BIAS
At its core BIAS controls the gain of the pedal. As you turn it, it will crackle. We assure
you, this is okay! Set to minimum, the pedal will be around unity gain and will get the
general response of the EP-3. (Remember, the Echoplex was not designed to boost
signal. Echoplex designers were just trying to come up with a unity driver and not effect
the sound. But the preamp did change the sound and everybody loved it for what it did).
Turn up the Bias for more gain. The Epoch Pre is super high headroom and won’t
distort, even at high Bias settings. What it will do is make everything sound bigger.
BOOST
This switch allows for an instantaneous preset boost, as determined by where the Boost
knob is set. The Boost function is part of the preamp; if you have the pedal bypassed,
the Boost does nothing. This boost function was voiced to make the signal bigger,
louder, and wider. The Naga Viper, for example, in contrast makes the sound more
focused.
EARLY/LATER push-button
What the frack does Early/Later mean? The EP-3 Echoplex went through a few
revisions during its production life. The first 400 units had a different preamp voicing and
has now become one of those holy grail legend type things.
The Early voicing had a tighter bass and more upper midrange boost which made it
perfect to enhance the big cranked up Marshalls everyone was playing through. As you
know, if you crank up a tube amp it gets thicker and you can lose definition and cut-
through power. Think of the Van Halen sound (although it is not known if he used early
or later models).
