RPA-W3EX Power Amplifier

All-new spruce side panel and rear insulator construction

The side panels have evolved even further, and feature insulators with a hybrid configuration that sandwich maple between spruce board. The weight of the body flows down the lines of front face and the underside, where it is conveyed to the contact surface. It is constructed of spruce, which is also used in the tops of stringed instruments (German Spruce), and has excellent musical properties. Maple possesses just the right amount of rigidity, and is also used on the backs of stringed instruments. The new hybrid panels combine these woods, with 15 mm sides and a 45 mm contact surface, and make effective use of resonance and controlled vibration to achieve a rich reverberation that is very similar to that of a musical instrument. To provide three-point support, the rear insulator features the same hybrid structure as the side panels. The large hybrid block supports the amplifier chassis with perfect vibration characteristics.

Pure Direct Connection

We have offered a new concept for preamplifiers and power amplifiers.

In the past, conventional systems used a preamplifier to adjust the volume of the signal from the source before feeding it to a power amplifier. Because power amplifiers possess high levels of gain, for normal listening tests the input level to the power amplifier must reduced significantly. However, this increases the likelihood of losing some of the nuances in the signal.

To deal with this, SPEC power amplifiers feature an analog electronic attenuator immediately ahead of the power stage able to take high signal levels from source devices

and able to adjust the volume by the external control signal.

This Pure Direct system is based around the concept that higher transmission levels mean reduced loss of small signal, reproducing the intentions of both composer and performer down to the most minute musical detail.

External volume control is available from the H-VC5 volume controller or from our RPA-P7 preamplifier.

High-quality audio grade switching power supply

In any amplifier, the DC power supply circuit has an important effect on sound quality.

Although switching power supplies have excellent energy supply characteristics, to date they have not commonly been used in audio device applications. We have combined Hibiki-ichi, a capacitor designed for class-D amplifiers that delivers abundant reverberation, with silicon carbide diodes optimized for high voltage, large current flows, in the development of a high-quality audio grade switching power supply. This power supply provides large amounts of clean current instantaneously at a class-D power stage.

Switching Power Supply and EMC coating

The combination of an audio grade switching power supply and a PWM-type class-D power stage allows energy to be conveyed instantaneously and directly to the speakers from an AC input for quick, powerful playback. Furthermore, the PWM-type class-D power stage absorbs any counter electromotive force generated by the speaker, and is able to both drive and halt the speaker instantaneously.

It is this accurate speaker function that makes it possible to reproduce the “music” of a live performance. We believe that these dynamic characteristics are essential to achieving realistic sound.

Noise countermeasures

The entire surface of the interior of the chassis and aluminum top have been coated with the same EMC coating as is used on the high-end RSA-F33, absorbing internal noise reflections and external noise to offer superbly transparent audio playback.

Flexible expandability

This power amplifier can be used in a standalone configuration as a two-channel amp, or in a dual-amp configuration in monaural mode to drive left and right channels independently, in a bi-amp connection, or a bridge-tied load connection, to achieve a whole new dimension of real sound playback. Bi-amp connection reproduces all of tone color at the recording.