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Classé Sigma SSP AV Processor and AMP5 Review

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Classé Sigma SSP and Sigma AMP5 five-channel amplifier

Classé Sigma SSP and Sigma AMP5 five-channel amplifier

  • Product Name: Sigma SSP and Sigma AMP5
  • Manufacturer: Classé
  • Performance Rating: StarStarStarStarhalf-star
  • Value Rating: StarStarStarStar
  • Review Date: May 28, 2015 08:00
  • MSRP: $ 5,000 (Sigma SSP) and $5,000 (Sigma AMP5)
  • Buy Now

Classé Sigma SSP

  • USB audio up to 24-bit/192 kHz
  • USB (Host) charging capability 2 Amps
  • AirPlay supported formats
    • AAC (8 to 320 kbps) 
    • Protected AAC (from iTunes Store), 
    • HE-AAC, MP3 (8 to 320 kbps), 
    • MP3 VBR, Audible (formats 2, 3, 4) 
    • Audible Enhanced Audio (AAX, and AAX+), 
    • Apple Lossless, AIFF, and WAV
  • DLNA supported formats
    • Apple Lossless (ALAC), mp3, FLAC, 
    • WAV, Ogg Vorbis, WMA, AAC
  • Frequency response  8 Hz - 200 kHz < 1 dB, stereo digital bypass  8 Hz - 20 kHz < 0.5 dB, all other sources
  • Channel Matching  (Left to Right) better than 0.05 dB Distortion (THD+noise) 0.0005%, digital source/bypassed analog source  .002%, processed analog source
  • Maximum input level (single-ended) 2 Vrms (DSP), 4.5Vrms (bypass)
  • Maximum input level (balanced) 4 Vrms (DSP), 9 Vrms (bypass)
  • Maximum output level (single-ended) 9 Vrms Maximum output level (balanced) 18 Vrms Gain Range  -93 dB to +14 dB 
  • Input impedance (single-ended) 100 kΩ (single-ended)
  • Input impedance (balanced) 50 kΩ (Balanced) 
  • Output impedance (single-ended) 100 Ω
  • Output impedance (balanced) 300 Ω
  • Signal-to-noise ratio (ref. 4Vrms input, unweighted) 104 dB, bypassed analog source 101 dB, processed analog source (re. full-scale input, unweighted) 105 dB, digital source
  • Channel separation better than 100 dB
  • Channel matching (left to right) >0.05 dB
  • Crosstalk (any input to any output) better than -130 dB @ 1 kHz
  • Rated power consumption 35 W 
  • Mains voltage 100-240 V, 50/60 Hz
  • Overall dimensions: 17.0” (433mm)  Depth (excluding connectors): 14.57” (370mm)  Height: 3.75” (95mm) 
  • Net weight:18 lb (8.21 kg) 
  • Shipping weight 25 lb (11.34 kg)

Classé Sigma AMP5 Five-Channel Amplifier

All tests un-weighted and 20Hz – 20kHz measurement bandwidth used.

  • Frequency response 10Hz – 20kHz, -1dB into 4Ω 
  • Output power 200W rms into 8Ω All channels driven; 400W rms into 4Ω Any two channels driven* 
  • Harmonic Distortion 0.018% @ 1kHz All channels driven to 1/8th power into 8Ω
  • Peak Output Voltage 113V peak to peak, 40V RMS no load; 113V peak to peak, 40V RMS into 8Ω 
  • Input Impedance 100kΩ Balanced / 50kΩ SE 
  • Voltage gain 29 dB 
  • Input level at clipping 1.4Vrms Balanced/SE
  • Intermodulation Distortion >80 dB below fundamental into 8Ω SE
  • Signal to Noise Ratio -100 dB at peak output into 8Ω (AES17)
  • Rated power consumption 200W @ 1/8th power into 8Ω 
  • Mains voltage 100V - 240V, 50/60Hz
  • Overall Dimensions Width: 17.00” (433mm)
  • Depth (excluding connectors): 14.57” (370mm)
  • Height: 3.75” (95mm)
  • Net weight 23.1 lb (10.48 kg)
  • Shipping weight 30.0 lb (13.61 kg) 

 

*Each channel in the AMP5 supports 400W output into 4 ohms but the AC Mains/power  supply cannot support all channels driven simultaneously at this level, which would require over 2,500W and only occur under a special test condition. According to Classé, every channel easily drives lower impedance loads.

Pros

  • Superb sonic performance for both two channel and multichannel
  • Fully balanced left and right channels
  • Exhaustive and flexible feature set
  • Intuitive interface
  • Excellent network streaming support
  • Exquisite industrial design including integrated rack mount

Cons

  • Lack of balanced connections throughout
  • Lack of automated room correction
  • Limited options for immersive sound formats
  • No video processing

Update 6/27/17:  Classé just released the Sigma SSP MkII Upgrade with Dolby Atmos/DTS:X and 4K UHD Support.

For die-hard audiophiles, Classé needs no introduction.  The company first got its start building amplifiers back in 1980. However, when Classé joined the B&W Group in 2001 it propelled the company to a whole new level in the audio and home theater world.  The B&W group is comprised of Bowers and Wilkins Loudspeakers, Classé, and Rotel.  

Since that time, many an audiophile has auditioned Bowers & Wilkins’ flagship speakers powered by Classé amplification.  I know I have.  Indeed, thanks to the distribution channels, financial resources, and technology of Bowers & Wilkins, it is safe to say that Classé is now perched upon the upper echelon of audio electronics. 

One thing that has particularly struck me about Classé’s electronics is the company’s focus on industrial design. Sleek curves and minimalist style highlighted by a thin-film-transistor (TFT) LCD touch-screen display have all been typical hallmarks of Classé’s products for years. It's some of the best looking gear in audio.  However, no matter how sleek and clean the products have looked, Classé’s lineup has had a very large physical footprint.  Complementing that large footprint has been an equally hefty price point.  

Classe-5300-amplifier

The smooth, sleek curves of the Classé 5300 Five Channel Amplifier

All that changed this past September when Classé announced their Sigma series, consisting of the 7.1 channel Sigma SSP preamp-processor (MSRP $5,000), the Sigma AMP2 amplifier (MSRP $3,500, rated at 2 x 200W into 8 ohms) and the Sigma AMP5 five-channel amplifier (MSRP $5,000, rated at 5 x 200W into 8 ohms).  While still expensive, new Sigma series electronics are the most affordable Classé products to date.  

I asked Dave Nauber, Classé’s president, about the goals of the Sigma series.  "We believe that customers who want something better than mainstream products are looking for a combination of higher performance, quality and exclusivity," Dave told me.  "And by exclusivity I mean that they prefer something that is special—not everyone knows about it and you can’t find it everywhere."

Classe builds products for music lovers that happen to have a TV between their speakers...

"First and foremost,” Dave went on to say,  “We build products for music lovers and the Sigma series is designed for music lovers or audiophiles who happen to have a TV between their speakers or want to have a theater in a family room where the number and location of speakers is limited, even if the budget is not.”  For Dave and the Classé team, the Sigma series is for individuals who prioritize audio quality.  Dave made it a point to tell me, “The Sigma series is clearly different and better than mass market products priced below it and the entry level components of other high-end brands that are priced just above it.”

Each product in the Sigma series is based on a small, standardized, and minimalist form factor.  While Classé has shrunk the outer box, one look will tell you that these units have all the typical hallmarks and performance on paper that make them all Classé.  Each component has exactly the same low-profile, custom-installer-friendly 2U chassis.  In fact, just looking at the front or side of the units, you’ll be hard-pressed to tell them apart.  

 I talked with Dave about the pedigree and circuitry of the Sigma SSP processor.  “The Sigma SSP shares common circuit blocks and critical parts with our more expensive Delta series CP-800 Stereo Preamp/Processor,” he said. “The digital circuits for USB, Network, Coax and Optical signal paths are literally cut and pasted from the CP-800. We use the same DACs for Left and Right channels as the CP-800, but there is one stereo DAC per channel (differential) rather than two (dual differential), so the circuitry is not as complex or costly. As an analog preamp, the Sigma SSP is extremely quiet and sounds beautiful. It also supports the same optional phono module as the CP-800. For anyone who wants a serious high-end stereo preamp that can integrate with AV sources and even provide multichannel processing, the Sigma SSP is a powerhouse.”

Classe Sigma SSP Cover Off

Top view of the Classé Sigma SSP's internal Circuitry

In both audiophile circles and in our own testing at Audioholics, Class D amplifiers have been a mixed bag.  To be frank, most Class D designs haven’t impressed us because of their performance.  However, it’s important to underscore that like so many other manufacturers, Classé is not using someone else’s Class D modules under the hood.  

I took the opportunity to talk with Dave a bit about Classé’s Class D solution.  “Unlike most Class D solutions on the market today, we do not use an off-the-shelf module. The design is a bespoke Classé solution. We expanded the Classé design team to bring decades of experience to the table in this design, employing a true digital topology to harness the power of DSP to achieve our design goals. Using the typical off-the-shelf options would have left us with certain technical/performance limitations such as excessive dead band time [see explanation below] that would have unacceptably limited the performance potential of the amplifiers.”  

Dave went into detail about one of the things that differentiates Classé’s Class D implementation over other vendors.  “There are many specific details, but our ability to achieve what’s called low dead band time (<3ns) is at the heart of why these amplifiers don’t sound like typical class D designs.  There’s quite a lot to talk about, but by reducing dead band time to such a small amount (an order of magnitude or more better than most other solutions), we start with very low distortion and therefore use only a small amount of overall negative feedback. We also supply lots of power to the audio circuitry, which is a shortcoming of many other designs.”  (If you’re interested more on this topic, Classé has a white paper at www.classeaudio.com/documents).  Classé says that the end result of their engineering should be “superb musical sonic performance along with other class D benefits like small size, low heat dissipation and high efficiency.”

 Even though I was familiar with Classé from past experience, I was still excited at the prospect of taking the new Sigma line a spin.  My review setup consisted of the Sigma SSP and Sigma AMP5.  

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Recent Forum Posts:

Alexandre posts on June 27, 2015 10:41
Alexandre, post: 1087631, member: 73792
Because the 2 components are in different rooms (the power amp is in a closet a little further away), I still want to go the trigger route. I'm going to play around with an Arduino but this also looks like a great option: http://www.nilesaudio.com/product.php?prodID=CS12V

I just installed the Niles Audio plug and it works perfectly! It even learns the standby draw of the device you're plugging to it which is really handy.
Alexandre posts on June 26, 2015 00:46
slipperybidness, post: 1087509, member: 56559
Get a power-sensing auto-on power strip for the amp. Problem solved.

Because the 2 components are in different rooms (the power amp is in a closet a little further away), I still want to go the trigger route. I'm going to play around with an Arduino but this also looks like a great option: http://www.nilesaudio.com/product.php?prodID=CS12V

Alexandre posts on June 25, 2015 12:58
slipperybidness, post: 1087553, member: 56559
You have a mistake in your logic. You avoid ground loops by insuring that you have only 1 return path to ground. One way to accomplish that would be to have all of your electronics plugged into the SAME outlet.

Right, thanks for the correction. And yes, I'm probably going to go the arduino route.
slipperybidness posts on June 25, 2015 12:09
Alexandre, post: 1087549, member: 73792
Thanks for the advice, in my setup, the amp is in a closet nearby while the SSP is under the TV, the 2 are plugged to different wall outlets so I'm not entirely sure the auto-on outlet would work for me but maybe (I was hoping to keep the amp plugged to a separate wall outlet to avoid ground loops and to avoid overloading that one outlet).

The other approach I'm thinking about might be a DIY arduino/CAN BUS/relay system… that could be a fun project… if I had time on my hands that is.

Alex.
You have a mistake in your logic. You avoid ground loops by insuring that you have only 1 return path to ground. One way to accomplish that would be to have all of your electronics plugged into the SAME outlet.

Yeah, an arduino or similar system would also do the trick, it really wouldn't be too tough to build at all.
Alexandre posts on June 25, 2015 11:36
slipperybidness, post: 1087509, member: 56559
Get a power-sensing auto-on power strip for the amp. Problem solved.

Thanks for the advice, in my setup, the amp is in a closet nearby while the SSP is under the TV, the 2 are plugged to different wall outlets so I'm not entirely sure the auto-on outlet would work for me but maybe (I was hoping to keep the amp plugged to a separate wall outlet to avoid ground loops and to avoid overloading that one outlet).

The other approach I'm thinking about might be a DIY arduino/CAN BUS/relay system… that could be a fun project… if I had time on my hands that is.

Alex.
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