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Home > Modifications


NOW Your McIntosh Tuner will perform even better (any model, any age). RICHARD MODAFFERI, an independent consultant to Audio Classics, has agreed to do repairs, modifications and updates for customers of AUDIO CLASSICS. His intimate knowledge of the circuits allow him to improve the units audibly and measurably beyond their original performance limits. Your investment in this service is protected by a limited 90 day parts and labor warranty.
Here is a list of some of the changes that may be made in your unit:

Modafferi Mod
  1. B- power supply - improved regulation, less hum.

  2. RF selectivity improved for better spurious rejection.

  3. IF regeneration fixed - better weak signal reception.

  4. IF 'tailbiting' fixed - this eliminates degraded reception
    at 96.3 and 107.0 Mhz from ninth and tenth IF harmonics.

  5. Stereo decoder slew-rate optimized by modifying op-amp
    feedback circuits; reduces distortion, improves separation.

  6. diode D307 installed (this was left out of MR78 but was
    used in MR77); this reduces 'klunk' noises on fixed output
    jacks when tuner is turned on and off.

  7. IF phase trimming - 'gimmick' capacitors added as needed in
    NORMAL IF filter for improved stereo separation.

  8. RF oscillator emitter tap re-dressed for minimum leakage
    inductance; reduces drift and eliminates oscillator
    pulling on strong signals.

  9. Jung-Marsh capacitor upgrade in MPX and audio circuits.

  10. cardas audio output, midas scope output jacks installed.

  11. Muting ground changed - improved muting performance.

  12. 19Khz stereo pilot circuit change, reduces stereo distortion.

  13. Buffer resistor installed in pointer lamp circuit, prevents
    lamp heat from burning red light filter material.

    Investment: Tuners approximately $1,200
    Turnaround Time: Approximately 8 weeks
    All changes are not applicable to every unit
Richard Modafferi

Richard Modafferi, inventor and independent consultant to AudioClassics, has established himself as one of the world's foremost authorities on tuner & loudspeaker design and development. He holds Masters degrees in Electrical Engineering and Computer Science from the NJ Institute of Technology. A Senior Engineer at McIntosh Laboratories from 1968-74, he designed the MR77 and MR78 tuners and the famous "Rimo" filter. The MR78 tuner has received world wide acclaim for its State of the Art performance. From 1974 to the present, Richard has been a self employed inventor at Modafferi Acoustical Systems, Inc. He has been granted a United States patent for Phase Shift Bass Loading and for the Infinite Slope Crossover. Richard also serves as a writer, reviewer and test lab for Audio Critic and The Sensible Sound.

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