Meridian 557 User manual

Background
Meridian have maintained a strong reputation for their power amplifier
technology for over 15 years. Until now, their power amp developments have
concentrated on high-transparency low-power models or on the custom
amplifiers in their renowned active and digital speaker designs.
Meridian 557
The 557 takes the Meridian 500 Series into new territory –with 200W of clean
clear power –for the first time allowing the option of a complete Meridian front
end for large passive speakers. The Meridian 557 can be used with the 502 or
501 preamps, or with a Meridian DSP Surround Processor.
The Meridian 557 houses two powerful amplifiers in a dual mono construction.
The amplifiers are both rated at 200W into 8 ohms. Each over-specified output
stage uses 8 high-power transistors. These, combined with a massive low-
noise 1.6kVA toroidal transformer, permit this amplifier to deliver currents in
excess of 30A, ensuring no loss of performance even into loads that dip below
2 ohms. The massive power delivery of this amplifier makes it ideal for driving
difficult loudspeaker loads.
557 can be operated in bridged mode giving power in excess of 680W into 8
ohms, 1000W into 4 ohms.
The 557 provides balanced and unbalanced inputs as well as twin outputs for
bi-wiring.
The topology of 557 is very much in the Meridian tradition. A high-precision fast
DC-precise input stage is combined with a fully complementary amplification
and output stage. Also, the 557 uses Meridian’s well established self-adjusting
bias and error-correction output topology.
The 557 is fully protected against DC and thermal overload. A proprietary
Meridian soft-start circuit is also fitted.
557
Stereo Power Amplifier
Sales information
1st December 2001
•Dual-mono 200-watt design
•Balanced and unbalanced
inputs
•Massive low-noise 1.6kVA
toroidal transformer
•Current delivery of over 30A
into difficult loads below 2
ohms
•Fully protected against DC and
thermal overload.
•Soft start using proprietary
Meridian circuit
Meridian Audio Limited
Stonehill, Stukeley Meadows
Huntingdon
Cambridgeshire PE29 6EX
T [phone]
F [phone]
Meridian America Inc.
Suite 122, Building 2400
3800 Camp Creek Parkway
Atlanta GA 30331
T [phone]
F [phone]
www.meridian-audio.com

Technical Specification
Power output: 200W into 8 ohms
680W into 8 ohms Bridged
1000W into 4 ohms Bridged
Distortion: <0.05%
Signal/Noise: –90dB
Inputs: Balanced on XLR–Sensitivity 3.00V rms (2.21V rms bridged).
Unbalanced on phono–Sensitivity 1.44V rms (1.34V rms
bridged).
Outputs: Twin outputs for bi-wiring.
Construction: Two-channel dual-mono construction –Stereo and Bridged.
4 pairs of output devices per side.
4 high quality smoothing capacitors per side.
Error corrected output stage.
Idealised magnetic circuit design.
Dynamic bridge front end gives fully balanced input operation.
Fully protected against DC and thermal overload.
Soft start using proprietary Meridian circuit.
Dimensions: 174mm (6.85in) H, 385 (15.16) W, 306 (12.05) D.
Weight 27kg (60lbs)
Controls: Rear-panel controls for Power On/Off, Bridge/Stereo Mode.
Front display: Power indicator lamp.
557
Stereo Power Amplifier
Sales information
1st December 2001
Meridian Audio Limited
Stonehill, Stukeley Meadows
Huntingdon
Cambridgeshire PE29 6EX
T [phone]
F [phone]
Meridian America Inc.
Suite 122, Building 2400
3800 Camp Creek Parkway
Atlanta GA 30331
T [phone]
F [phone]
www.meridian-audio.com