Product Review

Lamm L2 Reference Stereo Hybrid Line-Stage Preamplifier

Part III

June, 2007

John E. Johnson, Jr.


On the Bench

The following measurements are with one channel driven into 200 kOhms, using the XLR balanced output.

At 1 kHz and 2 volts output, THD+N was 0.01%, which is well within spec. Signal-to-Noise was 86 dB, better than spec.

IMD, using 60 Hz and 2 kHz sine waves, was 0.005% at 2 volts output.

At 5 volts output, IMD was even less, at 0.002%.

THD+N vs. Frequency for 2 volts and 5 volts output was 0.01% and 0.005% pretty much flat across the audible band, which translates to a very neutral sound. This is top notch performance.

THD+N vs. Output indicates that the L2 can deliver a huge amount of voltage. This is with just one channel being driven, but nevertheless, two channels will still be able to deliver lots of juice. Notice that with the RCA unbalanced output, the lowest distortion is at 2 volts, while with the XLR balanced output, the lowest distortion is at 15 volts. From 10 mV to 2 volts, the RCA output has about 25% less distortion than with the XLR output.

This kind of power will ensure that every bit of detail in the music reaches your power amplifiers. That includes any large transient peak, which translates to a fantastic dynamic range.

The measured frequency response was 10 Hz to 200 kHz 1 dB.


I can see why Lamm Industries has not changed the design of the L2 Reference Preamplifier over the years of its life. There is no reason to alter any part of the product. It is superb. What other adjective is there to upgrade to?

- John E. Johnson, Jr. -

Copyright 2007 Secrets of Home Theater & High Fidelity

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