Module A-138d can be used in two different ways:
If the module is used as a crossfader within the
A-100 the two audio signals are connected to the sockets In 1 and In 2.
The position of the CF (Crossfade) control
defines the relation between the levels of the signals In 1 and In 2
that appear at the Mix Output. In the leftmost position of CF only In
1 appears at the output, in the rightmost position only In 2. In the
center position both inputs appear with the same level at the Mix Output.
Each input is equipped with two sockets (miniature multiples) so that the input
signals can be forwarded to other modules too. Even the Mix Output has
two sockets available. The mute switch can be used to mute In 1 or In 2 independent of the
position of the crossfade control. In the center position it has no
function. The controls Atten. and Amp. and the 1/4"
sockets FX Send and FX Return are not used in this
application.
If the module is used as an effect send/return
module with dry/wet control the A-100 signal that has to be processed by the
external effect unit is connected to In 1. The signal can be attenuated
by control Atten. before it is output to the 1/4" socket FX Send.
The attenuator has been added because some effect units without input level
control (especially guitar stomp boxes) will distort with A-100 levels (~ 1 Vss
or more). The attenuator can be used to reduce the signal level so that no
distortion occurs. Atten. is adjusted so that the external effect unit does not
distort. The output of the external effect unit is connected to the 1/4"
socket FX Return. This socket is followed by an
amplifier and the control Amp. is used to amplify the signal to obtain
again A-100 audio level (~ 1Vss or more). Amp is
adjusted so that the loudness of both signals (i.e. original = dry = In 1 and
the effect return signal = wet = In 2) have nearly the same loudness. The
amplification range of the FX return amplifier is 1 to 50 (or 0 to 33dB). The
output of the amplifier is normalled to the upper socket of Input 2. In
this application no plug is inserted into the upper In 2 socket. The
lower In 2 socket can be used to obtain the effect return signal before
it is processed by the crossfade unit of the A-138d. The CF control of
the A-138d works now as a dry/wet control for the external effect. In the
leftmost position of CF only the original signal (i.e. not processed)
appears at the Mix Output, in the rightmost position only the effect
signal. In the center position the original and the processed signal appear with
the same level at the Mix Output. The mute switch can be used to mute the
original or the effect signal independent of the
position of the crossfade control. In the center position it has no
function.
Attention:
If the small sockets In 2 are used (i.e. no FX return via the 1/2" socket)
the signal has to be fed into the upper socket In 2. Then the
lower socket In 2 can be used to forward the signal to another module! The upper
socket In 2 is normalled to the output signal of the internal amplifier that
amplifies the FX return signal. If a plug is inserted into the upper In 2 socket
this internal signal is interrupted (switching contact). That's valid even if no
FX return signal is connected as in this case the output of the amplifier is ~
0V/GND. If a plug is inserted into the lower In 2 socket only a short circuit
between this signal and the output of the internal amplifier is made ! Nothing
can be damaged within the A-100 but the results will be strange. Please
refer to the sketch below for internal wiring details.
Typical applications:
-
Crossfader for two different A-100 signals
-
Crossfade between original and processed
audio signal (dry/wet control). For this the incoming audio signal is patched to input 1 of
the A-138d and passed on to the audio input of the sound processing module
in question (e.g. filter, phaser, flanger,
frequency shifter, wave multiplier, wave shaper ...). The audio output of the sound
processing module is patched to input 2 of the A-138d.
-
Involving external effect units into A-100
-
dry/wet control for the external effect
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