Solid State Power
Amplifier
At the very top of our amplifier line are the
Mark 2500 (XXV) Professional Power Amplifier , with 300 watts per channel, min.
RMS into 8 Ω at less than 0,05% Total
Harmonic Distortion , both channels driven, 20 Hz to 20 kHz), these amplifiers
represent years of sound reinforcement experience. They are offered in our
traditional satin-gold and black version (Mark XXV) for home music systems, and
the professional version (Mark 2500) complete with black rack-mountable front
panel and custom handles. They are easily transported since they weigh less
than sixty (60) pounds each.
Along with the fully
complementary input circuitry designed into all SAE amplifiers, a unique
Parallel-Series-Output circuit utilizes 16 output devices and combines the
inherent advantages of both parallel and series connected output stages.
Unit-to-unit
repeatability, ease of service, and minimal wiring are the benefits accuring
from plug-in drive, input, and relay boards. A massive heat sink of 1/8"
aluminum, and built-in forced-air cooling ensure cool operation under the most
demanding power and load conditions.
Amplifier Protection
Four means of
protection are included: Avolt/amp limiter which senses load impedances below 2
Ω (without being affected by reactive
loads such as electrostatic speakers which are rated at 4 Ω or higher). A thermal cut-out device for sensing
of abnormal heat-sink temperature, 4 B-supply fuses, and an AC-line
fuse.
Circuitry
The Mark 2500 (XXV)
are completely balanced from input to output utilizing full complementary
double differential inputs, complementary drives and full complementary series
connected output stages. Eight output devices per channel (in paralll/series)
are utilized for higher than normal safe-area operation. The output devices are
run so conservatively that failure is improbable.
Feedback Level
Controls
This type of level
control assures a constant input impedance of 50 kohm and reduces the noise figure to less
than -100 dB below rated output at all positions.
Meters
The meters in the
Mark 2500 (XXV) are direct power reading in Watts. They are extremely useful
and easy to read requiring no conversion charts. A dB reference is provided for
professional applications. In conjunction with the range switch, they cover output
levels from 20 mW to over 400 Watts
Plug-in Board Design
Easily accessible
input, drive , and relay boards make the amplifiers both simple to service and
consistant in performance from one amplifier to another in production. All
boards are constructed with military-grade, FR-10 glass-epoxy material to
ensure circuit integrity.
Loudspeaker
Protection
In case of subsonic
pulses or ±DC outputs the amplifier incorporates a relay activated disconnect
circuit, which will automatically disconnected the loudspeakers from the
amplifier. Used also during turn-on prevent annoying turn-on transients, this
dual relay circuit incorporates features unique to SAE products. The most
important of these alleviates high frequency distortion developed by the relay
due to "contact diode effect"
Power Supply
The engineering goal
was to develop a transformer which was small in size yet have a greater
copper-to-iron ratio resulting in better regulation. This was achieved by using
thicker square-section copper windings and special laminations which have extended window openings effecting lower
heat generation and greater efficiency. This transformer which is manufactured
within the SAE plant is coupled to 4 computer-grade capacitors totaling 40,000
microfarads. This combination creates a power supply which will very no more
than 10% from no load to full load.
Forced Air Cooling
A quiet, high-output
integral fan provides the necessary cooling for continuous operation under
demanding situations or confined installations. The Mark 2500 is equipped with
an extra high-speed fan.
Specifications
Continuous Power
Output per Channel (20 Hz -20 kHz both channels driven, 8 Ω , RMS min.): 300 Watts at 0,05% (T.H.D)
45Continuous Power
Output per Channel (20 Hz -20 kHz both channels driven, 4 Ω , RMS min.): 450 Watts at 0,1% (T.H.D)
Total Harmonic
Distortion (from 20 Hz to 20 kHz at 250 mW to rated power)
at 8 Ω :
0,05% Max.
at 4 Ω :
0,1% Max.
Intermodulation
Distortion (from 250 mW to rated power at 8 Ω
with any 2 mixed frequencies between 20 Hz to 20 kHz at 4/1 voltage
ratio): 0,05% Max.
Frequency response
(at rated power): 20 Hz - 20,000 Hz
±0,25 dB
Noise: greater than 100 dB below rated power
Transient Response
of any Square Wave: 2,5 microseconds
rise and fall time
Slew Rate: 40 Volts per microsecond
Stability: unconditionally stable with any type of load
or no load inclding full-range electrostatic loudspeakers
Damping Factor: 150 Min (100 Hz)
Input
Sensitivity: 1,84 V RMS for rated output
at 8 Ω
Input
Impedance: 50 k Ω
Semiconductor
Complement: 46 Transistors, 49 Diodes
Overload
Protection
Low impedance
electronic-sensing circuit limits with output current below 2 Ω without limiting with 4 Ω or higher (or reactive loads)
Thermal sensing of
inadequate ventilation
Internal B+, B-
suppy fuses
Loudspeaker
protection
Relay circuit
protects loudspeakers fom low frequency oscilations and plus or minus DC
output. Five second turn on/off delay eliminates on/off disturbances
Power
Requirements: 110 - 125 V, 50/60 Hz 100
watts at idling to 1100 watts at rated
output
Dimensions (W x H x
D): 483 x 178 x 400 mm ( 19" x
7" x 15,75") excluding handles controls, and connections)
Weight
(Shipping): 30,9 kg (68 pounds)
Options: Walnut Cabinet WC-25
No comments:
Post a Comment