Stellar S300

PS Audio Stellar S300

Power Amplifier

Midland HiFi Studio - Key Information

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Overview & Features

The problems faced when crafting a new power amplifier are many—delivering sufficient power, control, frequency extension, and dynamics while maintaining a perfectly layered soundstage under the most complex musical passages.

All amplifiers sound different. What determines sound quality are the components and topologies of the amp’s input voltage stage and output current stage. Each section should complement the other. Between them, the amp develops its sound.

Stellar’s design imperatives—affordable pricing, and uncompromised sonics—were major challenges solved by the invention of a unique new circuit christened the Analog Cell. 

Stellar engineer Darren Myers had planned from the outset to take advantage of Class D’s high current, low distortion, ruler flat linearity for the output stage—knowing full well it is the input stage that determines sonic character. This critical interface between preamplifier and power amplifier is where Stellar’s magic would be unveiled; where Myers could lavish upon the music the sweet, tube-like quality of Class A biased MOSFETs. His challenge was to synergistically marry both input and output topologies, for which he invented Stellar’s Analog Cell.

The Analog Cell is the heart of the S300’s musicality, where richly overlayed layers of music’s inner details are preserved even in the most complex orchestral crescendos. The Analog Cell is a proprietary, fully differential, zero feedback, discrete, Class A MOSFET circuit, hand-tuned to capture the smallest micro dynamics without sacrificing the loudest macro dynamics music has to offer.


Stereo power amplifier

Dual mono, each with their own power supply

Zero-loss Analog Cell input stage

Powerful MOSFET output stage

RCA Single ended input

XLR “true” balanced input

140 watts per channel 8Ω

300 watts per channel 4Ω

2Ω stable

Less than 0.1% thd 20Hz to 20kHz at rated power

Damping factor greater than 550 for excellent loudspeaker control

Front panel standby button

Efficient operation with very little heat

Dual, solid copper, plated, output binding posts

13 pounds

Input 12 volt trigger

Technical Specification

Unit Weight

13 lbs [5.9 kg]

Unit Dimensions

17” x 3” x 12” Chassis only. 13" deep including connectors.

Shipping Weight

16.5 lbs [7.5 kg]

Shipping Dimensions

22”x 8” x 17”

Color Options



Mains Power Inputs


Accessories Included

UK (BS 1363) (230V version)

Audio Inputs

RCA (Unbalanced)

XLR (Balanced)

Speaker Outputs

Copper base nickel plated binding posts (2 pair per channel)


DC Trigger Input

3.5mm 5-15VDC


3 years parts and labor



30.5dB +/-0.5dB

Sensitivity for rated output power



1kHz@300 Watts <-100dB

Input impedance

Unbalanced 50KΩ

Balanced 100KΩ

Output Impedance

50Hz, 2.8VRMS<0.007Ω

Damping factor

50Hz. 2.8VRMS

8Ω >1100

4Ω >550

Frequency Response @2.8VRMS

10Hz – 20KHz +/- 0.5dB

10Hz – 50KHz +0.1/-3.0dB


1KHz, 1W/4Ω:  <0.02%

10-20KHz, 1W/4Ω:  <0.02%

10-50KHz, 1W/4Ω:  < 0.05% (90kHz BW)

1KHz, 37.5W/4Ω:  < 0.01%

Output Power

Both channels driven 120vac mains, 1kHz, 1% THD

8Ω:  140W minimum

4Ω:  300W minimum

2Ω:  Stable for musical transients