T+A SDX 3100 HV Streaming Preamplifier DAC

The SDX 3100 HV is the digital heart of T+A's HV range — a preamplifier, digital-to-analogue converter and network streamer in one chassis, built to the same standards as the amplifiers it is designed to sit alongside. The HV designation refers to the high operating voltages T+A use throughout the range: run the amplifier stages at high voltage and they behave more linearly by nature, before any correction is applied. It is an expensive way to build electronics and the reason these units weigh what they do.

What separates the SDX 3100 HV from most one-box digital sources is that it does not treat PCM and DSD as the same problem. T+A build two entirely separate converters and route each format to the one designed for it. You can hear the thinking in the presentation — there is no sense of a single chip being asked to be adequate at everything. See the full T+A range we stock.

Two Converters, Not One

PCM is handled by a Double-Differential-Quadruple-Converter using four D/A converters per channel, running 32-bit Sigma Delta conversion at 705.6 / 768 kSps. Running four converters per channel in a double-differential arrangement cancels a great deal of the noise and distortion that a single converter generates, and it is the reason the measured figures are what they are.

DSD takes a completely different path through T+A's True-1Bit DSD converter, which handles the bitstream natively up to DSD 1024 without converting it to PCM first. Native means native — the signal is not resampled on the way through.

Four oversampling algorithms are selectable for PCM — FIR short, FIR long, Bezier/IIR and Bezier — followed by a phase-linear third-order Bessel filter switchable between 60 kHz and 120 kHz. These are worth experimenting with rather than leaving at the default; the differences are audible on a resolving system.

Connections

Digital inputs run to AES-EBU at 192 kSps/24-bit, six S/P-DIF inputs across coaxial, BNC and optical, two HDMI inputs, and two USB inputs accepting up to 768 kSps PCM and DSD 1024. Analogue output is balanced XLR, 1.45 Veff nominal and 19.6 Veff maximum into 50 ohms.

There is a proper headphone stage built in, on both 6.3 mm jack and 4.4 mm Pentaconn, running in Class A up to 200 mA into 6 ohms. It is not an afterthought output taken off the preamp bus.

Streaming

The network side handles MP3, AAC, OGG Vorbis, FLAC, WAV, AIFF, ALAC, DFF and DSF. Services covered are Tidal Connect, Qobuz Connect, Deezer, Spotify Connect, Amazon Music HD, Apple AirPlay 2, Roon and Audirvana. Roon users get a full endpoint, which for most people in this price bracket is the deciding factor.

Technical Specifications

Who Is It For?

The SDX 3100 HV is for someone building an HV system and wanting the entire digital front end in one box — source, DAC and preamplifier — feeding a PA 3100 HV or a power amplifier directly. If you already own a separate preamplifier you value, the streaming DAC duties overlap and you should talk to us about how the range splits up.

It suits large libraries and mixed formats particularly well. If you have accumulated DSD alongside high-resolution PCM and resent the compromise most converters force on one or the other, this is the machine built for that problem. It is also a serious headphone source in its own right, which is worth knowing before you budget for a separate amplifier.

Buying from Martins Hi-Fi

The HV range is not something to buy unheard — the units are heavy, the investment is significant, and system matching genuinely matters at this level. We can arrange a demonstration in Norwich and talk through how the SDX 3100 HV sits against the PSD 3100 HV for your system and your library.

When you get in touch, you'll be speaking with Dave, Chris and Tim at info@martinshifi.co.uk, call 01603 627010, or WhatsApp on 07554 687137. You can read more about how we work on our Why Martins page. We are at 85–91 Ber Street, Norwich, NR1 3EY.