My friend is letting me use his abu garcia ambassadeur round reel, but it doesn't have any magnetic brakes on it. Are all round reels like this? How do you guys deal with this?

Some Abu round reels have centrifugal brakes, others don 't, you control the spool rotation with the tension knob and ----> it 's all in the thumb.  

I have 4 Abu round reels, and they are indestructable! I was very reluctant to even try a LP reel until a couple of months ago when I bought  an BPS extreeme combo. I love my round reels. As far as the braking I am not sure, but I think mine only have a spool tension adjustment. I have used my thumb for so many years, since I started with an old Penn Round Reel for snagging that I didn't know there was a difference. In fact I have struggled a little bit with my new LP BC because it is spins so freely. I was so used to my old Abu's that I really whipped to get the lure  out there that I had to relearn to through my new one. I will always love round reels, but the new LP's are so comfortable I grab it everytime.

The only round reel I have is the calcutta and it has a break system.