A new chapter in the history of professional high-performance power amplifiers has begun.
The PowerH power amplifier series represents another
milestone in the 60-year pro audio tradition of
Dynacord. DYNACORD has long been established
world-wide as a manufacturer of professional power
amplifiers of the highest quality and has consolidated
its position at the top end of the market through many
innovations and a reputation for absolute reliability.
Electro-Voice has played a substantial role in this as a
sister company to Dynacord, and as one of its largest
OEM-customers. For years, power amplifiers from
Dynacord / EV have been used in large and very large
audio systems – whether installed or touring – all over
the world. Today there are literally thousands of amplifiers made by Dynacord powering major productions in
all four-corners of the globe and demonstrating time and
again their superlative quality and legendary reliability.
The requirements imposed upon modern power amplifiers are
enormous: they are expected to combine very high power,
minimal weight, outstanding audio performance, absolute reliability,
remote monitoring and control, and networking.
In order to realize power levels of 2500 W / 4 Ω, power amplifiers
must be able to supply peak output voltages between 180 V and 200 V.
This requirement limits the number of plausible topologies to two:
Class D and Dynacord's Linear Grounded Bridge Class-H.
After extensive research, the Dynacord engineering department decided against the use of Class D designs: the besetting evils of Class D
technology – primarily, distortion and a clear load-dependence in the
frequency response – cannot be overcome, even by modern designs,
and the result is an un-wanted discoloration of the output signal.
Linear push-pull designs with Class-H topology are acceptable solutions for output levels up to 1500 W / 4 Ω and are used in many
Dynacord power amplifiers. The limitation of the Class-H push-pull
approach is the 250 V specification of typical audio power transistors
and their second breakdown restrictions. Even exceeding the specified peak voltage or the second breakdown limit for a short period
leads directly to failure of the power transistors and the power amplifier. The use of exotic 350V-specified transistors presents no reliable
solution in view of their second breakdown behaviour, their performance and also their availability.
Higher power classes require different solutions! Dynacord's Linear
Grounded Bridge designs (e.g. L 2400/P3000) have proven extremely reliable over many years as well as outstanding in terms of audio
performance. One of the key advantages of Grounded Bridge solutions is the considerable reduction in 'voltage stress' for the power
transistors. This permits the design of high-power power amplifiers
with peak output voltages in excess even of 200 V. A logical step in
the direction of lowering power dissipation while increasing the output power at the same time was the development of a linear
Grounded Bridge topology using Class-H technology with a threestage switching, floating power supply. The use of an extremely stable switching power supply makes a decisive contribution to the very
low weight of these power amplifiers: 7 kW packed into 2 rackspaces and weighing less than 15 kg!
PowerH power amplifiers are ready for integration into IRIS-Net
based audio systems and networks. Retrofittable remote control
modules, e.g. the RCM-26, make possible complete system supervision and remote control combined with digital controller functions
including ultra-precise FIR filters and optimised loudspeaker protection algorithms
™
-
• stable, very high power output
• very high efficiency
• very light weight
• 3-stage Grounded Bridge Class-H topology
• floating switching power supply
• large LC-display
• integrated micro-controller for internal control
• retrofittable remote control module for integra-
™
tion into the IRIS-Net
with remote supervision,
remote control, digital controller functions and
digital audio inputs
The power amplifiers of the PowerH series represent a
milestone in the design and production of high-performance power amplifiers. Their innovative three-stage Grounded
Bridge Class-H topology with its floating switching power supply
offers very high and stable output power, very high efficiency, an
extremely high level in terms of audio performance and extreme
lightness. They are therefore the ideal drivers for professional
touring and high-end concert sound, as well as pro sound applications. Through the use of IRIS-Net
modules, they also offer extensive remote supervision and control functions as well as a universal two-channel digital controller
including ultra-precise FIR filtering and digital loudspeaker protection algorithms.
™
-compatible remote control
Dynacord power amplifiers are known for their absolute reliability under the most
arduous of conditions on the road. In addition to the legendary manufacturing quality
that comes with the 'Made in Germany' label, the comprehensive set of protective circuits
plays an important role here: an integrated micro-controller co-ordinates proven protections
against short-circuit, HF or DC at the output, back EMF, overheating and open-circuit operation, the power-up current limitation and dynamic audio limiters, as well as making additional
new and highly intelligent protective functions possible: for example, the temperature in the
power amplifiers is monitored at no fewer than six different points and the front-to-rear ventilators controlled accordingly. Under abnormal thermal 'worst case' conditions, the CPU activates a voltage limiter or gain reduction depending upon the requirements of the situation, so
as to prevent a thermal shutdown of the power amplifiers. All corrective measures are indicated on the front panel and spelt out clearly on the liquid crystal display. In addition, a report
is created making it possible to enquire later as to all such 'interventions', each of which is
time-stamped.
The mains voltage is monitored and displayed continuously, with the devices adapting automatically to 230 V, for example, or 120 V. At the same time, the mains current consumption
is also monitored and displayed.The user can adjust, via the front panel display, the threshold
value of the automatic circuit breakers. In the event of possibly overloading the mains, the
amount of amplification is reduced to prevent the circuit breakers tripping. Any short-circuits
at the output of the power amplifier are detected early on, even at low levels. The protective circuit is activated and the error report in question appears simultaneously on the front display. In the event of excessive high-frequency overload, there is an automatic level reduction
to protect the power amplifier itself and also the loudspeaker components connected.
The large, backlit liquid crystal display delivers comprehensive status information,
error reports and measurements as well as allowing you to control the basic
settings and (with the IRIS-Net
™
module integrated) select presets as well.
In addition to extreme reliability and forward-looking operating security, the
PowerH power amplifiers are impressive for their outstanding audio perfor-
mance. The THD, intermodulation distortion (IMD-SMPTE) and dynamic intermodulation (DIM) are all well below 0.05% and therefore far below the limit of audibility.
All the components of the switching power supply are so safely dimensioned that
they are capable of delivering the maximum peak output current of 70 A continuously, thereby allowing the power amplifier to operate as a stable voltage source even at
extremely low loads. PowerH power amplifiers therefore have a significant amount of
headroom at their disposal, which results in superior dynamics even at low loads.
PowerH power amplifiers leave nothing to be desired in the
way of connectors. For the inputs, XLR IN/parallel OUT
sockets are provided along with additional Phoenix connectors. The
input sensitivity is selectable between 0 dBu, +6 dBu and 32 dB
Constant Gain. In addition, there are switches for bridged operation
and parallel / dual as well and, naturally, a Ground Lift switch.
A latching PowerCon connector is provided for the mains power line,
which prevents the plug being yanked out accidentally. The power
outputs are implemented as Speakon sockets with parallel binding
posts. In terms of connectivity, therefore, PowerH power amplifiers
satisfy all the demands of both mobile applications and pro audio fixed
installations.
The RCM-26 is a dual-channel digital controller module for live sound, PA and fixed installation. It offers
all conventional signal-processing functions such as parametric equalizers, crossovers, delays, compressors and limiters. It also makes available linear phase FIR filters, zero-latency FIR filters and digital loudspeaker
protection algorithms to permit the dynamic range of the amplifier to be exploited to the full potential.
In addition to the electronically balanced analogue inputs, digital inputs in AES3(AES/EBU) format are on board.
Using the CAN bus, networks of up to 250 power amplifiers can be realized. Additional interfaces include the
RS-232 interface for media control and the Control Port with freely programmable control inputs and outputs
(GPIO). Despite its compact dimensions, the RCM-26 is unmatched in terms of its capabilities and audio performance. The IRIS-Net
™
Remote Control Module RCM-26 extends the functionality of PowerH power ampli-
fiers by providing:
• remote supervision and remote control
• AES3 (AES/EBU) digital inputs
• digital signal processing
• advanced loudspeaker protection algorithms
• system integration and networking
IRIS-Net™is
the integra-
platform for all remote-controllable devices and
systems from Telex Communications, Inc. It allows
complete audio systems with a multitude of identical
or different devices to be configured, supervised and
controlled centrally from a single user interface. IRIS-
™
supports Ethernet, CobraNet™, CAN-bus and
Net
USB and is open for further implementations in the
future. IRIS-Net
supervision of power amplifiers and loudspeakers including their cables and interfaces. System statuses are
being polled permanently, with errors detected and
reported instantaneously and all problems and other
™
makes possible the comprehensive
ted software
events logged along with the date and time of their
occurrence. The totality of parameters and settings of
all system components can be stored and reloaded at
the push of a button ('Total Recall'). Depending upon
the application, users can design their own control
panels, program automatic sequences, and form device and function groups.
™
IRIS-Net
dreds of audio installations and systems and has demonstrated its merits in a very wide variety of applications. Since the year 2002, IRIS-Net
form for the EV Precision series power amplifiers and
since 2005 also for the NetMax N8000 networked
matrix system.
has been used for several years now in hun-
™
has been the plat-
Supervision and Diagnosis
The RCM-26 transmits all relevant amplifier data to the
IRIS-Net
of the power amplifiers, the temperature in the power
blocks and in the power supply, voltages and currents at
the outputs, all protections, the mains voltage and current
consumption, pilot tone and network status.
™
user interface, supervising the operating status
• linear 24 Bit AD/DA converters,
Sigma-Delta, 128 x oversampling
• dynamic range > 116 dB
• 96 kHz sample rate, 48 kHz optional
• THD+N < 0,005%
• 2 DSPs 150 MHz / 300 MIPS computing power
• 48 Bit double-precision algorithms
The impedance measurement with a 20 Hz to 20 kHz sine
wave sweep and the comparison with the stored reference
data makes it possible to diagnose with precision the condition of the connected loudspeakers and even of their
individual components and cable connections. Problems
are therefore detected early and the system is able to respond in good time. It is even easy to examine the state of
loudspeakers that are difficult to access, such as those in
stadiums or large entertainment venues. The System
Check function allows you to measure comprehensively
and conduct a full examination of a very large audio system
at the push of a button. Even in live performance, the connected load is monitored continuously. Any undershooting
(short-circuit) or overshooting (interruption) of the set
tolerance limits is automatically detected and reported
immediately.
Remote Functions
Remote control via the IRIS-Net™provides Power On /
Standby switching and the programming of power-up
sequences for the power amplifiers as well as level settings
and the muting of individual channels or channel groups. In
the RCM-26, all parameters can be controlled in real time as
well as stored in user memories, from which they can be
retrieved and reloaded subsequently.
DSP Functions
X-Over:Linkwitz-Riley, Butterworth, Bessel
FIR Filters:zero-latency processing, linear phase x-over
Master EQ:6 filters per channel; PEQ, lo-shelf, hi-shelf, hi-pass, lo-pass selectable
Channel EQ:6 filters per channel; PEQ, lo-shelf, hi-shelf, hi-pass, lo-pass, all-pass selectable
Master-Delay:2 ms - 2000 ms per channel
Channel-Delay: speaker alignment
Dynamics:compressor, limiter per channel
Protection:advanced digital voice-coil protection algorithms
Misc.:input routing, level, mute, polarity, sine and noise generators, VU meter
FIR Filters
Although FIR filters require a massive
amount of processing and are highly complex, they are realized in the RCM-26 in addition to the classical filtering and signal processing functions. Available are linear-phase
FIR filters and 'zero latency' FIR filters, which
add no further latency to the time signals
require to pass through the device.
Users can create their own linear phase
'brick-wall X-overs' and edit them in real
time.
Example: Linearization of a floor monitor
Original frequency response of monitors on stage
Zero-latency FIR equalization
Potential FEEDBACK frequencies
Linear frequency response of the 'pre-linearized'
monitors on stage
For Dynacord loudspeaker cabinets, measurements of the frequency and phase response are already provided in the IRIS-
™
. This data can be displayed and merged in IRIS-Net
Net
together with the filter, crossover and delay settings. The
superposition then shows the acoustical frequency response of
the loudspeaker cabinet.
The IRIS-Net
™
instead of the AES3 digital input, a CobraNet
making it possible to integrate PowerH power amplifiers into
CobraNet