Un client vends un magnifique système Viola Labs composé du préampli Cadenza avec son alimentation externe et du bloc d’amplification stéréo Symphony.

CADENZA : 8 000€ à débattre

The Viola Cadenza is a pure analog wide bandwidth preamplifier. It has six line inputs, plus one additional input for an optional plug-in module. A high quality phono module is in the final stages of development and other modules are under consideration. The Cadenza offers an extremely high level of transparency, which is essential if the emotion that is the essence of a musical performance is to be faithfully reproduced.

Audio Design

All of the Cadenza’s amplification stages are fully balanced and are constructed as modules using discrete components. High precision (0.1%) thin film resistors are used to minimize noise. The modules plug into the motherboard, which allows for easy upgrading should improved versions become available in the future and also facilitates servicing. The input section has been designed to have an input impedance of one Mohm. This has three major benefits:

  • It preserves the balanced input’s ability to reject interference if the output impedances of the signal source are not perfectly matched.
  • Errors are reduced at connector contact junctions.
  • It conserves the source unit’s output drive current, so that more output current is available to drive the capacitance of the interconnecting cables, thus improving the high frequency performance and transient response.

Each channel has an 11 position stepped gain switch for controlling channel balance. These switches can also be used to “range” input sources with atypical output levels. They are located in the inverse feedback loop for minimum noise. The volume control is a custom made 59 position stepped attenuator with 1dB steps. It uses 0.1% Vishay film resistors and the contact material is a high gold content alloy, containing platinum, silver and copper. Careful design ensures that external vibrations do not modulate the wiper contact pressure, which would otherwise degrade the sound quality. To prevent ground loops between signal ended source units, all RCA inputs are completely isolated when not in use. Heavy oxygen free copper bus bars enhance the efficiency of power distribution within the preamplifier.

Low Noise Power Supply

The Cadenza uses a separate choke input filter type power supply. This produces far less electromagnetic interference than the capacitor input designs most often used. It also places less stress on the power supply components, leading to higher reliability and longer life. In addition, the Cadenza’s power supply design completely avoids the high frequency noise that occurs with switch mode power supplies. The Cadenza’s power supply design also virtually eliminates high peak ripple currents, minimizing intermodulation distortion on the power supply rails and ground returns. This further enhances the sound quality by reducing both noise and distortion.

Cadenza Preamplifier Specifications

Inputs 1 x Option Card
4 x RCA
1 x Fischer
1 x XLR
Outputs 1 x RCA
1 x Fischer
2 x XLR
1 x RCA (Tape)
Input Impedance 1M ohm
Frequency Response 20Hz to 20kHz ± 0.1dB
IMD Less than 0.005% @ 1V input
THD Less than 0.01% @ 20kHz 1v input
Noise -95dB
Dimensions Pre-amp: 44.7cm W x 9.1cm H x 40.6cm D
Psu: 22.3cm W x 9.1cm H x 40.6cm D
Weights Pre-amp: 7.3kg
Psu: 9.1kg

SYMPHONY : 8 800€ à débattre

The Viola Symphony is a 200W per channel stereo power
amplifier with an integral choke input filter type power
supply. It incorporates many of the technological advances
that were made during the development of the Viola Bravo
power amplifier. Like the Bravo, the Symphony is a virtuoso
performer with excellent stereo imaging and reproduction of
low level detail. The bottom end is extended and well
controlled. A generously rated choke input power supply
ensures that dynamics are reproduced without compression,
even when driving difficult speakers.
Viola Symphony Specifications
Output Power Stereo Mode
200W per channel into 8 ohms
20Hz to 20kHz , both channels driven, THD < 0.25%
400W per channel into 4 ohms
20Hz to 20kHz , both channels driven, THD < 0.5%
Bridge Mode
800W into 8 ohms 1600W into 4 ohms
All power figures quoted are continuous average power
Output Mode
Inputs per Channel
Outputs per Channel
2 pairs of WBT terminals
Frequency Response
10Hz to 20kHz ± 0.15dB at 1W into 8 ohms
5Hz to 100kHz, -3dB at 1W into 8 ohms
Power Bandwidth
5Hz to 100kHz +0, -3dB
SN Ratio -105dB referenced to 200W
44.7cm W x 44.7cm H x 19.6cm D