The Standard DEQ2496
The Good:
The
DEQ is sold by Behringer as a processor for mastering studios. It
features graphic and parametric EQs implemented in the digital domain.
To enable analog connections, it contains both an ADC and a DAC.
Through a microphone (ECM8000) the DEQ can measure the response of a
speaker / room combination and correct it to the desired target
response. In the 20Hz - 300Hz range this is ideal for improving uneven
resonant bass.
Input connections: 1 pair XLR analog, 1 AES/EBU digital and 1 Toslink
Optical. Outputs connections: 1 pair Main XLR analog, 1 pair Aux TRS
analog, 1 AES/EBU digital and 1 Toslink Optical.
A Problem:
The features of DEQ 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 DEQ 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 DEQ 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 DEQ 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 DEQ 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 DEQ 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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