Re: Need help on which USA Rat I just wound up with.
The later Rat II's are made in China, and the last U.S. ones before production went to China and the Chinese ones have the different (OP07) chip in them. Check to see if yours has the LM308 chip, if so it's a "good" one. Also, later ones went to a slanted top box, they are definitely Chinese and have the OP07 chip. Different knobs also. It's easy to check the chip, just open it up and look for the black 8-legged rectangular component on the board and see what it says on the top.
Al