Dan D'agostino in an extremist be it his love for cars, fine wine and especially when it come to ultra-off-the-charts, high-end audiophile equipment. And never before has he offered an amp with more extreme performance to the worldwide marketplace than the Krell Evolution 900 monoblocks. Priced at $20,000 each - these amps are not for the faint of heart when it comes to price and listener beware unlike other audiophile product you've heard and knew you couldn't afford - these amps have special powers over you. They will make you want - nay need them like the city of Las Vegas will ultimately find your weakness and break you. They are alluring, seductive and when it comes to making you part with insane volumes of your money - they are downright evil.

The technology in the amps is basically the pinnacle of Krell design and Krell is best known as a top provider of audiophile amplifiers. Each monoblock has a beefcake 6000 VA power supply and uses Krell's Active Cascode Topology. The amps are reported to sound their best when using Krell's CAST connection but I tested them both with Transparent Opus MM cables and the CAST system and used the Transparent Cable more often. You wouldn't throw either option out of bed - it was just what I preferred. The fit and finish of the silver beauties is a nice as you will find at any price and at this level you should expect this quality of finish. Their blue lights, just the thought of them, warm my soul.

The sound of the Krell Evolution 900 amplifiers are not exactly what you would stereotypically expect from a Krell amp. Yes, the bass is as good (honestly, better) than any amp at any price. It is fast and deep in ways no Mark Levinson, Classe', Audio Research or even (ancient) Cello amp at any price has been able to reproduce in my room. Having sold over five dozen pairs of Wilson WATT Puppy speakers in my career as a high end audio salesman, I felt like I knew what their bass limitations were and always recommended a subwoofer with them. With the Krell Evolution 900's in my rig - I was introduced to the potential of Wilson WATT Puppy bass. I hit depths never thought possible with control I have never heard before. Amazingly, it isn't the bass where these amps will catch you by surprise - it's the top end. Gone is the "cold" sound that some criticize Krell for. The Evolution 900s sound more light and warm on the top end than any Krell I have heard and I have owned a few of Dan's bigger non-Evolution monoblocks. Across the board, these amazing amplifiers were better-than-Krell Krell. They are game changers.

High Points
• Krell Evolution 900 power amplifiers create the best bass I have ever heard in any system ever. They currently set the standard for the best, deepest, most controlled bass I have ever experienced in my room and beyond. Other reviewers heard them in my system and seconded my opinion.
• The highs are better, more refined, more open and less cold than you might expect. Hell, at $40,000 a pair - you have the right to expect the world. With the Krell Evolution 900s Dan D'agostino delivers it to you on a silver platter.

Low Points
• These monsters create a good amount of heat and are too big to fit in a traditional equipment rack not unlike Mark Levinson's (now discontinued) No. 33 amps as well as Halcro's heralded top of the line amps. While Krell's Evolution amps are the right physical configuration - they are just too big and run too hot for a Middle Atlantic style rack.

Conclusion
Halcro's top-of-the-line amp was called the Best Amp In the World by Stereophile Magazine years ago and in many ways I understand their point. At the same time, that was before Krell came out with the Evolution 900s. If you are in the position to chose between the Halcros and the Krell Evolutions its tantamount to having to chose between a Porsche Carerra GT and a Mercedes SLR. Which was is better isn't really relevant. Which one you like better is all that matters. For me, I would have sold body parts to keep the Krell Evolution 900s in my rack if they fit. When it was time for me to ultimately say good bye I took the coward's way out and hired my installation company to pack them up and restore my system to the old configuration. Then I didn't listen to my rig for a month trying to forget what I lost out on. It was like a nasty, heart-breaking romance that ended and a girl you will never forget. And I am talking about a power amplifier here.