Sec 75 is a strict liability charge. That means you being unaware should be a good enough excuse but you have to be very careful how you present it in court. Also make sure it wasn't an "extended squeal" like drag racing but more a short clip (ie hitting gravel or momentary loss of traction). Request disclosure to see the cop's notes on how he describes it.
Also examine the road for evidence that the surface may have contributed to the noise (ie. wet road, gravel, debris) and therefore it was not intentional. Also weather reports for moisture can come in handy.
Finally testify that you were in care and control of the vehicle, had no intention to make a noise or squeal the tires. But something happened: foot slipped on the clutch, didn't realize you didn't have traction, road surface, etc. You can be as creative as you want but the justice is going to look at whether your explanation was probable, that is, is your version likely what happened. So don't stretch it!
Good luck and good fight.