Big power, small box: this is a goal that amplifier manufacturers are constantly trying to achieve. Of course there are exceptions—in some cases where a small, lightweight box is not important, there are huge amps with huge power (and increasingly huge DSP and other gee- whiz features). And there are plenty of applications for small amps with a dozen or three watts of power. But a key goal re- mains big power, small box. Price is a key consideration as well. If a manufacturer can achieve big power in a small box at a low price, folks will sit up and take notice. Ashly has introduced its KLR series of amplifiers, including the KLR-2000, KLR-3200, and KLR-4000. Touted by Ashly as high-efficiency, lightweight and “delivering quality and value” at an “extremely affordable price,” these amps appear to achieve our power/size/price trifecta, based on Ashly's claims. I spent time with a KLR-4000 to try to establish if these claims are true.
The Findings
The KLR-4000 is contained in a 16-inch deep 2U rack-mount enclosure. Its front panel features cooling air intake grilles on either side of an extremely sparse “control surface” consisting of input attenuation knobs for both of the amp's channels, and four-segment LED level meters. At the far right of the front panel is the amp's power switch. The rear panel is similarly Spartan; from left to right are found the amp's permanently attached AC power input cord, Speakon speaker outputs for both channels, a cooling air outlet grille, recessed switch access slots for control over input gain and operational mode (bridged, stereo, or parallel). The AC power input cord is a very beefy cable, which is simply necessary to deliver the kind of current required for high power output levels (nearly 20A for 1/3 power). At the far right of the rear panel are located the amp's two inputs—three-pin Euroblock or balanced inputs that accept both XLR and 1⁄4-inch TRS balanced connectors. A recessed switch is associated with each input toggle's insertion of a limiter circuit, and another recessed slider switch offers a high pass filter (HPF) of either 30 Hz or 50 Hz cutoff frequency. The HPF can be switched completely off, as well. The amp's enclosure is a very solid-feeling metal, and is covered in a black coating. In addition to the rack ears at the front of the amp, there are also ears in the rear for additional support, which is advisable considering the amp's weight of 26.4 lbs. The dust filters behind the amp's cooling air intakes are removable for cleaning.
The Deliverables
The KLR-2000 delivers 350W/channel at eight ohms, 600W/channel at four ohms, 1,000W/channel at two ohms, and 2,000W in bridged mono mode at four ohms. The KLR-3,200, on the other hand, delivers 650W/channel at eight ohms, 1,100W/ channel at four ohms, 1,600W/channel at two ohms, and 3,200W in bridged mono mode at four ohms. The KLR-4000 delivers 850W/channel at eight ohms, 1,400W/ channel at four ohms, 2,000W/channel at two ohms, and 4,000W in bridged mono mode at four ohms, in comparison. Signal- to-noise ratio for the KLR-2000 is >108 dB, and >109 dB for the other two amps.
Frequency response for all three amps is published as 20 Hz to 20,00 Hz, ±0.3 dB, with -3 dB down points at 5 Hz and 70 kHz. Damping factor for all three amps is published as >380, so I expected the amp to deliver nice, tight-sounding low end, and I was not disappointed. Published total harmonic distortion is <0.05% at four ohms, and the amp's inputs have an impedance of 12,000 ohms. The high pass filter available on the inputs is moderately steep: 12 dB/octave. The inputs also feature a slider switch that offers three input level options: 1V, 32 dB, and 26 dB. The amp is well protected, and will shift into protection mode on output over-current, DC output, high chassis temperature, and if the mains breaker is tripped. Cooling
is provided by an internal fan drawing cooling air from front to rear through the amp's enclosure. The LEDs on the amp's front panel indicate power, level, clipping, and protection mode.
The KLR-2000 is a Class AB topology, and the KLR-3200 and KLR-4000 models are a two-step Class H design. The clever two-step rail convention of the Class H design vastly increases efficiency, with a small compromise in terms of harmonic distortion, which is completely inaudible in this case. As a matter of fact, the KLR-4000 that I played with sounded great. I put it through its paces in service powering full-bandwidth PA speakers and also in bridged mode powering a large, power-thirsty subwoofer. In both cases, the amp's performance sounded every bit as linear to my ear as any other small, high-efficiency amp I'd heard. The frequency response sounded perfectly flat to my ear all the way across the audible spectrum, and even at high output levels there was no audible distortion. The noise floor was very low as well. In terms of audio quality, this amp performs very nicely. It doesn't have all the DSP bells and whistles avail- able in many of the other amplifier models available from Ashly Audio, but that was not the goal of the manufacturer here. They were attempting to deliver a straightforward power amplifier that delivers a lot of power considering its size and weight.
So, does the Ashly KLR-4000 meet our power/size/price trifecta? It can deliver up to a whopping 4,000 watts in bridged mono mode, it lives in a tidy 16-inch deep 2U rack- mount enclosure, and its suggested retail price is a reasonable $1,440. I would submit that it very much meets our requirements, and I would hence recommend checking it out if you need a small, lightweight power amp with a lot of power and not a lot of frills.
