|Krell FPB 700cx Stereo Power Amplifier|
|Home Theater Power Amplifiers Stereo Amplifiers|
|Written by Augie Bettencourt|
|Wednesday, 01 October 2003|
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In America, we love things big. We buy big houses, big vehicles and when we eat, we “super-size” our meals. We like monster trucks and enjoy watching big athletes play in the “Super Bowl” on our big-screen TVs. Therefore it’s no wonder that there is a market for huge audio amplifiers. For over 20 years, Krell Industries has been famous for making some of the biggest, baddest and most powerful amplifiers in the world.
The Krell FPB (Full Power Balanced) 700cx is Krell’s latest top-of-the-line amplifier in the FPB stereo amplifier line-up. The amplifier retails for $14,000 and is rated at 700 watts per channel into eight ohms, 1400 watts into four ohms and a whopping 2800 watts into two ohms. Having recently reviewed the Krell FPB 400cx, I was reminded of the Krell’s top build quality. Weighing in at 180 pounds and measuring 19 inches wide, 10.3 inches tall and 25.5 inches deep, makes the Krell FPB-700cx the title-holder for the most massive amplifier ever to grace my listening room. The 700cx’s large black anodized face and three small blue LEDs give the amplifier a very appealing, stately appearance. The front panel also has an infrared sensor for remote operation and interaction with other Krell products. The rear panel has two pairs of speaker binding posts per channel for bi-wire applications. These can be easily thumb-tightened, but they will not accept bare wire, banana plugs or pins -- only spade lugs will work. It offers balanced connections, as well as the proprietary Krell CAST™ inputs, which I’ll cover later in this review. The rear panel also includes the remote control Krell Link to turn the amplifier on and off, a very substantial non-detachable power cord, as well as a power breaker switch and a pair of handles to carry the beast around. Krell recommends a 20-amp circuit for this amplifier, which I was able to oblige.
As I unboxed the amplifier, I kept wondering how I would get this mammoth beast upstairs into my listening room. Fortunately, Krell supplies a packing system that includes handles, so that so that two people can lift the amplifier out of the box. Lifting the amplifier out of the box wasn’t difficult, although carrying it upstairs into my listening room was a different story. Once upstairs, I placed the Krell FPB 700cx on the bottom shelf of my rack and connected it to the Krell KCT preamp, via its CAST™ inputs. Speaker connections were made using the Cardas Golden Cross bi-wire speaker cables, which have long been my reference speaker cables. The Shanling CD-T100 CD player was used for all two-channel audio listening. For home theater viewing, the Krell FPB 700cx was connected to the Krell HTS 7.1.
The FPB 700cx is a Full Powered Balanced X Series Stereo Amplifier, which is what Krell calls their latest circuit design. The new X Series Amplifiers use the Krell Sustained Plateau Bias III microprocessor control system that maintains Class A operation, regardless of music or movie demands. Class A bias is the most accurate method used to amplify musical signals, but it has its engineering challenges. Class A operation means that all transistors in the amplifier draw current all the time. The large current consumption gives us one of the benefits of Class A operation, namely a distortion that is low and kind to our hearing. However, it’s a design that’s neither cheap nor easy to engineer, although it has obvious advantages. As I mentioned earlier in the review, the FPB 700cx has its own proprietary output design, called CAST™ Technology (Current Audio Signal Transmission), or in this case, CAST™ II Technology, Krell’s latest update. Krell claims the CAST™ II system improves every performance area, including speed, precision, dynamic range, depth and width of the soundstage, transient impact, tonal balance, harmonic distortion, and more. With the Krell KCT preamplifier on hand, I was anxious to try out the Krell CAST™ II system, something I couldn’t do during my previous review of the Krell FPB-400cx. Being a natural-born skeptic, I was looking forward to proof that the CAST™ II system was more than just hype.