Hifiverse

Direct Stream Digital (DSD)

Direct Stream Digital (DSD) is a 1-bit audio encoding sampled at 2.8224 MHz, the format behind Super Audio CD. For Hi-Fi listeners it offers a route apart from PCM, used for downloads, dedicated DACs, studio archives and the multichannel layers of SACD discs.

Stas Ustenko

Stas Ustenko

Audio

Holo Audio May KTE Review - One of the Most Impressive R2R DACs

How the Holo Audio May’s compensation matrix works, its four conversion modes, measurements (22+ bit resolution) and what the KTE version really adds.
John Makovsky

John Makovsky

Audio

2026 Hi-Res Streaming Services Compared: The Ultimate Analysis

Although all modern streaming services share broadly similar transmission algorithms and codecs - FLAC, ALAC - the same recordings can sound noticeably different from one platform to the next. Mastering choices, post-processing, server infrastructure, loudness normalization, and bitrate all influence the end result, and it is these small distinctions that separate a presentation that is merely good from one that is genuinely audiophile-grade. In this article we examine and compare the leading music streaming services and attempt to determine which one comes out on top for sound quality.

Hifiverse Editorial Team

Audio

APL HIFI DSD-GR – DSD digital-to-analog converter with tube output

APL HIFI DSD-GR is a new Pure DSD, “Galactic Reference” DAC, using a transformer-coupled tube differential Class-A output stage. The device is built on a fully balanced scheme and offers a proprietary asynchronous USB input module.

What DSD is & why it matters

Instead of multi-bit words, DSD stores a stream of single bits at 64 times the CD rate of 44.1 kHz. Noise shaping pushes quantisation noise far above the audio band. Sony developed the format with Philips for SACD, defined in the Scarlet Book. Today files come as DSD64, DSD128 and higher multiples, and a DAC must support native playback, accept it through DoP (DSD over PCM) packing, or convert it to PCM.

What you'll find in this tag

The tag mixes one product story with one long comparison. The news covers the APL HIFI DSD-GR, a converter that turns everything into DSD before conversion. The article compares hi-res streaming services, their codecs such as FLAC and ALAC, and how formats and delivery differ between platforms, including which services carry DSD-sourced albums at all.

Key models & brands to know

APL HIFI DSD-GR - a pure DSD converter whose 64-bit module upsamples PCM to DSD256 or DSD512, with a non-oversampling mode as well. The asynchronous USB input accepts DSD512 natively. Output runs through a balanced Class A stage on ECC99 tubes with Lundahl transformers and no negative feedback. The circuits avoid op-amps and use non-magnetic resistors throughout this hand-built unit.

Related topics & where to go next

Read Super Audio CD (SACD) for the disc side and High-Resolution Audio (Hi-Res) for PCM formats. USB Audio covers computer playback and R-2R Ladder DAC shows another conversion method, while converters sit in the DACs rubric.