Review: Carver Professional ZR500 Amplifier

Category: Amplifiers

The Carver Professional ZR500
12/16/02

If you have been reading the Audiophile press recently, you have probably already heard about the revolution going on in amplifier technology. In the October 2002 Stereophile, Sam Tellig raved about the PS Audio HCA-2 amplifier and gave it a class A rating. As you might know the HCA-2 is a class D switching amplifier, which reportedly switches at 500 KHZ.

Similarly, the Carver Professional ZR500 is a spread spectrum switching amplifier that switches at 700 KHZ. The object of a switching amplifier is to switch so fast that the output sounds like a constant stream. We will get more into the sound later; however, this amplifier is detailed, dimensional, dynamic, coherent and sweet. There is no harshness, and the output quality is superior to any amplifier that I have used or experienced in the past.

Published Specification
The ZR500 published specifications are listed below:
 95W per channel into 8 ohm loads, 20 Hz to 20 kHz, +0.5dB -3 dB with less than 0.5% THD at rated power
 150W per channel into 4 ohm loads, 20 Hz to 20 kHz, +0.5dB -3 dB with less than 0.5% THD at rated power
 250W per channel into 2 ohm loads, 1 kHz, +0.5dB -3 dB with less than 1% THD
 300W bridged mono into 8 ohms, with less than 1% THD, 1 kHz
 500W bridged mono into 4 ohms, with less than 1% THD, 1 kHz
 2 Ohm stable operation

Professional Rack Mount Amps:
As you probably know Carver Professional is a pro audio company, and because of this the ZR500 is a rack mount system. The inputs are balanced XLR, and the outputs are Neutrik Speakon. The front panel has one level control per channel, which can be defeated as a switch option thereby allowing for standard pre-amp input.

My System:
I have been an audiophile for years, and as such my system previously included the following:
1. Amplifier - Acurus DIA 100 - Modified by Stan Warren at Supermods to a Class A front end.
2. CD - Pioneer DV525 - Modified by Stan Warren - All capacitors replaced by Black Gate's.
3. Speakers - Custom Diaural speakers - Manufactured by Ray Kimber (Kimber Kable and Diaural).
4. Subwoofer - Monitor Audio ASW210
5. Speaker Cables - LAT International

When I received the ZR500 in September, I modified my system as follows:
1. Pre-Amp - Channel Island Audio VPC-1 - This is an outstanding passive pre-amp.
2. Amplifier - Carver Professional ZR500
3. Speaker Cables - Alpha Core Goertz PYTHON MI2

The old system components with a spare set of speakers have gone upstairs.

Listening
After two weeks of break-in I started to do some serious listening.

In playing Tous les Matin du monde, Valois V4640 which features Jordi Savall’s baroque and classic orchestra. In this recording the massed strings presented a detailed sound stage that delineated and real. The muddiness that commonly exists with stereo reproduction disappeared. The choral voices were layered and sounded as I had never heard them before. In previous playings of this CD, I was not impressed. My system was not capable of reproducing the recorded information.

In playing Louis Armstrong & Duke Ellington the complete sessions (Classic Records DAD 1031), the realism of Louis's voice accompanied by Duke's piano brought this 1961 recording to the present. The timbre of each piano note reverberated. When Louis played his trumpet, the timbre of the complex notes came through with unbelievable realism.

Playing Willie Nelson Stardust (Columbia Legacy CK65946 - remastered) the voice came through without any edge. Each guitar note showed all of the complexity of being there and nearby when it was played. Willie’s voice has a quality that can easily be destroyed by the edge commonly found in digital recordings. I remember that problem well from previous playing. The analogue and class A tube sound that audiophiles grew to love has returned with the ZR500. You would be amazed at how good some of our CD's can sound.

Sheets of sound rolled from John Coltrane / Setting The Pace (JVC XR-0202-2 XRCD). The tenor saxophone was in my living room. Red Garland's piano, Paul Chambers bass and Arthur Taylor’s drums came through with unbelievable clarity. Have you ever wished that you could produce the realistic sound of the bass cello that often appears muddy and recessed in most systems? I had that wish, until I installed the ZR500.

Some time ago, I bought a copy of Sheffield Labs “The Moscow Sessions” (CD-25). I played it and didn’t like it. Producing the grandiose sound of a full symphony orchestra has been near impossible for a recording. I thought that I would try it again when I got the ZR500. Wow, what a difference. The blend of sound that was once opaque has now separated into individual instruments. The sound stage was delineated, and I found that I could locate and identify individual instruments. This can be quite a feat with a symphony orchestra. The majesty of the concert hall with all of its dynamics came close to existence in my living room.

Steve Hoffmann from DCC is famous for his recordings, and Steve has been particularly proud of the album “Ray Charles and Betty Carter.” Listening to the cut “Every Time We Say Goodbye” the two voices were awe-inspiring, and the musical instruments came through with beguiling clarity. Similarly when I listened to the "Cowboy Junkies The Trinity Sessions" (BMG D 101043) the first cut Mining for Gold features the a cappella lyrics of Margo Timmins. Again, the clarity and naturalness of the voice was unbelievable.

In characterizing the sound of the ZR500, several thoughts come to mind, including tube magic, class A, warm, detailed, dimensional and sweet. This is the case across the entire sound and instrument spectrum. Voices are as realistic as if the performer was in my living room. The bass is tight with slam and dynamics. The mid-range and treble are crystal clear without any edge. The shimmering sound of symbols continues after the hit. The sound is holistic and seamless. Even at high levels I never heard a trace of stridency. Listener fatigue disappeared and I have found that I can listen for hours. The sound stage reached a state of realism that I thought was impossible to reproduce. Instrument placement often extends beyond the boundaries of my speakers and this shows up in the sound stage. Sure a lot of this comes from the outstanding speakers and other components, but I could not hear it with my old amplifier. Adding the ZR500 into my system has created the realism associated with a full range electrostatic with the dynamics of standard drivers. This is strange, because I do not have electrostatic speakers, but such is the transformation associated with the Carver ZR500.

Associated gear
1. Pre-Amp -Channel Island Audio VPC-1 -This is an outstanding passive pre-amp.
2. CD - Pioneer DV525 - Modified by Stan Warren - All capacitors replaced by Black Gate's.
3. Speakers - Custom Diaural speakers - Manufactured by Ray Kimber (Kimber Kable and Diaural).
4. Subwoofer - Monitor Audio ASW210
5. Speaker Cables - Alpha Core Goertz PYTHON MI2

Similar products
Amplifier - Acurus DIA 100 - Modified by Stan Warren at Supermods to a Class A front end.