sound by singer high end audio video tel: 212.924.8600 - fax: 212.366.6351
242 West 27th St, 2nd Floor
New York, NY 10001





A Pedigree of continual Excellence

Viola Audio Laboratories was founded in 2000 as part of a quest. At its heart was a longtime collaboration between two leading designers,

Paul Jayson and the late Tom Colangelo.

Their commitment to reproducing sound while retaining the musical and emotional impact of the source defined their careers.

Their vision is realized with industry leading components designed with sonic neutrality that defines Viola Audio Labs.

Paul and Tom began their careers at Mark Levinson Audio Systems (MLAS) in the 1970’s.

Mark Levinson is widely credited with being

In Tom Colangelo, Mark saw a young audio enthusiast with a keen understanding of physics. In Paul Jayson, Mark saw a young enthusiastic engineer intent on reinventing audio reproduction.

Tom and Jayson went with Mark Levinson to form Cello Music systems.

.As the principal design team at MLAS and Cello, Paul and Tom introduced many products that achieved legendary status among audiophiles.

Among them are the ML-2 Amplifier and ML-7 Preamplifier from MLAS; the game-changing Audio Palette, Audio Suite, and Performance II amplifiers from Cello.

Very few individuals have achieved this level of contribution to the audiophile community.  

But as the Viola Symphony Amplifier and Viola Cadenza Preamplifier would prove, high end audio reproduction was about to realize new altitudes that only these two men had vision to see.

Viola Labs' latest contribution to the advancement of music reproduction are Their Crescendo Preamp and Concerto Power Amp.Pictured above togeather.                



 Opining on the qualities of the Viola Crescendo Preamp and Concerto Power Amp

Robert Harley stated:

"Experiencing what a revelation these components produced  Robert Harley of the Absolute Sound concluded
The Viola Audio Laboratories Crescendo and Concerto are simply stunning musically, and among the best electronics I’ve heard. The transparency, the sense they convey of nothing coming between you and the music, their sensational treble resolution without a touch of the analytical, their wide dynamic expression, and their absolutely sensational bass vault the Viola electronics to world- class status.

Throughout this review I’ve felt the urge to temper my praise of these electronics only because these are the company’s “entry- level” components—what are Viola’s $69,000 Spirito preamplifier and $59,000 Legacy 100W pure Class A monoblocks capable of? It’s mind-blowing to consider that one of the following statements must be true: 1) the Crescendo and Concerto are very close in sound quality to Viola’s reference-level products; or 2) Viola’s top- of-the-line electronics are in a league that I’ve never experienced.

Whatever the case, you should seek out and listen to these extraordinary electronics for yourself. Viola products may be difficult to find, but you may consider them to be as great a discovery as I do."


Apr 10th, 2014



The Viola Crescendo

preamplifier is a single chassis stereo                                                                                                     
preamplifier. The Crescendo chassis is milled from a solid                       
billet of aircraft grade Aluminum. This results in a very rigid        
chassis with very low resonance. The Crescendo has a prism    
cut machine finish and a custom Viola anodize finish.
Crescendo Audio Design
The OPA-1 module used in the Crescendo preamplifier is a
discrete Class A operational amplifier. The first stage employs
a low noise FET input. This is followed by a differential voltage
gain section. The output is a high current, low output impedance
voltage follower which is capable of driving the most
demanding load. This results in a very open, fast and transparent
sound stage.
The Crescendo features a high resolution USB DAC input
capable of data streams up to 192 kHz/24 Bits. This allows
connection from a computer USB to stream music without the
need to purchase additional hardware.
The Crescendo uses Wi-Fi remote control on Apple devices.
This eliminates the line of site problems associated with IR
remote controls


Crescendo Preamplifier Specifications

Inputs: Analog

3 XLR balanced
3 RCA unbalanced
1 USB Audio
Outputs 1 RCA
1 FIXED (Tape)
Input Impedance 1 Million Ohms (Single Ended)
40k Ohms (Balanced)
Output Impedance Main Output 100 Ohms
Tape Output 600 Ohms
Maximum Gain 16dB, 26dB Switchable
Maximum Output 14.6Vrms Balanced
7.3Vrms Single Ended
Frequency Response 20Hz to 20kHz ± 0.2dB
IMD Less than 0.005% @ 1V input
THD Less than 0.01% @ 20n kHz 1V input
Noise > -90dBv 10Hz – 22 kHz
Power Consumption Approximately 37W
Weight 25.0 lbs. (11.3kg)
Dimensions 17.5’’W x 3.5’’H x 15’’D
44.5cm W x 8.9cm H x 38.1cm D

  Housed in the same size billet Aluminum chassis as the Crescendo,

the Viola Concerto delivers 100W into 8 ohms and 200W into 4 ohms.

Like all Viola power amplifiers the Concerto uses a choke input power supply.

This reduces peak charging currents that are prevalent in capacitor input supplies.

This minimizes intermodulation distortion on the power supply rails on ground returns.

The Concerto is a Class AB biased push-pull amplifier design.

The Concerto incorporates Motorola ThermalTrak™ into the bias network.

This provides fast thermal feedback information without the thermal lag of other bias topologies

. A center chassis Venturi style heat sink provides cooling for the amplifier.

Connections to loudspeakers are provided by a pair of WBT nextgen™ connectors per channel.


The Concerto can be connected to the Crescendo preamplifier via the CAN (Controller Area Network) connector.

When this is done Concerto status information including temperature and line voltage

are transmitted to the Wi-Fi remote application.

This also provides synchronization of the color displays and standby mode.



Concerto Power Amplifier Specifications

Output Power Stereo Mode
  100W into 8 ohms
  20Hz to 20kHz , THD < 0.2%
  200W into 4 ohms
  20Hz to 20kHz , THD < 0.2%
Bridge Mode
  400W into 8 ohms
  600W into 4 ohms
All power figures quoted are continuous average power
Inputs 2 x XLR
Outputs 1 pair of WBT nextgen  terminals
Frequency Response 10Hz to 20kHz ± 0.2dB at 1W into 8 ohms
5Hz to 100kHz, -3dB at 1W into 8 ohms
Power Bandwidth 5Hz to 100kHz +0, -3dB
SN Ratio > -90dB @ 1kHz 100W, C weighted
Dimensions 17.5’’W x 3.5’’H x 15’’D
44.5cm W x 8.9cm H x 38.1cm D
Weight 53 lbs. (24kg)

Symphony Power Amplifier

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 200W per channel into 8 ohms
20Hz to 20kHz , both channels driven, THD < 0.25%
400W per channel into 4 ohms
Bridge Mode
400W into 8 ohms
800W into 4 ohms


Output Mode AB2
Inputs per Channel 1 XLR 1 Fischer
Outputs 1 pair of WBT nextgen  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
Dimensions 44.7cm W x 44.7cm H x 19.6cm D
Weight 54kg



Though not to be released until this September, The Viola Sonata  has already received a remarkable reception

from those who have heard it  Shown in situ at a recent Hi-Fi show my hearing of The Sonata  revealed the magical quality

I have only ever heard with far more expensive line stages .A significant step up from Viola's Cadenza preamp ( a no mean feat!),

the Sonata Captures the Musical essence of the unsurpassable purpose built  Viola Spirito preamp at less than 1/2 the price!

Though by  no means inexpensive at the targeted price of about $ 30,000.00,  its Sonic Purity and effortless presentation

makes it The go to Solid state  line stage for any application and the perfect partner fo

r Viola's Symphony Amplifier,Bravo Amplifier or Legacy Class A Mono-Blocs


Bravo Power Amplifier

The Viola Bravo stereo power amplifier has been designed to be the last word in fidelity, musicality and dynamics. It will effortlessly deliver large amounts of power while preserving the delicate nuances in the music signal.

Viola Bravo Specifications:
Output Power Stereo Mode 350W per channel into 8 ohms
700W per channel into 4 ohms
Half-Bridge Parallel Mode 1,000W into 4 ohms
1,200W into 2 ohms
1,600W into 1 ohm
Full Bridge Mode 1,200W into 8 ohms
1,600W into 4 ohms
All power figures quoted are continuous average power



Bravo Audio Design

The signal path in the Bravo is fully balanced throughout the voltage gain stages. This is essential to achieve the maximum immunity from external sources of noise. Soft clipping circuitry limits sonic degradation should the amplifier be overdriven. Bandwidth control results in nearly identical small signal and large signal frequency responses and avoids slew rate limiting. To ensure accuracy in the time domain, the bandwidth control has a flat group delay characteristic. Great efforts have been made to minimize distortion at lower frequencies, because the majority of energy is encountered at these frequencies in most music. To improve transparency and the resolution of low level signals, the output stage operates with a relatively high quiescent current. Heavy oxygen free copper bus bars enhance the efficiency of power distribution within the amplifier. Film capacitors are used on the individual circuit boards in the unit to provide the high frequency bypass for the power supply and ensure that all sections of the amplifier see a uniformly low power supply impedance. This is key to the Bravo’s ability to deliver massive amounts of power while preserving all the subtle aspects of the music signal.

Bravo Power Supply

The heart of a power amplifier is its power supply. The Bravo uses a choke input filter type power supply with a generously rated 2kVA mains transformer. Four 80,000 μF filter capacitors are located in the power amplifier chassis, providing optimum decoupling for the audio power stages.

The Bravo’s power supply design completely avoids the generation of the high frequency noise that occurs with switch mode power supplies. It also places less stress on the power supply components, leading to higher reliability and longer life. An additional benefit is that high peak ripple currents are virtually eliminated, minimizing intermodulation distortion on the power supply rails and ground returns. This enhances sound quality by reducing noise and distortion levels.


Legacy Power Amplifier

The Viola Legacy mono power amplifier is capable of delivering 100 watts of Class A power into 16, 8, 4 and 2 ohms. The Legacy is fully balanced design with very low distortion, wide dynamics and reproduction of low level detail. Class A operation eliminates crossover distortion inherent in Class B and Class AB designs.


Legacy Audio Design

The Legacy is a Class A biased push-pull amplifier that utilizes low global feedback. Two matched power amplifier modules that are driven into a center-tapped output transformer. This allows fully balanced operation from input to output. Soft clipping circuitry limits sonic degradation should the amplifier be overdriven. The Legacy is capable of switching to Class AB to deliver more power into demanding loads while still preserving subtle aspects of the music signal. The Legacy is protected against overvoltage, over temperature, excessive current and DC offset.

Legacy Power Supply

As with all Viola amplifiers designs, the Legacy features a choke input power supply. The Legacy power supply reduces high charging currents that are prevalent in capacitor input supplies. This minimizes intermodulation distortion on the power supply rails and ground returns. This also has the benefit of reducing stress on the power supply components. Onboard decoupling capacitors eliminate wire inductance along with film capacitors provide a uniformly low power supply impedance.

Legacy Power Amplifier Specifications

Class of Output Operation A
IM Distortion (SMPTE) 1W to 100W <0.01%
THD <0.08% @ 20 kHz/100 watts
Frequency Response 1W into 8 ohms (10Hz - 20kHz) +/-0.25 db; 100k <-3 db
Power Bandwidth 5 Hz to 100 kHz (-3dB points)
SN Ratio <-110 db at 1 kHz / 100W; C weighted
Gain 26 dB
Input Impedance 1M Ohm / 1M Ohm balanced
Inputs 2 x Balanced - XLR
Output Connections 1 pair of binding posts for spade terminals for each impedance tap
Power Consumption Approximately 450W at idle
Weight Amplifier: 168 lbs. (76.2kg)
Dimensions Height w/Feet: 12 3/16”. (31.0 cm)
Width: 17 9/16” (44.6 cm)
Depth w/Binding Posts: 26 1/2”. (67.3cm)