Conversation so far:
Why did Vince Clarke leave Depeche Mode?
Clarke began to voice his discomfort at the direction Depeche Mode was taking and Clarke also said he was sick of touring.
Did Vince Clarke have other negative comments about Depeche Mode?
Clarke said about Depeche Mode, there was never enough time to do anything. Not with all the interviews and photo sessions.
Who did Depeche Mode get to replace Vince Clarke?
Alan Wilder, a classically trained keyboardist from West London, was hired by Depeche Mode to replace Vince Clarke after two auditions.
How did Depeche Mode find Alan Wilder?
In late 1981, Depeche Mode placed an anonymous ad in Melody Maker looking for another musician and Alan Wilder responded.
Did Depeche Mode audition other musicians besides Alan Wilder?
How did Depeche Mode's adjustment with Alan Wilder go?
Daniel Miller informed Alan Wilder that he was not needed for the recording of A Broken Frame, as the core trio wanted to prove they could succeed without Vince Clarke.

Question: What was unique about his sound?
Self-contained rewrite: What was unique about Depeche Mode's Alan Wilder's sound?