300B DHT Unity-Gain Tube Buffer — Balanced & Transformer-Coupled Output

The 300B DHT Advantage

At the heart of this design is the 300B DHT, one of the most highly regarded output tubes in the history of high-end tube audio.

The use of a large 300B directly heated triode brings a distinctive combination of air, harmonic richness, tonal warmth, microdynamic delicacy, and three-dimensional spatial presentation. Compared with conventional small-signal tube buffer stages, the larger 300B output stage provides an entirely different level of scale and physical presence.

The balanced output is transformer-coupled, allowing the 300B stage to deliver its signal through a properly designed balanced interface. This provides the system with the advantages of a fully balanced signal path, including excellent noise rejection and strong interface capability. RCA version comes without XLR+RCA transformer output, and cost can be much lowered.

The unit can also be connected to the output of a conventional RCA single-ended preamplifier, effectively providing that source with a high-performance balanced output stage. In other words, the 300B buffer can serve as a dedicated DHT output stage for an existing audio component without requiring modification to the original equipment.

And even when using only the RCA output, the direct 300B output stage remains fully active, providing the characteristic sonic benefits of the DHT buffer.

---

Tube Rectified Power Supply

The power supply employs a 5U4G / 274B vacuum-tube rectifier, rather than a conventional solid-state diode rectifier.

The tube-rectified supply is designed as an integral part of the overall sonic architecture, contributing to the open, spacious and natural presentation associated with classic tube amplification. Careful power-supply design, filtering and component selection are used to maintain a clean and stable operating environment for the 300B stage.

For enthusiasts seeking a further level of refinement, the power supply can be upgraded with our Super Rectifier (such as STR-104 or STR-1002) , providing an additional path for system-level performance optimization.

---

A Cost-Effective Path to 300B DHT Performance

This is a unity-gain 300B Directly Heated Triode (DHT) buffer amplifier featuring both direct RCA output and transformer-coupled balanced output. It can transform virtually any DAC, CD player, preamplifier or phono stage with line-level output into a high-performance 300B tube-output source, while dramatically improving output drive capability through its low-impedance output stage.

The large 300B DHT delivers an exceptionally open, airy, smooth and harmonically rich presentation, with greater transparency, natural texture, dynamics and three-dimensionality. The transformer-coupled balanced output also provides the benefits of a true balanced interface, while RCA output remains available.

Premium construction includes OFC RCA connectors, gold-plated tube sockets, silver-coated OFC internal wiring, high-grade capacitors and precision resistors.

Most importantly, this is one of the most cost-effective ways to add a true large-DHT analog output stage to an existing DAC. Instead of replacing your DAC with an ultra-expensive reference tube DAC costing $50,000+, simply add the 300B DHT Buffer and let your existing DAC handle the digital conversion while the 300B provides the high-end tube analog output stage.

Your DAC provides the digital source.
The 300B provides the music.