Components throughout the circuit have been upgraded, optimized and, selected to even tighter tolerances, while the boards have incorporated the layout and routing lessons learnt with the L10. The reduced noise levels that result from the revised gain structure and refined signal routing are of course, particularly critical to musical performance, given the enormous degree of amplification involved in a phono-stage.
Also in line with the L10, users are now able to select between local and global feedback. The P10 also adds phase inversion and a mono switch, previously limited to the L1/L10 line-stages. Just like the line-stage, the twin-chassis P10 can be doubled up to produce a ‘true monaural’ four-chassis phono-stage, with individual audio and power supply boxes for each channel. Unlike the P1, which simply installed one audio circuit board in each chassis, the P10 can accept two circuit boards per chassis in ‘true-monaural’ form, offering users twice the number of inputs – so if you running four tonearms/cartridges and they all need current sensing inputs, you know what to do…
Switchable EQ Curves
Like the P1, the P10 offers users the option to include switchable replay EQ curves, to accommodate correct playback of older records. But, like the rest of the unit, the switchable EQ facility has been upgraded in terms of performance and functionality. The most obvious changes are the addition of AES (Capitol), NAB and Philips curves, along with the ability to add the 50kHz Neumann pole to any curve, as opposed to just the RIAA curve in the P1.
The full list now runs as follows:
Standard –
RIAA (500R-13.7; t=3180/318/75 µs)
Optional –
EMI (500A-12.7; t=2273/318/63 µs)
Columbia LP (500C-16; t=1590/318/100 µs)
Decca London (500C-10.5; t=1590/318/57 µs)
DGG Teldec (500R-10; t=3180/318/50 µs)
Capitol AES (400N-12; t=5305/398/63 µs)
NARTB NAB (500B-16; t=2720/318/100 µs)
Philips (400N-6; t=5305/398/32 µs)
Taking advantage of the switchable colour display fitted to the CH products, the P10 arrives with each curve designated with a default colour, so that it is immediately apparent if a non-RIAA curve is selected, and if so, which one. The designated colours roughly follow the label shades of the most prominent companies, so RIAA is white, EMI is red, Columbia is pale blue, Decca is purple, DGG/Teldec is yellow, NAB is blue, Philips is plum and Capitol/AES is green. I know most Deccas have black/silver labels, but white was already taken, a black display does nobady any good and the company did use purple. Likewise, the pale blue for the Columbia curve suggests the shade of the beautiful silver lattice labels of their early stereo labels (or maybe the grey of the ‘Six-Eyes’). If that all seems a bit much, users can re-designate colours of their choice or revert to all the same colour. It seems like a small thing, but those who invest in and use the optional curves will find it extremely useful. P1 owners can expect a similar display capability in due course via a firmware upgrade.
Handy remote…
The other big news for any curve user is that the P10 comes with one of CH’s small, four button IR remote control handsets. This allows you to select phase, mono, local/global feedback, the rumble filter and switch curves from the listening seat – and helps explain the adoption of the colour coded display for the different EQ curves. This is one remote I might actually use!
