Krell S300i Integrated Amplifier (Hi-Fi+)

Integrated amplifiers
Krell S-300i
Krell S300i Integrated Amplifier (Hi-Fi+)

[This review originally appeared in issue 65 of Hi-Fi Plus magazine, which is published in the U.K.]

A new amp by Krell always piques the interest of audiophiles. But this one is perhaps the most significant Krell in a very long time. You see, the S300i integrated amplifier is the first Krell product to be made in China.

There’s nothing intrinsically wrong with building in the Far East, but the high-end community has been a notable hold-out on Chinese manufacture. However, a few that are doing what Krell is intent on doing; making the entry level products in the Far East and the more up-market equipment in its original factory.

This is a bold move on Krell’s part. We audio types fear change. Chinese Krell cannot be as good as Connecticut Krell… Can it? In fact, the odds look good. The words on the back of the S300i mention ISO 9001 – a very clear message to the nay-sayers. ISO 9001 is a formal statement of quality control that is common to all good engineering practice. It means constant monitoring, measurement, analysis and a heck of a lot of paperwork accompanying each product. ISO 9001 is one of the mislaid and hard to achieve standards that everyone was struggling to achieve in the 1990s and swiftly forgotten when it came down to building cheap abroad. It means the place of manufacture is completely immaterial, because the standards set by ISO 9001 remain a benchmark wherever that product is built. It means Krell is Krell, no matter where it comes from.

If the S300i could be made anywhere under ISO 9001 conditions, why move production of any product to China. Why not keep it made in America? Put simply, it would be hard to produce a product of the S300i’s calibre in the US without either compromising on performance or raising its price to thoroughly unrealistic levels. The S300i is a bit of a technological tour de force under the skin and Krell would either have to sacrifice some of its advanced features, or bring the sound quality down a few notches. Or, it would sell for about £5,000. None of these concepts sit comfortably, so the company decided that for this level of component, Chinese manufacturer was the only possible option. This is not the thin end of the wedge though; Krell is keen to limit the number of products made in China, as the economies of scale that apply to the S300i (or some AV equipment) don’t apply to Evo-type products and these are best hand-built by American expertise.

So, what do you get for your £2,640? Basically it’s a pre/power in a single box; there’s a stripped-down version of an Evolution preamp, and a Current Mode technology power amplifier stage that’s like a Evo 302 writ small. Not that small, as the thing packs a whopping great 750VA transformer and 38,000µF’s worth of reservoir capacitance into that 20kg chassis. There’s a single balanced (XLR) input – highly recommended – three single-ended line inputs and a power amp direct input. This can also be routed to act as a front channel power amp for a home cinema system. Next to these are a set of CI-chummy connectors (for AMX and Crestron remote handsets and multiroom triggers) and in between is a thin little connector designed to accommodate an Apple iPod.

The amp delivers a claimed 150 watts per channel into eight ohms and doubles that into four. This is the sign of a very ‘stiff’ power supply, so a relatively low impedance loudspeaker will prove no trouble at all. Such a power supply is common in Krell designs, but comparatively rare at the cheaper end of the market (Harman/Kardon being the notable exception). In musical terms, this means sustained deep bass is not a problem, even on ‘difficult’ loudspeaker loads. In fairness, if you were to engage in some cruel and unusual loudspeaker punishment – like partnering this amp with something like an old Apogee Scintilla from 20-plus years ago – the S300i might struggle. But, with any of the loudspeakers you would normally expect to partner with a sub-£3,000 amp, the Krell will breeze through the test.

One of the more smart features (part of that ‘technological tour de force’ mentioned above) is its ability to delve into menu systems and adjust a series of parameters to best suit the system context it ends up living in. Not only can you name individual inputs (let’s face it S-1, S-2 and S-3 are not exactly roll-off-the-tongue describers of inputs), but you can adjust the input trim (making sure the different sources are close to level match), balance adjustment (independent of main balance – good for those rare sources that might be slightly ‘out’ in one channel) and muting level. Such adjustment is becoming commonplace at the lower-middle end of the market – and at the very top – but is surprisingly rare among the up-scale integrateds this amp goes up against.

The front panel has a big blue LCD readout that tows that fine line between the tiny-wee letters of some amps and the unnecessarily huge graphics of Audio Research and Classé products. And then comes what I think is the one weak spot; the big knob in the middle. I know this is machined out of aluminium, and sits in front of a digital rotary control instead of a potentiometer or a stepped resistor ladder for good reason (it’s more accurate). However, it just feels light to the touch, with no weight or resistance to it.

No such comment could be made about the remote, though. If the Army decided it would be a good idea to equip the Parachute Regiment with remote handsets, they would look and feel like this one. In the hands of one who’s trained in such things, this could kill a man with a single blow. It’s a solid chunk of remote, all black and capable of controlling other Krell products and even a passing iPod hooked to the S300i. You need a Torx driver to gain access to the batteries, but this is a lot better than a sliver of plastic falling apart in a year or two. However, the beefy remote means Apple’s remarkable user-interface gets replaced with Krell’s own interpretation. This takes some getting used to and is nowhere near as intuitive as the iPod it handshakes with. Nevertheless, it does offer control of your iPod from an armchair, which is a not inconsiderable bonus.

Turn the S300i on and the first thing you get is ordered control. Seconds later, you reach for your killer bass track, because you can bet it sounds great. It will live up to expectations, too; my Spacemonkeyz remix of the first Gorillaz album has enough bottom end to give a trawlerman seasickness, but this often comes across as (double entendre fans please look away now) ‘all flap and no muscle’. The Krell reverses this beautifully – all muscle and no flap. 

There’s also a sense of grip and authority to the sound that becomes immediately apparent when listening to something with an expansive soundstage. Often, large stereo presentations become ‘blowsy’ and incorporeal at the extremes, as if the phase effects used to widen that soundstage began to encroach on the music itself. This Krell neither foreshortens the soundstage nor exaggerates that wispyness at the edges; it makes the sound seem more rock solid. This makes the crowd noise at the start of ‘Numbers’ from Kraftwerk’s Minimum-Maximum album appear less like slightly phasey white noise and more like an audience of middle-aged blokes wanting to recapture their youth.

‘Numbers’ also demonstrates just how taut the overall performance of the Krell really is. The precise, insistent sequenced rhythms and complex layering of sounds and altered voices within that rhythmic structure are a perfect test of an amplifier’s control over an instrument’s ‘envelope’; how individual sounds attack, decay, sustain and release. These are the sort of tone shaping descriptors used in synth programming, too. 

The S300i controls the envelope in a manner that would make Postman Pat hang his plastic little head in shame. Much of ‘Numbers’ is all about attack and release; half the sounds in the mix are transients of some kind or another. It handles this with ease. Other sounds are more legato – like the vocoder-coated voice intoning Russian numbers or the deliberately slowed German voice. This too it handles with ease. Then, there are the two side by side in the same mix; the regular rhythmic transients and the legato elements, arriving simultaneously; with such hard transients and blunted beats in the same mix, something usually gives. Again… ‘handle’, ‘ease’ come to mind.

So far, so potentially clinical; if all the S300i had in its arsenal was authority and a lot of control, it could easily be bested by any number of equally good integrated amps. Yes, so it can start and stop impressively despite having plenty of power behind it, but that’s not putting it in the exceptional stakes. What sets it apart from the most integrated amplifiers is that it seems to pull in all the properties of all good integrated amplifiers, and then do a Spinal Tap, by going up to 11. No, the analogy doesn’t extend to going louder than its rivals (although it can go very loud, very clean). Instead, it has a lot of the ‘bounce’ of a good UK design, a lot of the detail and large-scale soundstaging of its American counterparts, some of the warmth of a valve amp at the bottom end but with the cool neutrality of a well-engineered solid-state design at the top.

The amp is hugely powerful, but graceful and composed at quiet levels. There’s a paradox about amps that have huge power reserves, in that they often show their best side at incredibly low levels. Sometimes, at low, late night listening SPLs, the interaction between tweeter and woofer can appear less coherent. It’s as if the crossover stopped behaving itself and let the two drivers play their own games. Here, the Krell S300i’s power reserves keep woofer and tweeter on track, even when the volume level is at ‘001’. That kind of control doesn’t come cheap, and is normally the reason why people buy Krell pre/powers.

At this point though, the mild ‘shhhh’ of the background noise begins to be apparent. This is very mild (think ‘well designed valve amp’, rather than ‘someone making a cappuccino in the corner of the room’) and is quickly forgotten about when raising the volume even slightly, because this background noise is quieter than most CDs spinning up. So in many settings, you might not even hear it. It’s there, though and some will never be able to settle down with a solid-state amplifier that isn’t free from background noise. More fool them, the lose out on a remarkable sounding amplifier because of something they will struggle to hear under normal conditions. While we are on the subject of stray noises, the amp does make a whisper-quiet ‘phut-phut’ sound as the volume control goes through its steps. Consider it the computer-age version of relays switching in and out. Pay it no heed, though.

The S300i is a really good amplifier. It’s almost good enough to soak up sales of the Evolution 222 preamp and 302 power amplifier, unless you happen to try to partner it with really daft, punishing loads. With its combination of ‘next gen’ inputs (like that iPod connector) and the sort of build quality that could make ‘Black Box’ flight recorders look shoddy. Whether this is My First Krell, or the Krell you never thought you could afford, the S300i must rank as one of the best integrated amps in the business.

Technical Specifications

Krell S300i

Type: Stereo integrated amplifier, balanced Class A input stage, current mode power stage, 750 VA toroidal transformer, 38,000µF reservoir capacitance
Inputs: single ended line (X3), XLR balanced line (x1), direct iPod connection (x1), home theatre preamp input (x1), RS-232, RC-5, 12 VDC triggers
Outputs: WBT loudspeaker binding posts
Power output: 150W into eight ohms, 300W into four ohms
Dimensions (WxHxD): 43.82x10.16x44.45cm
Weight: 20kg
Price: £2,640



Krell Industries


Absolute Sounds
Tel: +44 (0)208 971 3909

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