Frequency Central Process 26 Manual

Frequency central
Build documentation for:
Process 26
Based on the ARP 2600 voltage processor
Process 26 features two separate voltage processors.
The upper voltage processor features four inputs which are mixed
and inverted at the output. Inputs 2 and 4 have their own attenuator.
Input 2 is normalised to a positive fixed voltage source, which may be
attenuated, and appears inverted at the output, useful for applying
negative offsets.
The lower voltage processor features two inputs which are mixed and
inverted at the output. Input 2 has it’s own attenuator. Input 2 is
normalised to a negative fixed voltage, which may be attenuated, and
appears inverted at the output, useful for applying positive offsets.
Bill of Materials
330R x 2
5K6 x 2
15K x 2
100K x 8
All resistors ¼ watt
metal film.
22pF x 2
47uF electrolytic x 2
TL072 x 1
8 pin IC socket x 1
B100K x 3
(or these)*
3.5mm socket x 8
Power header
(cut to size)
*I prefer the Song Huei tall trimmers because they have a longer shaft and a white notch.

PCB assembly –top side –part 1
1. Solder all resistors
2. Solder IC socket
3. Solder both 22pF capacitors
PCB assembly –bottom side
1. Solder power header
2. Solder both 47uF capacitors
PCB assembly –top side –part 2
1. Place all sockets on the PCB, making sure the ground tabs line up with the PCB’s
ground pads, then place the panel over them. This will assure that the sockets are
correctly positioned. Flip the whole lot over and solder the sockets into place.
2. Use cut off resistor legs to connect the sockets’ ground tabs line up with the PCB’s
ground pads.
Note: Not all pots and sockets are equal in height. Providing
you use the ones in the links provided, everything will line up
perfectly.
There’s no calibration to do!
Go ahead and mix, invert, offset, whatevs…
RDH 03/01/19
http://www.frequencycentral.co.uk/