I asked:
Re the [ʤ] in English "John".
The unvoiced equivalent would be [ʧ] as in 'chin'?

Juozas responds,
Yup, when trying to pronounce "the badge that dissapeared", I need to control my tongue because otherwise "the batch that..." comes out.

P.S. I'm not sure if I know what you meant by "re". Thanks.
Interesting. "The batch that disappeared" is possible in English too, and not as a result of too much booze, but it would be considered substandard in formal contexts.
[ʦ], as in tsar, rats lacks a corresponding IPA diagraph.