Anthem STR Power Amplifier – Stereo Power Amp

Anthem STR Power Amplifier

The STR Power Amplifier is the beating heart of a world-class 2-channel sound system. It delivers massive power generation, with audiophile-quality output in a smartly designed component. Designed, engineered, and Crafted in Canada, the STR Power Amplifier uses two colossal transformers and multiple high-current output devices so the most subtle details and dynamic peaks are handled equally well.

• Designed to pair with STR Preamplifier (sold separately)
• 400W / 600W / 800W continuous power into 8Ω / 4Ω / 2Ω (both channels driven)
• Dual mono design with 2 massive toroidal transformers
• Graphical front panel display with power meters
• Advanced Load Monitoring (ALM) Technology
• Balanced XLR and single-ended RCA inputs
• 4 power on/off options
• Available in Silver and Black finishes
• Crafted in Canada
• 5 Year Warranty

Highlights & Key Technologies

Cascoded Complementary Feedback Input Stage
The STR Power Amplifier benefits from our proprietary input topology — a unique departure from the classic differential input stage. Eight low-noise bipolar input devices are configured in a complementary active-loaded cascoded feedback arrangement for reduced distortion, exceptionally linear response and superior bandwidth. Transistors in critical stages are hand-selected and matched for lowest possible distortion.

Sixteen Bipolar Output Devices Per Channel
Anthem engineers incorporated sixteen bipolar output devices per channel, resulting in high peak power capability, effortlessly reproducing even the most challenging material. The use of multiple bipolar output devices in class AB configuration also dramatically reduces distortion while ensuring extreme linearity, extensive bandwidth, and stress-free reliability. Experience the immense dynamics of up to 800 clean watts delivered into demanding 2-ohm loads, or 400W into 8 ohms/600W into 4 ohms continuously and with both channels driven.

Massive Toroidal Transformers
Conservatively rated, in a low-profile design shaped to minimize hum, the low-impedance toroidal power transformers — one for each channel — make no sacrifices when it comes to delivering a supply of pure, clean, low-noise power. Both the power supply impedance and internal cabling inductance are minimized to deliver an unobstructed path for maximum power. This allows the two amplifier channels to produce stable, continuous power at maximum output without affecting one another, even when driving the lowest impedances. While some amplifiers oscillate or run out of power when driving lower impedance loads, the STR Power Amplifier remains perfectly stable under all conditions.

Soft Turn-On
A sequence-controlled soft turn-on significantly reduces power line transients and inrush current during start up, thereby preventing accidental tripping of circuit breakers.

No Rail Fuses
The amplifier sections are Direct Connected to the power supply capacitor bank. This keeps output impedance remarkably low while making more power available to the amplifier. Even when driving lower or complex impedance loads, the result is audibly superior performance.

Power On/Off Options
In addition to the traditional options for power-on, the STR Power Amplifier allows trigger mode and audio signal sensing to be combined so you would never need to think about turning the amplifier on or off manually. This can be useful when using a preamp with Home Theater Bypass mode together with a surround sound processor in the same system.

Advanced Load Monitoring Technology
Exclusive ALM technology monitors internal temperature, current and voltage to ensure safe and uninterrupted long-term operation. ALM is not in the signal path, so it never gets in the way. Instead, ALM engages instantly, but only in the most extreme circumstances, to protect your amplifier and speakers from damage, while lowering the chance of a line fuse blowing during an over-current condition. The front panel display confirms status at all times.

Details & Specifications

MODEL INFORMATION
Model: STR Power Amplifier
Warranty: 60-month warranty (Canada & USA)
Available Finishes: Black, Silver
Designed and Crafted in: Canada

POWER OUTPUT
Output Power (per channel, continuous, 20 Hz - 20 kHz, <1% THD):
8Ω: 400 W
4Ω: 600 W
2Ω: 800 W (maximum 3 seconds due to high current draw)
Both channels driven continuously

AMPLIFIER PERFORMANCE
THD (400 W): 0.0007% (1 kHz), 0.004% (20 kHz)
IMD (300 W):
ITU-R (19 kHz + 20 kHz): 0.0006%
SMPTE (60 Hz + 7 kHz): 0.0016%
SNR (IEC-A, ref. 400 W): 121 dB
Frequency Response (20 Hz - 20 kHz): ± 0.1 dB
Power Bandwidth (-3 dB at 400 W into 8 ohms): 91 kHz
Slew Rate: 30 V/μs
Damping Factor (20 Hz - 1 kHz): 360
Channel Separation: 101 dB (100 Hz), 98 dB (10 kHz)
Voltage Gain: 29 dB

INPUTS
Balanced XLR Inputs: 2 channels (Pin 1: Ground, Pin 2: Normal, Pin 3: Inverted)
Single-Ended RCA Inputs: 2 channels
Input Impedance: 10 kΩ (RCA), 15 kΩ (XLR)
Input Sensitivity (for 400 W into 8Ω): 2.1 Vrms

OUTPUTS
Speaker Terminals: Heavy-duty binding posts (2 channels)
Configuration: Accepts one speaker connection per binding post pair

CIRCUIT DESIGN
Topology: Class AB
Input Stage: Cascoded complementary feedback with 8 low-noise bipolar devices
Output Devices: 16 bipolar output devices per channel
Design Architecture: Dual mono with separate toroidal transformers per channel
Power Supply: Direct-connected to capacitor bank (no rail fuses)
Component Selection: Hand-selected and matched transistors in critical stages

PROTECTION & MONITORING
Advanced Load Monitoring (ALM): Monitors temperature, current, and voltage
Fault Protection: Thermal, Load, DC, Voltage Supply, High Frequency detection
Soft Turn-On: Sequence-controlled to reduce inrush current and prevent circuit breaker trips
Channel Fuses: Replaceable fuses on rear panel (per channel)

CONTROL & CONNECTIVITY
Front Panel Display: 7-inch graphic display with power meter and status information
Display Modes: Power meter, Power + Temperature
Power Meter: Instantaneous peaks with peak hold indicators
Trigger Input: 5-24V AC/DC (3.5mm jack)
Trigger Throughput: For daisy-chaining to additional devices
Audio Signal Sensing: Automatic power on/off based on input signal detection
Power On/Off Modes: Manual, Trigger, Audio Signal Sensing, Combined Trigger + Signal Sensing
USB Port: Rear panel for firmware updates via USB stick

POWER SPECIFICATIONS
Power Requirement:
120V version: Single phase AC, 108V to 132V at 60 Hz
220V-240V version: Single phase AC, 198V to 264V at 50 Hz

Power Consumption:
Standby: 310 mW
Idle: 65 W
Typical Playback Levels: 150 W - 300 W
High Playback Levels: 600 W - 1100 W

PHYSICAL SPECIFICATIONS
Dimensions (W x H x D): 17" x 6-¾" x 18-½" / 43.2 x 17.2 x 47 cm (depth not including power cord)
Weight: 60 lb / 27.3 kg (unpacked)
Power Cord Inlet: IEC C18 type
Chassis Ground: Screw terminal on rear panel

DISPLAY & INTERFACE
Display Brightness Settings: Low, Medium, High (adjustable 3-100)
Wake-Up Brightness: Configurable for 5-second boost when button pressed
Temperature Display: Optional display in lower corners
Temperature Units: Celsius or Fahrenheit
Speaker Impedance Setting: 8Ω, 4Ω, or 2Ω (for power meter accuracy only)

INCLUDED ACCESSORIES
STR Power Amplifier
Operating manual
3.5mm trigger cable
IEC power cord (country-specific: US / UK / EU / CN supplied by factory)