Behringer Eurorack MX2642A

The Behringer Eurorack MX2642A 26-input 4-bus mixing console is one of YSTV's spare sound desks. Typically used for medium-sized OBs that aren't worth the hassle of taking the ZED 428 (for example shows requiring multiple mics but no mixing of music).

Key Specifications

• 8 mono inputs
• 9 stereo inputs (4 on channels 9-16; 4 on inputs A-C with limited control; 1 on two track input ("2TK IN"))
• 2 pairs of mix groups (odd numbers go to Left, even numbers go to Right)
• 2 master outputs (L + R)
• 6 auxiliary outputs (2 switchable pre/post-fade, 4 post-fade. N.B. channels 1-16 can only send to 1, 2 and either 3+4 or 5+6)
• 3-band equalisation (EQ) with sweepable mid on channels 1-8; 4-band fixed EQ on channels 9-16
• Inserts on channels 1-8 and LR
• Direct outs on channels 1-8
• Globally switched phantom power
• "Control Room" stereo output - linked to PFL (pre-fade listen)
• PFL switchable to solo (post-fade listen)

What's in the Box

Repair work in October 2013 provided a great excuse to have a nosey inside the Eurorack's case. A set of schematics was also acquired. There are a few notes below that will hopefully be helpful for any future repair work.

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  The Eurorack in all its naked glory.

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  Schematics file. Seems to be accurate.

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  What you should see after removing the two bottom plates.

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  Apart from the two screws on the meters cover, there should be no need to remove any screws from the front panel,

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  because they're just attached to these PCB pillars. It's easier to remove the screws from the back of the main PCB.

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  The ribbon cables can be disconnected at the main PCB end (the glue has been removed).

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  Power management section. It is believed that the gunk around the electrolytic capacitors is some form of adhesive rather than a leak.

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  "Arty" picture of the smoothing caps. Who wouldn't fantasize about over-voltaging those beauties...

Faults/Repairs

Known Faults

The Eurorack is currently believed to be fault-free. Please contact the Technical Team if this isn't the case.

October 2013 Repairs

As mentioned above, repair work was undertaken at the start of the 2013-2014 academic year to fix the following previously reported faults:

"Channel 1 does not send to main/group mix"

Further testing revealed that whilst the channel sent to auxes 1 and 2, auxes 3-6 and the group and main mix buses (everything post-fader) received no signal. The original ALPS RS6011 10K P series linear potentiometer was difficult to obtain in Europe, but fortunately Farnell stocked a suitable replacement: RS6011Y10K. The pot fit in the space on the PCB (although it didn't have reinforcing lugs), but a little careful work with the hacksaw was required to shorten the fader control to the same length as the others.

"Channel 7 XLR port is dead"; "Channel 8 is far too quiet (probably a dead preamp)"

Initial testing suggested that channel 8 was working, but that channel 7 had a faulty mic preamp; channel 7's mic input was very quiet but the line input seemed OK. However, in the stage-by-stage analysis of of the channel that took place when the case had been removed no problems could be found. Both channels would go on to work perfectly with mics in the recording of Have I Got News For York that took place at the end of the month. Failing an act of cunning sabotage by URY, the only credible explanation that anyone could think of at the time was a dodgy solder joint that was knocked back into place whilst removing the PCB from the case. If either of these channels doesn't seem to be working as expected, please don't hesitate to contact the techies as above.

Retirement

As of 2019 the functional status of the MX2642A is, at best, questionable. It has been completely replaced and is not used any more.

External links

• Behringer EURORACK MX2642A 26-Channel 4-Bus Mixing Console discontinued product page
• EURORACK MX2642A user manual