Multiplex Echo Machine

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1776 Effects Multiplex Echo Machine. This is a delay pedal that appears to have been wholly designed and implemented by 1776 Effects. What makes this delay different from other delays available in the marketplace is that it enables emulation of three different magnetic tape-style echo/delays from days past:

  • The Binson Echorec
  • The Roland RE-201 Space Echo
  • The Echoplex Ep3

This is done by using two different ICs (integrated circuits) and controlling the timing and order in which each IC has signal fed into it.

Thermionic Studios has purchased this PCB and sourced the parts necessary to build this pedal. We are in the process of building the pedal and will have more to report upon completion.


  • Knob 1 - "Delay 1": Sets the delay time of the first delay - turning the knob clockwise increases the length of the delay.
  • Knob 2 - "Delay 2": Sets the delay time of the second delay - turning the knob clockwise increases the length of the delay.
  • Knob 3 - "Feedback": Increases / decreases the number of repeats - turning the knob clockwise increases the number of repeats.
  • Knob 4 - "Mix": Adjusts the dry/wet blend. Align the knob directly in the middle to have a 50/50 dry/wet mix.
  • Knob 5 (3-position switch) - "Tape Mode": Changes the way the signal is routed through the PT2399’s to simulate tape delays of the past:
    1. Binson Echo rec
    2. Roland RE-201 Space Echo
    3. Echoplex v. Ep3
  • Footswitch 1 - "Tape Speed": Holding down the momentary footswitch slowly speeds up the delay speed. Releasing the switch slows the speed back down to the time setting of the knob. The tape speed is highly interactive depending on how you have "Delay 2" set.
  • Footswitch 2 -"On/Off": This turns the effect on and off in the signal chain


The Multiplex Echo Machine is a true bypass pedal.

General Information

One thing to note about the Multiplex Echo Machine is that 1776 Effects also builds a modulation PCB that is meant to compliment it. With the purchase, population, and installation of this additional PCB, it is possible to create chorused, phased, or warbled sounds - sounds that emulate what would actually be created with those old original physical tape echo/delay systems. In many cases on those original units, the addition of some out-of-service modulation was preferred. Delays that end up getting chorused, whether by accident or on purpose, can sound very good to the human ear.

Pedal Manual

As of this time, has not issued a separate manual on how to use the pedal. The best current references that we're aware of are this wiki page, or the build manual linked here to the 1776 Effects website which describes the architecture of, and how to build the pedal.

Phase Inversion: No

From our examination of the schematic below, the Multiplex Echo Machine appears to not invert phase on the output as compared with the signal that goes into the pedal.

Schematic ID Electronic Part Action Phase State
IC1a TL072 Inverts Inverted
IC1b TL072 Inverts Reverted - back to Original
Q1 2N3904 Inverts* Unaffected - please see note
  • NOTE: Q1 modifies the period of the H11F1 IC. Q1 is engaged by means of the momentary switch (the Tape Speed control). So Q1 doesn't actually touch signal - just modifies the delay control. So while the transistor itself inverts phase, because it doesn't ever touch the signal. As such, it can't cause a phase inversion of the signal coming out of the pedal.

As with all schematic observations, this will need to be born out by testing of the actual pedal.


© Copyright 2016, JRM/


We are currently unaware of any artists actively using the pedal now, or who have in the past.

Additional Sources