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Conference cookie::notes$archive:cd_v1

Title:Welcome to the CD Notes Conference
Notice:Welcome to COOKIE
Moderator:COOKIE::ROLLOW
Created:Mon Feb 17 1986
Last Modified:Fri Mar 03 1989
Last Successful Update:Fri Jun 06 1997
Number of topics:1517
Total number of notes:13349

388.0. "Calling hardware hackers-to mod or not" by NCCSB::DPARKER (Dave Parker - NCO SWS) Thu Jun 19 1986 15:33

        Well, I finally broke down and bought a Magnavox 2041 on sale
        at $149. In some ways, it's better than my Sony D5, and in
        some ways not as good.  I'd like some feedback from those of
        you with Maggies on modifications - have you done them yourself,
        tried Mod Squad or Musical Concepts; with what results, etc.
        
        Also, if someone could give me a pointer to Mark's modification
        article, I'd appreciate it. I'm in the mood to haul out the
        old soldering iron if there are real gains to be made. Also,
        seems like a good summer project while waiting for the new
        PS clones of the new Phillips players and while waiting for
        my dealer to get his sample of the California Audio player.
        
        Thanks,
        Dave
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388.1AMBER::KAEPPLEINThu Jun 19 1986 18:2853
    Wow, that's a good price!  My stuff is in note 179, but is kind
    of dated now.  I might suggest also that you might want to return
    your great deal for the CDB650 which will supposedly appear within
    the month (not much time left) at about $375.  Its a 16-bit 4x
    oversampled player with remote and whiz-bang 80 disk program memory.
    It also has a digital output port.
    
    At the CES show I compared a Musical Concepts 2041 with the PS Audio
    2041 and a Distech 2040.  The Musical Concepts won hands down. 
    2nd place depended upon how long you had to listen to CDs.  The
    Distech was soft and veiled with constricted soundstage.  The PS
    was better in those respects, but harsh.
    
    Spectral announced that they were working on a very serious studio
    quality CD player.  They are using the Philips professional transport
    and lots of digital processing (in a Eurocard backplane).  They
    claim much higher resolution, better sideband attenuation, less
    ringing, and better linearity.  Supposedly, some of the linearity
    improvement comes from fudging the DAC inputs to correspond to the
    desired output (old, but expensive technique).
    
    Anyway, in a reasonable price range, a modified CDB650 would be
    worth waiting for.  It will probably take less time and parts to
    modify a 650 than a 2041.  This is because of the lower chip count
    in the 650 (single DAC package and single op amp package).  The
    unknown at this point is how good the Philips op-amps are.  There
    is room inside the chassis (same one as 2041) for an added PC board,
    but it would have to layer on top of another.  In July, a machine
    without the FTS program memory will be available and have more room
    inside to play with.
    
    So, my suggestion is:
    1.  Return the 2041 and wait for the 650 or cheaper 16-bitter and
    send it to Musical Concepts.  I doubt PS will do as well.
                      or
    2.  Send 2041 to Musical Concepts for the $280 mod.  Mention me
    and he might give you a break.
                      or
    3.  Do the $40 biggest bang for the buck mods.
    	1.  Replace the DC blocking electrolytics with 10uf metalized
    polypropelenes.  The next Stereophile (got it at CES) finally has
    the article on this mod albeit very outdated by reffering to the
    the FD1000 and FD2000.  I like Musical Concept's Musicaps.  They
    are sweeter than Wondercaps.  Havn't heard Siderial's.
    	I did just this mod on Druid::kardell's machine and it improved
    detail and tightened up the bass.
    	2.  Beef-up power supply capacitance to the opamps and the DACs.
    Essentially replace existing ones with bigger versions (preferably
    low ESR types) with small (.1uf) film bypasses.  This will widen
    the soundstage (maybie deepen too).
                 
    Mark
    
388.2on hold awaiting a real high-end playerNCCSB::DPARKERDave Parker - NCO SWSThu Jun 19 1986 23:2937
        Yeah, I thought it a good price, too, so I jumped on it.  What
        I'm really waiting for is the high-end to sort itself out a
        bit.  I own ARC stuff, (SP-10 and D-115), along with SOTA and
        Vandersteens.  The SOTA sill blows away ANY CD I've heard,
        but I've got to admit they're making more progress than I thought
        possible.
        
        The Maggie dealers in this area deal mostly in closeouts, so
        I'm sure that's why the price was so cheap.  So I'm not holding
        my breath for the new Phillips players.
        
        The 2041's most annoying faults to me are it's boomy, woolly,
        loose bass, (almost to the point of boomy) and the raspy, nasal
        high end.  I think it is better than the D5 in the mid-range,
        and on good CDs, better than the D5 in the high end.  That's
        why I'm interested in the $40 midnight special; my understanding
        is that the bass benefits most from the mods.
        
        Since you've now done a 2041, Mark, I'd be most appreciative
        of any more explicit instructions you can give. I don't have
        the schematics for the unit yet....
        
        How do you feel about the $40 mod vs. the Musical Concepts
        $280 job - where are the trade-offs?  80%?  70%?  I'd really
        like to cheap it out as long as possible until a real high-end
        player is available - and I don't consider the PS to be high
        end (yet, anyway, maybe their version of the new Phillips,
        or maybe cj's version, etc).  So, I'd like to stall for time.
        
        BTW, while it may be obvious from the above, I consider the
        D5 superior to the 2041 in the bass. As for imageing, the players
        are different, but subtly so - I haven't decided which I like
        best on this score yet.
        
        Thanks for the pointer, any other comments out there?
        
        Dave
388.3M.K. plusGRAMPS::WCLARKWalt ClarkFri Jun 20 1986 11:4019
    On the cheap and dirty side, in addition to Marks suggestions I might
    suggest you include a pair of 5uf polypropylenes as supply bypassing 
    at the DAC/opamp supply etch area (IE: within an inch of the DAC/opamp 
    terminals if possible).  This isnt as good as a killer regulator
    but the price is about 5-10 times better.  This should help smooth
    out the mid-hi end by improving DAC and opamp dynamic recovery.
    
    The 5uf value isnt critical, actually the larger the better but
    I found the inductive reactance of the physically large 10uf caps
    reduces their effectiveness in the supply. I have not tried several
    brands, but I suspect that they sound less different here than when
    in the signal path.
    
    
    FYI: I am recommending this based on preamp, tuner, tape deck work.
         I havent been able to bring myself to dive into the CD format
         yet.
    
    Walt
388.4AMBER::KAEPPLEINFri Jun 20 1986 16:3531
    The pp caps will just about solve the bass problem and take some
    edge off too.  Better power supply will probably improve the bass
    a little more.
    
    I have not had the opportunity to do step by step modifications
    and comparisons on a good reference system with the 2041.  What
    you miss in the $40 job that the top Musical Concepts mod gives
    (judging by the Distech and PS comparisons) is an open, coherrent
    soundstage and sweet, relaxed high-end.  The $40 job won't be
    satisfying in comparison, thus making it 0% of the MC mod.  By other
    sonic standards, its probably 50%.
    
    So, if you just want to tinker a little and eventually replace the
    2041 with a real machine, OK.  I think that the full-blown 2041
    mod gets very close to an LP.  A full-blown 650 will probably be
    better (for CDs recorded with decent digital recorders).  I don't
    expect any other machine from anyone else to be much better, unless
    it is a really big $$$$ machine like the Spectral.
    
    As for Walt's suggestion, the problem is space.  You might be able
    to fit some very small 1uf caps underneath, but the secret is still
    to use the best electrolytics (typically specified for switching
    power supply use).
    
    At one point, I made a diagram of the 2041 PC board showing the
    caps to replace.  I don't remember if it is here anywhere or it
    is long gone.  I'll type in another if I can't find it.
    
    One change you can do almost for free is to solder the crystal
    oscillator can to the ground plane.  This reduces some noise, though
    I haven't AB'd it on a stock machine.