A-100 DIY page

Timing capacitors of A-100 modules 

 
as of April 17, 2012
 

This document is intended for experienced A-100 users who want to modify the timing range of some modules (e.g. envelope generators, LFOs, slew limiters). The pictures show the position(s) of the capacitor(s) which is(are) responsible for the timing of the module in question. To lengten the time or period the capacitor value has to be increased and vice versa. The capacitor value is proportional to the time or period (e.g. doubling the capacitor value even doubles the time or period, when the capacitor value is increased tenfold even the time or period increases tenfold). If an electrolytic capacitor is used one has to pay attention to the polarity (minus and/or plus sign).

All modules that can be modified in that way will be added little by little to this page. Please send a message to hardware@doepfer.de if you need the capacitor position of a module that is still missing.


A-118 Noise/Random Voltage

 
Timing (smoothing) capacitors for random voltage: C8+C8', C9+C9'
Standard value: 4.7uF (electrolytic)
Polarity C8: minus = top
Polarity C8': minus = bottom
Polarity C9: minus = top
Polarity C9': minus = bottom

Remark:

For C8 and C8' same values have to be used
For C9 and C9' same values have to be used

 

 


A-119 External Input / Envelope Follower

 
Timing (smoothing) capacitors for envelope follower: C6
Standard value: 100 nF = 0,1uF
(foil/mylar)
Polarity: none

Remark: If a electrolytic capacitor is used a bipolar version is required. Alternatively two standard electrolytic capacitor with the same value connected together in opposite direction can be used (the resulting capacity is half the value of each capacitor). For example refer to C8/C8' and C9/C9' of A-118.


A-140 ADSR

 
Timing capacitors (long range): C4
Standard value: 100uF (electrolytic)
Polarity: minus = left

Timing capacitor (mid range): C3
Standard value: 2.2uF (electrolytic)
Polarity: minus = right

Timing capacitor (short range): C2
Standard value: 100nF = 0.1uF (foil/mylar)
Polarity: none

 

 


A-141 VCADSR

 
Timing capacitor: C2
Standard value: 100nF = 0.1uF (foil/mylar)
Polarity: none
if electrolytic capacitors are used the minus pole has to be connected to GND (i.e. to the pin that is connected to the GND plane of the pc board)

A-142 VC Decay/Gate

 
Timing capacitor: C3
Standard value: 100nF = 0.1uF (foil/mylar)
Polarity: none
if electrolytic capacitors are used the minus pole has to be connected to GND (i.e. to the pin that is connected to the GND plane of the pc board)

A-142-4 Quad Gate

 
Timing capacitors: C2, C4, C6, C8
Standard value: 470nF = 0.47uF
Polarity: none
if electrolytic capacitors are used the minus pole has to be connected to GND (i.e. to the pin that is connected to the GND plane of the pc board)

A-143-1 Quad AD

 
Timing capacitor: C1
Standard value: 2.2uF (electrolytic), corresponds to about 5 ms shortest Attack/Decay time
Polarity: plus = left

A-143-2 Quad ADSR

 
Timing capacitor (long range): C1
Standard value: 100uF (electrolytic)
Polarity: plus = left

Timing capacitor (mid range): C9
Standard value: 2.2uF (electrolytic)
Polarity: plus = left

Timing capacitor (short range): C10
Standard value: 100nF (foil/mylar)
Polarity: none


A-143-3 Quad LFO

 
Timing capacitors (long range): C3+C4
Standard value: 2.2uF (electrolytic)
Polarity (upper): minus = left
Polarity (lower): plus = left

Remark: If C3 and C4 are replaced same values have to be used (e.g. 2 x 1uF)

Timing capacitor (mid range): C2
Standard value: 100nF (foil/mylar)
Polarity: none

Timing capacitor (short range): C1
Standard value: 470pF (foil/mylar)
Polarity: none


A-145 Standard LFO (LFO I)

 
Timing capacitors (long range): C3+C4
Standard value: 2.2uF (electrolytic)
Polarity C3: minus = top
Polarity C4: minus = bottom

Remark: If C3 and C4 are replaced same values have to be used (e.g. 2 x 10uF)

Timing capacitor (mid range): C2
Standard value: 100nF = 0.1uF (foil/mylar)
Polarity: none

Timing capacitor (short range): C1
Standard value: 470pF (foil/mylar)
Polarity: none

 


A-146 Variable Waveform LFO (LFO II)

 
Timing capacitors (long range): C3+C4
Standard value: 2.2uF (electrolytic)
Polarity C3: minus = right
Polarity C4: minus = left

Remark: If C3 and C4 are replaced same values have to be used (e.g. 2 x 10uF)

Timing capacitor (mid range): C2
Standard value: 47nF (foil/mylar)
Polarity: none

Timing capacitor (short range): C1
Standard value: 470pF (foil/mylar)
Polarity: none

 


A-147 VCLFO

 

Timing capacitor: C2
Standard value: 100nF = 0.1uF (foil/mylar)
Polarity: none


A-162 Dual Trigger Delay

 

Timing capacitors:
C2 (delay time)
C5 (length)
Standard value: 10uF
Polarity:
minus = left