THÖRESS Preamplifier Full-function

Planet Audio
Planet Audio
Planet Audio

THÖRESS introduces the Integrated “Super” Preamplifier…

a versatile full-function tube preamplifier incorporating a state-of-the-art line control amplifier
and a ground-breaking phono stage in one case. The preamplifier is entirely hard-wired and
much care has been taken in arranging each aspect of the internal construction to ensure the highest reliability, low noise performance and ease of service. We believe our preamplifier offers the best possible sound from both the line and phono sections, making it a reference device. The sound quality is of the utmost refinement and will certainly measure up to the expectations of even the most critical and experienced music enthusiast.

Our preamplifier offers two inputs for high-output sources (such as CD or DVD players), one input for low-level line sources, and three phono inputs for MC phono cartridges. Each phono input allows for customized cartridge loading by means of resistors soldered to tags adjacent to the phono jacks. To maximize versatility, the preamp includes two (paralleled) main outputs and a monitor output for the chosen source (but no monitor-switch).

Importantly, the output resistance of the main outputs is low enough to drive long interconnect cables and input impedances as low as 10,000 ohms  (solid-state amplifiers of an active subwoofer) without compromising sound quality.

The phono section within the “Super” employs one PCC88 and two 12SN7GT tubes. Thanks to an outstanding circuit topology, amplification of the moving coil signal is purely active (no built-in step-up transformers). And nonetheless, we have achieved an extraordinary signal-to-noise ratio (despite the built-in power transformer). In addition, we have designed the circuit to maintain extremely accurate RIAA equalization independently of tube parameter tolerances and tube ageing. Note that the integrated preamplifier is also available in a modified version employing a low-gain phono circuit suitable for moving magnet/iron cartridges,
though it is not possible to “mix” MC and MM inputs! To add moving coil compatibility, we offer our own (standalone) step-up transformer with three inputs and selectable cartridge loading. Line amplification is performed by a one-stage, zero-feedback circuit employing a single 12SN7GT tube per channel. The volume of each channel
is controlled separately by carefully matched, high-grade rotary potentiometers.

The low-noise, low-leakage mains transformer is produced in-house to the highest possible standard. As this unit is mechanically decoupled from the case with damping units, even the slightest residual transformer vibrations are prevented from reaching sensitive parts of the amplifier.