Accustic Arts Audio Mono II monoblock power amplifier Associated Equipment

Sidebar 2: Associated Equipment

Digital Sources: dCS Rossini Transport SACD/CD transport & Rossini DAC & Rossini Clock; Intel NUC7i7BNH with 8GB RAM, 128GB SSD, running Roon; Linksys routers with two sets TP-Link gigabit Ethernet media converters plus multimode duplex fiber optic cables; Small Green Computer linear power supply (2) & Small Green Computer 200W Linear Power Supply; external hard drives, SSD USB sticks, iPad Pro.
Power Amplifiers: Dan D'Agostino Master Systems Progression Monos.
Loudspeakers: Wilson Audio Specialties Alexia 2.
Cables: Digital: Nordost Odin 1 & Odin 2 & Valhalla 2 (USB), Wireworld Platinum Starlight Cat8 and AudioQuest Diamond (Ethernet). Interconnect: Nordost Odin 2. Speaker: Nordost Odin 2. AC: Nordost Odin 2, Kimber Palladian, AudioQuest FireBird HC.
Accessories: Grand Prix Monaco rack & amp stands, 1.5" Formula platform; Nordost QB8, QX4 (2), QK1 & QV2 AC power accessories, QKore 1 & 6 with QKore Wires, Titanium and Bronze Sort Kones, Sort Lifts; PS Audio P20 power regenerator: AudioQuest Niagara 5000 power conditioner & NRG Edison outlets & JitterBugs; GreenWave AC filter; Marigo Aida CD mat; Stein Music Super Naturals, Signature Harmonizers, Blue Suns/Diamonds, Quantum Organizer; Bybee Room Neutralizers; Absolare Stabilians; Resolution Acoustics room treatment; Stillpoints Aperture panels.
Room: 20' L by 16' W by 9' H.—Jason Victor Serinus

COMPANY INFO
Accustic Arts Audio GmbH
US representative: Finest Fidelity
3 Sagebrook Drive
Bluffton, SC 29910
(386) 341-9103
ARTICLE CONTENTS

COMMENTS
JRT's picture

I would like to see Stereophile subjectively and objectively review and test a ~$3k Rotel RB-1590 stereo amplifier, claimed to be two separate monoblocks in one enclosure. Rotel rates it at 350W/channel into 8_Ohms, 4_Ohm min load, 120_dB s/n A-weighted (presumably referenced to full power), 0.03%_THD over the range of 20_Hz to 20_kHz, frequency response 10_Hz to 100_kHz ±0.5dB.

It would have been interesting to know how that $3k Rotel subjectively and objectively compares to this $25k/pair Accustic Arts Audio Mono II monoblock power amplifier, after being rebuilt with proper power supply transformer (these big mistakes are not confidence building). More than 8x the price should buy some nontrivial improvement, else the opportunity costs need further consideration.

Bogolu Haranath's picture

For $3,000, we can also get PS Audio Stellar mono-blocks (Stereophile Class-A) 350 WPC 8 Ohms and 700 WPC 4 Ohms :-) ...........

Ortofan's picture

... following are a couple of other subjective and objective reviews to tide you over:

https://www.bwgroup.ch/wp-content/uploads/2016/11/Hi-Fi-News-11-2015-Test-Rotel-RC-1590-RB-1590.pdf

https://hometheaterhifi.com/reviews/amplifier/preamplifier/rotel-rb1590-rc1590-preamplifier-power-amplifier-review/

JRT's picture

I had not seen those.

Ortofan's picture

... in the Mono II's price range, you know what to do next."

Permit me to finish that thought.
Buy a pair McIntosh MC1.25KW or a pair of Pass Labs X600.8 amps.
Or, if you can live with a two-channel amp, then a Pass Labs X350.8 or a D'Agostino Classic 2 will save you about $10K.
Better yet, save another $10K with a Parasound JC5.

Bogolu Haranath's picture

You could also consider the new Krell Duo 300-XD stereo-amp ($10,500), 300 WPC into 8 Ohms :-) ........

Ortofan's picture

... four fans. No thank you.

Bogolu Haranath's picture

For most of the listening levels those fans probably won't turn on ........ Even if they did, the noise levels would be low enough, not to interfere with the listening to music ......... See Stereophile review of albeit more powerful older model Krell Solo 575 mono-blocks .......... MF did not mention any thing about fan noise interfering with his listening :-) ..........

Bogolu Haranath's picture

Or, you could also consider McIntosh MC462 stereo-amp ($9,000, Stereophile Class-A), 450 WPC 2, 4 or 8 Ohms :-) ..........

Ortofan's picture

... high enough into lower impedances. Good try, though.

Bogolu Haranath's picture

450 WPC 2, 4 or 8 Ohms ....... For most of the music, for most listeners, for most of the listening levels, with sensitive speakers, we probably don't need more than 450 WPC :-) .........

Bogolu Haranath's picture

McIntosh MC462 can deliver more power than specified 450 WPC ........ See Stereophile measurements :-) ..........

Bogolu Haranath's picture

Or, you could also consider Bel Canto REF600M mono-blocks ($4,990, Stereophile Class-A), 300 WPC into 8 Ohms :-) ..........

Ortofan's picture

... emits ultrasonic switching noise. Strike three.

Bogolu Haranath's picture

No human being can hear that high ultrasonic switching noise ......... No tweeter can reproduce that high ultrasonic switching noise ........ No music extends into that high ultrasonic switching noise ........ See Stereophile measurements of Bel Canto REF600M :-) .........

Ortofan's picture

... what we can or cannot hear. No audio amp should be radiating RFI.

Bogolu Haranath's picture

Ok ..... Don't use your smartphone or AM/FM radio or turn on your TV, while listening to music :-) .......

Bogolu Haranath's picture

If you insist on high power, in addition to the amplifiers you mentioned above, we can also consider the Bryston 28-B/3 ......... 1000 Watts into 8 Ohms and 1800 Watts into 4 Ohms ....... $24,000/pair ....... See Stereophile review of older model Bryston 28-B :-) ..........

Ortofan's picture

... suggestion. Even the 7B³ would be sufficient to far exceed the power ratings of the Accustic Arts amp, plus the Bryston 20-year warranty is not to be sneezed at, unless you're afflicted with upgrade-itis.

Bogolu Haranath's picture

Thank you ....... I could finally appease you :-) .......

Bogolu Haranath's picture

I think that 20 year warranty is also transferable :-) ........

georgehifi's picture

"Manufacturer's Comment
Editor: The lack of performance of the Accustic Arts Mono II power amplifiers was caused by the fact that we unfortunately installed wrong transformers."

When sending a product sample to be reviewed and thoroughly bench tested to Stereophile, one would think that a company would give it's very best sample, (even "cough" better spec'd) than a production one, to be showcased in a magazine that will make or break that product.

this sort of answer happens way to much for my liking
Cheers "cynical" George

georgehifi's picture

"Bel Canto REF600M .........
Submitted by Bogolu Haranath on October 4, 2019 - 2:26am
No human being can hear that high ultrasonic switching noise ......... No tweeter can reproduce that high ultrasonic switching noise ........"

You are correct, but you can hear the effects of the Class-D's output filter that has to get rid of that switching noise, with phase shifts that are large (up to 70 degrees!!!) that reach down to 1khz. That's why many complain about the upper mids and highs with class-D.

(copy and paste this link to your browser)
https://ibb.co/hd9qNC7

Cheers George

Bogolu Haranath's picture

There are/were several Class-D amps and integrated amps included in the Stereophile recommended component lists ....... Many of of them earned Class-A distinction in sound quality and in measurements ....... Bel Canto models are one among them ....... Why is that? ........ Heaven forbid, you are not questioning the hearing ability of the Stereophile reviewers, are you? :-) .......

georgehifi's picture

Reviewers have subjective outlooks, each to his own, but surely no one would turn a blind eye to the phase graph linked in my last post above?

Cheers George

Bogolu Haranath's picture

That one is above my pay-grade ........ May be JA1 with his technical expertise could shed some light on that particular topic :-) ..........

X