Carver Power Amps

It's hard to imagine that any audio power amp would have problems in the LF range. That's the easy part. Making it work well at high audio frequencies (above 10KHz) is harder.

Pro sound amps, which Carver now makes, are serious business, not a hobby, and performance (and price) sells. The current Carver ZR 1600 (PWM digital)is specd both at 1 khz and for 20 to 20KHz, 660 and 600 watts respectively into 4 ohms. Not much difference. "Power Bandwidth" is specd also: 20 to 20KHz. Below 60 watts, where the amp will mostly operate in the home audio application, distortion is comparable to "audiophile" amps, and much better than some. At 600 watts they just say "less than 0.5 percent". The "less than" terminology reflects typical professional conservatism. I have an ancient "outboard" Shure phono preamp specd at "less than 1 percent" but when tested it's good to 0.1 percent just like any other decent preamp circuit.

The ZR 1600 has recieved glowing reports from those who have tried it. Perhaps it's the Spectron without the audiophile hype. At less than $800 a copy it's worth a trial, and I have a set of three on order to drive my array of Magneplanars and subwoofers.

Being a digital amp, efficiency is very high so I will save a few bucks on electricity. And, just like military electronics, they actually quote a MTBF (Mean Time Between Failures) at 43,824 hours! Can a Krell match that?

Ears...I made a typo.. it is less than $900, but may be down to $800 by the time you order. I was going to order one and give it the listening test. But then I really needed three channels for the Maggies, that meant two Carvers. But that left one unused channel, so why not get one more Carver, and use each one in a mains/subwoofer application. (I have three SW). Please don't get me started on the rear channels!

If you are just involved with 2-channel, the cost to check out this new technology is so low that it is hard to pass up.

Being a prosound unit it has lots of nice bells and whistles, like remote turn-on by 12VDC, with delayed 12vdc ouput so that several amps can be daisy chained with staggered turnon so you don't open a 115vdc breaker.

I remember when Carver introduced the Phase Linear 300. "Three Hundred watts! You must be crazy!" is what they said.

But Bob Carver's inventiveness is, I think, best exemplified, not by power amps (although his were certainly different) but by his preamp, particularly the Autocorrelator, which was also available as an outboard unit. I had two (for quadraphonic use). The Autocorrelator was a dynamic multiband filter designed to surpress the noise characteristic of LPs. What made it different from other dynamic filters was the way that the filter gains were controlled. Bob realized that above some surprising low frequency (I seem to remember 2000 Hz) there are no music fundamentals: just harmonics. The frequency bands that will have harmonics are predictable from the signal content in the range of fundamentals. So, in the Autocorrelator, a filter required two things to be opened (gain increased). (1) Signal in that frequency range. (2) Proper harmonic relationship to signal in the fundamental range.

The unit worked quite well for conventional stereo, but for quad, where the inherently inferior L-R signal of LPs (vertical groove modulation) was amplified and broadcast by the rear speakers, the Autocorrelator in the rear channels made a very big improvement. It also had a dynamic rumble filter operating below the frequency range used for gain control, and a Peak Unlimiter (to counteract what recording engineers need to do to stop your stylus from hopping out of the groove).

Clever guy.