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Author Topic: Revox A77 Abbey Road Mod  (Read 3332 times)

Offline pederb

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Revox A77 Abbey Road Mod
« on: February 26, 2016, 05:38:32 AM »
Hello,

Do anybody here have a schematics on how the so called EMI / Abbey Road mod is done ? It bypassed the microphone amps in the recording path

Cheers
-Peder Beckman-
Adagio Audio & Music
Vinyl Pussy Cat Records

Offline eds65gto

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Re: Revox A77 Abbey Road Mod
« Reply #1 on: September 21, 2016, 01:54:07 PM »
  Hi:
  To modify the A77 to bypass the input board jumper pin 1 to pin 4 , and pin 7 to pin 10 with a 5k resistor, This eliminates the input board.
  You can also replace R809 on the playback amp board with a 10 K trimpot to adjust the hi freq equalization on playback.
  These and other mods are from an article " Greening the Revox A77 " by Charles Repka from Audio Amateur magazine 4/1981 issue.
  You can also check out posts from " Audio Karma "  "Diy Audio " and " Reel to Reel Groups "
  Hope all this helps
  Ed