1999 Integra SE alternator/electrical problem

About a week ago my car stereo shut off as I was driving and my car died like a minute later, and I got it towed to a guy who said I needed to replace the alternator and battery. So I went ahead and did this. The car ran fine for a day and then did the exact same thing as I was driving. The guy came out and said I had blown a fuse, and replaced the 7.5 fuse that had blown with a 30 so I could get home, telling me to check with the people who had installed my stereo because he thought the stereo was causing the blown fuse. Anyways I was driving back home on saturday and the exact same thing happened again. The 30 fuse had blown so I replaced it with a spare 20 fuse which blew again within 2 miles. I did this 3 times replacing that fuse in order to get to a mechanic shop. I just had them "diagnose" the car and they said the fuse that keeps blowing is for the alternator sensor that tells the alternator to work while the car is on. The reason the car keeps dying is because that fuse blows and then the alternator turns itself off thinking the car is off.
I literally just had the alternator and battery replaced a week ago, so it seems like it cant actually be the alternator doing this. To my noob mechanic mind, it seems like it must be a wire between the alternator and the fuse that is shorting. I am going to tow the car to the original mechanic tomorow, but as he is a friend of a friend and doesn't have a full garage, I figured I would ask for some other opinions online. Do any of you have any experience with something like this or have any recommendations on what you think is happening? Both mechanics say that the wiring harness is fine. The second mechanic said something about the line that goes from the fuse to the alternator splices off to the integrated control unit or something, but when I asked if he could check the charge flowing through this spliced wire he said he didn't have the tools to do it.
I should also mention that the catalytic converter has had a hole in it for 3 weeks and needs to be replaced, and the car is very loud and vibrates slightly as I drive because of this. Also as I was driving home, about an hour before the fuse blew this last time, for some reason my spedometer and odometer stopped working and were just stuck at 0 and 176999 km respectively.

Anyways the car is a manual '99 acura integra SE, and any help you guys can provide is greatly appreciated.

i had this problem happen to me on my 88 civic with an obd1 y8 swap. the car didnt run right and it would do that to me every now and again... not sure its the same but here goes.. i ended up changing the head temp sensor and it fixed the problem.. also i had another car were the alternator went out, battery died.. new alternator installed and the battery still died 2 days later, it ended up being a bad alternator.. if your not getting charge it will freak out the whole car, lights, ecu, acc.. etc..