Seymour AV Ice Block 5001 Monoblock Amplifiers: An audiophile bargain?

by admin on April 27, 2009 · 10 comments

in Amplifiers

by Martin Appel

In my search for new and interesting equipment, I came across several intriguing companies which produce a variety of audio/video products. The one that most interested me was Seymour AV.  Their power-based, Class D monoblock amplifiers are based on Bang & Olufsen’s ICEpower technology (ICEpower technology gets the efficiency of a Class D, but with a low distortion modulation and improved MOSFET output stage). Seymour produces three models: the 2001, 120 watts, the 5001,300 watts and the 10001, 600 watts (all at 8ohms). They made some challenging statements as to their performance and at a price that is mind boggling low ($1,099 each for the 5001). Chris Seymour, the man behind the company, explained to me that he only sells direct online to keep the price low.

I knew I was hooked, emailed Chris and requested review samples of the 5001 model. I explained that I’d need four monoblocks due to my bi-amplified system requirements. Chris graciously responded to my request and sent me a pair in the Stainless Steel finish and a pair in their Black pearl blue finish.

As mentioned, these amps are Class D and are wonderfully efficient, using only 9 watts at idle. They weigh in at 11.2 lbs each. The configuration of the rear panel is very similar to the reference Nuforce 9V2 SE amp. Provisions for either single ended (WBT Nextgen RCA) and balanced (Neutrik) operation are provided for via a toggle switch. There is a power on/off switch next to the power cord socket. Five way speaker binding posts are provided as well and DH Labs pure silver wiring is used throughout. This is clearly a quality product.

The Seymour 5001 impressed and right out of the box. Chris only ships the amps after he’s burned them in for 100 hours. A Godsend for audio reviewers. I put at least another 100 hours on them before critical listening began. And yes, they did improve.

My first impression of these amps was that they threw a really big soundstage, equal to any amps I’ve ever had in my listening room. I mean wide, deep and high. Instruments and voices exhibited weight, body and separation that was very impressive. The sheer clarity of the musical presentation, aided by the air and space around instruments, was at least the equal of my reference and in some instances exceeded them. Imaging was excellent and very three dimensional. Symphonic music was especially well presented by these amps with beautiful layering of instruments giving a most realistic presentation. Jazz groups and chamber groups were handled with equal aplomb. And when I spun some blues, they kicked butt. These amps stepped up to every dynamic challenge thrown at them.

Simultaneously, the 5001s are smooth and very detailed. Rare. Sometimes, detail can equate with edginess, especially with solid state amps. Not here. They possess tube-like smoothness and liquidity with micro detail adding up to greater palpability and a sound that doesn’t fatigue. Very impressive.

The ability of the Seymours to handle bass with slam and impact was excellent. While perhaps not quite as taught as my Nuforce amps, they produced equal nuance and micro detail. Your preference for fuller vs. tighter might sway you in one direction or another. Although these differences aren’t huge, they offer insight into the voicing choice made by the designers. The differences manifest themselves in the midrange and high frequency performance. The Seymours  demonstrated a slightly ‘bigger’ voice consistently than the Nuforce. This is not to imply that the Nuforce amp produces a smaller than life size image or a lean sound — simply,  the character of the Seymours offers another choice.

In the area of high frequency performance, it’s apparent that the Nuforce has greater air and extension - a little more life and sparkle. The Seymour’s voicing, being akin to a more traditional tube-like quality, could be a blessing in some systems.

The answer to my opening question in the title is a resounding, yes. These amps produce so much of what the high end has to offer at such a ridiculously low price that it is practically a steal. Not only is it easy on the ears but it is visually stunning. The Seymours come with a thirty day return policy so I strongly urge you to try them. They might just floor you.

The one nit I have to pick is the placement of the on/off switch. Placing it on the rear makes access to the power switch more difficult. I know that these are very efficient amplifiers but having the switch on the rear makes it more difficult to turn them off and therefore burn more energy. I know some manufacturers never want you to turn off equipment. Perhaps an idle switch could then be incorporated thus maintaining a minimal current running through the amplifier. I’ve already expressed that same view about several other amplifier manufacturers’ products. I hope this is not a trend.

Musical Choices

Reference Recordings RR-96CD Rachmaninoff: Symphonic Dances Oue/Minnesota Orchestra
Pablo OJCCD-744-2 Clark Terry/Freddie Hubbard/Dizzy Gillespie/Oscar Peterson: The Alternate Blues
Telarc CD-83373 Ray Brown: Some of My Best Friends…The Piano Players
Capital 72434 94756 2 5 Frank Sinatra: Sinatra Sing for Only the Lonely
Telarc SACD-60042Moussorgsky: Pictures at an Exhibition-Maazel/The Cleveland Orchestra
Telarc SACD-60575 ORFF: Carmina Burana-Runnicles/Atlanta Symphony Orchestra and Chorus

Associated Equipment

Amplifiers: 4-Nuforce 9V2 SE’s monoblocks
Processor: DEQX PDC-2.6P-modified w/transformer upgrade.
Preamplifier: Marantz SC-7S2
CD source: Marantz SA-7S1
Analogue source: Avid Volvere / RB300 arm.
Cartridge: Shelter 7000
Speaker cables: Acoustic Zen’s Absolute, Wasatch’s Ultama
Power Cords, Acoustic Zen Absolute
Interconnects: Acoustic Zen’s Absolute(xlr)
Accessories: Herbie’s Audio Lab: Tenderfeet, Soundcare products, Acme Audio Labs wall outlets.
Power Conditioning: PS Audio Power Plant Premier.
Surge protection: Brick Wall 2R and 8R Surge Protectors.


Seymour AV 5001 specs web page

Manufactured by Seymour AV

Review source: Manufacturer loan

Tel. 515 450 5694

Seymour AV website

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{ 7 comments… read them below or add one }

admin 04.14.09 at 12:30 pm

Marty, excellent review.

Quick question. How much is Seymour and how much is Bang & Olufsen? Lots of modifications, etc?

Cheers, a

Matt 04.15.09 at 6:06 am

ICE technology sounds incredible. From what I understand, it handles everything from the amplifiers mains power input to the loudspeaker output? Is that correct?

All we need now is an stereo integrated version for us paupers :D

Martin Appel 04.15.09 at 9:24 am

Hi Admin and Matt, I’m not a technical guy so I’d urge you to contact Chris Seymour for the technical info. I’ll also pass this along to Chris. By the way, Chris is getting ready to launch a 7-channel home theater amplifier.

Chris Seymour 04.16.09 at 2:55 pm

“How much is Seymour and how much is Bang & Olufsen? Lots of modifications, etc?”

With the ICEpower boards we’ve chosen, most of what is going on is ICEpower. They make boards without their 100kHz PAM SMPS, but we found that the ones with the SMPS had far less ripple and faster power delivery than traditional 60Hz power supplies, which are comparatively slow, inefficient, heavy and rough. Less power supply ripple results in smoother midrange details. Faster power supply delivery results in better woofer control and dynamics. So, we stuck to their boards with integrated power supplies.

We also experimented with input buffers that raise the input impedance, which is typically important only for passive preamps, but found that they added a haze over the sound and wouldn’t be beneficial to enough applications to justify their downsides. So, we nixed that added component that some other manufacturers add.

Which left us with focusing on the component additions that we either thought helped sonically and/or added to the general slickness of the package without a price hit.

Chris Seymour 04.16.09 at 3:04 pm

“ICE technology sounds incredible. From what I understand, it handles everything from the amplifiers mains power input to the loudspeaker output? Is that correct?

All we need now is an stereo integrated version for us paupers :D”

The majority of “ICEpower” is in their analog (note: not digital) switching output stage, but they do have some powerful technology in their switching power supplies. In this case, they are handling from the mains input to the output, with our focus on how best to do what we can outside the board to make it as slick a package as possible.

Currently we’re working on 2, 3, 4, 5 and 7 channel standard width (2x as wide as the monoblocks) multichannel amps. They still won’t have the power switch on the front (sorry…), but they will have an optional 12Vdc trigger power activation. While they sound better being allowed to idle, as we increase the power in one box and get into automation-friendly home theater applications, being able to trigger the power is a valuable option.

Andy Fawcett 04.17.09 at 2:52 am

Great review, Marty, and what a find! These things have got me very tempted.

One question though. Many were critical of the early Class D amps for their claimed lack of timbral fidelity and sterile sound. It seems like the Seymours have cured that, but is there really nothing in their sonic signature (compared to the conventional amps we’re all used to) that those critics could still seize upon to criticise as a “digital amp” flaw?

Martin Appel 04.17.09 at 2:42 pm

Hi Andy, I think that digital amps have come of age. Individual preferences always enter the picture and early digital amps had problems. I think these problems have been solved and just as there is a wide variety of linear amps, and we’re not even talking tubes vs. solid state, there will be a variety of class D amps with differing sonic sigatures as well. You really have to audition any amp your interested in to form a final judgement. Happy listening.

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