I had been wanting to try this new Electro-Voice series, which in theory offers one of the best watts-per-kilo ratios and, at the same time, one of the highest output-power-to-consumed-power (AC power watts) ratios on the market. Its weight (8.5 kilograms) is deeply surprising. When I picked it up at our offices I thought they were handing me a processor or a box of accessories, not the beast I was expecting: a 1,100 W per channel "rig" at four ohms. Something comparable to a Crest 8000 or 9000 series, or, of course, an Altair MF24, amps that are a struggle to lift off the floor. Now I had to see whether the "hollow box" I had taken from the warehouse really kept up with our "heavy" princesses of amplification. So I set out to find the limits of our new friend.
RACKING IT UP
When unpacking the amp we discovered several very interesting points. Only two rack units; a front panel made of a solid 3 mm aluminum plate, knobs flush with the front panel and a very useful LED layout. With them we have the classic "signal" LED, which lights up progressively as it receives signal; a "limit" LED similar to the classic red clip; and finally, as befits a high-end amp, a 0 dB LED, which is extremely useful because it lets us extract maximum power, see it graphically and thus play with it and with the limit LED, bearing in mind that there is no more power once we go beyond the indication of the latter, since the protection kicks in via the limiter, and all we would achieve is dirtying the signal by considerably increasing the final distortion, and we would also begin to notice a certain compressor "pumping."
We sorely missed two handles or grips on either side of the front panel. Even though it weighs only 8.5 kilos, you still smash your fingers racking amps. To me it is an absurd saving. It also has protection and power LEDs, as well as a main power switch.
ON THE BACK
The first thing we noticed were the two ventilation outlets, each with a three-speed fan with progressive DC switching controlled by temperature sensors. Three Speakon-type speaker outputs: one for each channel and another for "bridge" mode. We also see the ground lift, a switch to bridge the amp, another to run the signal in parallel (a single signal for both channels), its power fuse, the IEC power inlet and the female XLR signal inputs, accompanied by their corresponding (directly wired) male XLR outputs so the signal can be "linked" to other amplifiers.
FIRING IT UP
To begin with, we connected the Electro-Voice outputs to two 600 W RMS Beyma LX60s on each channel, wired in parallel at 4 ohms, with the crossover set at 280Hz. We had another complete system with Altair MF24 amps for comparison. Then, to check the low end, we tried several types of music: house, funk, rock... The result is impressive; it is not afraid of a good kick drum punch, and the transients produced in the signal's attack are handled with power and great quality. Perhaps the sound at these frequencies is not as "big" as with conventionally powered amps (this one has a switch-mode power supply, which I will explain later), but the response is quite flat, better than most, and remarkably faithful, which points to a great circuit design. We also found a great balance between heat dissipation, energy consumed and real watts delivered, as well as its bass power. And then there is the damping factor, greater than 300, which is not a great figure. All of this adds up to a tremendous investment in research.
The second test we put it through was running at 2 ohms at high temperatures, since the manual warns us not to push these situations (continuous use at 2 ohms and no more than 40ºC). We decided to cover the backs of all the Spanish buyers who, when on tour or running a mobile disco in, say, Écija, with 45ºC in the shade, don't want to be left wondering what happened. This time the output of each channel fed two HK LP112s (12-inch plus 1, 300 W) and two 18-inch, 600 W subwoofers in parallel. We set the amp out in the sun in Las Rozas de Madrid, at 27ºC in the shade and who knows how much in the sun, with Metallica's S&M at 0 dB, and waited.
After two hours of operation we noticed some loss in the low end, but the thing was still delivering plenty of punch, lots of punch. So we decided to heat the air with a theater heater with a regulator and the bathtub thermometer from home, up to 45ºC! After 30 minutes of operation the thermal protection kicked in. I was already getting bored of waiting, which puts this amp on a par with the best switch-mode amps in the world.
As for sound, the midrange frequencies can be described as very good and the highs as exceptional, with a magnificent and extremely fast response. This is explained by the class H amplifier design which, compared to class AB configurations, powers the circuit depending on the amount of signal, doubling the amount of energy supplied to it only when needed.
"CHOPPED" POWER SUPPLY
We technicians call a switch-mode power supply a "chopped" or electronic supply. This means that if we raise the frequency of the current from 50 Hz to a much higher figure, its current will drop proportionally. Amps have to transform the alternating current supply (from the mains) into direct current, which is stored in the capacitors and consumed by the transistors to amplify the signal, which goes from a measly one volt to almost two hundred; that implies large amounts of transformed energy, in other words, a big, very heavy transformer. If the current is low, the transformer will be small and therefore light.
There are complications too, and all that glitters is not gold. The first is that the process produces a great deal of heat dissipation, raising the temperature dangerously. Another problem is the linearity of the response, not always forceful in the low end, and low damping factors. As I have explained, the Electro-Voice CP3000S Precision Series comes out of these drawbacks quite well, as long as we house it in well-ventilated racks and do not overload it to the extreme under bad conditions (temperatures above 40ºC and 2 ohms).
CONCLUSION
This is a fantastic amp for touring, in proportionate racks where saving weight is essential, with impeccable quality and every kind of protection (audio temperature, DC, HF, limiters for transient peaks through current feedback, current drop, three-second power-on delay...)
We will also have to configure the system at a minimum of 4 ohms, using the 2-ohm option only for emergencies, and if we do so, make sure the amp racks are ventilated in the hot Spanish summer.
A small sacrifice in power delivery at low frequencies does not seem so terrible to me, especially considering the large accumulation of watts in today's PA systems, where the in-phase coupling of many 15-, 18- and even 21-inch subwoofer cones makes up for that shortcoming. Some handles for mounting the amp wouldn't hurt.
Finally, we have to consider the option of an internal analog crossover card, with filters included and factory configuration. We missed the possibility of these cards including delays, limiters and a remote digital control interface so they could be processed externally with programs such as Smaart Live and a PC. This, which may seem a bit excessive, is in my view the future of PA control and the best competition for self-powered systems such as Meyer's.