Basic Concepts
Tape echo effects were invented towards the end of the fifties.
Presumably the very first tape echo machine was invented by Charlie
Watkins of London, England, in 1958. It was based on a small loop of
1/4" tape onto which audio was recorded by a magnetic head and then
read by three separated heads. What was read from the tape was
amplified by the internal all-valve circuit and eventually recorded
back to the tape, creating the feedback or "sustaining" echo effect.
The delay time of the unit was determined by distance of the write
head from the read heads, in conjunction with the speed of the tape.
Many manufacturers of this era produced their versions of echo
machines, mostly based on the magnetic tape system. The famous Binson
Echorec was based on a circular drum head with a metallic magnetic
stripe. It was used by Pink Floyd at the time of their album "Echoes".
Another famous tape echo machine was the Maestro Echoplex, heavily
used by pianist Herbie Hancock. Other notable units were the Selmer
TruVoice Echo, the Dynacord Echocord, along one of the most famous and
widely used from 1973 to present day: the Roland RE-201. This
particular model has a tape loop about 4 meters long which is
recorded, read and erased continuously. It consists of one erase head,
one write head and three pick-up heads, which when combined with the
variable speed DC capstan motor allows many different delay
configurations. This machine also offers a reverberation effect based
on a spring reverb tank. The combination of echo and reverb gives an
"ethereal" ambience effect which eventually inspired the engineers so
to name it "Space Echo".
Nowadays these machines are very sought after but quite rare to find
on the market, and their evaluation increases year after year. There
are many aspects that make the tape echo stand out from a modern
digital delay. Here are a few of the main features:
1) the unpredictability. A capstan motor is never perfect like a
digital clock signal, resulting in slight variations of the delay
times and pitched sound.
2) the frequency response and dynamic range. A magnetic tape is not as
clean and flat as a digital recording. Especially a loop of tape which
is cyclically erased and re-recorded many times in a short time lapse.
3) noise, hum, distortion. Defects that a digital system shouldn't
have, sometimes are wanted and can become "musically acceptable".
There is one way only to obtain all of this. To get the real thing.
Actually there's a much affordable and easy alternative: to use an
accurate digital simulation.
GS-201 is an accurate simulation of a japanese Tape Echo machine of
the early seventies, featuring:
Distinctive dynamic range and frequency response
Realistic response to the panel controls
Motor "wow and flutter"
Sound degradation and distortion at high feedback levels
Very natural hum and background tape noise
Three different kinds of magnetic tape models
Ultra-low CPU usage
Easy "MIDI Learn" feature
Panel Controls
Input Left, Input Right: GS-201 is a monoaural effect but it works for
either mono or stereo buses or insert slots. With these two knobs you
can set the input volume of the two stereo channels separately.
Direct Level, on/off: The input audio signal is copied to the output
unchanged. With this knob you can set its level. Use the little on/off
switch to turn on or off the dry signal. More generally, you should
turn off the dry signal when using GS-201 on an effect bus
(send/return), and leave it on when you're using GS-201 as an insert
effect.
Mode Selector: This 12 way rotary selector lets you choose among
various combinations of echoes and reverb.
Modes 1 to 4 exclude the reverb effect, and include the following
combinations:
1. First head (shorter delay time)
2. Second head (medium delay time)
3. Third head (longer delay time)
4. Two taps: Second + Third head.
Modes from 5 to 11 include both the echo and the reverb effect, and
are organized as follows:
5. First head (like mode #1)
6. Second head (like mode #2)
7. Third head (like mode #3)
8. Two taps: First + Second head
9. Two taps: Second + Third head (like mode #4)
10. Two taps: First + Third head
11. Three taps: First + Second + Third head
Mode #12 is "Reverb only" which excludes the echo effect.
Repeat Rate: This knob lets you vary the speed of the capstan motor
which leads the tape, consequently changing the overall delay time.
Turn it counterclockwise for longer delay times and clockwise for
shorter delay times. When moving this knob, a pop-up window will show
the actual delay times in milliseconds for all three heads.
Please refer to the section Frequently Asked Questions for useful tips
about this control.
Intensity: With this knob you can choose the quantity of signal to be
reproduced and recorded back on the tape, thus affecting the delay
feedback level. At high feedback levels the tape echo could engage an
infinite feedback with drastic signal degradation.
Bass, Treble: With these two knobs you can adjust the frequency
response of the sound output from the tape.
Echo Volume, Reverb Volume: With these two knobs you can adjust the
volume of the two effects separately.
Power: This switch turns off or on the effect unit.
RT, 456, 468: This 3-way selector lets you choose between three
different kinds of tape used by the echo machine.
RT: this is the original tape model.
456: this is the famous "Grand Master" tape model, mostly used for
multitrack recorders and not so suitable for these machines. It has a
brighter response, a higher gain and less distortion than the original
tape.
468: this is the famous "Low Print" tape model, mostly used for hi-fi
tape decks. Its characteristics are half-way between the RT and the
456 tape models.
You won't notice huge differences between the three tape models in a
normal situation. The difference becomes more noticeable with longer
feedback levels, especially when the tape goes into the
self-oscillation state.
In version 1.1, when you move a control on the User Interface, a small
display appears on the screen showing the current value of the active
control. When you move the "Mode Selector" knob, another display shows
the tape heads and reverb arrangement based on the active knob
position. Passing your mouse pointer over the controls, a pop-up text
describes their function.
Tips on using the interface:
* to reset a control to its default value, hold down CTRL and click it;
* for "fine tuning" knob movements, hold down SHIFT while moving the knob;
* all the knobs react to both vertical and horizontal movement;
* hold down the ALT key to activate the circular control of the knobs.
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