Фонокорректоры — Lamm Industries LP1 Signature Phono

The LP1 Signature is Vladimir Lamm's dual-mono valve phono stage, built by Lamm Industries in Brooklyn, New York. It completes the Signature Series triad alongside the ML3 Signature power amplifier and LL1 Signature line preamplifier, and Lamm describes it as the best phono stage he knows how to make. It is sold as a set of three chassis, the audio unit and a separate power supply for each channel.

Key specs that matter

There are three inputs, two for moving-coil and one for moving-magnet cartridges. Input impedance is 31.5 ohms on the first MC input, 430 ohms on the second MC input and 47 kohm on the MM input. The audio circuit uses two 6C3P and two 6C45P-E valves, and each power supply adds five valves. Frequency response is 20 Hz to 20 kHz. The circuit runs in pure Class A with no loop feedback.

Engineering and use context

Both channels of the audio circuit share one chassis but are separate and identical. Each channel uses two high-transconductance triodes. The circuit requires 55 mA of plate current per channel, far above the few milliamps typical of valve phono stages, and new-generation tubes make this possible. For MC cartridges, step-up transformers provide part of the gain, which reaches 71 dB on the low-impedance MC input and 59.7 dB on the second MC input. The power supplies were derived from the one used in Lamm's L2 preamplifier, and two would not fit in a single chassis, which explains the three-box format. Each uses full-wave vacuum rectification, choke-input filtering, vacuum tube high-voltage regulation and solid-state analogue, non-switching regulators for the heaters. Custom low-noise transformers are fitted, and energy storage exceeds 100 joules. The valve complement of the supplies includes 12AX3 or 12BE3 rectifiers, 6C19P regulators, 6AK5 and 5651A tubes. Although designed to complement Lamm electronics, the LP1 Signature connects to any preamplifier with suitable line inputs. Three shelves are needed to house the set. The high plate current and the step-up transformers let the circuit reach MC gain with few active stages.

Pairing

The two MC inputs with different loadings allow two MC cartridges to be connected at once, or one MC and one MM. Lamm's LL1.1 Signature and L2.1 Reference preamplifiers are the natural partners.

Alternatives

Lamm Industries' LP2.1 is the dual-mono valve phono preamplifier of the range in a simpler format.