Dual Active Multiple solderpads and hacks?



The dual active multiple has some solderpads that you can use to change some functions on it.

TIP-signals

On the top left side you can solder a 2×8 angled pinstrip.
The outline for this connector is marked with the text TIP.
This gives you access to all the signals that are present at the tip of the 8 jacks.
The signal-pins are the pins nearest the printed numbers.
The GND pins are nearest the edge, at the back, of the PCB.

NORMALIZE/BREAK-signals

In the middle, near the electrolytic capacitors, you can solder a 2×8 angled pinstrip.
The outline for this connector is marked with the text NORM.
This gives you access to all the normalize/break-signals that are present at the jacks when no plug is inserted at the jack.
The signal-pins are the pins nearest the printed numbers and nearest the capacitors.
The GND pins are nearest the edge, at the back, of the PCB.

Disable the 100K input resistor

Note! This hack can only be done if the module have light blue resistors for R8 and R9 and black resistors for R1 and R3. If they are not blue, and R1/R3 is missing, then this modification is already done for you from the manufacturing and there is nothing here to configure.

If R1/R3 is in place then you have the possibility to make this hack.
On the top side of the PCB there are a number of solder-switches, each to the right of a resistor.
The first/top/left one is for the input for jack 1.
The solderswitch to the right of the R3 resistor is for the lower input on jack 5.
If you solder any of these solder-switches you will eliminate the 100K input resistor.

Disable the 1K output resistor

On the top side of the PCB there are 8 solder-switches near the jacks, each to the right of a resistor.
The first/top/left one is for the input jack 1.
The other 7 are for the output jacks 2 to 8.
(Yes, jack 5 is also an input jack but has its resistor and solder switch where R3 is).
If you solder any of these solder-switches you will eliminate the 1K output resistor.
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.

Convert it to a 1 input and 7 outputs active multiple

This is a BONUS-hack!
It is possible to convert this multiple to a 1 input and 7 outputs multiple.
If you look at the underside of the PCB you will see 2 solder-selectors each with 3 solder-pads.
Both should all be soldered the same direction and only 2 of the 3 solder-pads should be connected at the same time.
When they are soldered in the direction to the backside (3), the mixer will be a dual 3 output multiple (the default).
If you change the direction of these solder-switches in the direction to the jacks instead (7), the mixer will become a 7 output multiple instead.
Use a multimeter with continuity test to check that you only have connected 2 and not made any short-circuits to all 3 solder-pads for each solder-switch.
The PCB is marked with the numbers 3 and 7 at the side of the solder-switches for guidance.
The frontpanel has printed text on both sides, and the backside has the labels for the 7 output multiple.
Loosen and remove the 8 nuts and swap side for the new layout. Tighten the 8 nuts gently again.
There may be a printed serial number on one of the sides of the frontpanel. You can use a black pen to hide it or gently remove it with a razor-blade if you wish.