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StellarTM S300 Stereo Amplifier

300 watt dual mono Analog Cell power amplifier

Built in Boulder
All units handmade in Boulder, Colorado.

Breathe new life into your loudspeakers with the Stellar™ S300, one of the most extraordinary under $5,000 stereo power amplifiers ever crafted. The S300 combines the slam, linearity, and toe-tapping pacing of a Class D output stage with the warmth, grace, and rich inner detail of Stellar’s Class A Analog Cell. The results are nothing short of ground breaking. Liberate a wealth of untapped energy trapped in your media library. Plumb music’s subterranean depths and finally hear the bass your speakers were capable of. Revel in rich layers of fine, full detail. Marvel at the deep, extraordinary, wall-to-wall soundstage. Effortless. Lush. Stellar.

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Stellar S300 Power Amplifier

Product Description

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.

If you’re able to invest in a cost-no-object performance stereo amplifier, you want the BHK Signature 250. For everyone else who refuses to compromise music’s promise, Stellar represents breakthrough performance at stellar pricing.

This product qualifies for our risk free in-home trial in the continental United States when purchased directly from PS Audio. And, trade in and save. Let us repurchase your old equipment at its full and original retail price. We’ll give it a good home and make sure you have the best power in the world. Just click the green Trade Up and Save button above these words to take advantage.

  • 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


Tone Audio

Rob Johnson

“The result of all these strengths gives the S300 a beautiful voice which mates well
with the variety of upstream gear we had on hand for testing. It holds its own against
components that exceed its price tag. This PS Audio component deserves a spot on a short
list of bargain amps that perform beyond what one should expect for the money.

“After a few weeks with the S300 in my reference system, I must admit I am smitten with it.
I applaud PS Audio’s new approach to circuit design bringing together the benefits of both
Class A and Class D technology.”

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Steve Guttenberg

They sounded so good together I couldn't bring myself to try too many other speakers. The sound was rich with resolution to die for.
Magnepan speakers aren't known for their deep bass punch, but here with the two Stellars the .7 speakers' low bass was kicking with "The Legendary Skatalites in Dub" reggae album with really low, feel-it-through-your-toes bass. Austin Wintory's orchestral score for "The Banner Saga" sounded downright huge, and the low bass drums definition was truly stellar!

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HiFi Pig

David Blumenstein

The Stellar DAC/Pre-Amp/Power Amplifier filled my listening room with 3D sound, and they matched well with each of my speakers; the floor standing Audio Physic Tempos, the stand mounted Platinum Audio ST 1’s and the low-to-the ground Mission 727s. I was surprised how different they made each sound and I spent a great deal of time swapping out my Parasound Halo 2.1 integrated amplifier, Bel Canto s300 integrated amplifier to make sure I wasn’t fooling myself. And, yes, I was hearing something new and more evocative from my usual suspects.

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10 Audio

Jerry Seigel

Folks, this is the future. We have heard vast improvements of Class D amplifiers during the last 10 years, and we are at or near the point where the technology is largely irrelevant to the final sound. The sound of audio components is more dependent on the implementation than on the underlying technology. The PS Audio Stellar S300 gets so close to perfection that the low purchase price is an out-of-this-world value. The PS Audio Stellar S300 adds nothing objectionable while delivering wonderful musical performances.

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Don't want to be the competition


I will simply say Paul & his fine team have, what I truly believe is the best amp @1.5k that you could possibly hope own. I wouldn't want to be the competition @ 3k & have to take the S300 on! Every listen just brings smiles. Clarity, depth, balance, dynamic range, and this thing just doesn't seem to run out of gas! I have a pair of Magnapan 1.6 QR's with an SVS subwoofer, the S300 delivers slam & articulation, like I haven't heard before. I had the 1.6's rebuilt by Magnapan 1 year ago after 13 years of serious use, so I am confident they are up to the task. Okay, I did spin some superlatives, sorry. I will sum it up by saying I am totally satisfied with the S300 & would recommend it to all, save your coin, this amp kicks some very serious butt! Thank you Paul & everyone @ PS Audio!

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Two thumbs up!


The S300 delivers a non-fatiguing presentation, with excellent bass control, and gobs and gobs of detail, all emerging from a black background. And it does so even at very low listening levels (living in an apartment, ability to listen at low levels late in the evening is important to me.)

With the Red Wine amp. I had the powered subs crossed over around 70 Hz, at a higher output, to augment the Red Wine's lower bass output. The S300 delivers such powerful, detailed bass that the powered subs are almost unnecessary.

I eventually added the subs back in, but crossed over around 45 Hz, just to provide that low end that you feel almost more than you hear. Just to be clear, the subs are making up for the bass shortcomings of the open baffle speakers, not any shortcomings of the S300.

I give the S300 two thumbs, way up! Anyone want to buy a Red Wine amp?

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Whole new ballgame

JM Unger

I received my Stellar 300 Amp about a week ago. My system is modest: Cambridge Audio CXA 80, Cambridge Audio CXC transport, Ohm Walsh Tall 100's with 2.1 Anti Cables. The 300 replaces the 80 watt amp in the CXA 80 and is connected with low quality single end cables. (the balanced Anticables await the Gain Cell DAC still on it's way.)

The 300 made an immediate difference in the overall sound of the system, beyond just the additional power. The Ohm speakers create a broad and deep soundstage, but with the 300 instrument placement and clarity were clearly improved. Bass was more specific and apparent while the mid-range was richer with greater texture. Treble seemed heightened as well, though without strident overtones. I listen mostly to jazz and classical pieces on CD and through Tidal over a Sonos system. The extra quality power showed enhancement with Tidal as well.

I have to imagine with the Gain Cell DAC in place it will be whole new ballgame.

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My impression in one word: stellar!

The S300's performance is really outstanding. It's very energetic and crisp, has very decent control and momentum. What I like most are its amazing vivid clarity and detail, this is not the kind of slow, warm, laid back and dull amp. Yes, maybe it lacks the last bit of extension at both end of frequency extreme. It's a tiny little bit on the forward and cool side of neutral, but definitely not aggressive, artificial or edgy. It's textured and colorful with very wide soundstage. And the punchy bass! If this is the one and only amp I have in a desert island, I can live with it happily ever after. Sound wise, it's that good.

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Amazing soundstage


I'm not adept at audiophile descriptions so I'll keep this relatively short. I replaced a modded HCA-2 with the S300 and have been mightily impressed. Most noticeable has been the blackness and silence of the background. That might have been a function of the mods done to the HCA-2, which I did love but always had a slight hum. The S300 is dead silent. Amazing soundstage and definition between instruments. Perhaps slightly dry but not overly analytical. I'll take the amazing detail on well-recorded material over warmth hiding poor recordings. I have plenty of poorly recorded albums that I love, I still can listen to them with this amp. The trade off is that well-recorded material sounds unreal. I hear things I never heard before! I'm impressed, and the music sounds wonderful. Thank you!

My system - JA Michell Tecnodec and PS Audio Nuwave front end, Emotiva XSP-1 preamp, PS Audio S300, Alon Mark IV speakers

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Simply amazed!


About 8 years ago I bought the Mark Levinson No. 434 monoblocks. They went for $8000 the pair, and they looked and sounded as good as I’d come to expect for that kind of money. I was happy! They are still very good amps by today’s standards. When I think about how much performance PS Audio has managed to put into a stereo amp that costs less than 20% of what the Mark Levinson’s cost, however, I’m simply amazed. The S300 doesn’t look as expensive, but it’s performance leaves little to forgive. When I’m listening to the Stellar S300, I’ve found myself not thinking about any of that—just the music, with the S300.

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Love the amp

Daniel Dennis

Love the amp and I'm gonna buy it. I found the sound open and detailed with LP vinyl and CDs . Detailed soundstage and very musical in my opinion. I'm a construction worker so my computer skills are kind of limited. My associated equipment is Primaluna prologue 3 tube preamp project Debut carbon turntable and phono stage. Otrofon 2m red cart, Emotiva Erc 1 CD player, Klipsch RF 42 tower speakers, and energy sub in a 2.1 stereo system and PS Audio power cables and Audioquest interconnects. Pretty basic system by High end standards but wow did Freddie Hubbard and Pink Floyd sound great. Eva Cassidy's vocals were so rich and real and Dire straights Ride Across the River blew me away.

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Pete Wilson

Goodness! Despite the slightly lower power of the Stellars, I was able to get 90+dB levels in the (largeish) room. And, for the first time sans subwoofers, there was solid chest-impacting bass.
Next up was Blue Nile’s A Walk Across the Rooftops; Heatwave is a perennial favourite. Again, from the Olive, transferred to digital through the NuWave Phono Converter. Ooh – goodness, even on casual listening there was a bit more going on than I remembered.
Now I have to drive away and do some errands, so the machinery is left playing Best of the Shadows – you know, there’s a bit more going on in there than I’d noticed before, too. And, begum, there’s actual bass.
Bottom line – straight out of the box, these Stellars make my system sound better.

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Fun stuff!


Right out of the box, the S-300 presented a sound stage larger than previously experienced with the older Rotel amplifier. Control was tighter, base was tighter, and the overall experience tighter. After about 3 hours, I adjusted speaker placement to take better advantage of the expanded sound stage. Fun stuff!
One thing surprising, the experience was not strained at all, the sound is very relaxed, not overly bright. After approximately 6 hours, the unit is settling in nicely, both vinyl and digital sources are benefiting from the Stellar. I have other systems to reference back to (not just getting used to the new sound), and am looking forward to reporting back as to how the burn in continues and settles in.

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Finding renewed enjoyment


I find myself digging further back in my CD collection and finding renewed enjoyment in old favorites. Many are digitally mastered (or 20 bit remastered) from the time when that was a new thing. Many selections from Sheffield Labs, DMP, ECM, Telarc and GRP make for good critical listening. My previous impressions (vs my previous preamp and DAC) are reinforced: excellent bass extension, deeper front to back soundstage, more precise placement and crisp percussion.

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This is going to be fun!


The sound is already coming alive… in fact, it’s faaaantastic! I’m currently listening to Robert Cray, Strong Persuader (high rez FLAC file). The detail and punch are just what they should be. His voice is clear and centered, surrounded by nicely balanced treble and bass. Another wonderfully engineered recording and the Stellar GCD shows it off in fine fashion. The clarity has improved and the veil has lifted. Wow, this is going to be fun!

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Stellar S300 Stereo Amplifier

Unit Weight13 lbs [5.9 kg]
Unit Dimensions17”W x 3”H x 12”D (13"D w/connectors)
Shipping Weight16.5 lbs [7.5 kg]
Shipping Dimensions22”W x 8”H x 17”D
Color OptionsBlack
Voltage Options
(Factory set only)
Japan 100V
North America 120V
Europe/Asia/Australia/New Zealand 230V
Mains Power InputsIEC C14
Idle Power Consumption13W
Accessories IncludedUS (NEMA 5-15P) (all versions)
Schuko (CEE7/7) (230V version)
UK (BS 1363) (230V version)
Audio InputsRCA (Unbalanced)
XLR (Balanced)
Speaker Outputs Copper base nickel plated binding posts (2 pair per channel)
DC Trigger Input 3.5mm 5-15VDC
Warranty3 years parts and labor


Gain30.5dB +/-0.5dB
Sensitivity for rated output power1.01V
Noise[email protected] Watts < -100dB
Input impedance Unbalanced 50KΩ
Balanced 100KΩ
Output Impedance50Hz, 2.8VRMS <0.007Ω
Damping factor50Hz. 2.8VRMS
8Ω >1100
4Ω >550
Frequency Response2.8VRMS into 4Ω
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
8Ω140W minimum
4Ω300W minimum
2ΩStable for musical transients


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