Preamplifiers — Vincent SA-T7 Diamond

The Vincent SA-T7 Diamond is a limited-production valve preamplifier, a special edition of the SA-T7MK based on a rare stock of unused German Telefunken PCF803 valves made decades ago. Designer Frank Blohbaum found these New Old Stock valves and, instead of simply fitting them to the existing SA-T7 circuit, redesigned the audio circuitry entirely around them. Vincent has said no further Diamond editions will be made once this stock of valves runs out, so the model is a finite run rather than a permanent catalogue item.

Key specs that matter

Connections include six stereo RCA inputs, a coaxial and an optical digital input, and Bluetooth 5.0. Outputs comprise two stereo RCA preamplifier outputs, one stereo RCA record output and two 3.5mm jacks for power control. Gain is typically 13.3dB with the volume control at maximum, and the signal-to-noise ratio is typically better than 100dB (A-weighted). Maximum power consumption is 58W and the unit weighs about 8.5kg.

Engineering and use context

The valve stage is a BestPentode circuit fed through low-noise power supply couplings, and Vincent adds its own Vimala module to this stage. Its name is taken from a Sanskrit word for purity. A second gain stage carries the bass and treble controls, which can be switched out of the signal path completely. A DAC based on the PCM5102 chip handles digital conversion internally at up to 24-bit/192kHz. The Diamond edition builds on the circuit of the standard SA-T7 and SA-T7MK.

Pairing

Six analogue inputs leave room for a large collection of sources, while the internal DAC and Bluetooth let digital sources connect without a separate converter. The two preamplifier outputs can feed two power amplifiers, for instance one stereo amplifier per driver section when bi-amping, or one amplifier plus a powered subwoofer, while a recorder takes its signal from the dedicated record output. The 3.5mm control jacks let matching Vincent power amplifiers follow the preamplifier when it is switched on and off.

Alternatives

The Vincent SA-T7MK is the regular-production preamplifier that shares its platform with the Diamond, without the rare Telefunken valves.