This card was designed in collaboration with Onur Ozer, a great Synthi enthusiast who loves the KS and was looking for a neat solution to control his other synths with, either standalone or together with his Synthi.
The card plugs onto the KS' male Jones socket with a female socket installed on the back.

It's immediately available pre-built with red or blue LEDs and bargraph.
The price is 390€ + VAT if due and shipping.
Contact me to order.

Users manual



Besides a PSU to power the KS, it not only features standard CV/gate/trigger outputs and CV processing functions such as portamento and transpose but also an output for the KS' sequencer internal clock.

Clocking the KS' sequencer from an external clock never worked properly and heavy modifications are required to implement this feature into a KS : extra circuitry needs to be added, which is a real challenge in the slim case, and holes need to be drilled in the case for switches and socket, with the risk of ending up with long slits instead of neat small holes because the plastic became fragile and brittle with aging.
Robin Wood considers this modification a "lost cause" and I came to the same conclusion after my various attempts.
However, many users badly want to be able to sync their KS' sequencer with external devices. The alternative solution is to use the KS' 256 step sequencer clock as a master instead of slaving it : the card features a clock output coupled with a /1 to /512 divider that can be used to sync other devices and to fire events precisely at regular intervals.
A reversible and straightforward rewiring of the KS' Jones socket (can be done by any person with basic soldering skills) is explained in the manual to route the sequencer clock to the socket's contact 6, which is either unused on late KS or used for the dynamic CV on early ones (this feature can be found on early KS only, the crystal mic used is fragile and often dead nowadays, anyway it never worked very well and proved not very useful, hence EMS quickly dropped it, not a big loss if replaced by the clock output).

The processed sequencer CV can be routed with the card to the Synthi A's or VCS3's input channel 2, which makes it a handy plug and play solution to connect a KS to a MK1 Synthi A or VCS3/Putney, which are not compatible with the KS because in MK1 units the PSU is not able to power it and the routing to matrix row 16 for the sequencer CV output is not present.

With 24 DIP switches directly accessible, the card can be configured easily to meet each user's own needs and preferences.

PSU
The card has a built-in PSU to power it and the KS, it needs DC voltage between 9 and 36V, 1.5A or more.
When the card is used, no power is taken from the Synthi A or VCS3.

gate
Gate minijack output.
The length depends on how long the key is touched.
The LED monitors the gate.
The switch mutes the gate.
The signal amplitude can be set to +5V or +10V (details in the DIP switches section below).

trigger
Short trigger minijack output.
The length doesn't depend on how long the key is touched.
The LED monitors the trigger.
The switch mutes the trigger.
The signal amplitude can be set to +5V or +8V (details in the DIP switches section below).
The signal length can be set to 4ms or 8ms (details in the DIP switches section below).

realtime
Realtime 1V/oct CV minijack output.
Fine tuning is adjusted with the KS' "realtime pitch spread" thumbwheel.
The "porta" pot ads portamento.
The "trans" switch transposes the CV either up or down, each transpose interval is adjusted with own multiturn trimmer easily accessible through the panel hole.

sequence
Sequencer 1V/oct CV minijack output.
Fine tuning is adjusted with the KS' "sequence pitch spread" thumbwheel.
The "trim" pot scales the CV routed to the minijack to compensate for the tracking difference when the thumbwheel is set to control a Synthi A or VCS3.
The "porta" pot ads portamento.
The "trans" switch transposes the CV either up or down, each transpose interval is adjusted with own multiturn trimmer easily accessible through the panel hole.
The "realtime" enables transpose from the KS keyboard.

"clock - dyn" minijack
Either the KS' sequencer clock or dynamic CV output (details in the DIP switches section below).
The signal amplitude can be set to +5V, +10V or +12V (details in the DIP switches section below).

memory
Bargraph monitoring the KS sequencer memory, like the vu-meter on a Synthi A or VCS3.

male Jones socket
Connect your Synthi A or VCS3 here (details in the DIP switches section below).

on switch
Turns the card and KS on or off.

DIP switches
There are 3, each with 8 toggles.
The function is enabled when the toggle is set to its bottom "on" position.

1. G5 : +5V gate
2. T5 : +5V trigger
3. TLG : 8ms trigger
4. BAR : moving bar instead of a moving dot on the bargraph
5. DYN : routes the dynamic CV (if the KS modification is not done) to the minijack
6. CK : routes the sequencer clock (if the KS modification is done) to the minijack
7. C5 : +5V sequencer clock
8. C10 : +10V sequencer clock

1. 512 : divides the sequencer clock by 512
2. 256 : divides the sequencer clock by 256
3. 128 : divides the sequencer clock by 128
4. 64 : divides the sequencer clock by 64
5. 32 : divides the sequencer clock by 32  
6. 16 : divides the sequencer clock by 16
7. 8 : divides the sequencer clock by 8   
8. 4 : divides the sequencer clock by 4

1. 2 : divides the sequencer clock by 2
2. 1 : undivided sequencer clock
3. RTP : routes the processed (transpose and portamento) realtime CV to the Synthi A's or VCS3's input channel 1
4. RTN : routes the normal unprocessed realtime CV to the Synthi' A's or VCS3's input channel 1
5. SQP : routes the processed (transpose and portamento) sequencer CV to the Synthi A's or VCS3's input channel 2
6. DYN : routes de dynamic CV (if the KS modification is not done) to the Synthi A's or VCS3's input channel 2
7. GAT : connects the Synthi A's or VCS3's envelope to the card's gate minijack output
   
8. VU : monitors the sequencer memory on the Synthi A's or VCS3's vu-meter