Vendetta Research SCP-2 phono preamplifier Measurements
To provide some feel for how the Vendetta Research phono preamp measured in comparison with the Jeff Rowland Design Group Consummate, I ran the Vendetta through two tests: frequency response (fig.1) and THD+noise (fig.2). The latter was taken with a 5mV input at 1kHz and is largely noise. The RIAA response of the Vendetta, while not flatter than that of the Consummate phono stage on an absolute basis, has a slightly different curve. The Consummate's response shelves down 0.25dB below 1kHz, which could account, at least to a degree, for the preamps' sonic differences.—Thomas J. Norton
Fig.1 Vendetta Research SCP-2, RIAA error (0.5dB/vertical div., right channel dashed).
Fig.2 Vendetta Research SCP-2, THD+N vs frequency, input level 5mV at 1kHz.
Remeasured in 2002, the Vendetta's wideband S/N Ratio was a superb 62.5dB ref. the MC reference level of 0.5mV at 1kHz, this improving to 76dB when A-weighted. Fig.3 shows the spectrum of that noise floor. It is slightly boosted in the bass, as to be expected from the RIAA equalization, but it is still low overall. The measured voltage gain was 56.4dB at 1kHz, which is slightly lower than specified. However, this is explained by the Ohm's Law interaction between the Vendetta's low input impedance and the 25 ohm output impedance of the Audio Precision System One.
Fig.3 Vendetta Research SCP-2, spectrum of noise floor ref. 5mV at 1kHz (10dB/vertical div.).
Peculiarly, despite J. Gordon Holt stating back in 1988 that the SCP-2 inverts polarity, I found the Stereophile-owned sample to be non-inverting. The Vendetta's output impedance was very low at 16 ohms at 20Hz, though it did rise smoothly with increasing frequency to a still low 95 ohms at 20kHz. The measured overload margins (ref. 0.5mV at 1kHz) were among the best I have ever measured, at 32.75dB at 20Hz, 31.6dB at 1kHz, and 29.4dB at 20kHz. The output level at the 1% clipping point was more than 15V! To sum up, this superbly uncompromised measured performance is a tribute to the Vendetta's designer.—John Atkinson.