– Drew Kalbach, The Absolute Sound
AMG PRA
Overall, the PRA’s design is simple, but attractive and effective.
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Before I dive into listening, it’s time to look at the “Active Low Frequency and Harmonic Gain” control feature. To put it very simply, this knob is somewhat like Ye Olde Loudness switch of yore. When turned on it very noticeably boosts bass, without increasing the overall volume. It is an interesting EQ effect, and definitely achieves NuPrime’s stated goal of giving smaller speakers a bit more natural low end. It worked well with my Wharfedale 225s, and actually sounded fairly nice with my Omen Dirty Weekend on its lowest setting. However, through the Polk L600 (review forthcoming), the knob made the bass a little too flabby, which makes sense. (The L600 have a very deep low end, and compensating made the bass a little too intense.)
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The backgrounds were shockingly black, and it almost felt as if the AMG PRA preamp was nearly transparent, if you’ll forgive a reviewing cliché. That deep noise floor allowed the music to shine with a crispness and dynamism that I absolutely loved.
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AMG STA
…“Active Low Frequency and Harmonic Gain” control feature. To put it very simply, this knob is somewhat like Ye Olde Loudness switch of yore. When turned on it very noticeably boosts bass, without increasing the overall volume…It worked well with my Wharfedale 225s, and actually sounded fairly nice with my Omen Dirty Weekend on its lowest setting.
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The single STA was more than enough to power my Zu Omen Dirty Weekends, and made my copy of the recent Ray Charles vinyl reissue Genius + Soul = Jazz sing and scream and shout. Lows were suitably solid, and the midrange really shone with an extremely pleasant smoothness. I never felt as though the AMG STA lagged behind or ran out of headroom powering the Zu DWs, even on this very dynamic recording.
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Where this dual-mono configuration really worked was with the Polk L600s, the more difficult pair of speakers to drive. The AMG STA retained its signature relaxed and easy sound, but with that much power on tap really opened up the full potential of the Polks. The backgrounds were shockingly black, and it almost felt as if the AMG PRA preamp was nearly transparent, if you’ll forgive a reviewing cliché. That deep noise floor allowed the music to shine with a crispness and dynamism that I absolutely loved.
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Williams’ fills sounded exuberant and rhythmically complex, and the system never compromised or slowed down his fascinating drumming. In the midrange, the piano and horns were smooth and silky with a hint of nice, heavy warmth down in their lower regions. Hancock’s solo was quick and slithering, like the song’s namesake, and each note was clearly delineated. Attacks and decays were on point, which added to the whole rhythmic picture building throughout the song. When the horns massed for the theme, each instrument remained wholly itself and focused, creating a wide sense of soundstage. The STA/PRA dual-mono combo worked very well with the L600s, since the speakers have a very solid and deep lower end, and the amp/preamp shines in the lower registers. It was that deep heft that really brought a difficult song like “King Cobra” to life, and leant the entire ensemble a massive sound.
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For many folks, I suspect a single STA will provide enough power, but for those who have more difficult-to-drive speakers, or those who want a massive amount of power on tap and ready to go, the monoblock setup is fantastic. This is a system worth trying and comes highly recommended.