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 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 DEQ 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 DEQ 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. The DEQ 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.

The circuit comes with through-hole mounted DC blocking and power smoothing capacitors from arguably the most respected brand Panasonic.

The Behringer DEQ 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. The signal elvel switch on the rear of the DEQ will be ineffecitive after upgrade.

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

 

 


 

DEQ Upgrade PCB

 

DEQ Link PCB

 

 

 

 

 

DEQ Install Guide
BehringerMods DEQ Install Guide