Luxman SQ505X solid state integrated amplifier

In the early seventies, the product engineering at Luxman was probably one of the best among high-fidelity companies. For this series of amplifiers, the sum of talent erected a circuit design considered one of the best ever elaborated.

It is still uncertain due to limited literature, but SQ is referred to stand for "Studio Quality", that is also stated as "Superior Quality". Both statements equally make sense, as this equipment is such a milestone in customer oriented audio equipment.

The press was acclaiming the work of Luxman for these integrated amplifiers in that time, today specialists agree around "a decisive model" in this SQ-505X, an improved version of the 505.

The Pre-amplifier section is equipped with 3-stage direct coupling circuit at equalizer stage. Superior PNP-NPN-PNP transistors were chosen to ensure the maximum linearity. The phono section uses ultra low noise silicon transistors, so that signal is kept at the best possible level from the start. In general terms, Luxman was pionneering a new era of transistors, more targeted at high-quality audio reproduction.

The power amplifier section integrates full stage direct coupling circuit without output condensers. Adopting a dual power supply system, low end frequency supply is managed while the 2-stage differential powering scheme eliminates the unpleasant shock-noise in the speakers when switching the mains power. In terms of technology, the power transistors were soldered to the pcb, eliminating extra wiring. In 1970 this was a proof of mastered craftmanship, that quickly inspired other brand targeting high-end products.

Visually, the real Brazilian Rosewood woodcase, associated with the thick brushed aluminium fascia and the refinement of control buttons and actioners is just delightful to the eye.

Now, if ever it is still needed to mention… the sound. It's so warm, so tube-like, so there with you in the room, singers are singing, brass is brassing, drums are drumming… Words are missing. It's an emotional thing. 

In a search for investing in quality vintage equipment, you can't be wrong with this Luxman if fanatically revised like here. The next level being heading towards niche brands like Accuphase, or for separate components for pre- and main- amplifiers, all this leading us to a totally different story, mainly budget-wise, where Luxman and other brands were also top of the list.