Source Audio ZIO User Manual page 7

and bass frequency overlap. Without all that extra bass and mud, you also will gain more volume in the
most useful frequencies. This mode works very well after fuzz and overdrive pedals for tone shaping as
well!
E-PLEX:
A recreation of the feel, character, and frequency response of a classic early 1970s tape echo
unit, the E-PLEX mode offers a vintage-style FET buffer/boost tone that is warm, clear, and a little bit
dirty. Many players used to turn off the echo on these old units and simply use the dry preamp for its
tone and feel as an always-on effect. In the original units, the output impedance was quite high, and this
led to a high frequency roll off with long cable runs. This was difficult to control, but also part of the
unit's top end character.
The ZIO can internally recreate the sound of a short cable run after the echo unit (as if it were sitting
near or on top of the amplifier) and a variable length of cable in front of the unit, using the TONE switch.
The combined effect gives a focus in the midrange without too much brightness or boomy bass.
SA271 ZIO User Guide 7