1. Time for some upgrades in server hardware and software to enhance security and take AK to the next level. Please contribute what you can to sales@audiokarma.org at PayPal.com - Thanks from the AK Team
    Dismiss Notice

CD Player with Fixed and Variable Outputs

Discussion in 'Digital Sources' started by TedNeu, Sep 17, 2018.

  1. TedNeu

    TedNeu AK Subscriber Subscriber

    Messages:
    134
    Location:
    San Francisco
    I am original owner of a Denon CD player (DCM 460) from late '90s.

    There is a fixed output for RCA plugs and a variable output for RCA plugs.

    I only used the "fixed" one, as the other sounds lousy. What does these fixed and var outputs even mean?
     

     

    Please register to disable this ad.

  2. stish

    stish AK Subscriber Subscriber

    Messages:
    675
    Location:
    Huntsville AL
    The variable outputs allow volume control at the player. It could be useful if a single source connected directly to a power amp, eliminating a pre-amp. The fixed level outputs have been better on every such player I've owned.
     
    david1111 and TedNeu like this.
  3. TedNeu

    TedNeu AK Subscriber Subscriber

    Messages:
    134
    Location:
    San Francisco
    Thanks for the explanation.
     
    stish likes this.
  4. Hajidub

    Hajidub Chihuahua/Pug = Chug Subscriber

    Messages:
    5,291
    Location:
    Colorado Springs, CO
    I use the variable rca's on my Sony CD-85es because it has an output knob that will move via the remote control. Different CD's have huge differences in SPL output, many newer ones play HOT.
     
    pskaudio, stish and TedNeu like this.
  5. Bob

    Bob AK Subscriber Subscriber

    Messages:
    2,113
    Location:
    West coast
    it allows matching the output of your CDP to other inputs to your preamp
    like tuner, SACD so when you switch inputs you don't have to adjust the
    volume up or down. as long as all but one have this variable output level
    control (everyone matches that input without an output level control).

    if you have only one input, doesn't matter, your preamp (master) volume control
    will already be doing its job.
     
    stish and TedNeu like this.
  6. charles 1973

    charles 1973 Super Member

    Messages:
    3,023
    I had the Denon 1500II CD player with the variable and fixed volume analog outputs. I used the fixed because "They" said it would have better quality sound. I found they both sounded the same, Both produced very good sound.

    It just provides a convenient remote control volume to use as you see fit. If your variable sounds as bad as you say, Something is malfunctioning. Perhaps the volume pot is dirty or the connections or cables are bad.
     
    Last edited: Sep 19, 2018
    TedNeu likes this.

     

    Please register to disable this ad.

  7. TedNeu

    TedNeu AK Subscriber Subscriber

    Messages:
    134
    Location:
    San Francisco
    The last time I checked this the Variable option did not sound good. I am using a "new" vintage integrated amplifier and they sound similar. Go figure!
     
  8. WobblySam

    WobblySam Well-Known Member

    Messages:
    572
    Location:
    Middle of NC
    One possible reason for the disparity in SQ is where the "volume" control is implemented. If it's done in the digital domain, the volume or amplitude is reduced by lowering the bit resolution. Not a good thing, but this type of control is used in oodles and gobs of electronics. No way to be sure without a schematic.
     
    Bratwurst7s, stish and TedNeu like this.
  9. SoCal Sam

    SoCal Sam Lunatic Member

    Messages:
    18,446
    There are plus and minus to variable and lot depends on model and design. Some variable outputs are electronic like in some Yamaha's. Some are analog like in some Sony's. Variable adds to the circuit path which is bad. I wish I knew where the variable control resides in a CD, whether it is before the output stage or not. Personally, I prefer using variable output over fixed even with receivers and preamp equipped separates. I always preferred Sony variable output as it was transparent and easy to fine tune. Yamaha variable output had a limited number of steps so finding the sweet spot was more difficult and sometimes impossible.
     
    TedNeu likes this.
  10. Bob

    Bob AK Subscriber Subscriber

    Messages:
    2,113
    Location:
    West coast
    for my HK 7500II the variable output is a branch tap of the fixed and is fed through a 5K
    VR so you could either put a high quality switched attenuator or bypass it.

    Service manual page 35.
     
  11. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

    Messages:
    4,105
    Location:
    Munich, Germany
    This.

    I haven't used the Denon in question but do have 2 other Denon's that have variable outputs.

    In my DCD-1290 the signal path is split just before the fixed outputs and the signal for each channel then goes through one channel of a dual op-amp (µPC4570C), then through a digital control chip (MN6632A) that does the volume control (for both channels), and then through the 2nd channel of the op-amp op-amp before going to the output jacks. So there are at the least 2 chips added to the signal path that aren't in the fixed output signal path. Another downside is that the 1290 doesn't remember the volume setting at shut-off and defaults to -20db with each turn-on. The headphone output is derived from the end of this chain, with another op-amp, so the phones output is also digitally throttled.

    In my DCD-2700 the signal path for the variable is tapped from the fixed just before the output and then goes through a motor driven pot direct to the var output without any further processing. After the pot the signal is also sent to the phones amp, so the motor driven pot also throttles the phones outputs.

    These 2 different schemes could potentially account for different SQ qualities from the Fix and Var outputs.

    Cheers,
    James
     
    Last edited: Sep 20, 2018
    stish, WobblySam and TedNeu like this.

     

    Please register to disable this ad.

  12. lini

    lini just me...

    Messages:
    5,878
    Location:
    Munich, Bavaria
    I'd concur that the quality of variable output depends on the particular implementation. Whereas I wouldn't quite concur that a digital output level control necessarily means a loss of resolution or, more generally put, more of a loss of signal quality than an analgue output level control.

    Greetings from Munich!

    Manfred / lini
     
    Bratwurst7s likes this.
  13. david1111

    david1111 Active Member

    Messages:
    195
    Location:
    Toronto, Canada
    @TedNeu
    I have a Denon DCM 380 with left and right RCA outs, and a single RCA coax digital out. It also has a toslink out, but that really sounds like sh**.
    The coax is fixed volume, but the RCA analogue is electronically variable thru a volume control on the remote.
    I would much prefer to use the variable outs, cuz my YS-Audio Symphonies tube preamp doesn't have a bloody remote, but the coax out sounds soooo much better.
    I don't know if the digital coax sounds better because of the way the coaxial connection processes the signal, or because its probably a shorter/simpler signal path.
    I run the DCM 380 thru an MF A3-24 Dac which also makes it sound way better, but the dac makes either connection sound better.

    Dave
     
    TedNeu likes this.
  14. david1111

    david1111 Active Member

    Messages:
    195
    Location:
    Toronto, Canada
    So, I was wondering, as you were. Why can't a digital signal be variable. They only ever provide this on an analogue signal. (At least on the less expensive CD transports).
    Does snyone know?

    Dave
     
    TedNeu likes this.
  15. lini

    lini just me...

    Messages:
    5,878
    Location:
    Munich, Bavaria
    Dave: Too little users having any use for that feature in relation to the required technical effort, I'd assume - especially in the earlier days...

    Greetings from Munich!

    Manfred / lini
     
  16. david1111

    david1111 Active Member

    Messages:
    195
    Location:
    Toronto, Canada
    Yes, you're probably right Manfred. Thanks for the input.
    And greetings from Toronto!

    Dave
     

     

    Please register to disable this ad.

  17. Powertech

    Powertech Active Member

    Messages:
    488
    Location:
    South Wales, U.K.
    My Denon DCD820 has variable outputs controlled from the remote control.
     
    TedNeu likes this.
  18. david1111

    david1111 Active Member

    Messages:
    195
    Location:
    Toronto, Canada
    @Powertech
    My Denon 380 also has a variable output option which is controlled by the remote.
    (See my earlier post; the long one).
    But, as on your 820, the variable out is a L and R, rca analogue out.
    The single rca coaxial, digital out, which sounds way better than the pair of analogue outs, is fixed. They all seem to be made this way.
    You can check your manual online, it explains them as item 27 and 28.
    Happy listening.

    Dave
     
  19. Mellotronix

    Mellotronix Active Member

    Messages:
    343
    Many digital devices have volume controls that actually reduce the sampling rates as they are turned down. Someone else can explain the principle involved here, but you should run all of your devices full on in front of an integrated amp or pre/power amp.
     
  20. david1111

    david1111 Active Member

    Messages:
    195
    Location:
    Toronto, Canada
    That makes sense. So, even if the coax did have volume controls on the remote, I wouldn't be using them anyway, I guess.
    The only reason that I bring it up is cuz my tube pre wasn't designed with a remote. I probably need the exercise anyway.
    Thanks.

    Dave
     

Share This Page