Phasemation Passive Preamp CM-1500

〈Designing Back Ground〉
Phasemation has been advocating the “Control Meister,” a hybrid passive preamplifier with no
built-in active circuit, which is outstanding from the standard preamplifiers. In 2022, the CM-
2200, a culmination of these efforts, was released with a +6 dB amplification function and has
received much acclaim from both Japan and abroad.
In 2024, we will release its brother model, the CM-1500. The CM-1500 is equipped with
Phasemation's patented hybrid attenuator technology, making it possible to enjoy the pure
playing of the “Control Meister.” The CM-1500 can be used in all kinds of situations, including
high volumes played with today's low-efficiency speakers and low-gain amplifiers used together.
〈Features〉
 Equipped with a patented hybrid passive attenuator that delivers a very transparent sound
 A new development for balanced and optimally coiled attenuator for superior sound image localization
 Loaded with a 3-step gain switching (-10, 0, +6 dB) making any volume setting to be possible
 Balanced/unbalanced outputs can be used at the same time
 High-performance core and winding materials are used in the transformers to reproduce realistic bass
and delicate treble sounds.
 Thoroughly eliminates external induced hums and unwanted vibrations to produce pure, blur-free
sounds
 Adoption of parts for various high sound quality that improves the expression in detail
 Equipped with a patented hybrid passive attenuator that delivers a very vivid sound
As well as CM-2200, CM-1500 is equipped with Phasemation's patented “Hybrid Passive Attenuator” that achieves
the ideal preamplifier having high input impedance and low output impedance. This ideal design, which is a
combination of taking only the pros of the resistive type and transformer type attenuators, plays a highly
expressive, vivid and transparent sound.
 Newly developed balanced winding attenuator for superior sound imaging
For the attenuator transformer, we adopted a balanced attenuator transformer with two attenuator windings for
the HOT and COLD sides of the balanced connection coiled onto a single transformer. Furthermore, since there are
two attenuator windings, the COLD side signal is generated inside the transformer even for an unbalanced input,
enabling a complete balanced output. The balanced volume control circuit transformer produces excellent
frequency and phase characteristics over a wide range, reduces phase distortion within the audible bandwidth, and
above all, contributes to a clearer and precise sound image localization
 3-step gain switching (-10, 0, +6 dB) making any volume setting to be possible
The balanced attenuator transformer with +6 dB gain that was used in the CM-2200 is also adopted for CM-1500.
The CM-1500 has three gain switching of +6dB/0/-10dB, which, in combination with the attenuator's 23
contacting-points that can be changed within a range of 0 dB to -50 dB, allows even finer volume settings. The
transformer winding structure has been re-examined to ensure a wide-range frequency response and to guarantee
impedance characteristics regardless of which combination is selected so that the CM-1500's fine, clear sound
image localization can be enjoyed at any gain level. The CM-1500 uses a printed circuit board and has a simplified
housing structure, which improves productivity and makes it available at a price that is affordable to many people.
 Balanced/unbalanced outputs can be used at the same time
The input provides 3 unbalanced (RCA) and 2 balanced (XLR) inputs. The output provides 2
unbalanced (RCA) and 2 balanced (XLR) outputs, and the circuit design allows simultaneous
output, increasing the flexibility of system construction.
 High-performance core and winding materials reproduce the bass realism and the delicacy
treble sounds.
The core material of the transformer is “ultra-thin 0.1mm Super Malloy material” that is used in
the CM-2200 superior model. The winding material also uses PC-TripleC polyurethane wire, which
is the most suitable wire for audio materials to achieve excellent low-range linearity and in
combination with a large core the subtle and relaxed high frequency characteristics are realized.
 Thoroughly eliminates external induced hums and unwanted vibrations to produce pure, blur-free sounds
The 10mm thick aluminum slanted front panel follows the elegant design of the CM-2200. The chassis and top
cover panel are made of sturdy 1.6mm thick steel plate with copper plating to ensure thorough measures against
external induced hum. In addition, the top cover panel is coated with a low dielectric paint. In addition, a double
magnetic shielding material is placed under the transformer to ensure rigidity and reduce magnetic distortion. The
legs are made of heavy metal insulators made of a combination of different materials to prevent external
vibrations.
 Use of high-quality parts to enhance the expression of sound details
All rotary switches use gold-plated contacts. The RCA terminals are made from high-quality machined brass and
then gold-plated, and the XLR terminals use gold-plated terminals made by Neutrik, thoroughly improving the
expressiveness of every detail.