Audiotweaks is distributor of SPEC, information from the SPEC website:

We aim to manufacture best amps to experience music. The sound full of “MUSICALITY” faithfully reproduces the artistry of the performer. The musicality can be achieved by the tone as close as possible to the actual sound and the drive ability to follow the change without delay.We make an amplifier that is closest to the world’s most realistic sound.

SPEC-Corp in Japan was founded by the legendary audio designer Shirokazu Yasaki. He contributed to many breakthroughs at the best Japanese audio manufacturers. Aside from that he always kept developing products on his own as well. His heart has always been at tube amplifiers in combination with high efficiency horn systems. Naturally, he has developed a lot of those over the years.
Yasaki-san has now brought all of his knowledge and experience together in one place with SPEC.
He started developing what he would consider to be the ultimate amp. This became the SPEC-RSA F33EX.

An extremely musical amplifier of which its components have been heavily tested by the human ear. As a result, this unique concept has grown to have all the best of the tube amplifiers, but without its drawbacks.

All the knowledge that has been acquired by developing this top notch amp, has later been applied to the development of all other SPEC amplifiers.
Currently, Yasaki-san and his team also develop high end network players, a beautiful vinyl player and a phono preamplifier. Aside from that, a remarkable product of theirs is the Real Sound Processer: the RSP-901EX.
This “backward electromotive force absorber” is connected to the speakers to make sure the negative effect the speakers have on the amplifier is being cancelled out.