The Standard DCX2496
The Good:
The
DCX is a highly flexible digital crossover for loudspeaker builders or
live sound systems. It can accept stereo analog or digital inputs and
split the signal for tweeter, mid and woofer (or other configurations),
sending the signals to 6 analog outputs. Parametric EQ and adjustable
time delays are also possible, allowing correction of the speakers and
room. The adjustable crossover slopes allow more flexibility than
typical analog crossovers.
Input connections: 1 pair XLR analog, 1 AES/EBU digital, 1 Microphone XLR. Outputs: 6 XLR analog XLR (3 stereo pair).
A Problem:
The features of DCX mentioned above are superb,
however there is an achilles heel; the analog inputs
and outputs have relatively high distortion compared
to the best alternatives.
The solution - Modification
In
fact, the DAC and ADC chips inside the DCX are high-end items from AKM and
Cirrus Logic. Much of the music you listen to will
have been recorded using these same converters, as
they have been used inside audio interfaces from
industry leader ProTools.
The distortion of the
DCX is created by the analog signal conditioning circuits, not the
converters themselves. Unfortunatly, simply replacing the op-amp chips in the
exisiting circuit does not correct the distortion issues. The solution is to replace the analog
circuits in their entirety with new circuit designs.
Upgrade circuits
availible from BehringerMods are offered as a self-install kit or with
installation provided by BehringerMods for those less confident at soldering.
These new upgrade
circuits allow the signal converters in the DCX to
reach their full potential with low
distortion and noise of all kinds.
Upgrade Circuit - The
BehringerMods upgrade PCB conviniently handles both
analog input and output conditioning on a single
board for Inputs A,B and Outputs 1-6. The DCX kit also includes a 'link PCB' which
reduces the soldering nesicary to install the upgrade.
The input section is implimented using a fully
differential op-amp from Texas Instruments (LME49724),
purpose made for driving audio ADC chips. The circuit
can be fed from either a single-ended or balanced
input. A dedicated voltage reference is used to
provide bias for the ADC, allowing for the lowest
possible noise level.
The output section is designed to emulate the
behaviour of a transformer coupled circuit, enabling
it to provide active noise cancellation whether
connnected single-ended or balanced. The design is
built around Texas Instruments 'SoundPlus' OPA1652
op-amps allowing the full performance of the DAC chip
to be heard. This single PCB upgrades
The circuit comes with through-hole mounted DC
blocking and power smoothing capacitors from arguably
the most respected brand Panasonic.
The Behringer DCX when
modified with this new circuit is capable of less than
0.0005% THD and IMD from analog input to output.
The input and output signal
level for 0dBFS digital is 3.5V RMS.
Input C is not upgraded.
Learn more about
the distortion types of the DEQ and DCX here:
Proof of Upgrade Performance
Short FAQ here.
Pricing can be found in the the Online Shop
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