Conference cookie::notes$archive:cd_v1

It is a good price for the D7.

    Note - The dealer price for the D7 is in the neighborhood of $220
    (though Lechmere probably gets a better deal), so I wouldn't expect
    prices much lower than that anywhere.
    				Steve

    Anyone know how long this sale lasts?
    
    Dave W.

Through the 31st.

Some questions/concerns, if you will:

	I have in my hands a raincheck for the D7.  I also have in my hands
the June 1986 issue if 'Digital Audio & Compact Disk Review'.  In reading the
review of the Denon DCD-1500 I read and don't understand 'things' like:

'...dedicated D/A converter for each channel to eliminate interchannel
	phase difference.'  Huh?  I know what D/A converter is but what are
		the last three 'buzz' words?

'...zero-crossing distortion...'  Huh?

I believe that the D7 is a single beam CD.  If I remember the add for a
Toshiba portable it has three beams.  What is the benefits of the three
beam?  

O.K., now that I have gotten my head into a spin, let me tell you what I want
in a CD:
	- portability
	- good, clear, crisp sound reproduction


Is the D7 a good portable model or just Brand name hype?

What am I sacrificing by choosing a portable .vs. table-top?  (How do they get
all those electronics out of the table-top and into the portable?  VLSI  :-)

Just another naive CD purchaser interested in portability,
Dan

PS: Comments from other D7 buyers?

BTW: Lechmere had some BOSE speakers connected with the D7 at a product
	demonstration booth.  Billy Joel sounded excellent on them!  The
	name of the speakers was "ROOMmate".

    I'll admit it -- I'm a mid-fi type.  I like my D7 -- both on the
    move and at home.  Where else do you get "two" systems (portable
    and home) for about $250?
    
                            Roak
    

    re: .5:
    
    Forget about all that.  If you don't understand it, fine, you don't
    have to!  Why not buy what sounds best? 

    It's not only buying what sounds best, it's buying what sounds best
    and is reliable. The one thing I hate is to buy a new piece of audio
    gear and then have to bring it back for repair!
    
    Jeff
    

RE: -.1,-.2,-.3

	Thanks for the input.  Other than at Lechmere, where can I test the D7?
A straped in D7 w/mini AIWA speakers doesn't cut it for me.

	Also, can anyone give me info on those and other buzzwords?  Maybe
that's a note in itself.

Thanks,
Dan

    
    There is a Sony Dealership on Franklin Street in Framingham.
    Its called Garino's Audio/Video. Phone number is 875-5969,
    They match Lechemere's price on the D7 last week.
    

    > '...interchannel phase difference.'

    If you have only one D/A converter you have to process both channels
    one at a time. So one channel will always be delayed by the time
    period it takes to process itself thus introducing the phase
    difference. Of course the time it takes to process one channel's
    data is so infinitesimal that you'll never notice it!
    
    > '...zero-crossing distortion...' 

    Beats me!
    
    Paul.

    Re .11:
        Using a single converter doesn't always mean that you'll
    get a phase difference - a bit of extra delay circuitry can take
    care of that.  Sony's "UniLinear" converters have very little
    phase difference.  Personally, I don't think it matters one whit.
    At the frequencies where the difference becomes "significant" (in
    terms of seeing it on a scope), being a fraction of an inch closer
    to one speaker than another will swamp any phase difference.
    
        In fact, two converters introduce another problem, beat
    frequency distortion, caused by clocks that are slightly out of
    synch.  Anyway, it's all for those who watch their players through
    scopes rather than speakers....
    					Steve

    re .12: surely any sensible designer has only one clock, not two???
    
    re .11: zero crossing distortion: at zero crossing, all bits of
    the input change at the same time (from 10000000 to 011111111...);
    quite often d/a converters that are well-behaved at other times
    produce a noticeable glitch at this point.  By careful design and
    additional money spent on the converter(s) you can reduce such glitches
    dramatically; the best d/a converters are spec'ed as always being
    monotonic, i.e. all glitches guaranteed to be smaller than the step
    size.  Not sure if you'll find d/a's that good in ANY CD player,
    though.
    
    	paul

    Re zero crossing distortion... there are designs for DAC's that are
    inherently monotonic at the major bit transition.  These use a bunch
    of parallel current sources switched in one at a time for the high
    bits; the Sony DAC's achieve this with current accumulation on a
    capacitor, so it can be done.  The Phillips DAC uses a different
    technique which ought to be good near the LSB, at least at 14 bits
    (and the oversampling helps there).

     Re time delay between channels...  the important thing is not the
     static time delay (which magazines like Audio test for), but any
     variation of this delay with frequency.  Oversampling players are
     better than others in this regard, but probably all CD players have
     much less interchannel skew than cassette decks, or even the highest
     end LP/phono cartridge chain.  This just isn't a serious audio problem.

     Multiple DAC's, and 16 bit DAC's in 4X oversampling players are largely
     marketing issues, not real performance issues.

     I would rate a single clock as more important than dual DAC's, other
     things being equal.

    - Jim

    
    I've begun considering the purchase of a CD portable to use both
    in my office and "on the move".  I've looked at both the Sony D7
    and the Sony D5, Technics, etc.
    
    Does anyone have any comments to make on the relative differences
    between the so-called 1st generation portables and the newer generation
    of portables?  It's real tempting to get a D5 deluxe with so many
    places putting them on sale!!!!
    
    
    		-Jeff

    Well, the old Sony D5 had 
    	1) severe reliability problems (it wore out REAL quick)
    	2) very poor power supply protection (it died at 10 volts)
    	3) no battery- unless you got the tricorder which made it
    	   slightly larger than a desktop portable cassette recorder.
    	4) wore down the tricorder batteries in 2 disks (2 hrs).
    
    The new Sony (D7, or is it D5 deluxe?) has a built-in battery,
    supposedly better power protection, and plays 3 hours on rechargeable
    batteries.  It looks about the same.
    	
    The silver Technics thing works quite well, it has built-in battery
    power and a nice sound.  It's also been out quite a while.  A friend
    of mine has one- hasn't broken yet, while friend#2 with a D5 is
    on his third D5 (thank goodness for replacement service contracts).
    
    

    We covered this in other notes, but my experience with the D-5
    has been nothing but fantastic.  I've had it a year and it has
    never given me a problem.
    
    Also, the D-7 is not the same as D-5 Deluxe.  The latter (which
    I have) is a D-5 that comes with the power supply in a base that
    the player slides on to, rather than a "pack" that plugs in separately.
    The line outputs are also on this base, so you can leave it 
    permanently attached to your home system.
    				Steve

        My D5 gets about 4 hours per charge in the 'tricorder' case.
        I also have the D5 Deluxe and have been quite pleased with
        it. I use it about 70% of the time at home in it's docking
        base; the rest of the time as a walkman. Never had a problem,
        and I've had it about 9 months now.
        
        If you want it as a portable, I'd say go for it. If you really
        want a home deck, the Magnavox seems to be preferred in that
        price range.  I got it as a first player that I can use as
        a portable later on when I get a high-end player for the house.
        
        Dave
        

    What is the difference between D7, D7-S and D77?  Is $200.00 mail-order
    price reasonable for D7?  Any local place selling D7 in that price
    range?
    
    Thanks,
    - Vikas

    The D77 has an AM/FM/FM stereo radio builtin.  Not great radio quality
    but adequate.  It also comes with rechargable battery pack and a
    nifty adapter that allows you to play it on any cassette player
    (say in a friend's car) without doing any wiring.  The gadjet looks
    like a casette with a wire coming out of it.  You plug the wire
    into the line out of the D77 and then "play" the cassette.  Not
    as good sound as going in directly but certainly adequate for most
    car use (I only use this combo when in someone else's car - mine's
    already equipped).
    
    The D55 is almost the same as the D77 except (1) no AM radio (aw
    shucks), (2) no adapter gadget (but you can buy it if you want)
    and (3) larger pattery pack that needs AA cells or something.
    
    When I bought my D77 a while back, they weren't very available.
    Service Merchandise had a reasonable price on the D55.
     
    Steveg

    
    Re: .-1:

   > The D55 is almost the same as the D77 except (1) no AM radio (aw
   > shucks), (2) no adapter gadget (but you can buy it if you want)
   > and (3) larger pattery pack that needs AA cells or something.

	I just got from Japan a Sony D-55T, it has an AM/FM radio, and
    the battery pack is rechargable (its called a BP-200, and is about
    1 cm thick).  Apparently they hadn't heared of the D-77 in Japan, so
    maybe the D-55T is the Japaneese model no. for the US D-77, but there
    was no fancy cassette do-dack with it, so I'm not too sure.

	Anyway it sounds good to me, but then again I've only had it two
    days.  (I havn't got around to hooking it up to my scope yet :-) ).

	Robert. (New Zealand).