Preamplifiers

Lamm LL2.1 Stereo Tube Preamplifier

ARTICLE INDEX

The Design

The LL2.1 comes in two versions, the Deluxe and the Standard. The Deluxe has two additional power supply capacitors, and additional capacitors in parallel with the standard capacitors in a certain part of the signal path. Both versions have a new On/Off jack on the rear panel that connects to other Lamm products so that you only have to turn one On/Off switch to power a complete audio system. There is also a new 15 dB attenuation switch which gives you more room in the volume control should your power amplifiers and/or speakers have high sensitivity. The knobs on the front are also different.

lamm-ll21-preamplifier-rear-panel

There are three sets of stereo inputs, Line 1, Line 2, and Direct. The Direct mode passes the signal from the input to the volume control and then to the output, without preamplification. Two sets of outputs and a tape loop complete the layout. All of the RCA jacks are very heavy copper with gold plating.

The inside of the chassis is very simple, and consumers sometimes think, "Wow, there is not much in there for such an expensive product." But you see, that is the basis of a great audio product. Having the least amount of parts in the signal path is the key to good sound, because there are less items to degrade the signal.

lamm-ll21-preamplifier-inside-chassis

In the photo above, the red arrows indicate two 12AU7's, which are the first amplification stage, the yellow arrows indicate two 6DJ8's, which are the second stage. Rectification (changing the incoming AC to DC) is performed by a third tube, a 6X4 (blue arrow). Smoothing the power after it is rectified is performed by the blue capacitors just to the right of the 6X4.

The LL2.1 operates in Pure Class A, Single-Ended, which to high end audio aficionados, is a heavenly specification.