| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 184.1 | | AMBER::KAEPPLEIN | | Fri Sep 20 1985 11:15 | 7 |
| Yes, there is something negative.
It only has one D/A converter. While this is better than zero D/A converters,
it causes inter-chanel phase shift that increases with frequency up to
45 degrees at 20khz. Two D/A converter machines don't have this "feature."
Indeed, Sony's newest players use two DACs.
|
| 184.2 | | PISA::LIONEL | | Fri Sep 20 1985 12:46 | 8 |
| Sony's most expensive players use two DACs. The "Unilinear Converter"
system that the CDP-302 uses has a built-in analog delay so that phase
shift is eliminated. Several reviews of these units have shown that this
works just fine. In fact, one could argue that one DAC is better than two,
because with two you run the slight risk that they behave slightly differently
and get wierd sound (not saying this ever happens, but...). I know several
people with the CDP-302 and they all love it.
Steve
|
| 184.3 | | LATOUR::APPELLOF | | Mon Sep 23 1985 09:06 | 10 |
| Please correct me if I'm wrong. I thought that the digital info on a disk
was encoded in a serial bit-stream. If that is true, it would mean that
the digital value for the sample from one channel would be available before
the value for the other channel. Thus, unless a digital delay were introduced,
a dual-DAC player might still have a phase shift problem. Is there a
digital delay in the dual-DAC players? Are the signals encoded in parallel
on the track? What's the true story?
Carl
|
| 184.4 | | AMBER::KAEPPLEIN | | Mon Sep 23 1985 17:02 | 18 |
| The chanels are alternated. Data flows from the amp to a demodulator to
the error detection/correction unit and into a FIFO stack before the D/A
converters.
The fullness of the FIFO stack also controls the motor speed! When it goes
below midpoint, it tells the servo to speed up the disk, and when it goes
above midpoint it tells the servo to slow down the disk. Neat huh?
And you Sony lovers are wrong. Sony lists the interchanel phase shift as
less than 45 degrees at 20khz. If there were an effective compensator it
would be 0. Sony claims that with their outboard D/A converter the shift
is zero. Phillips lists theirs as less than .5 degrees at 20khz.
There is alot of nifty theory of operation type information in the $4.00
factory service training manual I bought.
Mark
|
| 184.5 | | BAGELS::ROSENBAUM | | Mon Sep 23 1985 22:22 | 5 |
| factory service manual
address?
store?
|
| 184.6 | | AMBER::KAEPPLEIN | | Tue Sep 24 1985 15:23 | 9 |
| Call North American Phillips (NAP) in Tenn. ( 615-475-3801 ) and ask for
the publications department. Tell them you would like the service training
manual for Magnavox CD players (a model number would help like FD1000 or
something) and ask for any service manuals you would like also. If the
total is under $15 they can bill you, or else MC/VISA it. Package comes
UPS in a few days.
The service training manual is $4.00 and most service manuals are $12.50.
|
| 184.7 | | CRVAX1::KAPLOW | | Mon Sep 30 1985 19:31 | 9 |
| The SONY repair centers (there should be a list of them in with the instructions
and warranty card) either stock or will order service manuals for various
products. You can buy them at a reasonable price. I got the set for my VCR,
and for $15.00 was deluged with over an inch thick stack of stuff. I would
imagine that the CD stuff is similar in detail and cost.
Other manufacturers probably do similar things. Call or write their local
service center. After all, all of those "authorized" centers have to get
the manuals somewhere too!
|