XceR wrote:BA662A was made by Roland, thus it's impossible to get unless you salvage a Roland synth. Sometimes they pop up on eBay.
I managed to get a brand spanking new one from Vintage Planet. They often have them. But at the time of writing, they have none.
It is NOT a key component to the 303 sound though. So considering that it is usually an expensive part, it is not worth seeking out. The 6110 is plenty good enough.