1 across. Jittery. 6-6 letters.
9 across. Made of a particular wood. 5 letters.
10 across. Top voice. 7 letters.
11 across. Void partner? 4 letters.
12 across. Music recorder – in the 1980s? 4 letters and 4 letters.
14 across. To vary (anag.) – staunch believer. 6 letters.
15 across. Good (business) judgement. 6 letters.
18 across. More than peckish! 8 letters.
20 across. Mastery – hold tight! 4 letters.
22 across. Persistently annoying. 7 letters.
23 across. Amalgamate. 5 letters.
24 across. Radio set. 6-6 letters.