Viola Systems | Spirito Reference Series Preamplifier | Low Res - Viola Audio Laboratories

AUDIO
LABORATORIES
REFERENCE PREAMPLIFIER
SPIRITO II
The Viola Spirito offers a level of transparency and musicality
that is truly state-of-the-art. It’s modular design uses an open
architecture to give the maximum flexibility for upgrading and
expansion. To ensure the greatest isolation from mains borne
noise, it employs a choke input filter type power supply,
housed in a separate chassis.
Spirito II Audio Design
The Spirito uses Class A discrete circuitry and is fully
balanced throughout. The input impedance of the input
module is unusually high at 1Mohm. This avoids the loading
that can be imposed on source equipment when lower input
impedance designs are used. The fully balanced topology
ensures the maximum rejection of common mode noise,
greatly contributing to the stunning clarity and silent
backgrounds that the Spirito provides. The ability of audio
equipment to reject noise is an important consideration in the
increasing noisy modern domestic environment.
Simple User Interface
Discrete volume and balance controls are located on the front
panel. All other unit functions are controlled by a large touch
sensitive display. This allows the unit to be easily configured
and controlled in stereo, multi-channel and multi-room
modes. It also provides the flexibility necessary to allow other
types of modules to be easily added in the future. The user can
assign alpha-numeric names of their choice to each input.
The Spirito’s choke input power supply 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.
Modular Construction
The Spirito’s main chassis has ten user accessible card slots.
These are loaded from the rear of the unit and permit the
Spirito to be configured to suit a wide range of applications.
Low Noise Power Supply
The Spirito’s choke input filter power supply produces far less
electromagnetic interference than the capacitor input designs
most often used in preamplifiers. It also places less stress on
the power supply components, leading to higher reliability
and longer life. In addition it completely avoids the high
frequency noise that occurs when switch mode power
supplies are used.
Viola Spirito Specifications
Spirito with V20 Reference Input Module and V30 Reference Output Module
Inputs per Channel
Input Impedance
Frequency Response
SN Ratio
THD
Outputs per Channel
Output Impedance
SSP Loop
Maximum Gain
Frequency Response
SN Ratio
THD
Dimensions
Power Supply
Weights
© Viola Audio Labs 2010
1
2 XLR
1 RCA
1Mohm
20Hz to 20kHz +0, -0.2dB
< - 90 dBv
< 0.002 % @1kHz, 2v out, unity gain, 22kHz filter
Output 1
2 XLR in parallel
Output 2
2 XLR in parallel
Output 3
RCA (Tape)
Main Out
100 Ohms
Tape Out
620 Ohms
Yes
+16dB
20Hz to 20kHz ± 0.2dB
< - 90 dBv
< 0.002 % @ 1kHz, 2v out, unity gain, 22kHz filter
Spirito 44.7cm W x 20cm H x 51cm D
44.7cm W x 11cm H x 51cm D
Spirito
21kg
Power Supply
23kg
REFERENCE POWER PREEAMPLIFIER
BRAVO II
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.
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.
Viola Bravo Specifications
Output Power
Stereo Mode
Half-Bridge Parallel Mode
350W per channel into 8 ohms
700W per channel into 4 ohms
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
Inputs per channel
2 XLR
Outputs per channel
3 pairs of WBT terminals
Frequency Response
10Hz to 20kHz ± 0.15dB
10Hz to 100kHz,
-3dB
Power Bandwidth
5Hz to 100kHz
THD
Less than 0.1% @ 20kHz and 350W
SN Ratio
-105dB referenced to 350W, C weighted
Dimensions
Amplifier
44.7cm W x 23.5cm H x 66cm D
Power Supply
44.7cm W x 23.5cm H x 66cm D
Weights
Amplifier
39kg
Power Supply
57kg
© Viola Audio Labs 2010
2
MONO PREAMPLIFIER
SOLO
The Solo preamplifier is comprised of separate chassis and
power supplies for true monaural operation. The Solo uses
discrete Class A circuitry and is fully balanced throughout the
signal path. Like all Viola products the Solo input impedance
is 1 million Ohms. This high input impedance provides a
light load to source output stages which usually consist of
amplifiers with limited drive current. Also the fully balanced
topology provides maximum rejection of common noise. The
Solo also features a choke input power supply. This helps
avoid high peak charging currents that occur in capacitor
input power supplies that can contaminate power supply and
ground returns.
Expandable
The Solo is expandable with up to 32 slave units controlled
by a master. The master sends volume, balance; mute, remote
trigger and input select commands to all slave units connected
to the network for multichannel operation. Pairs and single
units can be assigned to a group. This allows independent
volume and balance control for up to 6 pairs of Solo.
Baton Remote Control
The Baton provides remote operation of input switching,
volume, balance, mute and the remote trigger control. The
Baton will also control the volume and balance of groups of
preamplifiers, so you can control the volume of center and
surround channels independently.
3
Viola Solo Specifications
Inputs
Outputs
Input Impedance
Output Impedance
Maximum Gain
Maximum Output
Frequency Response
IMD
THD
Noise
Power Consumption
Dimensions
Power Supply
Weights
© Viola Audio Labs 2010
3 XLR balanced
3 RCA unbalanced
1 RCA
1 XLR
1 Fixed (Tape)
1 M Ohms
Main Out
100 Ohms
Tape Out
600 Ohms
16dB
15.5Vrms Balanced
7.75Vrms Single Ended
20Hz to 20kHz ± 0.2dB
< 0.005% @ 1V input
< 0.01 % @ 20kHz, 1v input
> -90dBv 10Hz - 22 kHz
Approximately 22W
Preamplifier 44.7cm W x 5.3cm H x 48.3cm D
22.3cm W x 9.1cm H x 40.6cm D
Preamplifier
7.7kg
Power Supply
7.3 kg
CLASS A MONO POWER AMPLIFIER
LEGACY
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
Viola Legacy Specifications
Class of Output Operation
Power Rating
IM Distortion (SMPTE)
THD
Frequency Response
Power Bandwidth
SN Ratio
Gain
Input Impedance
Inputs
Output Connections
Power Consumption
Weight
Dimensions
A
100W continuous average power into 16, 8, 4,
and 2 ohms 20 Hz to 20 kHz at less than
0.25% THD
1W to 100W <0.01%
<0.08% @ 20 kHz/100 watts
1W into 8 ohms (10Hz – 20kHz) +/-0.25 db;
100k <-3db
5 Hz to 100 kHz (-3dB points)
<-110 db at 1 kHz / 100W; C weighted
26 dB
1M Ohm / 1M Ohm balanced
2 x Balanced – XLR
1 pair of binding posts for spade terminals for
each impedance tap
Approximately 450W at idle
Amplifier
168 lbs. (76.2kg)
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)
© Viola Audio Labs 2010
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.
4
STEREO PREAMPLIFIER
CADENZA
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.
5
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.
Viola Cadenza Specifications
Inputs
Outputs
SSP Loop
Frequency Response
IMD
THD
Noise
Dimensions
Weights
© Viola Audio Labs 2010
1 Option Card
4 RCA
2 XLR
1 RCA
2 XLR
1 RCA (Tape)
Yes
20Hz to 20kHz ± 0.1dB
Less than 0.005% @ 1V input
Less than 0.01% @ 20kHz 1v input
-95dB
Preamplifier
44.7cm W x 9.1cm H x 40.6cm D
Power Supply
22.3cm W x 9.1cm H x 40.6cm D
Preamplifier
7.3kg
Power Supply
9.1kg
STEREO POWER AMPLIFIER
SYMPHONY
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
AB2
Inputs per Channel
2 XLR
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
Dimensions
44.7cm W x 44.7cm H x 19.6cm D
Weight
54kg
© Viola Audio Labs 2010
MONO POWER AMPLIFIER
FORTE
The Viola Forte is a compact high quality mono power
amplifier developed from the advanced circuitry used in the
Viola Symphony, Bravo, and Legacy amplifiers. It is rated at
75W into 8 ohms, or 150W into 4 ohms. 2 units may be
bridged to give 300W into 8 ohms, or 550W into 4 ohms.
These ratings are conservative. The Forte will comfortably
exceed them under most conditions.
Don’t be deceived by the unit’s compact dimensions.
Like its big brothers, the Forte will effortlessly deliver large
amounts of power without sacrificing the ability to accurately
reproduce the subtle threads in a musical performance.
Dynamics reproduced without compression; stereo images
re-created with excellent focus, and accurate and well
controlled bass, all contribute to portraying the emotion that
is the essence of a musical performance. A generously rated
choke input power supply allows the Forte to easily drive
even difficult speakers.
Viola Forte Specifications
Output Power
Stereo Mode
75W into 8 ohms
20Hz to 20kHz , THD < 0.25%
150W into 4 ohms
20Hz to 20kHz , THD < 0.5%
Bridge Mode
300W into 8 ohms
550W into 4 ohms
All power figures quoted are continuous average power
Inputs
2 x XLR
Outputs
1 pair 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 @ 1kHz 75W, C weighted
Dimensions
22.5cm W x 11.0cm H x 42.3cm D
Weight
15.9kg
© Viola Audio Labs 2010
6
ACTIVE CROSSOVER
QUARTET & DUET
Viola Quartet Mono Electronic Crossover
The Quartet is a high quality mono electronic crossover
intended for use with speaker systems with up to 4 bands. The
Quartet uses linear phase filters with a cut-off rate of 12, 24,
36, or 48 db per octave. Other cut-off rates and filter alignments are available on special order.
Low noise hybrid type potentiometers are used for the
output level controls. Each control is fitted with a 10 turn
vernier dial allowing extremely accurate settings. The vernier
is lockable for long term stability.
The Quartet uses the same precision class A amplifier
modules as the Cadenza preamplifier. As with the Cadenza
a separate choke input type power supply is used to provide
a very clean and stable power source for the crossover.
The Viola Duet Stereo Electronic Crossover is a high quality
2 way version of the Quartet crossover intended for use with
speaker systems with up to 2 bands.
7
Viola Quartet and Duet Specifications
Inputs
Outputs per band
Input Impedance
Frequency Response
IMD
THD
Noise
Dimensions
Weights
© Viola Audio Labs 2010
1xRCA
1xXLR
1xRCA
1xXLR
1M ohm
20Hz to 20kHz + 0.1 dB
Less than 0.005% @ 1V input
Less than 0.01% @ 20kHz 1v input
-95dB
Crossover
44.7cm W x 9.1cm H x 40.6cm D
Power Supply
22.3cm W x 9.1cm H x 40.6cm D
Crossover
7.3kg
Power Supply
9.1kg
STEREO PREAMPLIFIER
CRESCENDO
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.
Features
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 Specifications
Inputs: Analog
Digital
Outputs
Input Impedance
Output Impedance
Maximum Gain
Maximum Output
Frequency Response
IMD
THD
Noise
Power Consumption
Weight
Dimensions
3 XLR balanced
3 RCA unbalanced
1 USB Audio
1 SPDIF
1 RCA
1 XLR
1 FIXED (Tape)
1 Million Ohms (Single Ended)
40k Ohms (Balanced)
Main Output 100 Ohms
Tape Output 600 Ohms
16dB, 26dB Switchable
14.6Vrms Balanced
7.3Vrms Single Ended
20Hz to 20kHz ± 0.2dB
Less than 0.005% @ 1V input
Less than 0.01% @ 20n kHz 1V input
> -90dBv
10Hz – 22 kHz
Approximately 37W
25.0 lbs. (11.3kg)
17.5’’W x 3.5’’H x 15’’D
44.5cm W x 8.9cm H x 38.1cm D
© Viola Audio Labs 2010
8
STEREO POWER AMPLIFIER
CONCERTO
Housed in the same size billet Aluminum chassis as the Crescendo, the Concerto delivers 125W into 8 ohms and 225W
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.
Concerto Audio Design
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.
Network
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 modes.
Viola Concerto Specifications
Output Power
Stereo Mode
125W into 8 ohms
20Hz to 20kHz , THD < 0.25%
225W into 4 ohms
20Hz to 20kHz , THD < 0.5%
Bridge Mode
450W into 8 ohms
650W into 4 ohms
All power figures quoted are continuous average power
Inputs
2 x XLR
Outputs
1 pair 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
>85dB @ 1kHz 125W, 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
35 lbs. (15.9kg)
© Viola Audio Labs 2010
(Preliminary Specifications)
Warranty
Products of Viola Audio Labs are warranted to be free of defects
if used under normal conditions for a period of five years from
the date of manufacture.
All specifications are subject to change without notice.
Viola Audio Laboratories
446 Blake Street
New Haven, CT 06515
9
U.S.A.
www.VIOLALABS.COM
Download PDF