General Asylum: REVIEW: Conrad-Johnson (CJ,C-J) Evolution 2000 Amplifier (SS) by haziz
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Model: Evolution 2000 Category: Amplifier (SS) Suggested Retail Price: $ 5795 Description: Hybrid Tube input-Mosfet output amp (discontinued) Manufacturer URL: Conrad-Johnson (CJ,C-J) Model Picture: View
Review by haziz ( A ) on August 05, 2004 at 18:23:28
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for the Evolution 2000
I purchased this amp used approx 1 1/2 years ago at the time I bought a used pair of Thiel CS7 speakers (the older model CS7, not the current CS7.2), and needed a muscle amp to drive the notoriously tough load of the Thiels, without emphasizing some of their slight tendency to brightness in the highs. See my review of the Thiels for further details and for some of my agonizing over other amps at the time though the only other amp tested with my speakers at home was my old Krell KAV 300R receiver/integrated that I was using with my PSB Goldi now relegated to my bedroom system. I did test other amps at driving Thiel CS7.2 at a neighboring dealer though the source was a Cary CD player I am not familiar with.
This amp is Conrad Johnson's early nineties idea of a muscle amp, and was somewhat aimed at buyers contemplating Krells and other muscle amps of the era. It is a tube input (5751 tubesx4), with a SS mosfet output stage and was designed with a zero feedback topology, with the triode tubes providing the voltage gain and the Mosfets providing the current gain. Conrad Johnson at the time emphasized it's ability to deliver current and ability to drive tough loads, and in fact this is a 114 lbs monster with a 50 lbs power supply, though surprisingly it does not double it's output with halving of the impedance, and it's output figures appear modest by today's standards. In fact it puts out 200 watts into 8 ohms, approx 350 into 4 ohms and 600 watts into 2 ohms. It was well reviewed at the time and received a rating of Class A by Stereophile, with the reviewer interestingly emphasizing it's ability to drive tough loads after testing it at loud volumes (> 100 SPL if I remember correctly) on a pair of Martin Logan CLS
After having lived with the amp and speakers for almost a year and a half, I have gained increasing respect and some fondness for the amp. It is capable of driving the Thiels louder than I would wish with no apparent effort. Sound is probably marginally on the warm side but does not sound too warm or have an excessive tube bloom. Soundstaging is excellent. Human voices are reproduced beautifully and both female and male voices sound excellent with very realistic reproduction with enough fullness and just a hint of seductiveness. Individual instruments sound superb with piano, violin, cello and saxophone sounding quite realistic. I attend live concerts fairly often and am comparing it to live.
I still maintain my very slight hesitation re the amp with large orchestral pieces at both very soft and loud volumes and am not sure I can explain it any better than when I reviewed the speakers a year ago. At moderate volumes the system sound superb and the amp is totally effortless at driving the Thiels.
I have decided to stick to this amp for the time being, and have avoided the upgrade bug till now with great pleasure and enjoyment from the system.
Product Weakness: Output figures modest by today's super muscle amp standards. Product Strengths: Hint of warmth, abiltiy to drive tough loads, good price on the used market. Superb music (esp small group and vocal) reproduction.
Associated Equipment for this Review: Amplifier: Conrad Johnson Evolution 2000 (5751 Tube input, MOSFET output hybrid amp, 200 WPC into 8 ohms) Preamplifier (or None if Integrated): Conrad Johnson Premier 17 LS Sources (CDP/Turntable): Sony XA777ES SACD/CD-mostly Speakers: Thiel CS7 Cables/Interconnects: Transparent Cable Ultima Speaker wire, MIT 330 Plus Series II interconnect, Straight Wire Virtuoso interconnect Music Used (Genre/Selections): Classical (mainly 19th century orchestral, on modern instruments). Jazz (Brubeck, 50s-early 60s Miles Davis, MJQ, Paul Desmond, some Ellington, Gil Evans, Bossa Nova) Room Size (LxWxH): 21 x 12 x 8 Time Period/Length of Audition: 16 months Type of Audition/Review: Product Owner
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Topic - REVIEW: Conrad-Johnson (CJ,C-J) Evolution 2000 Amplifier (SS) - haziz 18:23:28 08/5/04 ( 0)