Powersoft K and M Series Digital Power Amplifiers

These unique, compact and lightweight digital amps are exceedingly powerful, user-friendly and sound great.
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These unique, compact and lightweight digital amps are exceedingly powerful, user-friendly and sound great.

Personally, I have never felt “a power amp is a power amp,” though some simply look at the dollar-per-watt ratio as a means of measurement for evaluating the value of amplifiers. Here we review two power amplifiers from Italian manufacturer Powersoft, which significantly raise the bar within the digital live amp field, representing what is possible when exceptionally good technology and build quality meets sheer power.

Powersoft M50Q (top) and K3 DSP audio power amplifiers.

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The M Series features 4-channel amplifiers with optional digital signal processing (DSP). Somewhat astounding, to me at least, is the fact the four channels of relatively high levels of RMS power are produced from one single power supply, and this entire package fits in one rack space. The manufacturer rates the Powersoft M50Q, which we reviewed, at 750 W RMS per channel (into 8 0hms), supplying power to four channels. Powersoft further rates the amp at four channels bridged to two channels to be 2,500 W RMS per channel (8 ohms).

The M50Q front panel is host to four volume controls — one per channel — and an on/off switch. The rear panel is home to the I/O, which include four Neutrik Speakon outputs and four XLR balanced inputs. Weight is 16 lbs.

The K Series amplifier is equal in size, but is a 2-channel unit with internal DSP, an Ethernet/AES3 interface and a digital menu. The model we received, the K3 DSP+AESOP, is capable of driving loads down to 2 ohms. The K3 DSP+AESOP is rated at 2,800 W RMS at 2 ohms, 2,600 W RMS at 4 ohms and 1,400 W RMS at 8 ohms; all ratings include both channels driven.

It is interesting to note this amplifier can be driven at a 4 ohm bridged mono rating of 5,600 W RMS. The manufacturer cites the slew rate here, also (as with the M50Q), at 50 V per microsecond. The weight is slightly more than the M50Q (at 17.5 lbs.), while dimensions remain the same.

Powersoft K Series amplifiers feature Powersoft’s Power Factor Correction (PFC) technology, which creates a buffer between the power network and the power supply, allowing storage of a large amount of energy in a storage bank. PFC technology keeps the storage inside the amplifier “full and ready,” independent from the power supply. This allows the delivery of very high current draw even at 2 ohm loads, regardless of voltage.

In Use

My company, Atlantis Audio and Lighting, operates primarily in the American Southwest. In summer, outdoor temperatures can be punishing on power amplifiers, as heat is always a major consideration with amps. Hence, proper airflow is essential. We decided to torture the 4-channel M50Q with the job of being a subwoofer amp at one of our casino gigs featuring the band Vertical Horizon.

We ran the amp as four independent channels with inputs 1, 2, 3 and 4 paralleled by means of the little recessed switch on the back panel, located between the channels to be paralleled. The subs were our A-Line Acoustics LS218 cabinets, which employ very high-efficiency, dual 18-inch speakers. The result was very nice: The subs purred along smoothly and responded with speed and definition.

One particular application I liked for the M50Q was as a monitor amplifier. We were doing an outdoor show with Korn, which has exceptionally loud stage volume. Along with a BSS MiniDrive as the processor, we used the Powersoft amplifier in a 2-channel/ biamped mode, using all four channels. I have to say, the M50Q amplifier responded exceedingly well with our Radian XD wedge monitors. They not only had excellent speed and definition, keeping up with all of our other conventional power amps, but more importantly they kept up with the needs of a band that has 110 dB stage levels.

What Is “Slew Rate”?

The speed with which an amplifier is able to translate swings in input voltage level to output voltage is referred to as slew rate. The high-voltage output stage (165 V for the K3 DSP+AESOP and 140 V for the M50Q) allows for large and fast diaphragm excursion. At the same time the robust switching power supply can instantly guarantee a very high current output on a load, dramatically improving the slew rate.

A high slew rate means the amp is able to accurately track transients and other rapid changes in input signal levels. Both the M50Q and K3 DSP+EASOP are rated at 50 V per microsecond — an impressive number.

The K3 DSP+AESOP was employed extensively as an amp for our unpowered A-Line Acoustics AL10 line-array boxes, which were outfills for Korn, flown mid-stage from the roof. The K3 DSP+AESOP was a total hit, running all four boxes on one power amp, both channels driven, at 2-ohm loads. With both amplifiers, we found the attack speed was superb in both mains and monitor applications. I never really experienced any latency issues from A/D conversions; the amps actually felt “faster” than conventional amps we have used. In particular, I believe they excel on the attack of drums and percussion, the smoothness in the vocal range and the ability to handle subwoofer applications. Some users believe there is a certain sterility to digital audio; I, too, have experienced this with some pieces of equipment. These Powersoft amps felt as warm and as friendly as any pure analog amps I have heard. The amplifiers instilled a high-quality “feel” to the audio that passed through them.


All in all, these Powersoft M and K Series power amps are an excellent addition to any rig. I would love to have a fleet of the M Series amps for our monitor systems, employing each amplifier as a 2-channel, biamped unit. Each rack of eight mixes could be four amplifiers, making our monitor racks very easy to ship, as well as making the monitors sound superb.

The K Series unit with DSP+AESOP, in my opinion, is more suited to a main speaker system use, especially with the 2-ohm capability, onboard DSP, with digital menu. The front-panel access of the menu makes operation of the Powersoft K amplifier exceedingly simple. The optional Ethernet/AES3 interface allows easy connectivity to Powersoft’s Armonía software, which provides easy setup, network monitoring and control of Powersoft amplifiers.

Before this review, I had not experienced Powersoft amplifiers. After experimenting with these two units, I am quite impressed with how versatile these digital amps really are, as I have had prior experience with other digital amps through the years. These may be the best sounding and most powerful I have used. Thus, I give a full recommendation of the Powersoft K and M Series for touring, one-off gig, or installation applications.

They are fully roadworthy and handle extreme temperature locations very well.

Prices: $3,869 and $5,856 (M50Q and K3 DSP+AESOP, respectively)

Contact: Powersoft | powersoft-audio.com

Will James, owner and chief owner of Atlantis Audio and Lighting, is a longstanding PAR contributor.