Technical description of the PETROF 131 M1 upright piano
PETROF 131 M1 upright pianos are designed by and produced in PETROF company in the Czech Republic. P 131 M1 upright piano is the highest upright piano model with the greatest equipment and is fit for demanding players, for professional use, for specialized music schools. As with all PETROF upright pianos, the P 131 M1 is marked a „European Excellence“ label, which guarantees the European origin of the instrument.
Robust construction from spruce, 5 vertical posts, made in PETROF company.
The solid stabile rim supports the tuning stability of the instrument and ensures its total stability. The special constructive modification enables clear and long-lasting tone of upright piano.
PETROF construction, harp shape, agraffes construction, robust, made from grey cast iron in the Czech Republic. Plate working is done in PETROF factory on special CNC machines. Top surface modification is consistent with surface modification of grand piano plates.
Agraffe construction of the iron plate enables exact scale of strings and is the sign of the most advanced upright piano construction.
Massive polished brass, lacquered. Made in the Czech Republic.
All brass hardware is lacquered, corrosion resistant and do not require any maintenance.
Special beech plywood type Multiplex. Original veneer thickness 2 mm compressed to the density 800 – 850 kg/m3 (= 6 veneer layers/cm). High moisture resistant glue.
The pinblock is highly resistant to atmospheric changes (e.g. humidity). It guarantees high stability of tuning.
The soundboard is made from massive spruce in PETROF company. It is shaped into wedge block. Its active surface is 1,2222 m2.
PETROF sound boards have to go through a special long term moisture conditioning and care during the whole production process which guarantee their exact and equal moisture content. This process increases its resistance to cracking due to climate change. Surface treatment with PUR lacquer raises its resistively against climate changes.
The ribs are circular shaped and are made from European spruce in PETROF factory. The cross rib is produced from beech wood. The board is enforced by 10 ribs.
The ribs from European spruce supports a crown stability of the sound board.
The bridges are made from solid beech wood in PETROF company.
Agraffe construction in the whole range of 88 tones.
The agraffes construction enables the exact scale of strings and is the sign of the most advanced upright piano construction.
Steel, nickeled. The pins are produced with high exactness in the Czech Republic.
The tuning pins are corrosion resistant.
Steel wire Mapes USA, Röslau Germany. Copper Degen Germany. Made in PETROF factory. Longest string 1135 mm.
The strings are made from string wire of the world's finest quality.
There are used top German hammers Renner or Abel in the P 131 E1 upright piano.
Hammer heads are fitted for romantic rounded tones, characteristic for PETROF instruments.
Renner original action. Petrof moderator. Action is installed in PETROF factory.
Renner action is very quick, with good repetition, enables good control in creating tones, provides great feeling from play.
Renner original dampers. High quality special French felt (Laoureux). 70 dampers.
Keys are produced from the finest spruce in PETROF factory. White and black acrylic tops - Polyplex Sweden.
The keys are carefully individually balanced for 48 - 52 g. The keyboard provides very good feeling from play.
Robust spruce sandwich board, two-sided covered by thin chipboard and counter veneer.
The key bed is highly resistant to corrosion which is a prerequisite for stable regulation.
Pedals are from solid brass, made in the Czech Republic. The upright piano is provided with 3 pedals: the right is for dampers, the left helps to hammers to be more closer to strings, the middle controls prolongement.
Installation, regulation, tuning of the upright piano
Whole production and installation of the P 131 E1 upright piano is held in PETROF factory in the Czech Republic.
Mechanism of the upright piano is carefully and repeatedly regulated for standard values so that regulation is stable in the long term and its action provides good feeling during play, characteristic for European upright pianos.
Hammers are intonated for soft romantic tone, characteristic for PETROF upright pianos.