Sound City Schematics

Please note that some of the following schematics are PDF files and others are JPEG files. Print quality might be affected accordingly. Also, some links are external, so if anything is broken, please let me know.

Please also note that PDF files require Adobe Reader be installed on your computer. (Click here to download a free copy of Adobe Reader if you need it.)


Studio 20 Schematics

Model "One Hundred" (Lead 105; Mark 1) Schematics

L/B100 (Mark 3) Schematics

PA 100 (Mark 3) Schematics

L/B200 (Mark 3) Schematics

  • L/B 200 (large schematic, left side)
  • L/B 200 (large schematic, right side)

Sound City Schematic Assortment

  • Sound City Schematic Assortment (a very clever PDF file, courtesy of Mick H.)
    Included in this PDF file are schematics for the following Sound City amps: 120 Energiser Slave, L/B200 (Mark 3), Bass 150 (DMI), Concord, L/B120 (Mark 4), L/B50 Plus (Mark 4), L/B100 (Mark 3), and L/B200 Plus (Mark 4).

50 Plus (Mark 4) Schematics

L/B120 (Mark 4) Schematics

  • L/B120 (w/Mods) (copyright, Satamax, et al.)
  • Please Note: In the following two transformer wiring diagrams, orange wires are indicated. According to some users, however, these wires might be a sort of tan or light brown; therefore, please use caution and apply common sense when referring to the following two transformer wiring diagrams.

    "Rest assured that the circuit [shown in the preceding schematic] is correctly installed. The center tap has been disconnected. That's what the schematic shows, and this was done instead of connecting the two 100-Ohm resistors to ground, as is done in numerous designs. The center tap is connected to a DC voltage. (See the 50V designation?) This effectively raises the AC heater supply above the noise floor (0 volts). Simple, effective and cheap. I use this on all my amps."

    L/B200 Plus (Mark 4) Schematics

    SMF Tour Series (DMI) Schematics

    Bass 150 (DMI) Schematics

    Miscellaneous Schematics

    Note: I purchased this PA 50 R schematic from and have the Paypal receipt to prove it.


    HomeHistory Photos Home Page   Catalog Pages

    Wiring Diagrams   Related Links   FAQs   Acknowledgements   Contact