Phono Preamplifier DS Audio TB-50 Black

Hybrid phono equaliser for optical cartridges with a valve output buffer

The TB-50 is a phono equaliser designed for DS Audio optical cartridges, combining a hybrid architecture with precise solid-state RIAA equalisation. The amplification section, including the correction curve, works in transistor technology, while the final stage passes through a valve output buffer. The result is accurate signal amplification complemented by the harmonic structure that a valve stage brings.

The output stage uses ECC82 (12AU7) valves, the same type as in the flagship TB-100 model. A separate air duct structure is built around the valves, drawing in air from outside the chassis and carrying away the heat generated by valve operation. Keeping the internal temperature within the optimal range stabilises the valves' operating point, so the sonic character does not change even during longer listening sessions.

The cartridge connection uses current supply and current signal transmission, which is considerably less sensitive to the properties of the phono cable and the quality of the contacts. Compared with conventional voltage transmission, the influence of cable length and connectors is reduced, which contributes to more stable transmission and better exploitation of the optical cartridge's potential — this shows in the legibility of fine detail and more precise localisation of instruments within the stereo image.

Beneath each valve there is LED backlighting with continuous adjustment controlled from the rear panel, so the intensity can be adapted to the room and the listening situation. The unit features RCA inputs and outputs, a nominal output voltage of 500 mV at 1 kHz and an output impedance of approximately 700 Ω. Dimensions are 420 × 120 × 320 mm including terminals, weight 10.8 kg.

Key features

• Hybrid architecture: Solid-state RIAA correction with a valve buffer
• ECC82 valves: The same type as in the flagship TB-100 model
• Cooling duct: Heat removal and a stable valve operating point
• Current transmission: Suppresses the influence of the phono cable and contacts
• Adjustable backlighting: Continuous LED dimming from the rear panel