LAB REPORT ARC REFERENCE ANNIVERSARY (£24k)

摘要

This is, by any measure, a cracking tube preamp. If there's an issue then it's one of channel symmetry because, on our sample, the left channel exceeded its rated spec. more convincingly than did the right. The 6H30P dual-triodes themselves are precisely matched, offering a total +12.2dB (left) and +12.1dB (right) gain via its balanced in/outputs and with a supremely wide 96.9dB A-wtd S/N ratio (re. OdBV). The channel responses are identical too, even if the -0.6dB/20kHz to -6.9dB/100kHz ultrasonic tailoring [see Graph 1, below] differs from Audio Research's -3d8/200kHz spec. Frankly, the tailored response is the more sensible when interfacing with modern wide-bandwidth sources so perhaps ARC has seen fit to adjust its performance in production. Interestingly, the 280ohm balanced output impedance (rising to 440ohm at 25Hz) is also lower than the suggested 600ohm, and no bad thing too.