Up for sale is a 24x2 passive balanced summing amplifier PCB for building your own console or passive 24 channel summing box. 24 balanced Left inputs, 24 balanced Right inputs and 2 balanced outputs (L/R). Printed schematic included with purchase. 

The outputs from the PCB are at mic level and need to be boosted by a preamp of your choice (any 1950's-1970's fixed gain solid state or tube amplifier would be perfect - for example a Langevin 5116 / 5117 / AM-16 / AM-17 or Altec 458A / 459A / 9470A / 9475A). These were made with 2oz thick and extra wide copper traces and were manufactured for our new "Control Series" consoles which feature passive balanced summing.  

Feel free to contact us for an assembly quote or with any other questions you have. Thank you!