Phono Preamplifiers

This latest ‘entry-level’ phono preamp from the Swiss brand is a simpler design than either the preceding VPS [HFN May ’13] or Classic Phono [HFN Aug ’22], those employing 12AX7EH/12AT7EH and ECC83/ECC81 triode tube-based RIAA networks, respectively. Arguably, the Compact Phono has more in common with the earlier BPS model [HFN Aug ’10], both being solid-state throughout, even though the Compact’s +10dB input step-up transformer bears close resemblance to that employed in the VPS (the Classic used a +16.5dB step-up). While the BPS ran off a 9V battery, and suffered from very restrictive input overload margins, the Compact Phono has a 12V DC supply and an internal gain structure offering a better balance between sensitivity, noise and headroom [see PM's Lab Report].

But what about that 12V PSU? The supplied ‘wall-wart’ is not entirely without compromise and is responsible for a series of correlated spikes radiating out at multiples of 257Hz at or below –105dBV across the Compact Phono’s noise floor. This low-level interference completely disappears with the superior Compact PSU [pictured, above] in tow. The difference in A-wtd S/N is 2dB in favour of the latter (77.9dB vs. 75.9dB), but this simple number does not fully reflect the subjective advantage it delivers. PM