Mark Levinson LNP-2

Dear all,

I'm operating an vintage ML LNP-2 pre-amp with the meters.
All line sources work fine but one phono-channel is almost dead and the other one works fine.
Strange thing is though that apart from the two Dick Burwen VU modules all modules are the same Line Drivers LD-2 or Fet Input Amplifier Module as they are called.
I've no glue how they get any RIAA correction and what extra phono-stage there is because I can't find any active part apart from one little IC.
Is anyone familiar with this pre-amp and perhaps knows how the phono (MM) works?
Thanks in advance,

Robert
 

Attachments

  • Levinson LNP-2 internal 1.jpg
    Levinson LNP-2 internal 1.jpg
    389.5 KB · Views: 534
  • Levinson LNP-2 internal 2.jpg
    Levinson LNP-2 internal 2.jpg
    460.1 KB · Views: 543
  • Levinson LNP-2 internal 3.jpg
    Levinson LNP-2 internal 3.jpg
    527.2 KB · Views: 868
  • Levinson LNP-2 pic_1.jpg
    Levinson LNP-2 pic_1.jpg
    499.5 KB · Views: 551
This Help?

ML made a number of "one off" variations. Also changed the equalizer section in later units.

Charles
 

Attachments

  • Layout.jpg
    Layout.jpg
    478.1 KB · Views: 505
  • Metering.jpg
    Metering.jpg
    586.7 KB · Views: 484
  • Input.jpg
    Input.jpg
    408 KB · Views: 481
  • Equalizer.jpg
    Equalizer.jpg
    719.5 KB · Views: 491
  • Block Diagram.jpg
    Block Diagram.jpg
    557.9 KB · Views: 483
Last edited:
Your picture of the units bottom shows the RIAA caps soldered under the modules. Swap the phono modules and if the problem reverses you have a bad module. Our unit had no phono modules so I came up with a two-IC plug-in replacement. Then, did get the phono working using the ML-1 RIAA feedback circuitry. I doubt that the "simple" phono circuit in your LNP (and the schematic) followed the playback curve very well.

ML did have two different amplifier modules. The LD was made for output/driver purposes and was used for the record amp module in their ML-5. The other module was for higher gain preamp circuits.