Krell KAV-300i integrated amplifier

Is Krell risking its reputation? With the KAV-300i, an integrated amplifier that was originally envisaged as an export model, but for which home demand is clearly increasing, the Connecticut-based amplifier manufacturer is dabbling in low-cost territory. Previous Krell amplifiers have been known for their prodigious drive capability. Time and time again, it is found that the true measure of the bass performance of a big speaker isn't realized until a Krell power amplifier is brought into service. But how could an amplifier with a meaty 150Wpc specification and full remote control be built to sell for just $2350.

The answer lies partly in the growth of Home Theater, an area where Krell has been gaining experience with good-quality, competitively priced, multi-channel amplifiers. There was also a precedent in the KST-100, a modestly priced 100Wpc Krell power amplifier that found favor in Europe a few years back.

The answer also lies in backing away from Krell's earlier design philosophy of maintaining the amplifier's output voltage into very low impedances, 1 ohm or below. If performance is to be sustained when the load impedance halves, then, all other things being equal, the size of the amplifier power supply as well as the number of output transistors and their heatsinks must double. For Krell to specify performance down to 2 ohms and below, they must pass the costs of doing so on to the customer.

In the end, it all boils down to application. So, if you back off from the unbreakable, drive-anything amplifier-design philosophy and say, "Hey, let's be reasonable, let's forget those possible 1 and 2 ohm loadings, and instead target and specify for well-designed 4 and 8 ohm nominal speaker systems. Now let's see how the design equations fall out." The KAV-300i's output is specified as 150Wpc into 8 ohms, doubling to 300Wpc into 4 ohms, but the amplifier is not intended to drive lower impedances. Sure, it will still be capable of frying a 3 ohm load, but you shouldn't expect the bass slam that you get with an amplifier designed to drive lower impedances.

What you get
Krell's literature describes the KAV-300i as belonging to their "A/V" range of products. It has significantly softer, rounder styling than the larger KSA amplifiers. It may lack macho handles, but the '300i is well-finished, mainly in black textured enamel, with a silver-charcoal aluminium fascia offset by black-anodized end caps. Its panel logo is the new, downward-arrow Krell "Audio-Visual" symbol.

But regardless of Krell's philosophy or the unit's origins, I determined to view this product as an entry-level Krell amplifier, one with an unusual combination of useful features, offered at a tempting price. You get five inputs, including the tape (monitor) facility. One input (B1) is balanced and may be configured, via an internal switch, as a direct or "through" input for an audio/video set-up, where the surround processor provides volume and balance control. (A hex wrench is supplied for getting inside, and also for replacing major fuses should this be necessary.)

Two kinds of output are available from the KAV-300i: loudspeakers are connected via one set of gold-plated five-way binding posts per channel; there is also a set of single-ended preamplifier outputs via gold-plated RCA jacks. Note that the loudspeaker terminals remain active even if the unit is run only as a preamp. This isn't a real problem since in this mode no power need be drawn from the speaker terminals. However, speaker cables should not be left connected, in case the plugs short-circuit the amplifier outputs.

A model of simplicity, the front panel carries a horizontal line of milled, stainless-steel, circular control buttons. From the left, we have the power switch, electrically servo'd, with soft-start and standby modes. The power light glows red for standby, changing to blue for "operate." The next five buttons deal with input selection, while the remaining two cover volume up and down. LEDs show the status of all modes—the balance offset, mute, the active input, standby/operate. In addition, a set of 11 LEDs graphically shows the volume setting.

This amplifier will mainly be operated, I expect, via the remote-control handset, a satisfactorily chunky plastic molding. As well as duplicating the power/standby, source select, and volume control buttons on the amplifier's front panel, the remote gives the user access to the balance facility. This can be shifted unambiguously in five 1dB increments in either direction. The final touch is the inclusion of some basic control functions for a Krell-compatible CD player or transport (including many Philips-type RC5-coded units). I grew to like the handset with its dulled finish and positive-click membrane-type buttons.

The case is of aluminium alloy, and its good conductivity is exploited in the form of additional surface area for the modestly finned internal heatsinks. Though these do not have an optimum orientation, an alloy block is bolted through to the lower case section to aid heat conduction. No external fins are present, though there are some ventilation slots in the top cover. I estimate that the unit should not be run continuously at full power into 4 ohm loads for extended periods. The heatsinking is fine for normal peak program duty, however.

45 Connair Rd.
P.O. Box 0533
Orange, CT 06477-0533
(203) 799-9954