Preamplifier

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.

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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.

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