السلام عليكم ورحمة الله وبركاته
I dont know about Sami Yousuf, But all types of musical instrument arent permitted.
the Prophet (SAW) said, according to Bukhari:
"There will be among my Ummah those who will allow adultery, silk (for men), wine and mazif (musical
instruments )."
here in this Hadith, he mentioned (musical instruments) along with prohibited things like adultry, drinking and wearing silk (for men).