Pre/Power Amplifiers

Just like the single-chassis L1 [HFN Sep ’25], the two-chassis L10 remains a fully analogue, balanced line preamplifier with no onboard streaming or DAC functions. Again, the volume control ‘number’ reflects absolute gain, so ‘0.0dB’ represents unity gain (1V in gives 1V out). Relay clicks are audible when advancing the volume rotary above 0.0dB, +6.0dB and +12.0dB, as additional R-2R gain blocks are switched into circuit, but the accuracy of all steps, above and below 0.0dB, remains very precise. From 0.0dB to the maximum +18.0dB volume setting the ±0.5dB steps are calibrated to within +0.03dB while from 0.0dB down to –90.0dB the maximum error is –0.1dB, loosening further to ±0.4dB over the final 9dB to –99.0dB. The L1 was more accurate still, but these differences fall within normal production tolerances.

The L10’s maximum balanced output is also slightly lower than the L1’s at 21.4V just as the A-wtd S/N ratio is 102.9dB vs. 103.2dB. The flat 26ohm source impedance is unchanged but the L1’s –0.1dB/+0.07dB response is ironed out further still to –0.00dB/+0.02dB (20Hz-100kHz) in the L10 [see Graph 1]. The AC-coupled mode introduces a mere –0.3dB/1Hz roll-off [dashed trace, Graph 1]. Distortion is where the real differences emerge for while both the L1 and L10 easily surpass the <0.001%/1kHz spec. the latter achieves the lowest 0.00005-0.00025% figures (20Hz-20kHz, re. 0dBV). Although CH Precision makes no special claims in this regard, the L10’s supremely low THD is a match for Halcro’s Equinox preamp [HFN Feb ’26]. This is with ‘Global’ feedback engaged [black trace, Graph 2], the figure increasing to 0.0002-0.0004% when switched to ‘Local’ feedback mode [red trace] where there’s a slight increase in output impedance to 29.2ohm but no change in frequency response. PM