I don't know, but have two suggestions:

1. Try removing and replacing the fuses one at a time until the drain
stops momentarily. This may show that it is more than one source (the
radio/clock is bound to be one of them, but not 1A, I would have
thought) and it might identify where it is going.

2. One of my previous cars had a 3rd party cellphone installed (the
works; microphone, speaker, and integrated phone) and this was drawing
about 1A. The previous owner had removed the microphone and speaker so
there was no sign of it, hidden under the rear parcel shelf. It took a
professional electrician to track it down.