Audio power amplifiers originated all the way back in 1909, invented by Lee De
Forest when he assembled the first operational triode vacuum tube. We’ve come a
long way since then.
The technical definition of a power amplifier is an electronic device that amplifies a
low-level audio signal to a level that is suitable to drive a loudspeaker. Early power
amplifiers, or “amps’, as they’re abbreviately known, were based on vacuum tubes
(known here in South Africa as valves) and some of them were very high quality,
such as the Williamson amplifier of 1947 to “49 which produced an output with less
than 0.1% harmonic distortion at full rated power.
So, fast forward into the 21st Century, look back and what do we see? We see
progress in the form of revised power amplifier designs, grouped into “classes’:
class A, class B, class AB, class C and class D, etc. There are more, to be sure, but
in this day and age we seek power amplifiers for our expensive loudspeaker
systems that are not only powerful and sound good, but are light, power efficient
and possibly even have on-board DSP to manage the system without any additional
hardware.
Well, there is a company that does all that and more while supplying thousands of
watts from a 1U rack space. I present to you Powersoft, the Florence, Italy-based
amplifier manufacturer that is becoming famous for its innovation and out-of-the-
box thinking.

Some background

Florence, Italy was one of the epicentres of the Renaissance. How apt, then, that
one of the most innovative audio companies in the world is located there, creating
their own revolution in the audio sciences.
Powersoft was founded in 1995 by brothers Luca and Claudio Lastrucci and mutual
friend Antonio Peruch and still remains a family-owned business today. One of the
hallmarks of the Powersoft story is that they are one of the leading companies in
the world making use of class D, or switch mode technology, in their amplifiers
which allows them to do amazing things, resulting in high efficiency and high power
in a very lightweight and compact design.
Indeed, they were the first amplifier manufacturer to introduce Pulse Width
Modulation (PWM) and Power Factor Correction (PFC) technologies in their
amplifiers and these technologies, among others as we shall see, are what seem to
have set Powersoft apart in the amplifier market. Interestingly, to date they have
announced that they have produced over 600 million watts in products since the
company’s founding; all manufactured in Italy. Try to get your head around a
system big enough to handle that power!
Today Powersoft is represented in over 50 countries and South Africa is no
exception. Local audio equipment distributors Surgesound were recently appointed
the regional agents and service centre for southern Africa so I was invited to the
Surgesound offices in northern Johannesburg to take a look at the range of
Powersoft amps, get a feel for their technologies and find out what makes the
company a little different. Turns out, a lot!

Technologies

Green Audio Power

One of the main tenets of the Powersoft philosophy is conservation of energy
because it stands to reason that the more efficient an amplifier is, the less power it
consumes and is therefore better for the environment. This embodies the Powersoft
design ethos.
The economic and environmental advantages of products that consume less
electricity and are highly efficient are obvious. Green Audio Power is a Powersoft
trademark that categorises environmentally friendly products via a green stamp on
the front side of the product and combines two technologies that, together, embody
the concept.
These two technologies are:
Power Factor Correction (PFC) integrated into a switching mode power supply; and
Class-D Pulse Width Modulation (PWM) high efficiency output stage.

Power Factor Correction (PFC)

PFC improves amplifier performance and contains the mains current draw and
consumption in Powersoft amplifier PSUs. Now, there is not a lot of information
available on how exactly Powersoft achieves this, but suffice to say that without
PFC, a power supply can produce huge peaks and generate harmonics which can in
turn agitate the mains. With a PFC enabled amplifier the result is lower RMS and
peak currents and higher instantaneous and average power.
All in all, PFC has the following advantages:
• An energy saving of approximately 40%.
• A reduction in required generator size.
• A reduction in cable sections since lower RMS currents are reached during use.

• Fewer cable emissions because of lower harmonics in the mains frequency. This
produces less hum and induced distortion resulting from a disturbed mains.
• An audio amplifier that delivers its full output regardless of mains voltage
fluctuations and load impedance. The PFC PSU regulates itself automatically.
• A product that is usable worldwide, regardless of mains voltage differences.

Pulse Width Modulation (PWM)

PWM technology was introduced by Powersoft in 1995. PWM, according to
Powersoft: “…transforms all energy from the mains into usable power’. It also
recycles reactive energy returned from the speakers. Interestingly, this is a similar
technology to how Formula One cars return energy back into the drive train from
energy produced during braking. The knock-on effects of this is ultra-high
efficiency, a reduction in the required energy for equivalent output power, less
strain on the cooling system and less amplifiers required to run an equivalent PA
system with non-PWM amps.

Differential Pressure Control (DPC)

DFC is another notable Powersoft patented technology and is the core of IPAL, or
Integrated Power Adaptive Loudspeaker (21IPAL and 18IPAL). DPC is essentially a
sensor system placed inside a subwoofer enclosure that measures transducer and
acoustical load parameters which, in turn through a “zero-latency’ DSP, corrects
any inconsistencies in the acoustical system. The DSP is very quick – a mere 10
microseconds – and processes the performance of the loudspeaker to the
parameters of a “virtual speaker model’, defined by the speaker designer.

Smart Rails Management (SRM)

SRM tracks real time voltage in the amplifier PSU and minimises the differences
between the output voltage rails. This improves overall efficiency. According to
Powersoft SRM: “…feeds back the output signal to the power supply and modulates
the rails voltage in order to reduce heat dissipation and improve efficiency’. The
advantages of SRM technology include lower idle consumption, lower audible noise
floor and reduced EMC (electromagnetic compatibility).

Amplifiers

Powersoft has become famous for their high power, highly efficient and intelligent
amplifiers in compact sizes. They offer solutions for the installation and touring
market and most of them can be purchased in either the standard configuration or
with optional on-board DSP and AES-over-Ethernet. The installation amplifiers and
some of the touring amplifiers can operate in high impedance, 70V or 100V and
almost all their amplifiers, except the X8 and Ottocanali K4 range, come in a 1RU
size, hence the designation “compact’.

X-series

The X-series is Powersoft’s newest line of flagship multi-channel amplifiers. The
range includes the X4 and the X8, both exhibiting the same specifications albeit
over four channels and eight channels, respectively. The only additional difference
is the size difference between the two boxes; 1RU for the X4 and 2RU for the X8.
The TI C6000 DSP-driven amplifier is managed by an ARM Cortex A-8 processor and
features 3000W per channel into 4 Ohms; universal, single-, bi- or three-phase
power acceptance from 85VAC up to 440VAC; switching mode PFC power supplies,
SRM technology and real time output signal measurement and processing via
Powersoft’s Armonia Pro Audio Suite. The DSP offers non-boolean routing and
mixing, multi-stage EQ with raised-cosine, IIR and FIR filters, input delay up to 4s,
200ms time alignment delay, gain and polarity, crossover, peak limiters, TruePower
limiters and Active DampingControl. Inputs include standard XLR analogue inputs
and AES3.

K-series

The K-series range of touring amplifiers is the benchmark standard workhorses of
the Powersoft range and the icons on which the brand is based. Six stereo models
are on offer at various power ratings (all power ratings are listed at 4Ohms and per
channel):
• K20: 5200W
• K10: 4000W
• K8: 3000W
• K6: 2500W
• K3: 2600W
• K2: 1950W

All K-series amps are available with or without SHARC DSP and AES-over-Ethernet
and can be run in high impedance, 70V or 100V configurations. All the usual
technologies we have covered such as PFC, PWM and SRM are found, along with full
digital control via Powersoft’s Armonia Pro Audio Suite. The DSP offers independent
input and output PEQ, raised cosine, shelving IIR filters and custom output FIR
filters, time alignment delay up to 1s, Active DampingControl for cable
compensation, power limiters (TruePower, RMS voltage, RMS current) and peak
limiters per channel. Firmware, presets and power pgrades can be initiated via
purchasing “step-up’ cards.

M-series

The M-series is the entry level range in the Powersoft line. Four models are on offer
with various wattage and channel variations (power ratings are given at 4Ohms):

• M50Q: four channels, 1250W per channel
• M28Q: four channels, 700W per channel
• M30D: two channels, 1500W per channel
• M20D: two channels, 1200W per channel
All models are also available in the HDSP+ETH versions which provide on-board
DSP with Ethernet interfaces. Like the other ranges, monitoring and amp settings
can be achieved via the Armonia Pro Audio Suite. Additionally the HDSP+ETH
versions allow the user to access up to four presets per button (there are two) on
the rear panel. Also, like the other ranges, EQ with numerous filters, limiting and
delay are available.

Installation amplifiers

Powersoft makes a range of installation-grade power amplifiers that can run in
high-impedance, 70V or 100V configurations. The amplifiers include all technologies
such as PFC, PWM and SRM.
The amplifiers include:
• Ottocanali 1204: eight channels, 1280W (total power), 1RU, optional DSP and
Ethernet in the DSP+ETH versions.
• Duecanali series
• Duecanali 5204: two channels, 2600W per channel (4Ohms), 1RU, optional DSP
and AES-over-Ethernet with DSP+AESOP versions.
• Duecanali 3904: two channels, 1950W per channel (4Ohms), 1RU, optional DSP
and AES-over-Ethernet with DSP+AESOP versions.
• Ottocanali series
• Ottocanali 12K4: eight channels, 1500W per channel (4Ohms), 2RU
• Ottocanali 8K4: eight channels, 1000W per channel (4Ohms), 2RU
• Ottocanali 4K4: eight channels, 500W per channel (4Ohms), 2RU

The wrap

Powersoft obviously is a powerhouse of a company that takes big steps in pushing
progress. Their patented technologies and smart thinking speaks for itself and given
the name that they’ve made worldwide, it might just be exciting to see what they
come up with in the future.