General Specifications:

  • High quality, all tube mic preamps
  • Input pad, pre-transformer
  • 1st stage pad, post-transformer
  • Polarity switch
  • Dual impedance input
  • 80Hz High Pass Filter
  • 48v Phantom Power
  • Channel mute w/selectable solenoid output control
  • Output Volume Control
  • Left/Right/Direct Out, Solo for each channel
  • Mic, Instrument, Line inputs
  • Expansion slots accept Series 500 style modules (shipped with our own line input module).
  • Left/Right Master Volume
  • Cinemag Input xfmrs
  • Cinemag Output xfmrs on Left/Right Outputs (optional on Direct Outs)
  • 2 VU Meters.
  • Mono and Dim on control room monitoring.
  • Headphone Outputs
  • Separate Rack Mounted Power Supply
  • Input/Output connections on High Density EDAC
6 channel $6800 

8 channel $8960

NOTE: Specifications on all Busby Electronics products are subject to change without notice. Such changes will be made as improvemnents to the design.

We are currently not accepting new orders. Please check this web site for updates.

Audio Sample

Haven't a Clue

(Tess Fama ©2009)

Recorded in our project studio using the first build of preamp and output buffer stage. You can expect better than this quality from our production model mixer and 2 channel rack mount preamp. There was no shielding in place on first stage tube or output section for this recording. As this is using only one channel, each instrument was laid down separately.

Acoustic guitar: Advanced Audio CM54 FET condensor mic, no eq, no compression.

Bass: Fender Precision through Hartke amp, GK 4x10 cab, Advanced Audio CM12 Tube microphone, no eq, no compression.

Vocal: Advanced Audio CM12 Tube microphone, no eq, no compression.

Slide Guitar: 1937 Epiphone Elektar lap steel, direct into preamp instrument input, no eq, no compression.

Mix: recorded using Ardour software on a Mac G5 tower. Reverb effect added in Ardour, as well as entire mix compressed 2:1 over -20db.

BE-62 Tube Mixer            

Busby Mixer

I/O on Breakout Cable or Optional Patch Bay or Multi-Snake. The actual mixer differs from this preliminary rendering in that the input modules include 4 small toggle switches where there are 2 shown. Compare to the photo below. Full specifications coming soon.

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A BE-62 preamp module 72 hours into burn in on the test bed. This photo of an actual module shows how amazing the rendering was in representing what we planned on as a finished product. Kudos to my mechanical consultant Kenn Danner for his 3D expertise!
Top: Fit test before wiring. Middle: inside chassis with flange.
Bottom: Dress plate before finishing/paint/markings.
The production model of the preamp module now uses a plug in tube board in place of the version shown here with standoffs. I should have a photo of the new module mid February once we've completed the first run of custom knobs.
The massive power supply for the mixer includes separate transformers and circuits for the high voltage, series 500 slots/phantom power, and heaters. This supply awaits connection to the face plate and front panel power switches. The open back design ensures adequate cooling.
Input/Preamp Module
High Gain, Low Noise:
  • Cinemag input transformers stock.
  • Hi-Z Instrument Input
  • Balanced microphone and line inputs (using pads).
  • Optional Balanced Direct Output transformers.
  • Dual Input Impedance Selector (values dependant on selected xfmr)
  • Input Polarity Switch
  • 48VDC Phantom Power on each input channel.

A closeup example of one of our preamp boards showing the fine milling possible with our Roland CNC engraver.

Using an engraver allows us quicker turnaround on custom designs than even etching can provide. Production boards are tinned unless ordered bare.

All parts placement and soldering are done by hand, all traces vigorously tested.


< Output/Control Section

  • Monitor & Meter switching (selected switch displays orange "winkie" button top).
  • Stepped Left and Right Master Output level controls.
  • Headphone output control for 2 Stereo Headphone jacks.
  • Master Send control.
  • 2" VU Meters for Left and Right output. Left meter switches to show solo level for selected inputs.
Switches shown with Main output and
Mono monitoring selected.


A 2 channel version of the output buffer board. Each 12BH7A tube handles one channel. The standard option is unbalanced output, but there is a connection for attaching the optional output transformer. We will supply Cinemag, Jensen, Lundahl or Sowter.

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