Case Study / PS Audio Inc

PMG Air DAC & Preamp Platform

A ground-up DAC/preamp/streamer platform delivering audiophile-grade performance at an accessible price point.

The Project

PS Audio needed the foundation for an entirely new integrated product line combining network streaming, digital-to-analog conversion, and preamplification, all at a significantly lower price point than their existing offerings. The system had to deliver advanced single-bit DSD audio processing across a wide range of digital and analog inputs while meeting strict BOM cost targets and using commonly available, manufacturable components. This was not a simple cost-reduction exercise; it was a ground-up platform design spanning digital, analog, UI, and streaming subsystems.

Our Solution

Grinalds Solutions architected and developed a complete DAC/preamp/streamer platform built around a discrete shift-register-based single-bit DAC topology. Digital inputs, including USB, HDMI, RCA, and optical, feed through a digital MUX controlled by a custom touchscreen UI powered by an ESP32-S3. A dedicated SBC handles streaming and system housekeeping, while the digital processing chain upsamples all sources to DSD256 before I2S conversion and reclocking. This architecture delivers advanced audio conversion using widely available components, keeping BOM costs firmly within the target range.

Technical Implementation

The DAC topology uses 32 shift registers generating balanced, summed outputs from differential DSD clock and data signals. The analog signal chain progresses through transimpedance amplification, Sallen-Key filtering, and a MUSES volume control stage, followed by a current source, gain stage with servo feedback, and a push-pull diamond buffer output stage currently under evaluation. Analog inputs, both RCA and balanced XLR, are also supported, making this a true all-in-one platform. We leveraged JLCPCB's component warehouse for part selection, focusing on parts with strong availability and assembly compatibility to ensure manufacturability from the start.

Results

The PMG Air platform is designed not as a single product but as the foundation for PS Audio's next generation of streamers, streaming DACs, and streaming DAC-preamps. A functional prototype has been delivered demonstrating digital input handling, DSD upsampling, and the majority of the analog signal chain, with certain subsystems, including the diamond buffer output stage and power supply optimization, under active refinement. By accepting iterative development of analog output stages rather than delaying overall system integration, we kept the project moving forward and enabled rapid learning across the full signal chain, proving that cost-constrained design and audiophile-grade architecture are not mutually exclusive.

Industry

High-End Audio & Consumer Electronics

Tech Stack

  • ARM-based SBC Platform
  • ESP32-S3 Touchscreen UI
  • Custom Shift-Register DAC
  • DSD256 Upsampling
  • I2S Reclocking
  • MUSES Volume Control
  • Mixed-Signal PCB Design
  • JLCPCB Manufacturing

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