There is no set timeframe for holding a revocation hearing once a probationer has been incarcerated on a probation warrant. Dekalb Superior Court is very busy and it might take a while for this to reach a revocation calendar.
More importantly, your husband is ultimately facing revocation of his First Offender status and prison time on a resentencing. 120 hours of community service can be done in a year at the rate of 2-3 hours a week, so he must have not done community service for a while in order for the probation department to be requiring him to do 8 hours in one day/week. Therefore, his defense will be difficult and will depend largely upon convincing the judge to give him another chance. This might be accomplished by his employment status (holding down two jobs) and family circumstances. I would probably ask for his community service to be commuted into the time that he is serving right now. Then the question becomes whether he gets to keep his First Offender status. He really needs to retain counsel to help him try to keep his First Offender. An attorney will know what evidence to present (and more importantly, what not to present) in order for him to have the best chance of retaining his First Offender status. Call me if I can be of assistance.
No one can tell you exactly how long in takes to get in court in DeKalb for a revocation; a lot will depend on the Judge to whom the case is assigned. That being said if your husband does not have a lawyer, it will take longer than if he has one. As to possible outcomes, again a lot depends on the Judge; and he is looking at anything from time served to being put in prison and having his first offender revoked. Call me at 404-812-4305 if you would like to discuss the case in detail.