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This is the first Archived Forum which was active between 17th April 2007 and 1st March February 2012

 

Latest post 05-27-2009 12:52 PM by j0hnbarker. 11 replies.
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  • 05-25-2009 8:15 PM

    BeoGram 4002 w/MMC6000 Quad?

    I'm trying to get the CD4 going on this old table.  There is a switch on the side for CD4 on/off.  It does not seem to be working, as I am not getting a signal from the rear L/R outputs.  The stereo front L/R works but seems to need a preamp.  Was there a quad preamp available for this record deck, or does it need a B&O quad receiver?  What was the optimum quad setup?

  • 05-25-2009 9:11 PM In reply to

    • Andrew
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    • Joined on 03-16-2009
    • Melbourne, Australia
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    Re: BeoGram 4002 w/MMC6000 Quad?

    I believe the optimum quad setup was the Beomaster 6000 amp matched to the quad Beogram 4x turntable.

    I dont believe you would easily find a quad pre-amp as a new item these days, you might need to consider two pre-amps for each pair of signals.

    Andrew

  • 05-26-2009 1:50 AM In reply to

    Re: BeoGram 4002 w/MMC6000 Quad?

    If the 4002 has the CD4 decoder fitted, it should have an output at line level. If you take the top plates off, the CD4 decoder and RIAA is under the keypad. I have a picture somewhere - I'll see if I can find it tonight. You do neever a quad receiver to get this to work - a 3400 or 6000.

  • 05-26-2009 8:28 AM In reply to

    Re: BeoGram 4002 w/MMC6000 Quad?

    I'm hoping to use a modern Sony surround receiver with analog inputs (I use it now for my 8-track quads)

  • 05-26-2009 8:57 AM In reply to

    Re: BeoGram 4002 w/MMC6000 Quad?

    ...and it's not putting out line level, even though there is a CD4 on/off switch on the side.  So either there is no RIAA inside, or the switch doesn't work!

  • 05-27-2009 10:37 AM In reply to

    • yachadm
    • Top 100 Contributor
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    • Joined on 06-24-2007
    • Jerusalem, Israel
    • Posts 687
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    Re: BeoGram 4002 w/MMC6000 Quad?

    Hi Joe,

    The CD4 switch is NOT an On/Off switch for the CD4 RIAA amplifier.

    The CD4 amplifier is permanently ON, as long as you have live electric power to the turntable.

    See my post here - explains EXACTLY what the CD4 switch does:

    http://forum.beoworld.org/forums/p/17966/135556.aspx#135556

    If you do not have line-level output from the connector, there is a problem somewhere in your system, and it is not the CD4 switch at fault.

    Check to see whether you have signal output (from the stylus) at the entrance to the CD4 circuit-board, on my picture at the top-left-hypotenuse - the blue/orange/red wires.

    If you have a signal there, but no output, then your CD4 board is no good.

    If you are not comfortable with repairing, I can rebuild it for you.

    Menahem


    Learn from the mistakes of others - you'll not live long enough to make them all yourself!

  • 05-27-2009 10:45 AM In reply to

    Re: BeoGram 4002 w/MMC6000 Quad?

    thanks for the info.  What is that switch for, Q or CD4?  Did all of these come with an RIAA amp?  

    And yes, if you want to give me a rough idea what a rebuild would cost, let me know!

     

    Joe

  • 05-27-2009 11:04 AM In reply to

    Re: BeoGram 4002 w/MMC6000 Quad?

    The RIAA amplification is a side effect of the CD-4 decoder and it does that all the time, even for pure stereo playback. As said, if you don't get line level signals out of your turntable, the decoder board option is not there - the switch may still be present, and does nothing in that case.

    Actual CD-4 detection and decoding is automatic. The switch in the stereo position just disables the decoder (not the RIAA amp), for those cases it would pick up signals resembling CD-4 carrier from stereo records and kick in when not wanted - or if you had a worn CD-4 record that won't play in quad properly any more. You can't force the decoder on, it needs the carrier for that.

    -mika

  • 05-27-2009 11:09 AM In reply to

    Re: BeoGram 4002 w/MMC6000 Quad?

    So I should open it up and see if the board is in there...if not, I guess it's unlikely to find the RIAA option, so I should look for a quad preamp.  Right now I am getting a signal from 1&2 that needs preamp, but I am getting NO signal at all from 3&4.

  • 05-27-2009 11:58 AM In reply to

    Re: BeoGram 4002 w/MMC6000 Quad?

    Just pull the wood trim forward on your BG and it should release the catches securing the top plates on the deck. Lift them off and you can have a look for the CD4 board. I have the same deck with the same switch and wondered whether mine had the board when I bought it off eBay. You'll soon see if you haven't (mine was lacking) as there will be a big gaping hole where the board would sit!

    President, Beomaster 8000 Appreciation Society

  • 05-27-2009 12:13 PM In reply to

    Re: BeoGram 4002 w/MMC6000 Quad?

    Thanks!  What did you do, look for a part to put the board in, or get an outboard preamp?

  • 05-27-2009 12:52 PM In reply to

    Re: BeoGram 4002 w/MMC6000 Quad?

    Neither as I don't have any CD4 records! I originally used the 4002 with a Beomaster 8000 that had an internal RIAA on the Phono line. Now, funnily enough, I use the 4002 with a Beomaster 6000 Quad, so if I had the board fitted (and some CD4 records) I could actually make use of that function!

    President, Beomaster 8000 Appreciation Society

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