|Krell Evolution 900 Monaural Power Amplifier|
|Home Theater Power Amplifiers Mono Amplifiers|
|Written by Jerry Del Colliano|
|Friday, 01 June 2007|
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I have owned various Krell amplifiers in my reference systems over the years, each providing hours upon hours of listening joy. Recently, Krell has released a new top-of-the-line lineup of gear under the Evolution moniker that speaks to those for a need for the best of the best and a willingness to pay for it. The review system under evaluation is comprised of a $10,000 Krell Evolution 505 SACD player with 24-bit 192 DACs, a $15,000 Krell Evolution 202 two-chassis stereo preamp and the monstrous Krell Evolution 900 monaural amplifiers at $20,000 each, or $40,000 for the stereo pair as reviewed. My review samples are done in Krell’s signature silver finish, which is breathtakingly beautiful out of the rack and poised on a simple table as it is installed in my reference system.
To start, it is important to note that the Krell Evolution 900 power amps are nothing short of huge. With a travel schedule that has me out of the country more than in the States over the past two months, I hired Simply Home Entertainment to come out and set up my Krell Evolution system in a way that simply and neatly bypasses my reference installed home theater. The SACD player was installed above the two-chassis preamp on a modern-looking table to the right of my seating position, which came out more elegant than expected. The amps were placed by two strong men beside my Wilson WATT Puppy Version 7 loudspeakers. Connections were made one of two ways during the review. The first was with Krell’s proprietary CAST system. Alternatively, the system was wired with Transparent Reference XL interconnects. The Krell Cast system is a unique system that allows for one voltage gain stage throughout the audio chain. In the world of absolute audio, less is always more, and I found the CAST system to be a very unique solution that I recommend any careful listener to audition. I also used Transparent Reference XL cables for the speaker connections. At this level, each gradation of high-end cable is easily audible, even to the untrained ear.
Starting with the power amps and without getting too geeky, these Krell mono blocks have a lot of goodies under the hood. Most notable are the massive 6000 VA power supplies, which surely make up quite a bit of the weight of each beefy amplifier. Krell’s CAST system boards also add to the unique design of the amps, allowing your entire Krell audio system to act as one in terms of the way they are connected. There are microprocessors that monitor the inner workings of the amp in order to protect your investment when you may have had one too many sips of Macallan 30 during a loud, late-night listening session. Krell’s Current Mode speaks to the overall design of the amp, which allows the component to operate in the current domain rather than the voltage domain, unlike most other high-end amps. Krell’s Active Cascode Topology reduces distortion by doubling or tripling the amount of active devices used in a gain stage, resulting in the Evolution’s very clean and fast sound.
The preamp is a dual chassis model like the Krell Evolution 2 and the Mark Levinson No. 32 which, among many benefits, allows the designer to keep the potentially noisy power supply away from the sensitive electronics in the controller unit. The $15,000 202 also operates in Krell’s CAST system and is a fully balanced design. The volume control is ultra-sexy, with a truly great feel. The volume “pot,” if you will, is computer-controlled by a 16-bit balanced resistor ladder, creating smooth volume transitions and resulting in no audible noise from the volume control.
The Krell 505 SACD/CD player is a $10,000 dedicated audio machine that uses some of the finest digital to analog conversion money can buy. The player is, not surprisingly, wired for a CAST connection and is built like a tank. The metalwork is so tightly machined that the player feels more watch-like than a high-end SACD/CD player. In fact, when a disc spools up, you can barely hear it with your ear to the side of the player. Strangely, a player at this price point cannot play a DVD-Audio disc but it can play CD, SACD, MP3 CDs and many other discs.