Yes I do have the same problem!
My teacher has an old Salvi Daphne harp, it’s concert grand 47 strings. Mine is a Lyon and Healy 85 Petite, 40 strings. Her pedals can’t be properly regulated because it’s so old, and I struggle pushing them up and down. The strings are old too and have a different “feel” from mine. I almost always play better at home than at her harp!
I suppose the main problem is just playing her harp once a week and mine all the rest, I’m very much used to mine.
Oh and my arm position changes because her harp is MUCH heavier than mine, and weighs down my right shoulder therefore making it harder to keep my arms at the “proper” height. But arm positioning is one of my weaknesses and I shouldn’t blame her harp, I’m bad at home too. 😉
God bless!
— Natalie