CH Precision 10 Series Amplification
By Roy Gregory
As with all equipment and all reviews, there’s more story than just the one that appears in print. Often, space restrictions mean that practical considerations take a back seat as sonic character gets prioritised. Fair enough. But sometimes, the practicalities loom large enough to warrant more than passing attention – and the CH Precision 10 Series amplifiers are one such case.
In this instance, the 10 Series units in general and the M10 amplifiers in particular – especially the power supplies – are big enough and heavy enough to require special consideration when it comes to installation, essential if you are to get the best out of them. Anything this heavy is awkward to move and should be approached with considerable caution. The situation is exacerbated with the M10s because the feet sit on rubber O-rings (so you can’t slide them) and are so low that it is difficult to get your fingers under them and even harder to get them out! Fortunately CH has learnt this lesson the hard way by handling the units themselves. The finger-gap isn’t an issue unless it catches you by surprise while the company also provides polymer footers that locate to the O-rings and allow the amps to slide easily. The problem is, if you don’t read the manual you probably won’t realise, so RTFM!
Next issue is locating the units: As twin chassis designs, both the L10 and M10 have umbilicals running from the power supply chassis to the amplification unit. These umbilicals are relatively stiff, captive to the power supply and terminated with multi-pin Lemo-type connectors – all of which makes them hard to dress well as the plugs will only fit in one position, which inevitably creates torque in the cables. I tried various layouts but by far the neatest was with the amplifier head units placed directly above the power supplies in a suitable rack – and that brings us to another consideration which is worth tackling before the amps arrive…
CH Precision has always built a mechanical grounding/stacking system into their products, consisting of four spiked posts located one in each corner. These can be dropped through removable caps in the top plate to reach screw threads in the bottom corners of the chassis, allowing owners to level and spike the amp to the supporting surface, or stack it on top of another CH unit. I was never a fan of the original system, largely because the hardened steel spikes were both magnetic and unsupported along their length. Using them was like introducing four resonators into the chassis in an inverse Faraday Cage arrangement, while stacking sensitive units was never going to be a great idea.
The good news is that CH took the criticism on the chin and came up with better spikes that make the mechanical grounding system work properly. Now composite designs, they combine a threaded titanium ‘bullet’ with a polymer post that adds the necessary height to allow adjustment without an impossibly long screwdriver. The polymer spike posts sport O-rings that also prevent them vibrating in their shafts, while the previous screw-on caps have been replaced with far more practical, magnetically attached versions. The really good news is that the system works. In fact, it works so well that the company has introduced a hardened aluminium/polymer version to use with the 1 Series (a subject I’ll cover shortly). Lift and level the 10 Series units on their spikes (making sure that you load or tension all four equally) and you’ll hear a significant improvement in focus of and blackness behind instruments, crisper leading edge dynamics and a broader, richer tonal palette. The challenge is that you need to remember to first drop the spikes into their sleeves before placing the amps and then you need enough space above each unit to get your hand and the stubby screwdriver provided in to adjust them. Given that each amp chassis already measures 285mm tall, that means you are going to need something like 400-450mm between levels in your rack.