AR4 solderpads and hacks



The AR4 quad AR envelope generator has some solderpads that you can use to change some functions on it.

Disable the 1K output resistor

On the bottom side of the PCB there are 4 solder-switches near the jacks.
By soldering a short for any of these solder pads, you can eliminate the 1K output resistor for that jack.
The OP’s used for this module is LM358 that has built in short-circuit protection on the outputs.
Therefore, it is possible to do this hack if you need, but it is still better to leave the 1K resistors working as default for extra protection.

  • SJ2 – AR1
  • SJ1 – AR2
  • SJ5 – AR3
  • SJ7 – AR4

Maximum output range

Each output has a voltage divider on the output to lower the maximum output level.
If you want maximum level outputs, you can solder the following solder-switches to bypass the voltage divider.

  • SJ3 – AR1
  • SJ4 – AR2
  • SJ6 – AR3
  • SJ8 – AR4

AR time (from v1.1)

Each AR can be faster or slower.
By default the two upper (1&2) are faster and the two lower (3&4) are slower.
If you want a slower AR, you can solder the following solder-switches for each AR. And, of course, desolder the solder-switch to make it faster again.

  • SJ9 – AR1
  • SJ10 – AR2
  • SJ11 – AR3
  • SJ12 – AR4

Normalization (from v1.1)

The gate inputs can be normalized to the gate input directly below.
If you don’t insert any plug in a gate jack, it will use the gate signal from the jack directly above, if it is normalized.
No normalizations are soldered by default.
Solder the solder-switches according to the following:

  • SJ13 – AR1 gate is normalized to the AR2 gate input
  • SJ14 – AR2 gate is normalized to the AR3 gate input
  • SJ15 – AR3 gate is normalized to the AR4 gate input

Release-pot

The first few modules up to serial number 110 had a 100k linear pot for the release. All newer modules now have a 1M linear pot for the release, which gives a much longer and nicer release. It is possible to replace this pot, but it can be difficult to unsolder the old pot without damaging the pcb traces. Warranty is voided if you make this modification.