doepfer
System A - 100
1. Introduction
Sampler
A-112
A-112
SAMPLER
MIDI In
MIDI Out
Man. Trig.
Gate In
Audio IN /
Wave-CV In
CV In
Audio Out
Modus
Atten.
Tune
Run
Module
including a voltage controlled 8 bit Sampler and a
voltage controlled Wavetable Oscillator.
The module has the characteristic “grungy“ sound
of the early 8 bit Samplers and is a welcome addition to the A-100’s sound generating capabilities.
But it should not be compared with the polyphonic 16
bit MIDI samplers available on the market.
The module contains an A/D converter (ADC) for
recording the audio signal (8 bit resolution), digital
memory
converter (DAC) for playback and the control unit.
The memory is divided into two
kbyte each. In wavetable mode each bank is arranged
as 256
The memory is
sampling data in the memory is maintained.
A-112 (SAMPLER
for storage of the the sampled signal, a
of 256 bytes.
pages
non-volatile
) is a combination module,
D/A
banks
, i.e. after power-off the
(S1, S2) with 64
1
A-112
Sampler
System A - 100
doepfer
Sampling mode
In sampling mode the incoming audio signal is sampled with a
manually and from the external control voltage
input. The audio signal is converted by the ADC into 8
bit digital data and
mory (memory address 0 ... 65 535). With a sampling
frequency of 32kHz this corresponds to 2 seconds
sampling time.
During playback the sampling data in the memory is
read sequentially (address 0 ... 65535) and converted
into the corresponding audio signal by the DAC. The
sampling frequency in play mode is controlled manually and from the external control voltage input. Playback is stopped if the last memory address (65535) is
reached.
Via MIDI dump the sampling memory can be sent to a
computer for storing the data on hard-disk or any other
storage device. The computer may also transmit
sampling data to the A-112 via MIDI dump.
Wavetable mode
In wavetable mode the memory access is not sequentially but by
an external voltage. This voltage can be may generated manually (e.g. with the manual control voltage
sampling frequency
sequentially
. The
page
page number
that is controlled
written into the me-
is selected by
source A-176) or it may come from any other voltage
source (e.g. LFO, ADSR, Sequencer). Both record and
play take place in a loop whereby the complete page
is always passed through. When reaching the end of a
page the run control determines if a jump to another
page takes place or the loop remains in the same page
- depending upon the voltage controlling the wavetable/page.
Playback with a dynamic control voltage (e.g. ADSR,
LFO, Random, Sequencer, MIDI-to-CV) results in
“sweeping through“ the different pages (Wavetable
principle). If the memory of the A-112 contains suitable wavetables in the 256 pages, the result is a
voltage controlled Wavetable Oscillator with two control voltages: one for the audio frequency (pitch, tune),
one for the wavetable number.
Normally suitable wavetables are generated by a computer and transferred to the A-112 via
Effect mode
Additionally the module offers some effects, like Delay, Reverse Delay
to the 8 bit resolution these effects are not to be
compared however with the results from high-end
effect devices, but should be considered as a free
extra gift for strange sounds.
and
Pitch Shifter
MIDI-Dump.
. Of course, due
2
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System A - 100
Sampler
A-112
2. SAMPLER Overview
➄
➅
➆
➌
➃
➊
➋
A-112
VC Sampler / Wavetable Osc.
Eff
Dmp
Pit
Loop Wav
Audio In /
Wave-CV In
S1
Play
Del
Norm
Gate In
CV In
SAMPLER
MIDI Out
S2
Rec
MIDI In
Rev
FrzLen
Man.
Trig.
Run
0
0
Audio Out
10
10
Atten.
Tune
➎
➏
➍
➂
➀
➁
Controls:
1 Atten. : Attenuator for Audio/Wave CV
Input
!
Tune : Manual control for Sampling fre-
2
quency
: Gate indicator LED / overload
Run
3
warning during record
Man. Trig.
4
... 7 Switches: 3-position switches for mode se-
5
: manual trigger/start button
lection
In / Outputs:
Audio /
!
Wave-CV In
CV In : pitch control input (1V/oct.) for
"
§ Gate In
Audio Out
$
% MIDI In : MIDI input
& MIDI Out
: Input for audio signal resp. wa-
vetable control voltage in wavetable mode
tuning or sampling frequency
: Gate input
: Audio output
: MIDI output
3
A-112
Sampler
System A - 100
doepfer
3. Controls
1 Atten.
Control 1 attenuates the
!. Depending upon the mode this voltage is the audio
signal (in sampling or effect mode) or the wavetable
control voltage (in wavetable mode).
2 Tune
The tune control 2 is used to adjust the sampling
frequency (during record) or the pitch/tune during
playback (see table below).
Exception: In
pages is selected with the tune control (see following
table). In this case the sampling frequency defaults to
the last frequency that was set prior to switching into
wavetable mode.
tune
position
0 0 2,0 6 154 18,5
1 26 2,9 7 179 26,5
2 51 4,2 8 205 38,5
3 77 6,1 9 231 56,2
4 103 8,8 10 255 79,4
5 128 12,7
wavetable record
page
(appr.)
samplingfreq. [kHz]
of the voltage at input
level
mode
tune-
position
one of the 256
page
(appr.)
samplingfreq. [kHz]
H
The voltage generated with the tune control
is internally added to the voltage at input ".
This input is normally used to control the
pitch of the sampler/wavetable oscillator in
play mode with an external control voltage
following the 1V/oct standard (e.g. the A-190
MIDI-to-CV interface).
3 Run
LED 3 is used for different
depending upon the mode selected. A description of
the respective function is given in the corresponding
paragraph elsewhere in this manual.
monitoring purposes
4 Man. Trig.
Button 4
is used to trigger the sampler
Depending upon the mode selected a Trigger or Gate
leads to different actions. A description of the
respective functions is given in the corresponding
paragraph elsewhere in this manual.
manually.
H The manual trigger generated with button 4
and the signal at the gate input § are internally connected, to produce a gate/trigger
signal used for all triggered/gated functions.
The data in the table are approximate values
4
doepfer
System A - 100
Sampler
A-112
55556
S1, S2 Play Norm
Eff
67
66
Dmp Norm
Rec Norm
Pit Norm
Del Norm
Rev Norm
7
77
Loop
Wav
Loop
Wav
Loop
Wav
Len
Frz.
Len
Frz.
Len
Frz.
Function
not implemented
Dump a sample
Dump a wave
Play a loop
Play a sample
Play a wave
Record a loop
Record a sample
Record a wave
Input sample length required
Pitch Shift
Pitch Shift with "Freeze"
Input sample length required
Delay
Delay with "Freeze"
Input sample length required
Reverse Delay
Reverse Delay with "Freeze"
5 Switch • 6 Switch • 7 Switch
With the 3-position switches 4 to 6 the operating
mode is selected. The table on the left lists all possible
modes. The modes are described in the following
paragraphs.
In particular the gate signal (gate input § / manual
trigger 4) controls different functions in the respective
operating modes.
H
Please note that in some modes it is not
sufficient to change the switches position to
exit the mode. In the following description of
the modes you will find detailed information
on how to exit a selected mode.
5
A-112
Sampler
System A - 100
doepfer
• Normal record mode
55556
67
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S1,S2Rec Norm
In this mode an audio signal at audio input 1 is
recorded into one of the 2 memory banks S1 or S2
(depending upon the position of switch
Gate = low :
In this case the pre-listening mode is active (LED 3
is off); the audio signal at input 1 is digitized by the
ADC, re-converted by the DAC and forwarded to audio
output 4 for pre-listening.
The pre-listening mode contains an
ping function: as soon as the audio signal exceeds a
predefined upper or lower threshold the LED 3 lights
up for a short moment (about 10 ms). During this time
the audio signal is not scanned and the output remains
at the last DAC value. The onset of clipping (i.e.
overload distortion) is immediately audible.
Audio / Wave-CV In
7
77
Audio signal sampling fre-
Tune / CV
quency (while
Gate = low)
5).
overload/ clip-
H The sound quality in the pre-listening mode
is very poor. The quality if a signal is recorded and played back is much better!
The pre-listening mode is also used to find out and
set the sampling frequency. When record mode is
entered (see below) the last sampling frequency in
pre-listening mode is used.
Gate = high:
When the gate level changes from low to high Record
is triggered and the audio signal is sampled into the
memory bank selected with switch
on. Recording starts at address 0 and continues until
the last address (65 535) is reached and LED 3 turns
off. If gate turns low before the end of the sampling
memory (address 65 535) is reached the record process stops. You can use this function to sample chosen segments of sound.
5. LED 3 is now
• Normal play mode
55556
67
66
S1,S2Play Norm
In this mode a previously recorded sample in the
sampling memory (S1 or S2, depending upon the
position of switch
Audio / Wave-CV In
7
77
- - - - - - - sampling fre-
5) is played back.
Tune / CV
quency
6
doepfer
System A - 100
Sampler
A-112
Gate = low:
The module is waiting for gate = high; LED 3 is off
(see fig. 1 - a).
Gate = high:
When the gate level changes from low to high
back is triggered and the audio signal in the memory
bank is played back. LED 3 is now on. Playback starts
at address 0 and continues until the last address (65
535) is reached and LED 3 turns off. Even if the gate
goes low before the end of the sampling memory is
reached the playback continues (see fig. 1 - b).
Only if the gate goes low and high again before the
end is reached the sample is retriggered, i.e. the
playback starts again at address 0 (see fig. 1 - c).
If the gate is still high when the end of the sample
memory is reached the playback stops (i.e. no loop if
gate remains high). For this purpose the loop mode is
used.
Play-
Audio
Out
Gate
fig. 1: normal play mode
•
55556
S1,S2Rec Loop
This mode is very similar to the normal record mode
(see above). The only difference to the normal re-
cord mode is that record continues when the end of
the sample memory is reached and the gate level is
still high
Sa m p l e
a
b
Loop record mode
67
66
.
Audio / Wave-CV In
7
77
c
Tune / CV
audio signal sampling fre-
quency (only if
Gate = low)
7
A-112
Sampler
System A - 100
doepfer
In this case the record starts again at the first memory
address. This loop continues (LED 3 on) until gate
turns low.
• Loop play mode
55556
67
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S1,S2Play Loop
Audio / Wave-CV In
7
77
- - - - - - - - - sampling fre-
In normal play mode the playback stops if the end of
the sample memory is reached. The loop play mode
allows the
continuous playback of a pre-defined
section of the sample memory.
Gate function:
As long as the gate level is high the sample is played
continuously. When the end of the sample is reached,
playback starts again at the beginning (see fig. 2 - a).
LED 3 is on.
As soon as the
gate goes low
the present position
within the sample is defined as loop end (see fig. 2 -
b). Playback starts at the beginning (address 0) and
runs continuously from the beginning to the loop end
Tune / CV
quency
as long as the gate level remains low (see fig. 2: loop
1).
If gate turns high (see fig. 1 - c) the loop end is
cancelled and the sample playback uses the full range
again (i.e. loop end = end of sample memory, see fig.
2 - d).
If the gate goes low again a new loop end is set (see
fig. 2 - e, loop 2).
To
loop play mode a short
exit
trigger pulse
(max.
duration 100 ms) is required (see fig. 2 -f).
Audio
Out
Gate
Sam pl e
b
c
a
Loop 1
d
e
Loop 2
fig. 2: Loop play mode
f
8
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System A - 100
Sampler
A-112
• Wave record mode
55556
67
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S1,S2Rec Wav
In this mode one or more wavetables are recorded
into the memory bank selected.
The
number of the wavetable (page)
position of the Tune control 2 and the voltage applied
to the CV input
Gate = low :
The pre-listening mode is active (LED 3 is off); the
audio signal at input 1 is digitized by the ADC, reconverted by the DAC and forwarded to audio output
for pre-listening.
4
All functions and controls (overload/clipping, adjustment of sampling frequency ...) are the same as in the
normal record mode (see above).
"
Audio / Wave-CV In
7
77
.
audio signal sampling fre-
Tune / CV
quency (if gate =
low) /
wavetable number
(if gate = high)
results from the
Gate = high:
When the gate goes high
The last sampling frequency while gate was low is
used as the sampling frequency. The wavetable number (page) is derived from the position of the Tune
control
The audio input is sampled and 256 bytes are written
into the wavetable memory (page) selected.
When the last byte of the page (i.e. byte no. 256 of the
page) is written record starts again at the first byte of
the page. This process continues (LED 3 on) until the
gate goes low.
The record process stops immediately at the present
position as soon as the gate goes low. You can use
this function to sample chosen segments of sound.
When reaching the last position of the current wavetable page the number of the next page is defined
by the position of the Tune control 2 and the voltage
applied to the CV input " (provided that gate is still
high). Consequently different pages may be selected
during record if the control voltage (e.g. from an
ADSR) or the position of the tune knob is changed .
and the voltage applied to the CV input
2
record
starts (
LED 3
is on).
"
.
9
A-112
Sampler
System A - 100
doepfer
In fig. 3, the CV input is fed from the sine output of a
LFO. The sampling frequency is 32kHz, the LFO frequency 21 Hz. The resulting wavetable pages are
shown in the boxes.
251
220
154
64
26
0
+5 V
-5 V
243
238
128
102
8
fig. 3: wave record mode with modulated wavetable
page number
Waves recorded in this way may be played back in the
normal play mode, often leading to some fairly drastic
effects.
• Wave play mode
55556
67
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S1,S2Play Wav
Audio / Wave-CV In
7
77
Number of wavepage
In this mode A-112 works as a wavetable oscillator.
The wavetable number (page) that determines the
sound of the audio output is set by the control voltage
applied to the audio/wave CV input
Gate = low:
51
The module is waiting for gate = high; LED 3 is off.
The initial sampling frequency (i.e. the first frequency
when gate turns to high, see below) is set.
listening mode is also used to find out and set the
sampling frequency.
Gate = high:
When the gate goes high the wavetable number
(audio/wave input) and the sampling frequency (tune
control and CV input) are set, and playback of the
recorded wavetable begins, using the sampling frequency previously set (LED 3 turns on). When the end
of the wavetable is reached the process starts again,
Tune / CV
sampling fre-
quency
!
Pre-
10
doepfer
System A - 100
Sampler
A-112
i.e. the next wavetable and the next sampling frequency are determined. This continues until the gate
goes low.
When a dynamic voltage -2.5...+2.5V is used as the
wavetable control voltage (e.g. ADSR output connected to audio/wave input !) wavetable are swept.
memory bank
Speicherbank
12 7118 13 5
Audio In
0,40
0,30
0,20
0, 10
0,00
-0,10
-0,20
-0,30
-0,40
Loop
fig. 4: wavetable selection with CV voltage applied
to audio/wave input
• Normal dump mode
55556
67
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Audio / Wave-CV In
7
77
S1,S2Dmp Norm
In this mode a sample (bank 1 or 2) can be transferred
as a MIDI system exclusive string (SysEx Dump) via
MIDI out &. You can then record this string with a MIDI
computer sequencer or download it using a MIDI dump
program for storage on hard disk or any other storage
device. The sampling frequency is also transferred
within the string.
It is also possible to receive a sample dump via MIDI
input %. The dump is written to the memory bank
selected (S1 or S2).
Gate = low:
In this state (LED 3 off) MIDI input % is scanned. As
soon as an
turns on and the dump data is written into the
3
incoming sample dump
memory bank selected.
If a sample dump request is received via MIDI IN the
sample memory is transferred via MIDI OUT as a
SysEx string. LED 3 turns on as well. Refer to the
description of MIDI input and output in chapter 5.
Tune / CV
is detected LED
11
A-112
Sampler
System A - 100
doepfer
H During Data transmission via MIDI OUT the
MIDI input and gate are not scanned. Therefore a new dump cannot be triggered by
mistake.
Gate = high:
As soon as the gate goes high (e.g. by pressing button
4) the sample memory is transferred as a SysEx dump
via MIDI OUT and LED 3 turns on (same function as
sample dump request via MIDI in).
H To trigger a sample dump manually a short
high gate level is sufficient. It is not necessary to keep the gate level high.
• Wave dump mode
55556
67
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S1,S2Dmp Wav
This mode is very similar to the normal dump mode
(see above). The
mode is that the data of a single wavetable (page) of
256 bytes is transferred instead of the complete
sampling memory of a bank.
Audio / Wave-CV In
7
77
difference from the normal dump
Tune / CV
wave page num-
ber
The number of the wavetable is determined by the
position of the tune control 2 and the voltage applied
to CV input ".
• Delay mode
55556
67
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Eff Del Norm
This mode generates a simple delay. The incoming
audio signal is delayed and passed to the audio output.
H
Principle: The incoming audio signal is sampled and
written into a memory position in bank S2. Before this
the old value at this position is transferred to the audio
output. The number of the memory position is increased by 1 and the process is repeated. When
reaching the last memory position the process starts at
memory position 1. The last memory position depends
upon the length (Len, see below).
The memory bank S2 is overwritten in this
mode!
Audio / Wave-CV In
7
77
audio signal sampling fre-
Tune / CV
quency
12
doepfer
System A - 100
Sampler
A-112
The length of the delay memory is defined by the
parameter Len (see below). The maximum length is
the complete sampling memory (64kbyte = 65536
bytes). With a sampling frequency of 32 kHz this
corresponds to 2 seconds delay time. The
delay time is decided by a combination of the length
of the delay memory (Len) and the sampling frequency
Gate = low:
The module is waiting for gate = high; LED 3 is off.
The initial sampling frequency is set.
Gate = high:
The delay mode is started; LED 3 turns on. Retrigger
is active, i.e. a gate transition to low and back to high
starts the delay mode again.
H
.
Moving from delay mode directly to delay
with freeze is not possible. To perform this
one has to interrupt the delay mode (switch
to S1/S2 or switch 7 to Len) and then
5
select the desired mode.
actual
P By feeding the A-112 output back to its input
one obtains a repeat or echo (see fig 5).
Beware: too much feedback leads to an
avalanche-like effect. In this case the feed
back component has to be reduced.
Audio
In
Feedback
fig. 5: Echo
A-1 12
A-1 12A-138
Audio
Out
• Reverse delay mode
55556
67
66
Eff Rev Norm
This mode is the same as the delay mode but the
playback of the delayed signal takes place in reverse.
H
Principle: Same as the normal delay mode but writing
into the delay memory is performed forward, and
reading the delay memory is performed backward. As
this is a very simple “bog standard“ algorithm, overlapping effects may occur and lead to interference, glitches or clicks in the audio output signal.
Memory bank S2 is overwritten in this mode!
Audio / Wave-CV In
7
77
audio signal sampling fre-
Tune / CV
quency
13
A-112
H
Sampler
All functions and controls (sampling frequency, length of delay memory ...) are the
same as in the normal delay mode (see
above).
• Pitch shift mode
System A - 100
If read and write frequency differ the audio signal is
read out faster or slower and the pitch shift effect
occurs.
Because of this very simple “bog standard“ algorithm
overlapping effects may occur and lead to interference, glitches or clicks in the audio output signal.
doepfer
55556
67
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Eff Pit Norm
In pitch shift mode the audio input signal is sampled
and played back at the audio output with shifted pitch/
tuning.
H
Principle: The incoming audio signal is sampled with a
fixed sampling frequency (about 16 kHz) and written
into memory bank S2. Each sample increases the
memory position by 1. Simultaneously the memory is
read out with a sampling frequency that is determined
by the Tune control 2 and the voltage applied to the
CV input ".
If the read frequency is nearly the same as the write
frequency (i.e. about 16 kHz) no pitch shift occurs just a delay depending upon the memory length (Len).
14
Memory bank S2 is overwritten in this mode!
Audio / Wave-CV In
7
77
audio signal sampling fre-
Tune / CV
quency
H
All functions and controls (read sampling
frequency, length of delay memory ...) are
the same as in the delay mode (see above).
P Very interesting sounds can be obtained if
the original audio signal is mixed with the
pitch shifted signal of the A-112 (using a
mixer A-138a/b).
doepfer
System A - 100
Sampler
A-112
• Freeze option
55556
67
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Del,
Eff
Rev,
Pit
The effect modes delay, reverse delay and pitch shift
may also run with the Freeze option.
In this case the audio input is no longer sampled and
the memory data no longer overwritten. Instead, the
frozen
memory length (Len) and sampling frequency determine the effect.
Gate control:
The module is waiting for gate = high; LED 3 is off.
The initial sampling frequency is determined.
If only a short gate pulse appears (i.e. gate turns to
high only for a short time and becomes low again) the
effect selected functions without freeze. LED 3 is off.
As soon as gate turns high and remains high the
freeze option of the effect in question is active. LED
3 is on. The data in the memory are “frozen“ as long
as the gate remains high.
memory data are played back. The parameters
7
77
Frz.
Audio / Wave-CV In
audio signal sampling fre-
Tune / CV
quency
When gate turns low the freeze option is cancelled
and the module returns to the respective effect without
freeze. To re-activate the freeze option, one simply
has to turn the gate to high.
H Changing directly to the normal effect without
freeze (permanently) is not possible. To perform this one has to interrupt the freeze
option (switch 5 to S1/S2 or switch 7 to Len)
and select the desired mode after this.
Effect parameter "Len"
•
55556
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Del,
Eff
Rev,
Pit
In this operation mode the parameter Len is adjusted.
This value determines the
memory in bank S2 used for the effect modes.
Gate = low:
In this state the
parameter. The resolution for the length is one page
(256 bytes). The tune knob turned fully to the left (ccw
position 0) corresponds to one page, turned fully to the
Audio / Wave-CV In
7
77
Len
Tune control 2222
length of the sampling
Tune / CV
memory length for
the effect in question
adjusts the
Len
15
A-112
Sampler
System A - 100
doepfer
right (cw position 10) it corresponds to the whole
memory (64 kbyte or 256 pages). During the adjustment of Len with the tune control no external voltage
should be applied to the CV input ".
Gate = high:
As soon as the gate goes high the current position of
the tune control is used to set the Len value.
For the different effect modes the following notes also
apply:
Delay, Pitch Shift:
The
factory setting
corresponds to a tune control setting of about 0.5.
Reverse Delay:
The factory setting is 64 kBytes (i.e. 256 pages).
This corresponds to tune control setting 10.
The reverse delay effect seems to go very strange with
tune control settings of about 1.5 down to 0, i.e. the
reverse delay becomes a normal delay, but with extreme distortion.
is
4 kBytes
(i.e. 16 pages). This
4. In / Outputs
! Audio In / Wave-CV In
At this socket the audio input signal is patched in (i.e.
the signal to be sampled or used for effects). This is a
line level input (+/-2.5V or 5Vss). Note that the audio
signal must be at line level – microphones won’t give
enough output.
H Exception: In
the wavetable control voltage input -
2.5...+2.5V (not an audio signal input)!
wavetable play mode
" CV In
Control voltage input for sampling frequency du-
ring
record, or pitch/tune
follows to the 1V/oct. standard and has 1/4 semitone
resolution.
during play. This input
H The control voltage applied to CV in " is
internally added to the voltage generated by
the tune control 2.
§ Gate In
this is
16
At the
Gate input §
function depends upon the mode selected.
the
gate signal
is patched in. The
doepfer
System A - 100
Sampler
A-112
The gate signal applied to this socket is inter-
H
nally connected with the signal coming from the
button 4. If either of these is high, the module
gate is high.
Gate In §§§§ Man. Trig. 7777 result. Gate
high high high
high low high
low high high
low low low
$ Audio Out
Socket $ is the
audio output
of the A-112.
H The audio signal from the DAC passes a
simple low-pass filter to suppress the
sampling frequency. It is possible to bypass
this internal filter if a more sophisticated lowpass filter (A-120, A-121, A-122) is used or if
the sampling frequency should not be suppressed for special effects. For this the internal jumper J1 has to be removed.
% MIDI In
Socket % is the
data (SysEx dump) via MIDI. For this the dump or
wave dump mode has to be selected (see above) and
the gate has to be low.
Moreover a sample dump request or a wave dump
request message can be received by the A-112 in this
mode.
The MIDI SysEx message for a
quest has the following structure:
F0
00 20 20 Doepfer SysEx-ID
7F
< bank> bank number (00 : S1, 01 : S2)
F7
When receiving this message the A-112 transmits at
the MIDI output
length of the dump is 74.909 bytes altogether. Additionally the current sampling frequency is transmitted.
The SysEx message for a wave dump request has
the following structure:
MIDI input
a sample dump (LED is on). The
&
used to receive sample
sample dump re-
17
A-112
Sampler
System A - 100
doepfer
F0
00 20 20 Doepfer SysEx-ID
7D
< Wave-Nr., Bit 7 - 1 >
< Wave-Nr., Bit 0 >
F7
As the data range in a SysEx message is 0...127 (7 bit)
the wave number requires 2 bytes.
Example: Dump of wave no. 201 ("11001001"):
F0
00 20 20
7D
64 "110100"
01 "1"
F7
When it receives this message the A-112
wave dump at the MIDI output & (LED is on). The
length of the dump is 305 Bytes altogether. Additionally the current sampling frequency is transmitted.
transmits a
& MIDI Out
The MIDI output
during sample or wave dumps.
transmits MIDI dump information
&
5. User Examples
The obvious application of the A-112 is the sampling
and playback of external sounds or sounds generated
with other A-100 modules. On top of this the module
opens up a huge number of sound experiment possibilities – far too many to be covered in this manual.
The following examples concentrate on
applications of the module.
Wavetable Oscillation
The wavetable oscillator feature and the loop feature
of the A-112 have already been described in chapter 3.
Smooth sequencing of the wavetables with an external
control voltage requires a certain amount of subtle
intuition - and additional A-100 modules - as it is
necessary to control the offset and amplitude of the
voltage applied. You do then also have the ability,
though, of selecting a specific starting wavetable
(offset) and starting the up/down sweep through the
waves (amplitude) at this particular point.
For the most effective wavetable control we recommend using the A-129/3 (attenuator and offset generator, see below).
wavetable
18
doepfer
System A - 100
Sampler
A-112
The control voltage range 0...+5V corresponds to the
256 tables (0V = table no. 1, +5V = table no. 256). To
move from one table to the next one a voltage difference of about 0.02 V (5V/256) is required.
Example: To sweep with an LFO (Triangle output)
through 64 tables starting with table no. 96 (i.e. passing through the tables 64...128) the following conditions are required: An offset voltage of 96*5V/256 =
1.875V and an attenuation of the LFO signal to 64*5V/
256 = 1.25V (peak-to-peak). Using a A-129/3 the offset
voltage is adjusted with the offset control and the LFO
level with the attenuator control.
If each of the 64 tables are to be used - i.e. none of the
tables is to be skipped - there is a maximum frequency
that the controlling signal (LFO) must not exceed. If the
sampling frequency is 32kHz each wavetable (256
byte) takes 8 milliseconds. All 64 tables take 512
milliseconds. This corresponds to 1.95 Hz LFO frequency. Consequently the frequency of the LFO must
be about 2 Hz or less to play each table without
skipping. This sounds very mathematical and theoretical but it is a good idea to understand these facts as
some unforeseen things may happen if one ignores
these details. In practice of course the resulting sound
is all that counts.
Sequencer-controlled wavetable playback
In the patch in fig. 6 the Analog/Trigger Sequencer
A-155 controls the playback of different wavetables
(step 1, 4, 5 and 7).
The sawtooth output of the LFO, patched via offset
generator A-129/3 generates the control voltage to
sweep through the wavetables. This voltage is added
to the sequencer voltage (post out 2). Thus different
ranges of the wavetable memory are used for each
step (displayed by different sound symbols). Regarding offset, attenuation and LFO frequency, see the
notes on the previous page.
The sequencer control voltage Post Out 1 is used to
control the decay of an VC-ADSR, i.e. for different
decay times for each step.
Instead of an LFO an ADSR or VC-ADSR may be
used. The attack control is used in this case to adjust
the speed of sweep (decay, sustain and release control = 0).
19
A-112
Sampler
System A - 100
doepfer
Wavetable playback of a normal sample
Very interesting sounds can be obtained if a normal
sample is played back in wavetable mode - especially
if human voice is recorded.
During normal sample playback the sample length
depends upon pitch and the so-called Mickey Mouse
effect occurs.
If the wavetable mode is used the sample length
depends only upon the slope of the controlling voltage
(e.g. sawtooth) but not upon the pitch. This is adjusted
independently with the tune control and pitch CV.
Suggestions for sound experiments:
• If the slope of the voltage controlling the wavetable
is running backwards (e.g. a falling sawtooth) sampled words seem to be spoken backwards (sort of).
By selective scanning of a spoken sample one may
•
obtain voice or vowel loops.
Using a random or S&H voltage for controlling the
•
wavetables leads to the basics of what is often
referred to as granular synthesis.
For the above suggestions it is important that the
period of the sampled sound fits almost exactly into the
space allotted to each wavetable (256 Bytes). If the
result is not satisfactory another record sampling frequency should be used until the desired sound is
obtained.
20
doepfer
A-155
1 2
3
4 5 6 7 8
Clo c k
Trig. 1
System A - 100
VC-ADSR
Sampler
A-112
Gat e
Po st Out 1
S & H Ctrl. 1
Po st Out 2
S & H Ctrl. 2
0 V 0 V
LFO
Ret r i g . In
A-129 /3
Atten. Off set
fig. 6: sequencer-controlled wavetable playback
A-130
CV D
Wave- CV In
+5 V
A-1 12
0
VCF
0
Clock
VCA
21
A-112
Sampler
System A - 100
doepfer
6. A-112 Sample Dump Loader
The A-112 MIDI interface enables the transfer of sample and wave data from and to the device using MIDI
SysEx strings. For that purpose a standard MIDI sequencer may be used.
In addition we include a 3 1/2“ floppy disk containing a
A-112 sample dump loader
Version 1.2
directional transfer between A-112 and the PC. Samples and waves can be organized and stored on the
storage device (e.g. hard disk) of a PC. In the PC each
sample or wave can be assigned any name (DOS
convention, i.e. max. 8 characters) and stored as a
WAV file (8 bit mono). The A-112 format is automatically converted into the WAV format.
Conversely, any WAV file can be transferred to the
A-112.
bit mono or stereo formats. Stereo WAV files are
converted to mono before transfer to the A-112.
of this software (see fig. 7) enables bi-
The program reads any WAV file in 8, 12 or 16
software for PC.
The WAV file format opens up a wide pool of sounds
for use with the A-112. You may try out Windows system sounds or modifying sounds with a sample editor
program and then re-loading back into to the A-112.
For the next version of the sample dump loader program we are planning to include the ability to generate
sample dump MIDI files.
H
The latest version of the sample dump
loader can be found on our internet home-
page (http://www.doepfer.com) for free
download.
22
doepfer
System A - 100
Sampler
A-112
: A-112 sample dump loader
fig. 7
23
A-112
Sampler
7. Patch-Sheet
System A - 100
doepfer
The following diagrams of the module can help you
recall your own Patches. They’re designed so that a
complete 19” rack of modules will fit onto an A4 sheet
of paper.
Photocopy this page, and cut out the pictures of this
and your other modules. You can then stick them onto
another piece of paper, and create a diagram of your
own system.
Make multiple copies of your composite diagram, to
use for remembering good patches and set-ups.
P
• Draw in patchleads with coloured pens
• Draw or write control settings in the little
white circles
A-112
VC Sampler / Wavetable Osc.
S1
Eff
S2
Play
Dmp
Rec
Rev
Pit
Del
Loop W av
FrzLen
Norm
Gate In
Audio In /
Wave-CV In
CV In
SAMPLER
MIDI Out
MIDI In
Man.
Audio Out
Trig.
Run
10
0
10
0
Atten.
Tune
A-112
S1
Play
Del
Norm
Gate In
CV In
SAMPLER
MIDI Out
S2
Rec
MIDI In
Rev
FrzLen
Man.
Trig.
Run
0
0
Audio Out
Atten.
10
Tune
10
VC Sampler / Wavetable Osc.
Eff
Dmp
Pit
Loop W av
Audio In /
Wave-CV In
24
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