Alan Sircom explores the latest from Karan
Back in issue 181, we explored in depth the very first creation of Milan Karan’s ‘Master Collection’; a growing family of no-holds-barred line and phono preamplifiers, as well as stereo and mono power amplifiers. All these Master Collection products are to mark 30 years since he embarked on the journey which has given the world of music lovers and audiophiles a plethora of worthy and true high-end products. For the occasion, we assessed the flagship of Master Collection LINE preamplifiers, a two-chassis affair named LINEa. In the end, we liked it enough to award it with the “Line Preamplifier Of The Year 2020” accolade.
What we have here is the logical sequence of the kind – a single chassis line preamplifier called, appropriately enough – LINEb. Some may see it as another attempt to prove the ‘less is more’ point, while others may welcome it as it requires less space or fewer shelves in one’s audio life. No doubt all those and the rest will welcome a purely pragmatic fact that the LINEb costs less than the LINEa. Bearing in mind this means just under £24k rather than £29k, the difference becomes even more crucial and helpful.
The kindest truth of the matter here is the fact that, apart from a less elaborate power supply and only a few, less ultimately relevant, solutions within both power supply and audio circuitry, LINEb gives its prospective owners everything they would get from the LINEa in terms of functionality, facilities and ergonomics. That means that the beautifully crafted front panel and the rest of the silver casing (bar rear panel, more on that in a moment) are identical. The remote control handset is also exactly the same. The option to connect or disconnect audio grounding is here, too. And, finally, LINEb has the same number of single-ended and balanced inputs and outputs as its bigger brother…with, possibly, one meaningful advantage for the LINEb. While the pure dual-mono circuit configuration and execution remain very much present, a single chassis concept did not allow for the L and R channel inputs and outputs to be spread as wide as possible across the whole width of the rear panel. Instead, they have been configured (very neatly) in a more condensed manner with the L channel above the R channel. As such, it’s much easier to keep interconnect cables coming into the LINEb from all the sources and the one exiting towards the power amplifier in a tidy and more natural layout. Utterly faithful to his belief into total purities of differential (balanced) approach, Karan, perhaps somewhat stubbornly, insists on two sets of balanced (XLR) main outputs. Thankfully, both LINEa and LINEb can be factory ordered with one set of high quality single-ended (RCA) output sockets if so desired.
As the XLRs suggest, the LINEb is a fully balanced design. Although many domestic audio components claim a symmetrical circuit, often this is little more than lip service. This Karan preamp, by way of contrast, is fully differential and DC coupled, with any potential DC offset resolved in custom DC servo circuits instead of putting capacitors in the signal path. There are two RCA inputs alongside the four XLRs and one of the two XLR outputs (shown in the photographic sample) is now also a single-ended RCA pair. The topology remains as complementary as it gets and this means noise, distortion and other interference are kept even and therefore low, cancelling out signal by-products. Of course, this degree of circuit symmetry is for nothing if there’s a pinch-point in the volume control, but even here, the output level of the signal (volume control) has been designed as four fully-balanced and symmetrical attenuators with ultra-fast relays and custom made, non-magnetic resistors of 0.1% tolerance. The result is a preamplifier that is LINEb to within +0/-3dB from 1.5Hz to 3mHz, while the LINEb’s extremely fast and DC coupled circuits guarantee no phase shift of the audio signal or any time aberration within the full audio bandwidth. Even by the obsessive levels often found in audio, this raises the bar.
LINEb’s circuit is conceptually very much of the same ilk as the one in the LINEa and overall gain has been kept the same, too. The default factory setting is 6dB and it can be easily adjusted to be 9dB in case the accompanying power amplifier has a very insensitive input.
The Critical Mass Systems CS2 supporting feet are identical to those on the LINEa and provide not just a solid and stable support for the LINEb, but also have a welcome and beneficial contribution to its overall sonic performance and signature, at least once the CS2 settle down and sound permanently at their best.
With any review like this, it’s almost a balancing act, between the LINEb’s performance in absolute terms and how it performs relative to the two-box LINEa. You don’t want to underplay the performance in order to differentiate between the two products, but neither should you hype up the one-box if there are better products out there!
Fortunately in this case, both proved extremely easy to do. Let’s dispense with the LINEa/LINEb comparison first; tonally the two are extremely close, but where the LINEa is ultra-resolving and almost preternaturally detailed, the LINEb is simply outstandingly resolving and detailed! In a way, pulling back from the brink here makes the LINEb possibly the more ‘approachable’ preamplifier; recordings that will ‘fold under investigation’ by the LINEa will sound acceptable on the LINEb. It’s not that the LINEa eviscerates music (if anything, it’s one of the more forgiving of top-end preamps), and neither is it that the LINEb presents a more soft and laid-back presentation; it’s simply that the LINEb is exceptionally resolving of musical information, and the LINEa is the exception to prove that rule. In truth, however, the LINEa and LINEb are incredibly close in performance terms, and to resolve those differences clearly and cleanly requires one heck of a high-performance system. If there is a difference that might manifest across the board, it’s that the LINEb’s presentation is slightly more rhythmically ‘bouncy’ and taut next to the LINEa’s ‘just the facts’ approach. You’ll most likely notice this on something with a swampy blues rhythm, such as ‘State Trooper’ from the Cowboy Junkies Whites Off Earth Now!! [Latent/BMG] because the LINEa’s overall precision and low-level resolution seems to slow down our ability to parse such rhythmic imprecision. The LINEb, on the other hand, just helps make that foot tap more readily.
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