Constellation Audio Performance Centaur Mono monoblock power amplifier Associated Equipment

Sidebar 2: Associated Equipment

Analog Sources: Continuum Audio Labs Caliburn, Cobra, & Castellon turntable, tonearm, & stand; Kuzma 4Point tonearm; Lyra Atlas, Ortofon Anna, Miyajima Labs Zero (mono) cartridges.
Digital Sources: dCS Vivaldi DAC, transport, clock, upsampler; BPT-modified Alesis Masterlink hard-disk recorder; Meridian Digital Media System; Pure Music software.
Preamplification: Ypsilon MC-10 & MC-16 SUTs step-up transformers; Ypsilon VPS-100, Thrax Orpheus phono preamplifiers; darTZeel NHB-18NS preamplifier.
Power Amplifiers: darTZeel NHB 458 monoblocks.
Loudspeakers: Wilson Audio Specialties Alexandria XLF.
Cables: Interconnect: TARA Labs Zero Gold, Wireworld Platinum Eclipse 7. Speaker: TARA Labs Omega Gold, Wireworld Platinum Eclipse 7. Teresonic Clarison Gold, Stealth Sakra & Indra. AC: Shunyata Research ZiTron Anaconda, Wireworld Platinum Electra.
Accessories: Shunyata Research Hydra Triton & Typhon power conditioners (2 sets); Oyaide AC wall box & receptacles; ASC Tube Traps; RPG BAD, Skyline & Abffusor panels; Symposium Rollerblocks & Ultra platform; HRS Signature SXR, Finite Elemente Pagode stands; Audiodharma Cable Cooker; Furutech, Stein Audio demagnetizers; Furutech deStat; Loricraft PRC4 Deluxe, Audio Desk Systeme record-cleaning machines.—Michael Fremer

Constellation Audio
3533 Old Conejo Road, Suite 107
Newbury Park, CA 91320
(805) 201-2610

xsipower's picture

Hello Mr. Atkinson,

I was wondering if you were told what failed on the first unit you were testing at 2 ohms. Was it a fuse? There are four small aluminum panels on the back of the amplifier when removed allow access to ATO (automotive type) fuses.

I'm also surprised the signal to noise measured so poorly. John Curl who designed the input side of the amplifier is known for his superb low noise small signal amplifier designs. See pictures of the inside of the Centaur (can be found by searching the web) they show a rats nets of wires crisscrossing around. Some of these wires come quite close to the transformer.

I understand from the article that this is a "budget" version of the flagship Hercules. It uses the same circuits, but with surface mount components and assembly done in China. Unfortunately the build quality inside the unit does not present itself as a piece of high end audio, especially at the price it's going for. I would say that the metal work of the case is amazing. They must spend a good percentage of the material cost on machining (probably done on a 5 or 6 axis machine).

I think the peaking in the high frequency response is because they do not use an output Zobel network in their design. From the picture of the amplifier module you can see that the output is directly fed from the Mosfets to the output terminals via bus bars that pass under the PCB. The output does not go through a high frequency filter (LRC network). This can make the amplifier susceptible to oscillation with capacitive loads and external ingress of RF signals.

I’m not against five or six figure amplifiers, but I am concerned with:

  1. Poor Signal to Noise for an amplifier of this price and pedigree.
  2. Input impedance way low (way out of specification).
  3. Iffy with loads less that 4 ohms ( specifications say 1000W into 2ohms)
  4. Innards build/wiring quality not up to the price being paid.
  5. Not a big deal, but it concerns me that it has a peaking response in the infra-frequencies.
  6. Probably paying a lot for the glitzy aluminum panels, rather than the meat inside.

Other than that I’m happy that Mr. Fremer enjoyed the units.


John Atkinson's picture

xsipower wrote:
I was wondering if you were told what failed on the first unit you were testing at 2 ohms. Was it a fuse?

Yes, as I write in the footnote to the measurements section in this Web reprint, Peter Madnick told me that a fuse had blown.

xsipower wrote:
I'm also surprised the signal to noise measured so poorly....

Me too, which is why I repeated the noisefloor measurement on both samples. But the noisefloor is still low enough not to be a factor in the amplifier's sound quality, I feel.

John Atkinson

Editor, Stereophile

Rick Tomaszewicz's picture

...for being so gimlet-eyed in reviewing ultra high-end gear.  This means we (the 99% - or 99.9%, as another commentor corrected me) can also rely on you for calling out underperforming affordable gear which has a more relaxed price/expectation ratio.

Perhaps your next gig should be evaluating, with the same thoroughness, large government programs prior to their launch!  

Vadim S's picture

Hello Mr. Fremer,

Thank you for the interesting reviews about some of the world's best power amplifiers.

Could you compare the Centaur monoblock performance to the performance of the Soulution 710 stereo power amplifier, at least concerning their basic sonic character? It seems like they share many qualities in common (basing on your reviews of the bespoke components).

Thank you in advance,