Product Review - Cinepro
600x Home Theater Amplifier - January, 1996
By John E. Johnson, Jr.
Cinepro 600x Home Theater Amplifier; Two channel bipolar output device power amplifier; 200 watts rms per channel into 8 Ohms; voltage rail 80 V; input impedance 15 kOhms (balanced), 47 kOhms (unbalanced); input sensitivity 1.45 V for full output; S/N 105 dB unweighted; damping factor 500; slew rate 50 v/microsecond; THD 0.15%; size 5.5"H x 18"W x 12.5" D; weight 32 pounds; black metal chassis; $699; Cinepro Theater Products, 1030 Vicente, San Francisco, California 94116; Phone (800)-395-1222 or (415)-564-6300.
Home theater brings with it what we call an "Approach-Avoidance" conflict. We all want high power for those thunderous sound tracks, but the closer we get to writing that four-digit check for power amplifiers that deliver three-digit wattage per channel (and the first digit is not a 1), the more we say, "Can I really afford this?"
Several companies make high end products that are marketed directly to consumers through mail order. They represent good value, when they are good performers, but the problem is that, since the manufacturer sells direct, you can't audition the product in a dealer showroom. Instead, potential buyers must rely on reviews in magazines that care about giving these small companies some space and also care about letting readers know about products that give a major bang for the buck. Secrets of Home Theater and High Fidelity is such a magazine, and the Cinepro 600x is such a product.
Although readers might not be familiar with the name Cinepro, apparently we have been listening to the industrial version for about 5 years. This amplifier was originally made for use in movie theaters (the ones where you pay $4.00 for popcorn, not the home movie theater variety). It is THX certified (the industrial version), and about 5000 of them are in use. Cinepro took the industrial model, beefed up the power supply, reduced the noise level, and upgraded various parts (capacitors and resistors). The newly designed brushed aluminum black faceplate now says Cinepro Professional, but the top of the chassis still has some yellow printing that warns the user, in English and French, about being careful not to get shocked and to guard against moisture (see photo). A rocker on/off switch is on the front panel along with three pairs of LEDs (one pair for each channel) that indicate power on, signal being fed to the amplifier, and soft clipping (when this light flashes, it means the amp is going into unacceptable distortion levels, and circuitry suppresses the high level signals so that hard clipping does not occur). The back of the amplifier has two 1/4" phone plug unbalanced inputs, to which RCA jack-Phone solid metal gold plated plug adapters (supplied) are inserted for standard RCA plug interconnects (see photo), two XLR balanced input jacks, a ground lift switch (for ground loop hum reduction), a bridged (mono)/stereo switch, and two pairs of plastic speaker cable binding posts. For bridged operation, you switch to bridged mode and use the red speaker binding posts (one from each of the two amplifier channels). The Cinepro is labeled as a "Six Hundred Watt Theater Amplifier". It is 600 watts rms: 300 watts rms/ch into 4 Ohms, which is the standard for movie theater operation. For home use, however, we feel it should be called a "Four Hundred Watt Home Theater Amplifier" since 8 Ohm speakers are more the norm in homes, and this is, after all, a home theater amp (and get rid of the yellow printing on the top, please).
In listening to the Cinepro, we found that it has an extremely clean, crisp mid-range. However, it is not overdone (not harsh or gritty). The highs and lows seem to be neutral. Perhaps the mid-range crispness is due to the original use of the amp in theaters where it would be difficult to understand dialog if the mid-range were soft. But, as I said, it is not overdone, and in fact, this sonic characteristic was preferred to a set of pure class A power amps by two of our three referees. Only 20 dB of negative feedback are employed, undoubtedly one reason the mid-range is not too sibilant. The output devices are bipolar (Motorola TO-3, six per channel), which can produce a crisp tonality in amplifiers, compared to the warmer sound of MOSFETs. Three gain stages are used before the final output stage. There is current protection circuitry and a servo-driven cooling fan present in spite of a bias setting of only about 5% into class A, and we found that even when the amp was driven hard, it did not get very warm at all. The protection and cooling fan are probably to protect it in the 12 hours/day - speakers in parallel abuse that it could get in commercial theaters. We were pleased to see the balanced XLR jacks since many amps these days have long interconnect runs to contend with. The bridged mono capability and ground lift are also handy (the Cinepro had a bit more noise and hum than other - much more expensive - amps). We would prefer that the unbalanced jacks were RCA to begin with, instead of having to use adapters for conversion of the phone plugs to RCA plug use, since, let's face it, any additional physical interface connections will detract from signal purity, even if it is ever so little. However, modifications of the basic original design cost money, and Eric Abraham (Cinepro's CEO) elected to keep the price as reasonable as possible (the yellow lettering isn't really all that bad).
We measured 103 dB SPL output from two 88 dB/W/M sensitivity speakers using a CD with a musical power spectrum of 63 Hz to 6 kHz (smaller amounts of signal on either side of this spectrum) before the sound began to get mushy and harsh. At 105 dB, the soft clipping lights came on, suggesting that the full usable output was being delivered at 103 dB. This is more than enough volume for any listener (really, we should be keeping the average volume much lower to protect our ears from damage). With a meatier power supply (the Cinepro has a hefty EI core transformer, but only 20,000 mfd capacitance), probably more usable power could be extracted from this amp, but again, at higher cost.
For $699, the Cinepro 600x is an excellent buy. It is well built, has plenty of features, and best of all, solid sound. With three of these, you could have (into 8 Ohm speakers) 200 watts to each of four channels (front left/right and rear left/right) and 600 watts (bridged mono) to the center channel, all for a hair more than two kilobucks. It has a 30 day no questions asked money back guarantee, and three years parts and labor warranty. If you are planning for AC-3, where full frequency spectrum sounds are being delivered to all channels, or you just want a high powered Pro Logic amp setup, this could be the ticket to ride at very reasonable cost.
John E. Johnson, Jr.
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