ATi AT1820 Series


Amplifier Topology – While there are numerous classes of amplifier design, the AT1820 Series amplifiers use the traditional Class-AB topology


At 200 Watts RMS per channel, the AT1820 Series provides the best price to performance ratio of any amplifiers available.

AT1820 Front

The AT1820 Series comprises six amplifier models.

The series starts with the two-channel AT1822, and finishes with the seven-chan­nel AT1827.

The AT1820 Series amps are passively cooled by large heat sinks.

This feature may be especially important in small home theater systems that can not hide the equipment in a rack or closet.

An optically-coupled protection circuit automatically shuts down the amplifier in an overload situation, such as when someone accidentally shorts out the amp.

Once the protection circuit is engaged, it checks the conditions regularly and restores output automatically when the overload situation is remedied.

Since the protection circuit is optically coupled to the audio circuit, there is no direct electrical connection for the protection circuit to affect sound quality.

A magnetic circuit breaker provides further protec­tion.

The AT1820 Series amps use the same transformer construction as the top-of-the-line AT6000 and AT4000 Series amps.

It also uses double-sided glass epoxy circuit boards and the same rug­ged, powder-coated chassis used in all their products.

The AT1820 Series amps include ATI’s Ultra Soft Turn-On circuit.

This circuit gradually powers up the amp and will not trip your household circuit breaker or dim the lights when you switch it on.

The amps also include a trigger input that allows it to be turned on and off, remotely.


Convection Cooling with Massive Heat Sinks

The AT1820 Series uses large extruded large heat sinks, one for each amplifier channel.

Huge Toroidal Transformers

Transformers AT1820 

The huge transformers used in ATI amplifiers employ high-grade silicon steel cores with bi-filar windings.

To reduce crosstalk through the transformer, each amplifier channel gets its own set of secondary transformer windings.

Remote Triggers

All ATI amplifiers feature a 12V trigger that allows them to inter­face with control systems or processors so they can be turned on and off remotely.

Optical Protection Circuitry

This safety feature instantaneously stops current from flowing in the amplifier’s output under three conditions; 1) an over-current / short circuit condition, 2) high frequency oscillation & 3) over-tem­perature condition.

If activated, this circuit will sample the con­dition every 10 seconds and restore output when the problem is cleared.

In case of an excessive DC offset on any channel, the chassis will shutdown and power will need to be cycled to restore operation.

Ultra-Soft Turn-On

ATi top

High power amplifiers draw a momentary – but tremendous – in­rush of electrical current when you turn them on.

This will not hap­pen because of ATI’s Ultra Soft Turn-On circuitry.

Low Distortion/Low Noise

The exact “nature” of sound is a matter of individual choice and environmental conditions, however distortion and noise are abso­lutely measurable in any situation.

All ATI amps are at the “cutting edge” of the lowest distortion and noise possible.

Amplifier Topology

While there are numerous classes of amplifier design, the AT1820 Series amplifiers use the traditional Class-AB topology

Specifications AT1820

Specifications AT1820 
Number of Channels 2 to 7
Output Power (FTC – 8Ω/4Ω) 200 / 300 Watts
THD+N (FTC Power – 8Ω/4Ω) < 0.03% / <0.075%
Output Power (EIA – 8Ω/4Ω) 250 / 375 Watts
THD+N (EIA – 8Ω/4Ω) < 0.005% / <0.015%
Frequency Response 20Hz – 20kHz ±0.1dB
Gain 28dB
Input Sensitivity 1.6 Volts
Input Impedance 28kΩ (nominal)
Load Impedance Rated for 4Ω to 16Ω

Safe with all types of loads

S/N Ratio (Ref. 8Ω FTC Power) > 120dB (A-Weighted)
Phase Response (1W into 8Ω) +5° to -15° from 20Hz to 20kHz
Power Bandwidth (1W into 8Ω) +0, -3dB from 5Hz – 100kHz
Damping Factor > 400 from 10Hz – 400Hz
Crosstalk > -100dB from 20Hz – 20kHz
DC Output Offset < ± 10mV
Slew Rate > 50V / μS
Remote Trigger Input 3.3 to 24 VDC – Tip Positive
Chassis Dimensions (W x D x H)

5 to 7 Channels

17.0 x 17.625 x 7.73 – inch

43.2 x 44.8 x 19.6 – cm

Chassis Dimensions (W x D x H)

2 to 4 Channels

17.0 x 14.625 x 7.73 – inch

43.2 x 37.2 x 19.6 – cm

ATi Power

Additional information


AT1822 2 Channel, AT1823 3 Channel, AT1824 4 Channel, AT1825 5 Channel, AT1826 6 Channel, AT1827 7 Channel



AMPLIFIER TECHNOLOGIES INC At ATI, they make heavy-duty amplifiers with proven circuitry, meticulous assembly and rigorous testing designed to deliver state-of-the-art audio for years, all designed by them and built in their own US factory. It’s a simple story, American amplifiers built by American people. They hope you enjoy listening.


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