Accuphase DF-75 Digital Active Crossover

Accuphase DF-75 Digital Active Crossover with 3,101 Selectable Cutoff Frequencies

The DF-75 Digital Frequency Dividing Network can support 4-way system setups. The high-speed 64-bit floating point DSP allows for optimal filtering. Cutoff frequency points have been expanded dramatically from 59 to 3,101, accommodating a variety of performance demands. The network also achieves a steep 96 dB/octave attenuation slope. Beyond that, the time delay function allows for time alignment in 0.5-cm steps while a delay compensator automatically corrects signal delays in the filter circuits. Each divider unit can also be configured in a monophonic setting.

High-Speed, High-Precision DSP Implements Fully Digital Signal Processing

This digital channel dividing network is designed to serve as the core component in a multi-amped system. The digital filter uses a 64-bit floating-point DSP capable of high-speed calculations thanks to a 52-bit mantissa and 12-bit exponent section. With its highly precise calculations, the floating-point DSP dramatically improves the dynamic range, allowing very steep cutoff slope settings of 48 dB or 96 dB per octave. Phase switching, delay, and level control are all performed in the digital domain ensuring high dimensionality of the source characteristics. The result is ultra-precise filtering performance free from adverse effects caused by temperature changes or aging.

3,101 Selectable Filter Cutoff Frequency Points

The conventional 59 cutoff frequency points have been greatly expanded to 3,101 points, allowing for radically more choices when selecting cutoff frequencies.

Six Filter Slope Characteristics with up to 96 dB Attenuation per Octave

The DF-75 has six filter slope characteristics (6 dB, 12 dB, 18 dB, 24 dB, 48 dB, and 96 dB per octave). The 96 dB/octave setting in particular minimizes sound interruption in adjacent bands, allowing for the creation of a multi-amped system that analogue channel dividers cannot achieve.

MDS+ (Multiple Delta Sigma) Converter with Four Parallel Circuits

The MDS+ conversion principle drives Delta Sigma type D/A converters in parallel to achieve a D/A converter with drastically improved performance. In the DF-75, four Hyperstream™ DAC chips (ES9028PRO made by ESS Technology) are driven in parallel to improve the theoretical performance specifications like distortion, noise characteristics, and linearity by a factor of 2 (= √4). Additionally, the I-V converter circuits rely on Accuphase’s original low-noise, low-distortion ANCC* circuits. Performance improvements from the MDS+ conversion principle operate independently of signal frequency and level, allowing for reduction of ultra-low level noise that conventional Delta Sigma D/A converters struggle to remove. *ANCC is a unique Accuphase technology that improves performance by using a secondary amplifier to cancel out noise and distortion from the main amplifier.

32-bit A/D Converter Driving 4 Parallel Circuits

The A/D converter incorporates the AK5578EN circuit from Asahi Kasei Microdevices. Combining this A/D converter with ANCC to drive four parallel circuits allows for low noise and ultra-low distortion.

Our Review

The Accuphase DF-75 Digital Active Crossover feels like the sort of quietly brilliant component that lets a multi-amped system really stretch its legs, blending serious DSP muscle with an unexpectedly elegant user experience. Its ultra-fast 64-bit floating-point processor makes filter adjustments feel effortless, and the jump to 3,101 selectable cutoff frequencies means you can fine-tune a system with almost surgical precision. The ability to run up to a steep 96 dB/octave slope - and keep everything in perfect sync with precise time alignment and automatic delay compensation - adds a level of control that analogue crossovers simply can’t match. With its parallel-driven MDS+ DACs, equally refined A/D stage, and the option to configure each divider channel in mono for even better performance, the DF-75 comes across as both a technical powerhouse and a surprisingly intuitive tool for shaping a system exactly the way you imagine it.