THE BIG PHONO
MC / MM PHONO PREAMP
At RCM Audio, ever since we began, we’ve been fascinated by the music captured in the grooves of a vinyl record. All our efforts have focused on reproducing that music as faithfully as possible. In many cases, vinyl is the primary sound source in numerous audio systems, and the catalog of releases is incredibly extensive. The vinyl record is also one of the finest sources for home audio systems. The two previous phono preamp designs, the Sensor and the Theriaa, allowed me to gain experience in this field. Now it was time to let my imagination run wild and design a phono preamp that would be the “icing on the cake,” the culmination of my quest. That’s how THE BIG PHONO was born—first in my mind, then in a dozen or so prototype versions.
The key to a phono preamp’s excellent sound quality is optimal frequency response and RIAA equalization, but without a proper power supply, all that effort is wasted. That’s why THE BIG PHONO is equipped with a power supply designed to minimize interference as much as possible. In THE BIG PHONO, the power supply circuits are housed in a separate enclosure. The symmetrical power supply consists of multi-stage regulation and a precisely selected filter capacitance to eliminate unwanted ripple. It is, of course, independent for the right and left channels.
The power transformers used are custom-made according to our design. The “cleaned-up” voltage is fed to a second module, which houses sensitive correction and amplification circuits as well as the control logic. Power for the right and left channels and the control logic is supplied from the power supply via separate wires. In the preamplifier, the signal undergoes four stages of amplification and passive RIAA equalization.
A characteristic feature of the preamplifier is its high output signal level. Our experience shows that, to achieve optimal sound quality, the signal level should not be lower than 1 V. These requirements place very high demands on the entire circuit, since the signal must be amplified several hundred times.
THE BIG PHONO is equipped with two pairs of inputs. This allows you to connect two analog systems and configure each one independently. The easy-to-read display on the front panel clearly shows which input is currently in use and its settings. These settings can be adjusted manually or using the remote control.
The chassis is an equally important element. It is the first thing you notice, and its appearance is significant. However, its mechanical construction and the materials from which it is made are far more important for proper operation. In THE BIG PHONO, the chassis consists of two separate components: the power supply and the preamplifier. The individual units have the same internal design but differ in their rear and front panels.
Each one was milled from two 65-mm-thick aluminum blocks, precisely fitted together. The wall thickness reaches nearly 30 mm in some places. This design gives THE BIG PHONO enclosures exceptional rigidity and provides excellent shielding for the preamplifier’s sensitive circuits. The net weight of a single enclosure, without any components installed, is over 16 kg.
In the THE BIG PHONO project, we used the best components available, selected through experimentation and listening tests of successive prototype versions. We focused entirely on sound quality and on reproducing as faithfully as possible the emotions that arise during the creation of music. Each unit is hand-assembled and thoroughly tested at our headquarters.
To help you enjoy music, we’re bringing you THE BIG PHONO!
Technical Specifications
| Input sensitivity: | 0,3 – 5 mV (adjustable) |
| Sensitivity adjustment: | 0,3 – 5 mV in 7 steps |
| Reinforcement: | 52 – 76 dB (2 V rms output) |
| Input impedance: | 30 ohm – 47 000 ohm |
| Impedance adjustment: | 30 – 47 000 ohm in 8 steps |
| Input capacity: | 150 pF |
| Entry: | 2 x RCA |
| THD: | >0,01% |
| S/N: | 87 dB |
| RIAA Linearity: | +/- 0,1 dB (20 Hz – 20 kHz) |
| Output impedance: | 70 ohm |
| Output: | XLR, RCA |
| Nominalny poziom wyjściowy: | 2 V rms |
| Maximum output level: | 9 V rms |
| Dimensions: | 430 x 410 x 145 mm – preamplifier 430 x 410 x 145 mm – power supply |
| Weight: | 20 kg – preamplifier 30 kg – power supply |
| Enlistment: | max 25 W |