson
www.rageaudio.com.au
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