Thank you very much
Opening this thread has caused me to question what I've been doing
I haven't explored the sounds for many years and I hadn't appreciated that the string volume balance varies according to the model selected
Therefore a global adjustment wouldn't work, and a visit to a repair shop wouldn't be the answer
I now see that if I want to improve the situation I need to edit each setting that I commonly use
I may have to come back here if I have any questions about the process, but in the meantime ...
SOLVED
CASE CLOSED!