Behringer DCX Series User manual

BehringerMods.com
Instructions for modification of Behringer DCX analog inputs and
outputs
The following instructions will cover the details of fully modifying a unit with analog output and
analog input upgrades. Steps that are specific to these options will be labelled and can be
skipped if you did not purchase them.
These modifications require a high level of assembly and skill. It is not recommended for a
beginner at electronics. If you doubt your ability to complete the mods correctly, please contact
BehringerMods to arrange an installation service. BehringerMods take no responsibility for
damage caused to your equipment by modification.

The modification package should come with the following parts:
Analog Out Mods
Populated PCB(s)
Ribbon signal cable
Ground wire
PCB Stands
Analog Input Mods
Populated PCB(s)
Ribbon signal cable
Ground wire
PCB Stands
Below is a diagram showing how the components should be connected for a fully modified unit. Colours are for visual clarity,
they do not match the actual wire colours.
Blue = Signal ribbon wires (Black, White, Grey, Violet) from the back of the Main PCB >> to the Output Upgrade PCB.
Red = Signal ribbon wires (Yellow, Orange, Red, Brown) from Output Upgrade PCB >> to Output XLRs.
Green = Signal ribbon wires (Black, White, Grey, Violet) from Rear PCB removed capacitors >> to Input Upgrade PCB.
Orange = Signal ribbon wires (Yellow, Orange, Red, Brown) from Input Upgrade PCB >> to the back of the Main PCB.
Yellow = Power ribbon wires (Blue, Green) from Rear PCB >> to 1st Output Upgrade PCB. Additional Upgrade PCBs can be linked
to each other by the ‘V+, V-‘ pads.
Purple = Ground wire from pin1 on the 1st Output XLR >> to 1st Output Upgrade PCB ‘GND1’ pad. Additional Upgrade PCBs can
be linked to each other by the ‘GND1, GND2’ pads.
Ribbon Code:
1) Black = In L +
2) White = In L -
3) Grey = In R +
4) Violet = In R -
5) Blue = V-
6) Green = V+
7) Yellow = Out L +
8) Orange = Out L -
9) Red = Out R +
10) Brown = Out R -

Remove the equipment cover and keep the screws in a dish.
The PCBs will be placed as shown. Input Upgrade PCB left, Output Upgrade PCBs right. The output PCBs come as a
stack of 3 to upgrade 6 channels. The output stack needs 3x 3.5mm holes drilled in the case.

(OUTPUT MODS)
Take one Output Upgrade PCB, hold it carefully in position and mark the 3 holes on the case.
Use sharp pliers to gently remove the glue securing the ribbon connectors on the Main PCB. If your DCX is older you can
also remove the power connector.
The PSU contains deadly voltages! Over 400V DC. Ensure the equipment is disconnected from power.

Disconnect the ribbon cables.
Remove all screws from the Rear PCB.
Remove Rear PCB and keep safe.

If your DCX does not have a detachable PSU connector:
Turn the DCX over and remove 4 screws holding the power supply.
Detach the mains power connector from the power supply.

Remove 4 screws holding Main PCB.
Keep Main PCB and Power Supply in a safe place.
(OUTPUT MODS)
If you have a center punch, use it to mark the PCB hole positions.

(OUTPUT MODS)
Place a piece of wood under the equipment and 3x 3.5mm holes carefully in the correct position.
(OUTPUT MODS)
Use a large drill by hand to remove rough edges on the holes.
(OUTPUT MODS)
Place M3 screw through bottom of case.

(OUTPUT MODS)
Attach the three 5mm PCB Stand in the case.
(OUTPUT MODS)
Ensure the Output Upgrade PCB fits on top.

Replace Main PCB temporarily.
Trim the length of all ribbon cables.
Output Upgrade Ribbons:
Black, White, Grey, Violet - must reach Main PCB Ribbon Socket.
Yellow, Orange, Red, Brown - must reach Output XLRs 1&2, 3&4, 5&6 per PCB ribbon.
Green, Blue - must reach Rear PCB area near output XLR 1. (Connected close to here, but not actually on XLR)
Input Upgrade Ribbon:
Black, White, Grey, Violet - must reach Rear PCB Near Input XLRs.
Yellow, Orange, Red, Brown - must reach Main PCB Ribbon Socket.
Green, Blue - must reach Output Upgrade Top PCB.
Remember: You can cut shorter, but not longer!

(OUTPUT MODS)
On the Rear PCB.
Cut pins 2 & 3 on each output XLR that you will upgrade. Make a clear gap to disconnect it from the Rear PCB.
(INPUT MODS)
Locate electrolytic capacitors C26, C27, C41, C42 and remove them carefully. Do not damage the PCB, it is delicate.
Tip: Apply new solder to the capacitor legs. Heat one leg until solder is fully liquid, then lean the capacitor to one side
pulling the leg partially from the PCB. Heat the other leg and lean capacitor the other way. Repeat process until the
capacitor is free from the PCB.

(INPUT MODS)
Clear the positive pads (round holes, not square) with a solder sucker or solder wick.
We will connect wires here.

To disable un-used op-amps the two power legs (Vcc+, Vcc-) must be cut.
Use a new sharp blade.
Cut towards the chip body, not the PCB.
Ensure a clear gap at the cut.
Be carful, the PCB must not be damaged.
Cut towards the chip body.

(OUTPUT MODS)
Op-amps to disable for output upgrades on Rear PCB top and bottom.
Output 1 & 2 = IC1, IC12, IC2, IC13.
Output 3&4 = IC3, IC14, IC4, IC15.
Output 5&6 = IC5, IC16, IC6, IC17.
(INPUT MODS)
Op-amps to disable for Input Upgrade, on back of Rear PCB. IC7, IC8, IC10.
Tip: Do not disable IC9, IC10 these control Input C.

(INPUT MODS)
Strip, twist and tin shown ribbon wires for the Input Upgrade PCB.
Solder them in the positive (round) pads of the removed capacitors:
White = C41, Black = C26, Violet = C42, Grey = C27
(INPUT MODS)
Solder Input Upgrade PCB ribbon wires to the back of the Main PCB Ribbon Socket.
Main PCB placed as shown, connector on the bottom.
Yellow = Bottom row, Pin 3. Red = Bottom row, Pin 4. Orange = Top row, Pin 3. Brown = Top row, Pin 4.
Tip 1: Tin the wire. Keep exposed wire very short (1mm). Place fresh solder on the pin to be soldered. Use tweezers
to hold wire. Heat pin and place wire against it. Let solder cool while holding wire.
Tip 2: Solder bottom row first. Ensure the wire does not touch any other connection!

(OUTPUT MODS)
Solder Output Upgrade PCB ribbon wires to the back of the Main PCB Ribbon Socket.
Main PCB placed as shown, connector on the bottom.
Channels 5&6: White = Bottom row, Pin7. Violet = Bottom row, Pin 8. Black = Top row, Pin 7. Grey = Top row, Pin 8.
Channels 3&4: White = Bottom row, Pin9. Violet = Bottom row, Pin 10. Black = Top row, Pin 9. Grey = Top row, Pin 10.
Channels 1&2: White = Bottom row, Pin11. Violet = Bottom row, Pin 12. Black = Top row, Pin 11. Grey = Top row, Pin 12.
Tip 1: Tin the wire. Keep exposed wire very short (1mm). Place fresh solder on the pin to be soldered. Use tweezers to hold
wire. Heat pin and place wire against it. Let solder cool while holding wire.
Tip 2: Solder bottom row first. Ensure the wire does not touch any other connection!
Check your work!

(INPUT MODS)
On the newer DCX version, look at the top of Main PCB.
Remove small capacitors C87, C88.
Tip: Heat both sides of the capacitor at the same time to easily remove with soldering iron. Do not leave solder bridging
the capacitor connection pads.
(INPUT MODS)
On the older DCX version, look at the back of Main PCB.
Remove small capacitors C31, C32.
Tip: Heat both sides of the capacitor at the same time to easily remove with soldering iron. Do not leave solder bridging
the capacitor connection pads.

Install everything back in the case.
(OUTPUT MODS)
Connect the Output Upgrade PCB ribs to the XLRs.
Yellow = XLR 1, Pin 2. Orange = XLR1, Pin 3.
Red = XLR 2, Pin 2. Brown = XLR 2, Pin 3.
Repeat for Outputs 3, 4, 5, 6.

(OUTPUT MODS)
This shows the DAC and Main Ribbon connection positions for each Output XLR. It may help you ensure connection
of the correct ribbons.
(OUTPUT MODS)
All output XLRs connected. Tidy up wires with zip-ties.

(OUTPUT MODS)
Connect Output Upgrade PCB 1 Green and Blue wires >> to Rear PCB.
(INPUT MODS)
If you *only* have an Input Upgrade (no output upgrades) connect the Green and Blue wires >> to Rear PCB.
If you have Input and Output upgrades together, connect the Output Upgrade PCB 1 as described above.
Green = Bottom of C3
Blue = Bottom of C4
Tip: Apply some fresh solder to the bottom of the capacitor pad. Heat the solder and place the tinned wire against it.
Hold until cool. Ensure the capacitor is not shorted and the wire is not touching other parts.