2155
Power Amplifier
Date of manufacture : Jan 85 - Jan 87
Please note that this document contains the text from the original product brochure, and some technical statements may now be out of date
• Power output conservatively rated at 55 watts per channel into 8 or 4 ohms.
• +3 dB IHF Dynamic Headroom for peaks: 110 W/ch at 8 ohms, 130 W/ch at 4 ohms.
• High-current output stage, able to deliver peak currents up to 40 amperes for precise control of voice
coil motion with speaker impedances as low as 2 ohms.
• Bridging circuit yields 150 watts continuous power, 250 watts IHF dynamic power.
• Exclusive NAD impedance selector optimises power delivery to either high or low speaker impedance.
• Soft Clipping™ minimises distortion at output levels above the rated power.
NAD leads the audio industry in producing amplifiers with high-headroom circuitry and high-current out-
put stages, precisely the qualities needed for musically accurate reproduction of today’s wide-range
analogue and digital recordings. The 2155 power amp is one of the finest in a long tradition of highly
praised NAD amplifiers, with increased power, improved reliability, and numerous refinements in sound
quality. As a high-current high-headroom power amplifier it drives even “difficult” loudspeakers to
surprisingly high volume levels with clean, solid, full-bodied musical sound that remains refreshingly free
from distortion even in transient peaks.
The 2155, which is simply the power amplifier section of the 3155 and 7155 packaged on a separate
chassis, is NAD’s “building-block” amp, offering a variety of convenient and economical approaches to
up-grading a stereo system for higher performance and power. The 2155 is an obvious choice if you
want to upgrade from a low-powered receiver or integrated amp, or if you are using a separate
preamplifier. If you need still higher power, a pair of 2155s in the “bridged” mode deliver nearly three
times as much power output for only twice the cost.
The 2155 delivers substantially more than its conservatively rated 55 watts/channel into the complex and
varying impedances of real loudspeakers. In the bridged monophonic mode this amplifier is rated
conservatively at 150 watts continuous output. And these amplifiers maintain a full 3 dB of IHF dynamic
headroom (2.5 dB in bridged mode), meaning that they deliver twice their rated power in brief bursts:
over 110 watts/channel in stereo and about 250 watts in bridged configuration. This headroom for
peaks is crucially important for reproducing the uncompressed transients in modern digital and DBX-
encoded recordings.
When combined as a bridged stereo pair, these amplifiers function as a 150 W/ch stereo amplifier with
250 watts per channel of short-term output. That power, together with the remarkable flexibility and
flawless sonic performance of the 7155 or 3155’s preamplifier section, make these combinations
remarkable best-buy systems.
