Some food for thought regarding historical bandoneons:

Like many other musical instruments, the Bandoneon was subject to the taste of the respective era/epoch. The original pitch was at a’ = 435 Hz. Meanwhile the general mood is at a’ = 442 Hz and sometimes even up to 448 Hz.

This modification means a massive change/intrusion into the original substance, since an increase of up to 13 Hz implicates an enormous material removal on the reed. So it is about time to preserve the very rare Bandoneons with the original lower pitch.

It is the only way that we will still be able to find out how e.g. an Alfred Arnold – Bandoneon originally sounded.

At the same time, these instruments offer new possibilities, e.g. at concerts, accompaniment of singers, recordings, or the recording of old music…

Often the brilliance in sound is searched for in higher tuning, has been lost through dirt, rust and wind tightness inside the instrument. 

A properly cleaned and restored bandoneon will surprise you with a clear and brilliant sound without having to raise the tuning frequency.