LFO4 solderpads and hacks
The LFO4 quad LFO 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 8 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 TL074 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 – Triangle LFO1
- SJ3 – Square LFO1
- SJ1 – Triangle LFO2
- SJ8 – Square LFO2
- SJ13 – Triangle LFO3
- SJ14 – Square LFO3
- SJ5 – Triangle LFO4
- SJ7 – Square LFO4
On the bottom side of the PCB there are 8 solder-switches that adds capacitors to the rate timing.
With these you can change the frequency range for each LFO individually.
By soldering or unsoldering a short for any of these solder pads, you add or remove a capacitor to the LFO.
The smallest capacitor is always connected and does not have any solder jumper.
You can add a medium capacitor and a big capacitor.
You can also combine them. The more capacitors, the slower the LFO will be.
If you remove both solder jumpers, you will remove all extra capacitors and the LFO will be configured for its fastest mode (max approx. 850Hz).
By soldering both jumpers, you will add all extra capacitors and the LFO will be configured for its slowest mode (max approx. 1Hz).
If you solder only the jumper for the medium capacitor, you will get a maximum frequency of about 80Hz.
- SJ4 – Medium capacitor LFO1
- SJ6 – Big capacitor LFO1
- SJ10 – Medium capacitor LFO2
- SJ9 – Big capacitor LFO2
- SJ15 – Medium capacitor LFO3
- SJ16 – Big capacitor LFO3
- SJ11 – Medium capacitor LFO4
- SJ12 – Big capacitor LFO4
The first few modules with serial number up to 104 and also 106, had 100k linear potentiometers for the symmetry, which gave a reduced symmetry. The new modules have a 1M linear pot for symmetry which gives a lot better symmetry range. The pot change also requires the following component changes: R6,R23,R41,R22 changed from 1k to 4k7. C11,C14,C17,C20 changed from 10nF to 1nF. C12,C16,C18,C21 changed from 100nF to 10nF. C13,C15,C19,C22 changed from 10uF to 1uF. This modification is difficult to make and is not recommended. Warranty will be voided.