Pianotech

Today I had the task of breathing life into an 1880s Pleyel instrument. 

In due course I'm going to be running issues past the restorer who last saw this instrument a decade ago but bearing in mind changes in the last decade perhaps others here might have helpful experience.

Knowing French instruments I was expecting either oblong pins or small square pins . . . and expected trouble on that front as my French size lever I keep in France. Upon arrival . . . yes it was small square pins - much smaller than a standard tuning lever can cope with. Luckily my Fletcher & Newman oblong lever from years ago fitted . . .  

However, that wasn't the main surprise - the strings are gold plated. Knowing the quality of the restoration I was expecting "authentic" metallurgy and scaling . . . so this was a task for "approach with caution". I consulted the restorer yesterday who advised A at 436. I found the pitch at 426 so a pitch raise was in order so I set A at 437 and was considering raising by quadrants over all octaves. On its way up, half way, the first string broke at the coil.

Bearing in mind the quality of the instrument and rarity of the stringing I went no further and settled to keep it substantially at its original pitch, but taking it down to around 423 to account for a sharpened C and F in unequal temperament.

Is anyone familiar with gold plated strings? Is the metallurgy likely to have changed as a result of plating? Breaking at the coil and on an instrument which hasn't been tuned since restoration in some years suggests a crystalisation issue, rather as broze harpsichord strings.

At the 423 pitch the instrument tuned brilliantly and excitingly, and really responding to the unequal temperament. For fun I measured inharmonicity which was extraordinarily low, and the top treble rang out very beautifully putting Duplex Scale instruments into the shade. 

One would have expected the restored instrument to take the standard French pitch without issue. Five strings were fresher than others and out of tune so clearly the instrument has experienced such a problem before. 

Apart from talking more with the original restorer my plan of action on pitch will be to analyse lengths and gauges and work out the scaling and resulting tensions . . . but has anyone had any experiences of such a nature and particularly if with such plated strings?

Best wishes

David P