The RC-1 features the usual ‘tank-like’ construction, as with all Boss models. There is one knob only, which adjusts the volume level of the playback.

I noticed that some online guitar forums were reporting pedal sync issues. On closer inspection though, the manual reveals a second configuration mode, resolving this.

Check the link below from the RC-1 manual to clarify:

BOSS RC-1 official manual:

The unit is factory default to cycle through its different functions as follows:

1st press = record

2nd press = overdub

3rd press = playback

This configuration is switchable if not to your liking. You can do this by powering up whilst holding down the pedal. Click the pedal once again and the LED ring lower half will illuminate.

You are then able to switch to an order of record, play, overdub. This seems a confusing way to switch modes if you want to but you’ll see it documented in the manual non the less.