OCL DAC

Design Goal: Minimization of Distortion (Straight Wire with Gain)

The “Straight Wire with Gain”—the North Star of audio design—is the goal of delivering an input signal with zero modulation or processing, increasing only its magnitude with absolute precision.

Unlike general amplifiers that amplify power, a DAC is a device that converts delicate digital signals into analog and transmits them to the next stage. Therefore, “precision” and “signal purity” are the highest priorities. To achieve this, the RD-7500 eliminates all interference that obstructs the signal flow throughout the entire digital and analog process.

Precise analog transmission begins with perfect digital reconstruction. The RD-7500 is equipped with the ES9039PRO, the flagship chip from ESS Technology, widely regarded as the finest DAC chip in existence.

HyperStream IV Architecture: Utilizing 4th-generation technology, it undergoes a conversion process far more sophisticated than previous generations.
Ultra-High Resolution Data Processing: Based on a 32-bit, 8-channel architecture, it achieves overwhelming Dynamic Range (DNR) and extreme Total Harmonic Distortion (THD+N). It perfectly restores even the micro-details hidden within digital sources.

The Essential Difference: If feedback is a method of “fixing a mistake after it happens,” Allnic’s Non-Feedback is a method of “ensuring no mistake happens from the very beginning.” This design is made possible by the overwhelming linearity of the 5687 vacuum tube

Through its OTL/OCL design, the RD-7500 completely removes the physical signal barriers of output transformers and coupling capacitors. This realizes true broadband transmission—from DC to ultra-high frequencies far exceeding the audible range—without phase distortion or information loss.

Removal of Transformer (L): By fundamentally blocking leakage inductance and distributed capacitance that degrade high-frequency resolution, it secures a crystal-clear high end.
Removal of Capacitor (C): By breaking down the reactance (XC) barrier that blocks low frequencies, it eliminates low-end phase shift. The result is an extremely elastic and fast bass response.

In a DAC, signal purity is more important than excessive amplification. For this reason, the RD-7500 insists on a Single-Stage 5687 amplification circuit.

Realization of the Shortest Path: Unlike IC/TR circuits or multi-stage amplification circuits that pass through dozens of components, the RD-7500 prevents signal contamination at the source through a single stage of amplification.
The Power of Direct Drive: The 5687 tube features very low internal resistance and high transconductance. This allows it to secure sufficient gain and low output impedance simultaneously with just one stage, driving the connected amplifier with powerful authority.

The RD-7500 is an uncompromising reference for audiophiles worldwide.

Combining the world’s best chip, the ES9039PRO, with Allnic’s proprietary Single-Stage, Non-Feedback, and OTL/OCL technologies into a single circuit is a high-level engineering achievement—designed to reach the pinnacle of digital precision and analog purity at the same time.

If you want to experience Allnic Audio’s products,

please contact your local authorized dealers or

Audio Mentors, which is Allnic Audio’s design & marketing company.