The Karan Acoustics Phono Reference phono stage is one of the very best we have ever tested in the pages of Hi-Fi+. It is extremely quiet, is capable of being used with unfeasibly demanding cartridge loads, and has a useful set of alternate EQ curves for non-RIAA equalised recordings. However, these superlatives come at a price, in pounds sterling and avoirdupois: the Phono Reference is a heavy two-box design with a matching power supply that both weigh in at 27kg, and the complete deal costs just shy of £15,000.
Although until recently Karan also produced the one-box PH2 Mk 3 phono stage, but it was clear to chief designer Milan Karan that many of the elements that made the Phono Reference so good could be slimmed down into just the one chassis without making too many sacrifices on performance. The result is the new PH1 phono stage. Of course, the reality of designing such a device isn’t as easy as simply writing about it happening, but a surprising number of core elements are shared between the two designs, least of all a true differential (balanced) circuit approach.
The principle differences between the Phono Reference and PH1 (aside from the extra box, of course) is the Reference’s ‘unconstrained by price’ stance. The Phono Reference is a fully dual-mono, balanced design, featuring three sets of RCA and XLR inputs physically isolated from channel to channel across a whole PCB. Essentially, this makes three sets of paired mono RCA/XLR phono stage input banks with a common dual mono balanced and single-ended output stage. The PH1 has one RCA input and one balanced XLR input, each with their own balanced output stage. The other half of the board is given over to power supply, with three separate transformers (one for each channel and a third for the control circuitry). Neither section is as comprehensively specified as the Phono Reference, but that comes down to PCB real estate as much as anything.
In a way, the PH1’s ‘less is more’ approach might pay dividends for some turntable users: the Left and Right inputs for the Phono Reference are spaced across the whole of the rear panel, and this might be too long for some conjoined phono cables. The shorter gap between left and right channels makes the PH1 more user friendly. Those multi-arm users might bemoan having just the one input, but the rest of us will love the simplicity of the PH1’s connections.
What is completely retained from the Phono Reference is the near infinite range of cartridges you can use with the Karan PH1. The input load, capacitance, and gain settings can all be adjusted from a series of DIP switches on the circuit board. This is less convenient than the front panel dials of our reference Pass Labs XP25, which allows more of a ‘dial-in-to-taste’ control over the loading of a cartridge, but this is more of a ‘fit-and-forget’ adjustment as befits the once-per-cartridge matching process. Both ways have their merits – but the Karan has the advantage of not being prone to ‘readjustment’ by cats, children, cleaners, and the curious.