K-300i Integrated Amplifier

Renowned American amp brand, Krell Industries, has just unleashed the K-300i Integrated Amplifier.
Krell made an impact with their KAV-300i integrated amplifier in 1999. Today, they are hoping that the all-new K-300i integrated will find similarly enthusiastic fans.

The 18.2kg K-300i incorporates a newly developed amplifier circuit design featuring Krell iBias tech. This delivers 150 Watts per channel into 8 Ohms and 300 Watts per channel into 4 Ohms. Additionally, iBias provides the sonic loveliness of Class A but without the traditional accompaniment of excessive heat and power consumption.

Regarding power, there is a 770VA transformer with 80,000 microfarads of capacitance. The upshot of all that is excellent signal control and dynamics.

Furthermore, with Krell Current Mode topology employed with fully differential circuitry running from the input stage through to the last output gain stage, we are told that we can expect an “extremely linear and extended frequency response curve with smooth, effortless highs and extremely dynamic bass energy”.

Analogue connections include two pairs of balanced XLR and three pairs of RCA on the input side, whereas outputs are catered for by two pairs of speaker binding posts and a single pair of RCA to run to a preamp.

Upgrade the analogue unit with the digital option, and you get the benefit of an ESS Sabre Pro DAC and networked streaming audio renderer with a dedicated mobile application.

The K-300i’s internal web server is optimised for tablets and hands the user convenient and intuitive control. The player is compatible with the latest digital audio formats including AAC, ALAC, AIFF, FLAC, WAV and DoP files up to 192kHx/24-bit from UPnP music servers or NAS devices.

The digital option also provides Spotify, vTuner Internet Radio, Tidal, Deezer, and QoBuz streaming services. Good news it is also Roon Ready and will decode MQA.

Connectivity-wise, the digital module brings HDMI 2.0 inputs and output supporting 4K UHD with HDR for audiophile-grade TV viewing. Upfront is a USB port enabling playback from flash drives. There is another USB port around the rear so that you can stream music directly from a laptop or computer. Wireless fans also are served by aptX Bluetooth. Rounding off the digital inputs are a coax and an optical port.

COOL RUNNING KRELL:
Nearly 40 years after Krell’s iconic Class A power amps hit the high-end, the company looks to be offering far less ‘brutal’ designs. When its iBias output stage technology was introduced [HFN Oct ’14] the company suggested it was doing its part to modernise flagship hi-fi, increasing its appeal to consumers who were not as accepting of bulky intrusions into their living spaces as dyed-in-the-wool audiophiles. Now, as then, Krell claims that its iBias circuit technique combines the ‘sonic benefits of Class A operation without the heat and power consumption of traditional Class A designs’. In practical terms, rather than maintain a constant, high standing current (or bias) in the output stage – the brute-force, but wasteful, Class A approach to eliminating NPN/PNP transistor crossover distortion – these iBias amplifiers spontaneously adjust the bias to suit the music signal. This sliding bias technology differs from Technics’ ‘New Class A’ and JVC’s ‘Super-A’ regimes promoted through the 1980s because, in the K-300i, bias is calculated from a direct measure of the current delivered by the output stage. As a result it incorporates your choice of speaker – with its distinctive sensitivity and impedance vs. frequency trend – into the calculation of required bias.