The Pinnacle of Craftsmanship Airiness that will take your breath away




An outstanding amplifier is a musical instrument that transcends the realm of technology and delivers the PRaT of music as if it were being performed live in a concert hall. Even when paired with a low-performance speaker, the amplifier will still be able to deliver open music with lushness and great volume. Regardless of the speed or complexity of signals sent from the source, the amplifier will be able to reproduce the sound with precision timing right from the first crescendo to the roll off of the final note. Just like a live performance, the music from an outstanding amplifier has the power to fully penetrate the listener’s body and soul, reaching even the deepest depths of one’s spirit.

Reproducing an incredible amount of information and detail from your music

For power amplification that is the heart of all amplifiers, we have chosen the latest power MOSFET with high precision switching controllers. The Power MOSFET boasts excellent responsiveness on timing and is capable of switching with high precision and low noise when handling complicated signals, even with instantaneous changes. With such an ideal switching device, RSA-F33EX makes it possible to deliver an incredible amount of information and high driving power for low-efficiency speakers by recreating fully detailed music with cadence, along with outstanding airiness and realistic soundstage.


A potent and stable power capable of handling signal spikes

RSA-F33EX is equipped with a large capacity R core transformer, which is capable of delivering ample and stable power supply. By accommodating sudden current spikes, the amplifier offers fast transient response. For the diode, we have chosen the latest “Ultra Fast Soft Recovery Diode” to provide clean and ample power with a minimum of high frequency noise. In addition to incorporating dedicated audio electrolytic capacitors that we have jointly developed with Chemi con in Japan, we have also used custom-built, high performance sealed PIO capacitors in a serial configuration to achieve substantially punchy bass.


High performance capacitors that are rich in musicality

For the final piece of the puzzle, the low-pass filter that is responsible for reducing PWM noise utilizes special capacitors that are capable of smoothing the mid-treble range while giving it luster. In addition, the customized PIO capacitors in the power supply provide the sound characteristics of a thick and powerful mid-bass. These capacitors, with their varying characteristics, have been carefully deployed in their corresponding positions to achieve SPEC’s charming signature sound across the entire sound range. To complete the package, we have also chosen premium mica capacitors to enhance the transparency of the sound, creating an exceptional product that is incredibly rich in musicality.


Strategies to overcome the negative cross-interference of electromagnetic waves among components

Electromagnetic waves generated by components such as the transformer are similar to discordant notes from different instruments – they have a negative impact on overall sound quality. To overcome this, we have created special steel shields that isolate the transformer in the power supply, the power amplifier and the low-pass filter to eradicate cross-interference of electromagnetic waves within the amplifier. We have also taken an additional step to coat the different shields within the chassis with EMT (electromagnetic wave absorbing finish).


Vibration control to deliver the amplifier’s full potentials

Some electronic parts are prone to produce minor vibrations, and thus it is important to eliminate the cross-interferences created by such vibrations. Therefore, installations of different parts have been carefully managed, with details such as torque control for various screws meticulously controlled.

特製RSR-1 專用遙控器 Custom built remote control RSR-1 (works with all amplifiers in the RSA series)
特製高純度銅輸出端子 Custom built high purity copper output connectors

Natural wood base with timbre akin to musical instruments

The wooden base and the isolating feet have a natural frequency response. The base is constructed with German spruce from Australia. German spruce has always been used as the surface material for string instruments and has the characteristics of natural attenuation for vibration. As a light yet sturdy material the wood provides significant vibration dampening during the process of vibration transmission and offers adequate natural dampening of vibration when installed as the base of the amplifier. The bases of the isolating feet are made with Hokkaido maple (a common material used to make the keys of pianos), filled with hickory from North America. The composite material of maple and hickory offers the solid support of the ductile spruce base in a three-point configuration.


Max output 60W×2(8Ω)、80W×2(6Ω)、120W×2(4Ω)   Frequency characteristics 10Hz∼30kHz±1dB(6Ω、1W)
THD 0.02% (at 1kHz, 80% load)   Input sensitivity, Gain 300mVrms, 37.3dB (at Volume MAX, 6Ω, 1KHz)
Line input terminals XLR input: 1 system RCA input: 3 systems   Speaker terminals 1 system
Power & Other
Voltage AC110V   60Hz   Power consumption 15W with no input signal, 215W (8Ω、100Hz)
External dimensions 440mm(W)×130mm(H)×422mm(D)   Weight 20.0Kg