We offered the Control Master Preamplifier in two versions: Line only or Line with Phono (MM and MC). The design is completely Dual-Mono with separate power supplies for each channel including two custom-designed power transformers. The audio boards are also separate. All the wiring from the rear input connectors to the front selector switch and precision custom stepped attenuator is painstakingly hand wired using professional studio twisted pair shielded six-9's copper cable for optimum shielding and low noise characteristics, and although it would be much cheaper, easier, and faster to simply put these leads on several feet of printed circuit board traces like most everybody else does, we opt for purity of sound however many more hours it takes. The high-current line amplifier circuit employed here is one we have developed and refined over the years in our MANLEY Professional series. We hope you agree with us, and hundreds of satisfied users and studios around the world, that this circuit really delivers. For more information about variable feedback, read "Notes on Negative Feedback".


A top view:


A newer chassis build:


An older chassis build:





  • 2 x 12AU7A (Line amplifiers)
  • 2 x 12AT7A
  • (White Follower Output Drivers)
  • Gold plated faceplate
  • Unbalanced and Balanced outputs
  • (Unbuffered) Record Output
  • MUTE switch
  • Input Impedance: 100 kOhm
  • Output Impedance: 50 Ohms
  • Power Consumption: 33 Watts
  • Precision stepped Volume control
  • All-Triode design
  • Gain with FB @MIN: OdB
  • Gain with FB @MAX: 6dB
  • Variable Feedback
  • Mains Voltage Frequency: 
  • Dimensions: W=19", L=13", H=2.5"
  • Shipping weight: 16 Ibs
  • Factory set for 100V, 120V or 220-240VAC
  • operation for original destination country's mains voltage.
  • Fuse Value for 100 or 120V operation: 1/2 Amp MDA or MDL type SLO-BLOW Time Delay size: 1/4" x 1 1/4"
  • Fuse Value for 220-240V operation: 1/4 Amp MDA or MDL type SLO-BLOW Time Delay size: 1/4" x 1 1/4"
  • Operating Mains Voltage changeable with
  • power transformer changeover switch and
  • fuse value change

Specifications subject to change because they just might.


  • 2 x 12AX7A (Line amplifiers)
  • 4 x 12AU7A (Phono Stage)
  • 2 x 12AT7A
  • (Cathode Follower Output Drivers)
  • Cathode follower buffered RECORD OUT
  • Gain (MM stage): 40 dB at REC OUT
  • Gain (MC stage): 50 dB at REC OUT
  • Transformer-coupled MC stage
  • Input Impedance MM stage: 47 kOhms
  • Input MM capacitive loading usually 
  • set at 100pf
  • Input Impedance MC stage: 38 Ohm
  • Pin Out of 5 Pin MC transformer input XLR is as follows:
  • Pin 1: Right Channel (+) positive (brown)
  • Pin 2: Right Channel (-) negative (red)
  • Pin 3: GROUND
  • Pin 4: Left Channel (+) negative (red)
  • Pin 5: Left Channel (-) positive (brown)
  • This transformer has a 1:13 step up ratio