The Belles 150A Reference power amplifier is the continuing refinement of the superb amplifier design of
Dave Belles. Design that exemplifies the science of accurately portraying the art of music in a way that stirs
the soul. It is one thing to engineer a product that is reliable, it is another to create a product that allows the
music to come through as it was meant to, in such a way that it allows you to forget you are listening to a
recording. It is a product that reveals every nuance of the system without emphasizing or adding coloration. It
is an amplifier that truly disappears, the ultimate compliment for any amplifier product. The 150A Reference
is one of those rare products that meld art and science in a heart gripping, soul stirring synergy.
The 150A Reference utilizes a dual mono design topology. This gives the amplifier better isolation between
channels. Soundstage imaging is improved, offering true soundstage width and depth. Instrument placement
and layering are more accurate, revealing the depth and texture of each instrument or vocalist. Each channel
shares a common 1000 VA toroidal transformer. By using a larger single transformer, rather than 2 smaller
ones as in typical dual mono designs, stronger and cleaner bass is maintained.
Each channel of the Belles 150A Reference is an all in one integrated assembly. The circuit components are
mounted directly to the heatsink, eliminating the need for additional wiring that can produce inconsistencies 
from one channel to the next.
The 150A Reference amplifier circuit consists of 3 stages:
• an input stage with matched dual J-FETS/Bi-polars in a cascaded differential pair
• a voltage gain stage using bi-polar transistors
• a final stage using a source follower with 8 power mosfets, class B biased
The 150A Reference has been engineered to be among the most effective products on the market at damp-
ening the back EMF from speakers. The results are heard as tightly controlled bass that has detail, texture 
and separation.
The technology behind the Belles 150A Reference is impressive. Even more impressive, however, is the
sound. Listening to the 150A Reference has been described as a memorable experience; you feel as though
you are part of the musical performance.
A pair of 150A Reference amplifiers have exceptional performance and power at 500 Watts per channel into 
8 ohms!
Audition this synthesis of mind and spirit at your nearest Power Modules dealer today. If there are no dealers
in your area, contact Power Modules and we will arrange for an audition of this incomparable amplifier.
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