DEQ2496 Modifications - ADC / DAC / with DRC

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.

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 LME49990 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.


A short FAQ regarding these mods is available.

Pricing can be found in the the Online Shop

Proof of Performance- BehringerMods offer extensive proof of the value of our work. Please visit the proof page to see details.

 

 

 

 

 


Standard DEQ2496

 

 

 

 

 

 

 

 

 

The Result

• Volume Controlled Output
• Lower Distortion inputs and outputs

• Floating connection reduces noise