Metaxas Audio Systems Ikarus Manuel utilisateur
KOSTAS METAXAS DESIGN
Ikarus
KOSTAS METAXAS DESIGN
KOSTAS METAXAS DESIGN
KOSTAS METAXAS DESIGN
Contents
Awards & Innovations 01
3 Decades of “Hi-End” 02
Listening Reference 05
Design Philosophy 06
Operating Instructions 11
What the critics say... 12
Specifications 14
Controls & Features 15
Maintenance 16
Schematic 18
EC Conformity 19
KOSTAS METAXAS DESIGN
Awards & Innovations
01
2 X AUSTRALIAN EXPORT AWARD, BHP STEEL DESIGN AWARD,
runner up in AUSTRALIAN SMALL BUSINESS AWARDS
First - Amplifiers- No wire construction with
shortest possible signal path
First - 'Capacitorless' circuits in Audio design
First power amplifier can put full power into
8 ohm load at 1.0MegaHertz!
(refer to article in USA "AUDIO").
First - High Speed diodes in power supply
First - DAC to use lowest jitter 'APOGEE CLOCK'
First - FULL range and high efficiency electrostatic
First - Audio Manufacturer to use BMW-Porsche CAD-PCB
software design systems
You are about to listen to
an amplifier which has
evolved from over 20 years
of dedicated listening and
the application of the
state-of-the-art in every
process of design and
manufacture. I’m sure
you’ll enjoy listening to it
as much as I do.
-Kostas Metaxas DESIGNER
KOSTAS METAXAS DESIGN
3 Decades of Hi-End : 1980’s
02
Opulence Preamplifier Assembly Engraving
Kostas Metaxas circa 1985 Soliloquy Monoblocks
Ecstatic & Revelation Electrostatics
KOSTAS METAXAS DESIGN
3 Decades of Hi-End : 1990’s
03
Apollo Speaker
Reference System circa 1992 Assembly Assembly CZAR 2-way full range electrostatic
Opulence, Marquis & Charisma Preamplifiers
Stainless Steel Turret Punching Iraklis “on-test”Empress Full-range electrostatics
using plastic-composite moulded
frame
PCB design EMPEROR Assembly
KOSTAS METAXAS DESIGN
04
Using technology borrowed from Aerospace and Formula 1, the new
Kostas Metaxas Audio designs reflect the extraordinary
advances that have been made recently in modelling and simulation
software.
For the first time, a High End Audio manufacturer offers audiophiles a
rare glimpse into the conception, design and execution of a complete
product on a component by component basis in 3D.
The Protel PCB software [www.protel.com] extends the quite normal
listening tests on a component by component level to the PCB level.
Schematic Based simulations can test [or verify] the PCB's signal integrity
by running the "Signal Integrity Simulator" which displays a Reflection and
Crosstalk Analysis. And the 3D visualization allows one to include the PCB
as part of the overall wholistic design.
Schematic Capture & PCB design Schematic “Spice” Circuit Simulation PCB Track Risetime & Slewrate signal
integrity testing. In-house RAPID PROTOTYPING Laser Engraving
3 Decades of Hi-End : 2000’s
KOSTAS METAXAS DESIGN
Listening Philosophy
05
The only way to design state-of-the-art audio equipment is to have
first-hand experience with the finest available recording equipment AND
playback equipment.
This is important for two reasons; it ensures that our designs work and
'mate-well' with other products and that their resolution is not limited
by the weakest link in the playback 'chain'.
Kostas Metaxas products have been conceived using
extensive listening tests with a variety of state-of-the-art ancillary
equipment for more than 25 years.
Our amplifiers have been designed using a variety of state-of-the-art
phono playback equipment and our ABSOLUTE REFERENCE -
a custom-made battery-powered Stellavox SM-8 Tape Recorder using
1/4" tape at 30 ips and a Stellavox TD-9 using 1/2" tape at 30 ips
specially calibrated for the Bruel & Kjaer 4003 1/4" omnidirectional
electrostatic instrumentation microphones.
REFERENCE
ULTRA-SHORT SIGNAL PATH :
NO-WIRE DESIGN
A prominent audio designer once described an amplifier as "A straight piece
of wire with gain". We take this further by featuring the shortest possible
signal path in a commercial amplifier. We do not use wire in any of our signal
paths and every component is directly soldered to one large printed circuit
board.
From input to output, the signal passes through no more than 150mm of P.C.
track. The transformer is connected with only 40mm of wiring to the PC
board. This is only possible with our unique construction which features the
complete amplifier (including filtering capacitors) is
assembled onto one single rectangular Printed Circuit Board where the four
sides connect directly to the inputs and outputs, power transistors on their
heat sinks and power transformer.
The audio signal passes through ONLY ONE TYPE OF WIRE which is the high
speed, wave controlled oxygen free copper of our PC board.
HIGH SPEED POWER SUPPLIES
Every power amplifier uses a large, high-current power transformer which
feeds a 'high-current' bridge rectifier to convert the AC from the transformer
into DC voltages which are then mains ripple filtered using massive, comput-
er grade capacitors.
The rectifier bridge that is normally used is relatively large, handles high
current and low voltage which slow switching speed because of its inherent
high internal capacitance.
It has a response time measured in milliseconds which if converted to fre-
quency would mean that it would have a frequency response from DC to
around 100Hz .
KOSTAS METAXAS DESIGN
Design Philosophy
06
Frequencies above 1 kHz would be unable to draw
current instantaneously from the power transformer and would need to
rely on the charge stored in the power supply filtering capacitors.
We replace this slow DC rectifier with ultra high speed diodes wired in
parallel with switching times in 'nanoseconds' which when converted to
audio frequencies have a frequency response from DC-10 MegaHertz.
High and low frequency currents can be drawn from the power supply
more effortlessly .
Design Philosophy
KOSTAS METAXAS DESIGN
Design Philosophy
07
LOW NOISE, HIGH SPEED VOLTAGE
REGULATOR DESIGN
The most significant difference between VALVE and TRANSISTOR circuits
is the amplifier/power supply interaction.
In VALVE amplifier, the high voltages (from 200-400 Volts DC) result in a
50,000 to 100,000 Ohms value for resistor R. The equivalent transistor
amplifier using much lower voltages (from 12-30 Volts) would have a
substantially lower value of R between 200 Ohms-100 Ohms. Therefore a
normal power supply in a transistor amplifier is more likely to affect the
transistor amplifier circuit compared to a Valve amplifier circuit.
If we assume that the regulator impedance at V+ is around 2 Ohms just for
the purpose of this illustration, then let us study the amplitude of the 10
VOLT sine wave as it goes through R and returns back to the OUTPUT of
the TRANSISTOR circuit and VALVE circuit.
In the VALVE circuit, when 10 VOLTS travels across the 50,000 Ohms R towards
the power supply impedance of 2 Ohms , the 10V signal is attenuated
50,000/2 = 25,000 times. Therefore 10V/25,000 = 0.0004 Volts of 1,0kHz sine
wave.
On its way back to the OUTPUT of the circuit it is attenuated by the
impedance of the amplifier (say 100 Ohms): 0.0004 Volts/50,000/1,000 =
0.000008 Volts. Therefore, 0.000008 VOLTS of out of phase sine wave
accompanies the 10 Volts sine wave as out-of-phase distortion in the VALVE
CIRCUIT.
In a normal TRANSISTOR circuit, the 10 VOLTS going across the 200 Ohms
resistor R would be attenuated only 10/200/2 = 0.1 VOLTS. On the way back
to the output, the voltage is attenuated by: 0.1V/200/1000 = 0.05 VOLTS of
out-of-phase sine wave added to the 10 VOLT output sine wave.
V1
12AX7
R1
47K R2
1.82k
RL
300k
C2
0.1uF
V+
Vin
VSIN
IN
OUT
V1
1kHz R1
47K
RL
7.75k
R2
1.8K
Q1
2N2222A
VCC
IN
C2
0.1uF
OUT
KOSTAS METAXAS DESIGN
Design Philosophy
08
In a normal Transistor circuit, the 'phase distortion' is 0.5% as compared to
0.000008% for a normal VALVE circuit .
If we monitor the V+ point of the transistor circuit using an oscilloscope, we
would notice this 0.1 Volts, 1.0 kHz signal. If we were to increase the
frequency to 10,000 Hz and up to 1.0 MegaHertz the speed of dynamic
behaviour of the power supply becomes critical. Using a normal I.C. regulator
would result in the signal at V+ actually increasing in amplitude as the
frequency increases to that at 1.0 MegaHertz the 1.0 Volt sine wave is now
over 1.0 Volt!
To fully understand this interaction between the amplifier an power supply,
it is necessary to understand how a voltage regulated power supply works.
A voltage regulated power supply is essentially a D.C. amplifier (not unlike a
normal power amplifier) which instead of having an audio signal at the input
which is then amplified to become a larger audio signal at the output, has a
fixed D.C. voltage reference at the input which is then amplified and
becomes a larger DC voltage of at the output. The output impedance of the
regulator, not unlike the output impedance (or "Damping Factor') of a power
amplifier is less than one ohm at D.C.
If we use a 2.0 Volt zener diode as our fixed DC voltage reference at the
input of the D.C. amplifier which has a gain of 10, the resulting output
voltage is 20 Volts D.C.
The negative feedback loop of the amplifier which fixes the gain of 10 times
the 2.0 Volt zener reference is very important because it maintains the
output voltage irrespective; of an increase or decrease in the power supply
voltage to the amplifier as long as there is a minimum voltage for the
regulator circuit to operate (for a 12 Volt regulator, the minimum voltage
is 15 Volts).
Figure 6. Output Impedance as a Function of
Output Voltage (MC78XXC, AC, B)
, OUTPUT IMPEDANCE (mą)
OΩ
10
5.0
3.0
2.0
1.0
0.5
0.3
0.2
0.1 .0 8.0 12 16 20 2
VO, OUTPUT VOLTAGE (V)
Z
f = 120 Hz
IO = 500 mA
CL = 0 µF
Figure 4. Ripple Rejection as a Function of
Frequency (MC78XXC, AC, B)
80
50
RR, RIPPLE REJECTION (dB)
0.1 10
f, FREQUENCY (kHz)
0.01
70
0
30
60
1.0
MC78XXB, C, AC
Vin = 8.0 V to 18 V
IO = 500 mA
f = 120 Hz
TA = 25°C
Figure 3. Ripple Rejection as a Function of
Output Voltages (MC78XXC, AC, B)
80
70
60
50
0
.0 6.0 8.0 10 12 1 16 18 20 22 2
VO, OUTPUT VOLTAGE (V)
RR, RIPPLE REJECTION (dB)
PART #ą ă Vin
MC7805Că= 10 V
MC7806Că= 11 V
MC7808Că= 1 V
MC7812Că= 19 V
MC7815Că= 23 V
MC7818Că= 27 V
MC782 Că= 33 V
f = 120 Hz
IO = 20 mA
∆Vin = 1.0 V(RMS)
DS009063-46
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