Review: Krell K-300i – Integrated Amplifier with Digital Streaming Module

Review: Krell K-300i - integrated amplifier with digital streaming module offers Very deep, always precise world-class bass that does not soften even at very high levels

Solid as a safe and almost heavy: This integrated amplifier seems indestructible and will outlive us all. Not that I threw him off the second floor, but the massive steel remote alone could drive nails into walls or rout Stormtroopers. The high-end legend Krell doesn’t do things by halves, which also applies to the only integrated amplifier in the American range. The listening test, which will not only interest tank crackers, shows what the massive hum with the name K-300i (13,650 euros)

Integrated amplifier technology between tradition and modernity

With its dimensions of 43.8 x 10.5 x 45.7 cm (W x H x D), the Krell K-300i doesn’t even look that big if you compare it, for example, with massive XXL integrated amplifiers from McIntosh – I own an MA8900 AC myself. But it’s just as massive and armored as a Mac, which you’ll notice when you take it out of the box: 23.6 kilograms are tugging on your arms and spine. And then there’s this steel remote control, which dwarfs everything I’ve held in my hand before massive, bold, heavy, and angular. If archaeologists or extraterrestrials find them in 10,000 years, they will nod approvingly and reverently put them in a museum (or hammer nails in the UFO wall). To insert the batteries, screw the good piece first and then screw it back on. The batteries, a corresponding Torx key, and an English-language operating manual are included. Unfortunately, there is no German one.

The Krell K-300i is something of a balancing act between tradition and modernity. The solid, safe look is old-school and typically American. Still, under the dress, we are dealing with a state-of-the-art integrated amplifier with an optional integrated streaming and converter tract. A massive 771 VA transformer sitting far forward and 80,000 μF filter capacitance mark the power supply and hopefully provide plenty of dynamics. You notice it when you lift the amplifier, which is significantly heavier at the front than at the back.

A closer look reveals the meticulous workmanship of the integrated amplifier, which also corresponds to the price range: small gaps, a housing that seems to be made of one piece, the keys click loudly when touched, and gold-plated speaker cable connections. One might think that the amp survives a fall unscathed – in contrast to the ground. In the black version of our test device, the Krell reminds me of Darth Vader, who snorkels around in the rack in front of him and waits until he can finally get started. The listening test later shows whether the sound is also on the dark side of the force.

The Krell integrated amplifier has been on the market for a few years. Still, according to Mansour Mamaghani, head of German sales Audio Reference, it was revised six months ago (new display, revised control, different fan). That’s why a test is still worthwhile in 2023. You can order the good piece with or without a digital package; the prices are 13,650 euros and 12,700 euros. The digital board makes the wallet just an additional 950 euros and is the first choice for most interested parties: According to Mr. Mamaghani, 80 percent of the amplifiers are ordered in this form.

Usability & interfaces

In both cases, it has a relatively small display not in the middle but on the right. Too bad, because there would have been enough space for a larger one on the front – unfortunately, I can no longer read it from a distance of three meters. I also find it irritating at first that the Krell does not have a classic volume control, but only arrow keys on the front and the remote control. You can do that – but you don’t have to. In summary: despite the innovations, there is room for improvement in user-friendliness.

On the other hand, applause erupts when you look at the back: the Krell K-300i with digital module has, in addition to an HDMI output, two 4K-UHD and HDR-capable HDMI inputs, with the help of which you can integrate the television and Blu-ray player into the stereo system – that’s a rarity! Of course, in addition to an Ethernet socket, other digital inputs are also available: USB-B for connecting PCs and notebooks and one optical and one electrical digital input each. Wireless Bluetooth playback with aptX audio technology also works; for classic analog playback, there are two XLR and three cinch-Variants. There is also a USB-A port on the front, to which USB sticks can be docked.

According to the manufacturer, the ESS Saber Pro DAC (ES9028 Pro from the 32-bit reference series) is made for high output currents and supports PCM up to 24-bit/192 kHz via the coaxial and HDMI inputs (optical only 24-bit/96 kHz). DSD 128 is also possible via HDMI. But that’s not all: the network streaming audio renderer plays AAC, ALAC, AIFF, FLAC, WAV, WMA, and DoP files up to 192 kHz/24 bit from UPnP music servers or NAS devices. If you want to stream Spotify, Tidal, Deezer, or Qobuz, you can download the free Mconnect Control app (iOS or Android version) expressly recommended by Krell or control via Roon. In both cases, MQA streaming is also possible. Streaming is generally only possible with a wire and not wireless wifi.

The iBias technology

Let’s get to the Krell K-300i’s main job: amplifying. After all, we’re dealing with a dual 300-watt integrated amp into four ohms (2 x 150 watts into eight ohms) that, on paper, can drive pretty much anything that three doesn’t have the power to do. Hence the name K-300i, which stands for 300 watts. It features an amplifier circuit design with Krell iBias technology. It delivers the sonic benefits that Class A operation should offer without disadvantages (great heat development, extreme power consumption, high space requirement). Hence, the bottom line is that it works more efficiently. True to the motto “a good horse doesn’t jump higher than it has to,” the power throughputs of the output transistors are constantly recorded, taking into account the speaker load. Their operating points are “intelligently” adjusted accordingly, whereas, with classic Class A, a permanently high quiescent current defines fixed operating points in higher areas of the characteristic curves.

We’ll come to the sound in a moment, but in practical use, it can be said about the heat development accompanying the sound: you can’t fry fried eggs on the Krell, but it still gets pretty warm. After going for a walk in winter, I like to warm my hands on it during the warm-up phase, but it doesn’t replace a classic radiator. And now let’s see if we’re dealing with a heavyweight musically…

Krell K-300i: Sound Test & Comparisons

Power & Control

On the one hand, I primarily listened to my CD player McIntosh MCD 301 AC (price at the time: 5,600 euros) connected via cinch (Goldkabel Executive) to analyze the pure amplifier section of the test device. On the other hand, to assess the converter of the Krell K-300i, I also extensively tested the digital playback via a coaxial digital cable (also Goldkabel Executive) via the converter-free music server NAD M50.2 (approx. 5,000 euros).

The first thing that ends on my note after a few hours of digital playback is, “Whoa, fat, powerful bass!” Not in the sense of an extremely exaggerated bass that one knows from tuned chav sleds, but tight, powerful, deep, and always controlled. And: “Has a grip on the speakers like a pair of pliers.” Although pliers are not meant negatively, you can feel the power and control this integrated amplifier exerts at every moment. My Sonus Faber Olympica Nova 3(13,400 euros per pair) don’t need a lot of power to get going, but they react precisely to the connected amplifier. And the Krell K-300i relentlessly clamps down on the Italian floorstanding speakers in impressive fashion, such as “Down In It” from industrial rockers Nine Inch Nails ‘ remastered 1989 debut album Pretty Hate Machine. The bass goes extremely low in this piece but remains as quick as a flash when the components allow it.

And here, the Krell even surpasses my powerful integrated amplifier McIntosh MA8900 AC (approx. 9,800 euros), as it descends just as deeply and vehemently into the bass cellar but reproduces the events a bit more detailed and drier. Not only is following the bass on “Down In It” great fun, but it’s also almost addictive. Big basement cinema.

You’ve probably already guessed what’s going on regarding coarse dynamics, to say the least: Even at very high volume levels, precise level jumps are effortless. Okay, the Sonus Faber aren’t the most explosive loudspeakers in their price range in terms of coarse dynamics, but the always confident gait of the Krell K-300i cannot be overheard and is very good for these loudspeakers. The American, however, is not one of those machines that first and foremost understand the rough and thresh with no regard for naturalness. Energy and flow are perfectly balanced.

There are small differences between analog and digital playback:

The Krell K-300i’s internal converter sounds more direct and dynamic, while the McIntosh CD player sounds more reserved. In my ears, that speaks for the converter of the Krell K-300i, especially since this observation is not limited to the dynamics. When the Krell DAC is in play, I have the feeling of getting a touch more of everything in homeopathic doses: more bass, more sovereignty, more stage, and more emotions.

The quiet nuances – fine dynamics

The quiet intermediate tones are not neglected, which brings us to the fine dynamics. I tested coarse and fine dynamics with audiophiles’ well-known “No Sanctuary Here” by Chris Jones, who released his music on the Stockfisch Records label concerned with natural acoustic sounds. The song has high dynamics in the bass and is also an excellent test piece in terms of fine dynamics when the guitar strings shimmer and vibrate.

The Krell K-300i follows every nuance down to the last detail and precisely reproduces every fine ramification – even at low volumes, it displays the finest level gradations. Here, too, jaggedness and flow complement each other almost perfectly. It doesn’t get any better in this respect – power en masse, not even remotely a rough-hewn lumberjack, but a fine spirit. It’s reference level and among the best, I’ve ever heard, even compared to the various McIntosh amps I’ve owned over the years.

Crackling & clapping

Regarding resolution, there is nothing to complain about in either transmission path; it corresponds to the significantly higher price range. The Krell K-300i is always excellent at working out details, as can be seen very nicely with “Ultra Truth,” the title track of Daniel Avery’s album of the same name. The British DJ and electronics specialist delivers excellently produced, varied work that has captivated me in front of the system for weeks with its experimental touch.

At the beginning of the title track, a faint hissing and crackling in the background for a few seconds was intentionally inserted and belonged to the mood. With the Krell amplifier, this effect comes to the fore; the American doesn’t miss a thing. He pulls it out a touch clearer than my McIntosh MA8900 AC. Despite the enormous detail, he never comes across as harsh or too analytical. The music retains its inner tension and does not risk falling apart due to its high resolution. Here you can see the Class A genes of the Krell.

Center display with a feel-good factor

In addition, there is a tonally slightly warmed mid-range representation, which increases the feel-good factor. Voices come across as very expressive and go straight to the heart. For example, the atypical soul-hip-hop piece “Tremolo” by the Young Fathers (album: Cocoa Sugar from 2018), which relies on polyphonic singing, touches me more than usual. However, the emotional element does not stem from the fact that anything in the middle is concealed; on the contrary, the Krell K-300i informs you in the best and most transparent way about all the details happening in this area.

The Krell K-300i does not sound as 100% strictly neutral as, for example, the NAD integrated amplifier M33 (now 6,800 euros, also with integrated streaming function), but that is not a flaw, but rather falls into the category of taste. In addition, the NAD is not as sovereign as the K-300i regarding coarse dynamics and does not sound quite natural and self-evident. It reminds me more of the Devialet 400 I owned a few years ago and impressed me with its extreme power and musical flow.

Long-term heights

This is also due to the long-term, more gentle than aggressive highs that harmonize the overall sound. With the integrated streaming amplifier Lindemann Musicbook Combo (4,500 euros), which I was allowed to test last year, the highs sounded a bit fresher and more dominant in comparison, which I don’t like so much, but of course, also falls into the category of taste. The Lindemann does not come close to the deep bass stability of the Krell, which is not surprising given the price difference.

Regarding height display, the Krell K-300i hits the spot for my taste: Nice, airy, and high-resolution according to the price range, but never uncomfortably prominent or bright – applause! Figuratively speaking: you can still see all the details in the snow on the distant mountain peak, but you are not dazzled by the white splendor. Even harshly recorded rock music or heavy metal is still fun without the dog starting to whimper.

stage design

The stage presentation is still missing, in which the Krell K-300i has to compete with my McIntosh MA8900 AC. In terms of stage depth, there is a tie in the battle between the two American giants, with both the events only taking place from the level of the loudspeaker baseline, without it expanding noticeably to the rear. The stage goes far forward and conveys great depth and a three-dimensional experience with tangible, three-dimensional instruments.

However, there is a difference in the stage size: the stage raised by the Krell is not particularly wide for an amplifier in this price range. I noticed that with the new Depeche Mode album Memento Mori, which deals with difficult themes such as transience and war but is unfortunately very disappointing musically. One of the few good tracks is the lead single “Ghosts Again,” which someone once aptly described as the younger cousin of “Enjoy The Silence.” With the Krell K-300i, it sounds less expansive; the stage is a bit narrower horizontally compared to the McIntosh MA 8900 AC, which is excellent in this respect.


The look of the Krell K-300i is a matter of taste. At first glance, the black version looks fairly inconspicuous, but it’s slightly grim at a second glance. The silver one looks more conspicuous and friendlier; the shape comes here. The workmanship is beyond reproach and exudes the longevity of a safe.

In terms of sound, the Krell K-300i goes through as something of a consensus device that all demanding connoisseurs can probably agree on: Listeners who enjoy listening get a small shot of warmth – and the bottom line is music playback free of any unpleasant overtones. On the other hand, more analytical ears will be happy about the high resolution, which does not omit even the smallest detail, even though the treble level is never superficial. Both groups of listeners enjoy the high inner tension of all kinds of music, which never falls apart into individual parts, but always appears as a well-rounded whole and touches the listener.

The only reason for criticism is the less-than-ideal operation in combination with the rather small display and the not-overly-wide stage. On the other hand, the Krell K-300i dominates almost every loudspeaker on the world market and drives it to dynamic peak performance, not least to the wonderfully involved bass range. A gentle Darth Vader, so to speak, who combines power and Master Yoda under one helmet. You’ll probably have to listen and buy if you have the spare change!

Factsheet Krell K-300i

  • Very deep, always precise world-class bass that does not soften even at very high levels.
  • Extremely good coarse dynamics, clean fine dynamics.
  • High resolution that matches the price range.
  • The extremely natural, homogeneous sound appeals to listeners and chief analysts.
  • Rather slightly warm than strictly neutral, very transparent and high-resolution mids convey a pleasant emotionality.
  • High-resolution, airy, level-side slightly reduced and therefore never uncomfortable highs.
  • Stage representation with high plasticity and pronounced depth gradation, the stage opens up nicely towards the listener. The stage width, on the other hand, could be a little wider.
  • Slight weaknesses in operation and a somewhat small display.
  • Processing beyond any doubt (including remote control).


  • Concept: integrated amplifier
  • Price: 13,650 euros (with the digital module, 12,700 euros without)
  • Colors: black, silver
  • Inputs: 3 x RCA pairs, 2 x XLR pairs, 1 x coax, 1 x optical, 2 x HDMI, 1 x USB host, 1 x USB device
  • Outputs: 1 x speaker pair, 1 x HDMI, 1 x RCA preamp out pair
  • Output power: 2 x 150 watts into eight ohms, 2 x 300 watts into four ohms
  • Dimensions & Weight: 43.8 x 10.5 x 45.7 cm (W x H x D), 23.6 kg
  • Miscellaneous: system remote control
  • Warranty: 2 years (plus two more years upon registration)