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Seymour AV Ice Block 5001 Monoblock Class-D Amplifier Review

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Sitting down to do some critical listening, I chose these cuts for review:

Queen | Bohemian Rhapsody | Classic Queen |Hollywood Records
Leonard Cohen | Suzanna (live) | More Best Of | Columbia
Leonard Cohen | Hallelujah (live) | More Best Of | Columbia
Tchaikovsky | Violin Concerto in D, Op. #5 | Jascha Heifetz & Chicago Symphony Orchestra | Recorded in 1957 | SACD | Living Stereo
Miles Davis | So What | Kind of Blue | Columbia
Eels with Strings | Live at Town Hall | Blinking Lights (for me) | Vagrant
Norah Jones | Chasing Pirates | The Fall | Blue Note Records
Richard Strauss | Einleitung | Also sprach Zarathustra op. 30 | Deutsche Grammophon

Across these selections of cuts the 5001 Ice Block mono-blocks revealed their sonic traits to me. Other amplifiers that I was also listening to for comparison purposes included the solid-state Pass Labs X250.5, the tube Mystere IA11, and a chip amplifier.


Bass guitar, synth bass and vocals, were all deep without being boomy. On the Queen and Leonard Cohen cuts, bass notes were plump and deep, with a bit of punch and good detail. It was similar to the bass from the Mystere IA11 EL34 amplifier but slightly cleaner, thus offering more detail and allowing raspy male vocals or the sound of a finger on a bass string and the initial plunk to be more distinct. There was punch with drum kicks and strikes, but these were a little slow. When the music became fast and complex, the articulation of stick strikes would slur together, causing the leading edges to become less distinct. With very deep bass, as on the opening organ of Straus’s Also Sprach Zarathustra, the bass was there, but it didn’t sound like an organ and wasn’t as powerful and resounding as the half in power but four times more expensive Pass Labs X250.5. But, I admit, this particular recording is very difficult for a system to do justice, and many amplifiers and I had in for review have had this similar issue.


The Seymour website states the silver internal wiring was used to achieve a more relax sounding amplifier. I believe Seymour has hit their mark. Almost all cuts played sounded several rows back from the “stage.” Compared to the Mystere IA11, the Pass Labs X250.0, and the chip amp, vocals, violins, French horns, saxophones, and other instruments though the 5001 all had a slightly recessed presentation. It took cranking the volume pretty high for the music to get in your face.

In the case of the 5001 Ice Block mono-block amplifiers, this trait has several effects. I could listen to these amplifiers all-day long and not become fatigued. At high volume or low, in the top end system or entry, the mid-range was smooth and offered no harshness. It made it very easy to pop in a jazz CD, especially an older jazz or blues album, without getting worn out. But, at the same time, specifically with vocals, the singer didn’t sound as big, as vibrant, or present. For some, this is a negative. They want all that hardness in all its glory laid bare. This can lead to quieter or shorter listening sessions. But if you like to rock out for long periods, or even want to play something at a louder volume for more than 4 or 5 tracks, the 5001s offer that option. Their relaxed sound offers just that. Though, when used with more moderate music at lower listening volumes, the mid-range seemed to sink back a bit too far, with either speaker, and thus the music was less engaging. With other speakers this might not be the case. But alas, I only had these two to compare.


Similar to the mid-range, the highs were smooth and here I found more dynamics than in the mid-range. Click sounds and rim shots, and cymbals, all sparkled without being zinging and irritating. Highs were fairly fast and were never thin, and sibilance had a bit more of a ‘zhh’ than ‘shh’ sound. The other thing I noticed was that the very top end of the highs was also relaxed. Jascha Heifetz’s violin, while not having as much detail or texture as when played through the X250.5, did sound nice, full and the high notes wear not grating and thin. From the selected cuts above, with the live Leonard Cohen recordings, and the Jascha Heifetz, the recording space was more apparent when amplified on the Pass Labs or the chip amp. Obviously, seeing as the Pass X250.5 was $6,000 more expensive, this could be expected. But on the chip amp, which was the same price as the 5001 mono-blocks, or the Mystere IA11, which was the same price, hearing more of the recording space, at least in my opinion, would be a positive. And the 5001 mono-blocks didn’t offer me that.

Sound Stage

With both the Bogdan Art Deco and the Eficion F-250 speakers the sound stage offered by the 5001 Ice Block mono-block amplifiers was as wide as the music needed to be and even with the relaxed sound, which seemed to put the ‘stage’ several row back from what the other amplifiers offered, there was still a three-dimensional quality to the music. Left- and right-panned instruments sounded several feet out of each speaker when called for, and more importantly, the sound just left and right of center was filled in. This was especially apparent on classic recordings.

Seymour AV Ice Block 5001 Monoblock Class-D Blue Glow

Final Thoughts

Near the end of the review period, I was able to hook up the RME Babyface DAC and DNM HFNT XLR cables to the amps. I listened to Miles Davis’ Kind of Blue from my Mac and compared it to the CD via the Marantz SA-7 and Superphon pre-amplifier. The sound from the DAC was a bit crisper and some of the lower mid-range was thinner, but in a good way that seemed to allow the horns to sound rougher and more metallic. But the low plunks of the standup bass were less defined and lacked detail and space when compared to the Marantz.

Wrapping up, I’d say the Seymour AV 5001 Ice Block Class-D amplifiers offered a smooth and relaxed sound and enough power to push the Eficion F250 and the less sensitive Bogdan Art Deco to their max. Their sound will offer those who might want to rock out, or ‘jazz’ out for hours, a powerful, relaxed, and cost effective way to achieve this. The relaxed mid-range and smooth highs as well as the deep bass are engaging at high volumes, allow for long listening periods, and these amplifiers should be on the demo list of anyone looking for these sonic traits in their next amplifier.

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