a greater understanding of the music is immediately possible

The dual monaural phono preamplifier model LP1 Signature is the ultimate statement of perfection in High End audio. Just like the ML3 Signature and LL1.1 Signature, the LP1 Signature is one of the best creations of its designer’s professional career.

design elements

The LP1 Signature has been designed to complement the ML3 amplifier and the LL1 preamplifier.  It completes the Signature Series triad and, in combination with the other two Signature components, represents a “match made in heaven”.  However, the LP1 Signature will perform its magic in any system provided it is of sufficient quality.

The experience of listening to the LP1 is a unique one.  It is, at once, intimate and expansive—as if being transported to a space that belongs to just the listener and the music as they merge with one another. With no electrical artifice to impede communication, a greater understanding of the music is immediately possible. Thus enabled, the listener can enjoy each and every musical element locked in the LP’s grooves with newfound depth, profundity and insight. 

The LP1 Signature features a topology that brings out the most natural sound performance in the audio path.  The main distinction of the LP1 Signature from any other comparable type of preamplifiers is its almost inaudible sonic signature.  When connected to the appropriate type of electronics, and especially LAMM amplifiers and preamplifiers, it assures the extraordinary transparency of perceived sound and recreation of a three dimensional soundstage in the home, recording studio, etc. without boundaries and limitations.  


The LP1 Signature is a vacuum tube preamplifier that employs a high current pure class A operation from input to output.  No loop feedback is employed.  Other features include:

  • Audibly neutral power supplies (one for each channel) featuring full-wave vacuum rectifiers, choke contained filters, vacuum tube high-voltage regulators, and solid-state low-voltage analogue non-switching regulators used as the heater supplies 
  • Three separate inputs for MM and MC (two inputs) cartridges
  • All amplification stages utilize high transconductance super low noise high-current vacuum triodes
  • Very accurate RIAA EQ network

Each preamplifier is carefully handcrafted of the finest materials and hand selected top quality parts like military-grade DALE metal-film resistors, RCD wire-wound resistors, BOURNS multi-turn potentiometers; ELECTROCUBE, CORNELL DUBILIER and ROEDERSTEIN film capacitors; high frequency switching grade CORNELL DUBILIER electrolytic capacitors; HAMMOND chokes; gold-plated NEUTRIC connectors; and military-grade low-noise long-life vacuum tubes. 

A custom-designed massive damping panel installed in the preamplifier unit significantly reduces all types of mechanical vibrations which, in turn, leads to a more extended, coherent and natural bass reproduction. 

The LP1 Signature features a custom-designed super-low noise power transformer.

audio critic reviews (coming soon)


The following data represents the LP1 Signature as performed by an independent party:
Mr. Bascom H. King of BHK Laboratory (bhk@rain.org).

Rated Output Voltage
F = 1KHz:
MC1 input to output: 0.135 Volts RMS.
MC2 input to output: 0.135 Volts RMS.
MM input to output: 0.135 Volts RMS.
Voltage Gain
F = 1KHz:
MC1 input to output: 3,560 + 2% or 71 + 0.2dB.
MC2 input to output: 970 + 2% or 59.7 + 0.2dB.
MM input to output: 100 + 2% or 40 + 0.2dB.
RIAA Accuracy*
From 20 Hz – 20 KHz: better than + 0.05 dB/-0.3 dB, typically.
Phono Overload
Input voltage @ F = 1KHz for 1% THD+N:
Phono MC1: 14 millivolts RMS, typically.
Phono MC2: 45 millivolts RMA, typically.
Phono MM: 425 millivolts RMS, typically.
Total Harmonic Distortion from 20 Hz – 20 KHz; RIAA de-emphasis
Vout=0.135 Volts RMS:
MC1 input to output: no more than 0.1%.
MC2 input to output: no more than 0.07%.
MM input to output: no more than 0.04%.
Vout=20 Volts RMS:
MC1 input to output: no more than 1%.
MC2 input to output: no more than 1%.
MM input to output: no more than 1%.
Unbalanced: gold plated single-ended RCA connectors.
Input Sensitivity
Vout=0.135 Volts RMS, F = 1KHz:
MC1 input: 0.038 millivolts RMS + 2%.
MC2 input: 0.14 millivolts RMS + 2%.
MM input: 1.35 millivolts RMS + 2%.
Input Impedance
F = 1KHz:
MC1 input: 31.5 Ohms, typically.
MC2 input: 430 Ohms, typically.
MM input (standard factory adjustment): 47 KOhms shunted by 200 pF.
MM impedance load settings: 100 Ohms, 10 KOhms, 47 KOhms, 75 KOhms, 100 KOhms
MM capacitance settings: 100 pF, 150 pF, 200 pF, 300 pF, 400 pF
Unbalanced: gold plated single-ended RCA connectors.
Corrected Output Impedance
Typically 1.3 KOhms.
Signal-to-noise ratio, below 1 Volts RMS output, A unweighted:
MC1 input to output (shorted input): better than 78dB.
MC2 input to output (shorted input): better than 79.5dB.
MM input to output (shorted input): better than 81.5dB
Absolute Phase
MC1 input to output; non-inverting.
MC1 input to output; non-inverting.
MC2 input to output; non-inverting.
Operating Temperature
-4 to +104 degrees Fahrenheit (-20 to +40 degrees Celsius) ambient.
Power Supply
Each LP1 contains two identical external power supplies – one for each channel. Therefore, all further information regarding power supply is shown for ONE power supply, unless otherwise indicated).
Nominal line voltage: 100-240 Volts, 50/60Hz.  
Input voltage range: ±10%.
Two power transformers; two vacuum tube rectifiers, three filter chokes; one high speed vacuum tube voltage regulator, two solid-state analog non-switching voltage regulators.  
AC voltage intensively filtered by special RFI power line filter.
Power Supply Energy Storage
Approximately 102 Joules.
Front Panel Controls: Preamplifier
OUTPUT LEVEL controls (separate for left and right channels).
SELECTOR switches (separate for left and right channels).
MONITOR switches (separate for left and right channels).
MUTING switch.
Rear Panel Connectors & Controls: Preamplifier
Four pairs of INPUT CONNECTORS RCA for line inputs and TAPE (play).
One pair OUTPUT CONNECTOR RCA for TAPE (record).
One pair of OUTPUT CONNECTORS RCA (single-ended outputs).
One pair of gold-plated XLR CONNECTORS (balanced outputs).
One XLR CONNECTOR (6 pins, gold-plated) for connecting the power supply cable.
Front Panel Controls: Preamplifier Power Supply
POWER switch.
OUTLETS switch.
REMOTE 1 turn-on/off switch for LAMM power amplifiers.
REMOTE 2 turn-on/off switch for LAMM power amplifiers.
Four LED controls.
Rear Panel Connectors & Controls: Power Supply
IEC 320 POWER INLET (3 lug).
Two AC OUTLETS, switched.
One XLR CONNECTOR (6 pins, gold-plated) for connecting the power supply cable.
EARTHING POST (gold plated).
Pure class A fully balanced MOS-FET zero feedback design. Power supply utilizes vacuum tube rectifier, choke contained filter and high speed vacuum tube voltage regulator.
High-current drive capability, in combination with unique single-ended class A circuitry, assure the preamplifier’s capability to drive any cable and any real world load, while maintaining its practically inaudible sonic signature.
This design is unique to LAMM INDUSTRIES, INC.
AC voltage selector:
100/120/220/230/240 Volts, internally switchable.
Remote Control:
Special built-in circuit enables the remote turn on/off of LAMM power amplifiers.
Available remote link cable coordinates the remote functions of two or more amplifiers.
Unique electronic protection circuit enables muting of the outputs until the preamplifier is stabilized after a turn-on, as well as functioning of the preamplifier in a “muting” mode during operation, and automatic switching to muting in case the AC line drops or is interrupted.
Vacuum tube voltage regulator overload protection: 0.125 Amps slo-blo fuse, internally mounted.

AC voltage fuses: 2 Amps slo-blo for 100/120 Volts. 1 Amp slo-blo for 220/230/240 Volts.

Power Consumption: Typically 95 Watts.
 Burn-in Time at Factory: Minimum 72 hours.
Recommended Burn-in Time in End-user’s System: Minimum 200 hours.
Warm-up time: Minimum 45 minutes.
Unit dimensions: 4.5 inches high x 19 inches wide x 13.875 deep + 1.375 inches for front handles.
Crate dimensions: 23″ x 19″ x 10″ (58.42cm x 48.26cm x 25.4cm).
Unit weight preamplifier: 15.42 Lbs (7 Kg).
Unit weight power supply: 19 Lbs (8.63 Kg).
Shipping weight preamplifier: 34.6 Lbs (15.7 Kg).
Shipping weight power supply: 39 Lbs (17.71 Kg).
Tube Complement Power Supply:
one12AX7/ECC83, voltage regulator tube;
one 6C19P, voltage regulator tube;
one 5651A, voltage reference tube;
two 12AX3, rectifier tubes.

*All the measurements were taken with a 41-KOhm load connected to the preamplifier’s output.
All the measurements were taken with A weighted filter.