The original organ in the Concert Hall of the Slovak Philharmonic was built in 1956 according to a design by Ing. Veverka and manufactured by VARHANY Krnov, Czechoslovakia. It was a Rieger-Kloss Opus 3210 organ; its technical construction consisted of the following parts: 4 manuals and a pedal, 84 sounding registers, approx. 6,000 pipes, electric action, cone-shaped windchests, and a movable console.

The appearance of the organ – the prospect, i.e. its decorative front part, otherwise known as the "face" – was adapted by its builder to the artistic decoration of the SF concert hall. The visual design fit into the interior of the concert hall and, by adopting some of the artistic motifs, continued the overall interior decoration. 
However, its appearance, i.e., the artistic design of the facade, became the subject of consideration when designing a new artistic solution for the nowaday organ.

REASONS THAT LED TO THE REPLACEMENT OF THE ORIGINAL ORGAN:

Adapting the technical solution to the artistic solution was very disadvantageous for the sound of the organ – many pipes were deaf – non-functional, only decorative in nature and disproportionately long, which is an unsuitable solution from the point of view of the technical construction of the organ and acoustics
Over time, the condition of the organ became unsuitable for demanding artistic performances; the organ was permanently faulty and it was not possible to modify or rebuild it effectively.
The internal construction had only negligible material value and, apart from a small part of the pipe stock, was not usable anywhere else.
From an artistic and historical point of view, the organ was of no value.
The organ's construction system took up too much space.
The pipe section was made of poor-quality (zinc) and difficult-to-tune material (insufficient sound transmission, inappropriate resonance, etc.).
The visual appearance of the organ pipes was also poor, especially the unsuitable silver coating.
the central balcony-like projection of the organ (positive) was also unsuitable, as it interfered with musical performances; there was a need to embed it in the future into the level of the side parts so that it would not lose the plasticity of its structure; the facade was moved back by 1 m