8×2 Passive Summing Mixer with Input Vol Pot Attenuators – XLR / TRS / DB25 I/O

A high-quality custom rackmount passive summing mixer designed for engineers and producers who want true analog summing without coloration. This 1U 19” unit features a dual stereo, fully balanced signal path, delivering clean, transparent summing from your DAW, synthesizers, keyboards, drum machines, or professional audio interfaces.

A key feature is the precision attenuator control on each stereo channel, allowing accurate and repeatable level adjustment down to -70 dB. This gives you tight control over gain staging directly at the summing stage—ideal for balancing multiple sources without compromising stereo imaging or introducing noise.

Built for flexibility, the mixer integrates seamlessly with systems such as UAD Apollo, RME Fireface, Apogee, Motu, or any other interface with balanced outputs.

This is a pure passive design—no power, no noise, no active circuitry—just accurate summing with maximum headroom and phase integrity. The unit is hand-built and customizable, including connector types and a laser-engraved unique name for a personalized, professional finish.

Ideal for hybrid mixing setups where analog summing adds depth, separation, and clarity to digital productions.

Specifications

• 1U standard 19″ rackmount unit
• 8 × balanced stereo inputs (DB25 / TRS / XLR – selectable)
• 8 × 21 Step precision volume control attenuators (down to -70 dB)
• 2 outputs – 1 × stereo balanced TRS or XLR (selectable)
• Custom laser engraving with unique name (on request)

Design:
Floating differential bus with dual stereo discrete signal path, fully balanced from input to output for maximum signal integrity and channel separation.