Products

Designer Notebook: Inside New Crown XLS Series Power Amplifiers

A look at a new series of DSP-equipped power amplifiers from two members of the product development team

A couple of years ago, we surveyed the landscape of the pro audio marketplace and noticed something: there was a distinct lack of genuinely professional caliber power amplifiers incorporating onboard digital signal processing for portable PA and smaller scale fixed installation applications at a truly affordable price point.

Meeting this need drove the development of the XLS Series, which sports many of our latest technology breakthroughs and refinements to deliver not just exceptional sonic performance, but configuration flexibility and features not found in units for this segment of the market.

The line consists of four 2-channel models – XLS 1000, XLS 1500, XLS 2000, and XLS 2500 – all in a uniform, rugged 2RU chassis.

They are identical except for output power and weight, and the XLS 2000/2500 are 3 inches deeper. Power ratings at 4 ohms range from 350 watts per channel for the XLS 1000 up to 775 watts for the XLS 2500, and all are also rated to drive 2-ohm loads (1,200 watts per channel for the XLS 2500.) Single unit weight spans from 8.6 pounds to 10.8 pounds.

In our survey of the “entry level” portion of the amplifier segment, we observed that there’s a glut of similar designs – largely Class AB topology and heavy transformers – with a few models offering certain additional features that, while handy in some applications, don’t offer a significant difference.

click to enlarge

Certainly, this is acceptable for less demanding portable uses, but our vision was to offer a completely new solution for both “less critical” uses up through more mainstream professional markets such as church, retail and bar/restaurant systems.

This meant that we needed to go beyond “just another amplifier” and integrate some of the leading-edge technologies developed for our products serving larger, more sophisticated applications.

We explored whether this technology could be fine-tuned to meet the needs of our target markets, and the answer was a resounding yes.

HIGH EFFICIENCY
We began with a highly efficient switching power supply optimized for maximum power transfer from the AC line through a Class D output stage to the loudspeakers.

As a type, Class D amplifiers are notable for extraordinarily high efficiency, approaching 90 percent. In addition, inherently low output impedance makes Class D well suited to driving difficult reactive loads such as subwoofers.

However, a number of complexities make it difficult to design – and to manufacture at modest cost – professional caliber Class D amplifiers with sonic performance comparable to the best Class AB designs.