Used Audible Illusions Modulus M3B Preamplifier with Phono Pre

Audible Illusions

  • $2,650.00
    Unit price per 

This Used Audible Illusions Modulus M3B Preamplifier with Phono Pre is fully functioning and it is clean, cosmetically.

The Audible Illusions Modulus M3B Preamplifier with Phono Pre is a deceptively simple design, employing a single gain stage, class A triode circuit utilizing no cathode followers or buffers to degrade the sound. It's basic design concept has remained a focus of the Modulus circuit topology since its inception and is one of the reasons for the sparkling sonic clarity and resolution.

Inside you'll find a host of superb parts and pieces, along with excellent quality workmanship and great attention to detail. The list of parts includes: a Teflon solder mask, OFC circuit board traces, custom film capacitors, and custom stepped attenuators using high-quality metal film resistors.

What makes the Modulus M3B stand out is a balance of strengths with few, very few, weaknesses. A strong suit has always been the soundstage, and the M3B competes with almost any preamp. It develops a holographic panorama, that is truly a delight to experience.

The MM phono input will accept any cartridge with 1mV of output, or greater. For those using low-output moving coil cartridges, optional Gold Phono Boards are available for increased gain. Designed by the legendary John Curl, the ultra-quiet pre-pre amp boards give the M3B the ability to handle even very low-output MC cartridges with low noise and superb fidelity.


Circuit design is Pure Class-A, Single-Ended Triode, Zero Feedback, Dual-Mono
Audio Circuit has no Cathode Followers or Buffers
To prevent unwanted AC-induced distortions, the M3B features an External Power Supply housing three separate regulated supplies and a large-shielded custom-wound transformer
The main chassis has three-separate, fully-regulated FET power supplies driving the audio circuitry in addition to separate filament supplies
Automatic-timed muting circuit with Dual-Color LED indicator
Low-light illumination for Selector Switch and Volume Controls
Standby Mode avoids cold starts and prolongs tube life and circuit components
Active Tape Output Circuit is FET regulated, set for unity gain
Circuit boards are OFC copper and hand-soldered with silver solder. Polypropylene and Polystyrene capacitors used are proprietary designs of Audible Illusions.
Resistors are 1% film Vishay-Dale and Roederstein
Proprietary gold-plated RCA Jacks with Teflon Insulators
Volume-Balance controls are precision stepped attenuators

The Modulus M3B adds a host of features and performance enhancements over its predecessor, the M3A.

M3B vs M3A

  • Relay Switching – the signal does not pass through switches resulting in better clarity and definition
  • Upgraded interstage coupling capacitors – All capacitors in the signal path are film and foil for better resolution and lower noise
  • Larger, low-noise toroid transformer in the outboard power supply for improved performance in all areas
  • Cleaner, more direct signal path resulting in improved performance in all areas
  • Revised taper on attenuator for better matching with a wider range of source components
  • User-adjustable gain settings
  • Overall Gain: 58dB at 1kHz
  • Tube Compliment: 4-6922 or 6H23EB twin-triodes, graded & matched
  • Weight: 20.5 lbs, 24 lbs (shipping weight)
  • Dimensions: 19″W x 3.5″H standard rack
  • Chassis is 17″W x 11″D x 3″H
  • Power Supply, 6″W x 10″D x 5″H
  • Muting:45 second warm-up and automatic brown-out protection
  • Power Requirements: 115-125VAC, 60Hz
  • Optional 100, 220, 230, 240 50-60Hz transformers.


  • Gain: 28dB at 1kHz
  • Frequency Response: +/- .25dB of RIAA from 20hz to 20kHz
  • Signal Phase: Non-Inverting
  • Signal to Noise: 74dB below a 5mV input wideband
  • Distortion: Less than .015% at 20 kHz
  • Input Impedance: 47 kOhms
  • Phono Overload: 1.2v RMS at 1 kHz (100k load)
  • 750mv RMS at 1 kHz (IHF load)


  • Gain: 30dB, Tape & S/S Processor 0dB
  • Frequency Response: Within +/-1 dB
  • 2Hz to 100kHz measured w 1-1 probe
  • (50 kOhms, 100pf load)
  • Signal to Noise: 90dB below 1.5V RMS output wideband
  • Input Impedance: 50kOhm – all
  • Output Impedance: Main-1.2 kOhms, Tape-150 Ohms
  • Distortion: .10% at 1.5V RMS, 20-50 kHz, into 50kOhm load. Less than .12% THD at 1v out into IHF load
  • Signal Phase: Main Outputs – Inverting
  • Tape Outputs – Non-Inverting
  • Maximum Input: 9v RMS

Please don't hesitate to reach out.

Send an email to Tim

Or give me a call at 847-217-8985

We Also Recommend