Review and Measurements of Accuphase E-270 Amplifier

[aamwgm]

Where the magic lies is in Accuphase’s reliability and serviceability.

And the looks I was a bit skeptical at first (I found the typeface & champagne colour a little 'loud'), until I saw one in the flesh and I feel head over heels in love with the design.
I also own a second hand E-202, which, to my ears, also sounds transparent enough to be functional and power my PeLeon speakers.

Having said that, yes, the reliability of these machines (as demonstrated by my E-202) is legendary.

It would be interesting to see the new Accuphase E-3000 tested, to see if Accuphase has resolved the flaws of the E-270.

Does Accuphase publish the schematics of their integrateds? If so, it might be useful to try and spot the differences for the first clues.

 

[Sal1950]

And the looks I was a bit skeptical at first (I found the typeface & champagne colour a little 'loud'), until I saw one in the flesh and I feel head over heels in love with the design.

They sure are purdy, everything about the look just shouts class.
I wonder if I could do a special order for a black anodize coloring instead of the champagne?

 

[aamwgm]

They sure are purdy, everything about the look just shouts class.

Here's mine.

I wonder if I could do a special order for a black anodize coloring instead of the champagne?

I'll be on board!

 

[Moises]

Thank You for a very intersting review Amir. I have an Accuphase E-370, the next in the lineup. I’ve used the amp as integrated. As integrated I’ve found the amp pleasant, but not the very last word in dynamics and resolution. I now use the E-370 solely as a preamp. Poweramp is an Anaview AMS 1000. A High quality class D amp which is close to Hypex Ncore In specs.

Interestingly this subjectively outperforms E-370 with a comfortable margin. It sounds more nyanced, dynamic and relaxed at the same time. And yes, I use XLR input in the E-370. Guess I have to try RCA now.

I know this is all subjective, and not based on measurements, but what the heck. Thought I’ll share anyway

Did the same with an Accuphase E-280 to drive Kudos C10 with better results using PS Audio S300. Got all items at discount from display sales along many years.

 

[aamwgm]

with better results using PS Audio S300

 

[Moises]

I take that back! I wasn’t paying attention to more details and depth on Accuphase compared to S300, that sounds fast on the low frequency, but less layers of detail.

 

[Moises]

I take that back! I wasn’t paying attention to more details and depth on Accuphase compared to S300, that sounds fast on the low frequency, but less layers of detail.

Further testing: The Accuphase sounds really good as well in what is details and layers with in music, After testing same music, I find the S300fills some gaps where the Accuphase lacked energy to drive the midrange in some deep bass songs, where the the S300 made it tighter and faster. Both complement each other well!

 

[Willem]

Any chance you could rephrase/redefine depth and layering in scientific terms, and provide measurements and/or blind level controlled listening tests?

 

[Moises]

Any chance you could rephrase/redefine depth and layering in scientific terms, and provide measurements and/or blind level controlled listening tests?

The PS Audio Stellar S300 improves soundstage and Kudos C10 performance through its high damping factor, MOSFET Analog Cell precision, and current reserves.[1][2][3]

## High Damping Factor (>550 into 4Ω)
The S300's damping factor exceeds 550 (4Ω) and 1100 (8Ω), providing superior woofer control on the C10's 180mm midbass driver. This minimizes cone overshoot/ringing post-transients, tightening bass while enabling precise phase alignment between drivers for holographic imaging and deeper soundstage. The C10's 8Ω nominal impedance and 87dB sensitivity demand strong grip for its 40Hz extension without bloat.[4][3][5][1]

## MOSFET Analog Cell Microdynamics
The discrete Class A MOSFET input stage captures subtle timing cues and low-level details with zero-feedback linearity, feeding the C10's SEAS Crescendo K2 tweeter and midbass cleanly. This enhances midrange texture and air, expanding perceived depth/width beyond the C10's compact cabinet—reviewers note "layered soundstage" and "expansive" staging.[2][6][1]

## Current Delivery & Stability
140W/8Ω and 300W/4Ω (2Ω stable) with <0.007Ω output impedance deliver headroom for the C10's 25-200W recommendation, preserving dynamics without compression. Low THD (<0.02%) and 50kHz bandwidth ensure smeared-free transients, improving driver coherence and "3D" imaging in reflective rooms.[7][8][4][1]

Sources
[1] S300 Amplifier https://www.psaudio.com/products/stellar-s300-power-amplifier
[2] PS Audio Stellar S300 Power Amplifier https://www.theabsolutesound.com/articles/ps-audio-stellar-s300-power-amplifier/
[3] PS Audio Stellar S300 Stereo Power Amplifier https://lenwallisaudio.com/products/hifi/amplifiers/power-amplifier/ps-audio-stellar-s300/
[4] Kudos Audio Cardea C10 Loudspeakers https://www.soundstageaustralia.com/index.php/reviews/740-kudos-audio-cardea-c10-loudspeakers
[5] Damping factor for M700's vs S300 - Integrateds https://forum.psaudio.com/t/damping-factor-for-m700s-vs-s300/4564
[6] PS Audio Stellar S300 Stereo Amplifier https://magentaaudio.com.au/product/ps-audio-stellar-s300-stereo-amplifier/
[7] Kudos Cardea C10 speakers https://krispyaudio.com.au/products/kudos-cardea-c10-speakers.html
[8] Review and Measurements of PS Audio S300 PWR Amp https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-ps-audio-s300-pwr-amp.9302/
[9] High-End Audio Buyer's Guide 2024: PS Audio S300 https://www.theabsolutesound.com/articles/high-end-audio-buyers-guide-2024-ps-audio-s300/
[10] Kudos Super 10A Loudspeaker - Soundstage HiFi https://www.soundstagehifi.co.uk/shop/p/kudos-super-10a-loudspeaker
[11] Kudos Cardea C10 https://hifiandmusicsource.com/2021/05/kudos-cardea-c10/
[12] [PDF] Analogue and RF performances of Fully Depleted SOI MOSFET https://dial.uclouvain.be/pr/boreal/object/boreal:219125/datastream/PDF_01/view
[13] Cardea Instruction Manual https://kudosaudio.com/wp-content/uploads/2019/02/Kudos-Cardea-C-10-20-Instruction-Manual.pdf
[14] Back to basics https://kudosaudio.com/wp-content/uploads/2021/08/HFC_479_Kudos-Cardea_Reprint-LOW.pdf
[15] Stellar S300 https://midlandhifistudio.one/teaching/poweramplifiers/psaudio/stellar-s300
[16] A review on performance comparison of advanced MOSFET ... https://www.jos.ac.cn/article/doi/10.1088/1674-4926/41/6/061401?pageType=en
[17] CARDEA INSTRUCTION MANUAL https://kudosaudio.com/wp-content/uploads/2021/08/Cardea-Instruction-Manual_New-2021.pdf
[18] PS Audio in the News https://www.psaudio.com/blogs/copper/ps-audio-in-the-news-21
[19] Performance analysis of pulse analog control schemes for LLC ... https://www.sciencedirect.com/science/article/pii/S2314717216300459
[20] C A R D E A I N S T R U C T I O N... https://kudosaudio.com/wp-content/uploads/2022/07/170891_Cardea-4pp-A5-200qty.pdf

Disclaimer: using perplexity to get the content. I do enjoy my Accuphase experience, just the upgrade from ProAc DB1 speakers to Kudos C10, the base sounds “boomy” not tight as before with other speakers. The PS Audio S300 damping factor is double the one of the Accuphase e-280, which reasonably works better.

 

[Moises]

The PS Audio Stellar S300 improves soundstage and Kudos C10 performance through its high damping factor, MOSFET Analog Cell precision, and current reserves.[1][2][3]

## High Damping Factor (>550 into 4Ω)
The S300's damping factor exceeds 550 (4Ω) and 1100 (8Ω), providing superior woofer control on the C10's 180mm midbass driver. This minimizes cone overshoot/ringing post-transients, tightening bass while enabling precise phase alignment between drivers for holographic imaging and deeper soundstage. The C10's 8Ω nominal impedance and 87dB sensitivity demand strong grip for its 40Hz extension without bloat.[4][3][5][1]

## MOSFET Analog Cell Microdynamics
The discrete Class A MOSFET input stage captures subtle timing cues and low-level details with zero-feedback linearity, feeding the C10's SEAS Crescendo K2 tweeter and midbass cleanly. This enhances midrange texture and air, expanding perceived depth/width beyond the C10's compact cabinet—reviewers note "layered soundstage" and "expansive" staging.[2][6][1]

## Current Delivery & Stability
140W/8Ω and 300W/4Ω (2Ω stable) with <0.007Ω output impedance deliver headroom for the C10's 25-200W recommendation, preserving dynamics without compression. Low THD (<0.02%) and 50kHz bandwidth ensure smeared-free transients, improving driver coherence and "3D" imaging in reflective rooms.[7][8][4][1]

Sources
[1] S300 Amplifier https://www.psaudio.com/products/stellar-s300-power-amplifier
[2] PS Audio Stellar S300 Power Amplifier https://www.theabsolutesound.com/articles/ps-audio-stellar-s300-power-amplifier/
[3] PS Audio Stellar S300 Stereo Power Amplifier https://lenwallisaudio.com/products/hifi/amplifiers/power-amplifier/ps-audio-stellar-s300/
[4] Kudos Audio Cardea C10 Loudspeakers https://www.soundstageaustralia.com/index.php/reviews/740-kudos-audio-cardea-c10-loudspeakers
[5] Damping factor for M700's vs S300 - Integrateds https://forum.psaudio.com/t/damping-factor-for-m700s-vs-s300/4564
[6] PS Audio Stellar S300 Stereo Amplifier https://magentaaudio.com.au/product/ps-audio-stellar-s300-stereo-amplifier/
[7] Kudos Cardea C10 speakers https://krispyaudio.com.au/products/kudos-cardea-c10-speakers.html
[8] Review and Measurements of PS Audio S300 PWR Amp https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-ps-audio-s300-pwr-amp.9302/
[9] High-End Audio Buyer's Guide 2024: PS Audio S300 https://www.theabsolutesound.com/articles/high-end-audio-buyers-guide-2024-ps-audio-s300/
[10] Kudos Super 10A Loudspeaker - Soundstage HiFi https://www.soundstagehifi.co.uk/shop/p/kudos-super-10a-loudspeaker
[11] Kudos Cardea C10 https://hifiandmusicsource.com/2021/05/kudos-cardea-c10/
[12] [PDF] Analogue and RF performances of Fully Depleted SOI MOSFET https://dial.uclouvain.be/pr/boreal/object/boreal:219125/datastream/PDF_01/view
[13] Cardea Instruction Manual https://kudosaudio.com/wp-content/uploads/2019/02/Kudos-Cardea-C-10-20-Instruction-Manual.pdf
[14] Back to basics https://kudosaudio.com/wp-content/uploads/2021/08/HFC_479_Kudos-Cardea_Reprint-LOW.pdf
[15] Stellar S300 https://midlandhifistudio.one/teaching/poweramplifiers/psaudio/stellar-s300
[16] A review on performance comparison of advanced MOSFET ... https://www.jos.ac.cn/article/doi/10.1088/1674-4926/41/6/061401?pageType=en
[17] CARDEA INSTRUCTION MANUAL https://kudosaudio.com/wp-content/uploads/2021/08/Cardea-Instruction-Manual_New-2021.pdf
[18] PS Audio in the News https://www.psaudio.com/blogs/copper/ps-audio-in-the-news-21
[19] Performance analysis of pulse analog control schemes for LLC ... https://www.sciencedirect.com/science/article/pii/S2314717216300459
[20] C A R D E A I N S T R U C T I O N... https://kudosaudio.com/wp-content/uploads/2022/07/170891_Cardea-4pp-A5-200qty.pdf

Disclaimer: using perplexity to get the content. I do enjoy my Accuphase experience, just the upgrade from ProAc DB1 speakers to Kudos C10, the base sounds “boomy” not tight as before with other speakers. The PS Audio S300 damping factor is double the one of the Accuphase e-280, which reasonably works better.

Further listening, and adjusting DAC settings from DSD512 to DSD256, less bummy base (tighter now)and more warm sounds on voice, (higher frequencies) using E-280 Accuphase, less exhaustion for longer listening. Coming back to be the favorite for the Accuphase E-280.

Here’s my room correction, impulse response and filter design using Audiolense.

 

[Janck O'Neill]

This review has left me quite confused. I've been saving for a long time to buy one of the basic/older Accuphase models from over a decade ago.
Pretty much all of them show significantly lower SNR on the XLR inputs than on RCA according to the manufacturer's own specifications, and unfortunately I need to use XLR.
Does this mean I should give up on the idea of getting an Accuphase because of this?

 

[Moises]

This review has left me quite confused. I've been saving for a long time to buy one of the basic/older Accuphase models from over a decade ago.
Pretty much all of them show significantly lower SNR on the XLR inputs than on RCA according to the manufacturer's own specifications, and unfortunately I need to use XLR.
Does this mean I should give up on the idea of getting an Accuphase because of this?

I have an e-280 and sounds to me much better using the xlr than the RCA. I even tried an external amplifier PS Audio S300 and overall I found it much better with the XLR.
I’m using holo audio spring KTE L3.

One more thing the resell price is much higher than other brands. It’s a fact!

 

[Sal1950]

One more thing the resell price is much higher than other brands. It’s a fact!

It is! Only a few others like McIntosh can match the resale power.

 

[AnalogSteph]

This review has left me quite confused. I've been saving for a long time to buy one of the basic/older Accuphase models from over a decade ago.
Pretty much all of them show significantly lower SNR on the XLR inputs than on RCA according to the manufacturer's own specifications, and unfortunately I need to use XLR.
Does this mean I should give up on the idea of getting an Accuphase because of this?

I mean, it's nothing that some reverse-engineering and solder work in the XLR input circuitry couldn't help address, but you have to at least know somebody capable of doing that. (Chances are the total modification work would consist in swapping out a total of two pairs of resistors for matching new metal film leaded or thin-film SMD types, using hand-matched values, but you obviously have to identify which ones and what value you need. Having a full schematic of the input stage would make it easier to assess its performance in general, it may warrant some more comprehensive mods. Some common topologies are discussed here.)

The average balanced input has a not-insubstantial noise penalty over an unbalanced one, which is part of why pro levels tend to be that much higher than consumer levels. As such, an input like that should generally have some negative gain (at least -6 dB to match the usual difference between bal and unbal outputs in modern-day DACs, maybe even -12), but the Accuphase ones are unity gain affairs instead. I can only guess that the circuitry was designed some time in the dark ages when consumer audio folks didn't have much of a clue about pro audio, a.k.a. the early 1990s or so, and then dragged along for consistency's sake.