Not quite the unloved stepchildren of pro audio equipment, power amplifiers are taken for granted when they are functioning normally and berated mercilessly when they fail. As we know, malfunctioning power amplifiers have the potential to completely fry speaker systems; drivers have been known to actually combust.
Product PointsApplications: Studio, project studio, installations
Key Features: Two channel power amp; 150 W x 2 at 8 ohms; 200 W x 2 at 4 ohms; 400 W in bridged mono at 8 ohms; Neutrik combo XLR-1/4-inch connectors
Contact: Hafler Professional at 888-423-5371 480-517-3157; Web Site
+ Sound quality
+ Solid construction
+ Quiet operation (no fan!)
+ Five-year warranty
– Module-based, surface-mount construction can make component level repairs difficult
The Score: Another fine studio quality power amp from the Hafler trans•nova series.
Equally destructive – but more subtle – are amps that color the sound, adding a touch of brightness here, or a pinch of image reduction there. These amps cause mixes to skew off course or can lead to ear fatigue after hours of usage. Now that I have exposed the dark, seamy underbelly of power amps, let’s take a look at an amp that is designed to avoid the aforementioned pitfalls.
The Hafler P3000 trans•nova amplifier ($779) is located in the middle power range of the Hafler line, rated for 150 Watts per channel output into an 8-ohm load, 200 Watts per channel into a 4-ohm load and, for bridged usage, 400 Watts into an 8-ohm load.
The amp uses Hafler’s trans•nova topology, which is a patented application of MOSFET output transistors. Benefits such as a simplified and shortened signal path as compared with conventional MOSFET implementation are claimed as a result. Internal construction utilizes surface-mount technology on the two modular channels’ circuit boards; in the event of a failure, the channel’s board may be swapped out by a service center by simply disconnecting the module from the heat sink, power transformer and binding posts.
The P3000 features a sensing circuit that shuts the amp down in case of overheating or short circuit, preventing damage either to itself or to equipment downstream. A soft-start feature eliminates the risk of speaker damage due to start-up transients.
The P3000 is two rack-spaces high, conforms to standard rack width and weighs 23 pounds. The unit’s case is unusual in its design – the rack ears and heat sinks are one-piece (per side) units that are attached to the amplifier chassis. While there are perforations in the top and bottom panels of the amplifier that allow for some ventilation of the internal circuitry, the heat sinks are essential to the operation of the P3000 since it relies upon convection cooling, shunning the use of an internal fan. The manual details the provisions for proper ventilation if you decide to rack mount the amplifier. In some installations an external fan may be required.
The overall effect of picking up the P3000 is somewhat akin to hefting a cinder block – the amplifier feels solidly put together and feels heavier than its appearance suggests.
The front panel features a lighted power switch toward the center right of the faceplate. Flanking the power switch on both sides are a series of four LED indicators signifying the presence of audio signal, amplifier clipping, thermal fault and the presence of a short circuit.
The LEDs are mirror imaged, but at somewhat different heights on the faceplate. On the edge of the faceplate are continuous level potentiometers for each channel. These are calibrated (unstepped) to provide a maximum of 15 dB of attenuation. The user manual recommends leaving the level controls set to the maximum (0 dB attenuation) in most installations.
The rear panel includes the now ubiquitous Neutrik combination jacks, which allow for either balanced XLR or 1/4-inch connection. Screened upon the back panel are diagrams showing the correct wiring of both types of connectors (pin 2 hot). I wish all manufacturers would do this!
Binding posts accept up to 12 AWG wire or banana plugs of the single or dual variety. Also on the back panel is a sliding switch to select two-channel or bridged operation, a socket for a standard IEC power cord and an easily accessible fuse. The P3000 is made in the U.S.A. and carries a five-year warranty.
I used the P3000 mainly as a monitor amplifier for several different sets of speakers in my control room. I also put it to novel use driving a stereo Marshall 4×12 cabinet for some guitar recordings.
The first thing that I noticed about the Hafler was that it was extremely quiet. The amplifier is almost free from any mechanical noise generated by the transformer and, since it is convection cooled, there is no whirring fan to contend with. The self-noise of the Hafler also seems quite low (the manual states a 100 dB signal-to-noise ratio). The sound of the Hafler was the antithesis of the solid-state sound that audiophiles love to hate. As opposed to being etched or forward sounding, the Hafler has a realistic and unhyped spectral and soundstage balance. The P3000 also seems to be free of the image instability commonly referred to as MOSFET mist, which is sometimes a byproduct of amplifiers that use MOSFET (rather than bipolar transistor) output stages.
The Hafler is also free from the annoying sonic artifacts that seem to plague amplifiers that are obviously built to a price, or are underbuilt for their rated power output. I would add that I tried the Hafler with a few different monitors, ranging from some up-to-date highly efficient models all the way down to a pair of Auratones, with good results.
I used the P3000 to drive a Marshall 4×12 loaded with Celestion 70 Watt speakers. Driving the P3000 was a late 1980s vintage Marshall 9001 tube preamp. The P3000 turned out to be a pretty sweet amplifier for use in a guitar rack system. It had a much smoother sound than the PA class of amplifier I normally use. For players who enjoy jazz or country-type clean sounds, the Hafler is a much better bet than a lower grade PA power amp. Thrash players may prefer something more aggressive and grungy sounding. So be it!
The P3000 is a solid performer and very easy to recommend to anyone in need of a medium-powered, good sounding amplifier. While it certainly belongs in the studio, it held its own performing tasks that one would not normally expect a studio-grade amplifier to comfortably perform. Thumbs up!