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 the DCX mentioned above are superb, however there is an
achilles heel; the analog inputs and outputs have relatively high
distortion and noise compared to the best alternatives.
The solution - Modification
In
fact, the DAC and ADC chips inside the DCX are high-end items from AKM.
The distortion is created by the analog buffer circuits, not the
converters themselves. The solution is to replace the analog sections
in their entirety with new circuit designs from BehringerMods. These
upgrade circuits are available as a self-install kit or with
installation provided by BehringerMods.
They allow the converters in the DCX to reach their
full potential with significantly lower distortion and
noise of all kinds.
Output Circuit -
The improved output circuit features LM4562 non-inverting buffers to
provide a low noise, high impedance input. These are capable of feeding
the very low impedances required to make the low noise differential
floating output stage based on 4x TLE2027 ICs. This output stage
emulates a transformer such that it can provide the noise rejection
capabilities of a balanced connection even over a single-ended line.
Additionally the output voltage stays constant regardless of the method
of connection.
The
Behringer DCX when modified with this new circuit is capable of less
than 0.0005% THD and 117dB S/N ratio at it's analog outputs. The
circuit alone can actually achieve even better figures and can be used
to upgrade any DAC that has a differential voltage output, such as
those based on the AKM AK4393, AK4396, Cirrus CS4392, CS4398, Wolfson
WM8740, WM8741, WM8742.
Input Circuit -
The improved analog input circuit is uses the Texas Instruments
LME49724 IC, specifically designed for driving differential ADCs. The
circuit can accept balanced or single-ended inputs. ADCs typically
require a bias voltage, and this is provided by a dedicated LM285
voltage reference IC with additional filtering for the lowest noise
level.
The
Behringer DCX when modified with this new circuit can achieve
<0.0005% THD and 117dB S/N from the analog inputs. In conjunction
with the digital outputs, the modified DCX can serve as a reference
class ADC for archiving vinyl and tape. Using the analog inputs and
analog outputs, room correction can be applied to any source. The
input circuit alone is capable of 123dB S/N ratio (4V rms input) and
0.00005% THD and can be used to upgrade any voltage input ADCs such as
. AKM AK5393, AK5394, Cirrus CS5391 and others.
Short FAQ here.
Pricing can be found in the the Online Shop
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