What happens if I plugged a 20amp unit..15amp outl

Rapogee,

You used the word "requires". Did you choose that word or was that from the manufacturer's owner manual. For a required 20 amp receptacle/20 amp branch circuit the FLA (full load amps) would have to be greater than 12 amps. That would be a pretty powerful amplifier.

Sometimes a manufacture may "recommend" that a 20 amp branch circuit be used to get the best performance from his amp but it is not "required".

A couple of ways to check for sure....
If the unit does require that it must be connected to a 20 amp branch circuit the factory cord that came with the unit will have a 20 amp plug on the end of the power cord.

Check the data info on the back of the unit. Usually near the power inlet it will give the AC voltage and power consumption. FLA, VA (volt amps), or watts.
The max connected load that can be plugged into a 15 amp receptacle is FLA 12 amps, 1440 VA or 1440 watts.

I already have an electrician about to make the change for me......
12-17-09: Rapogee

Rapogee,

You will need a 20 amp branch circuit then. #12 awg wire minimum with a 20 amp breaker.

Just an added note if the breaker trips on occasion due to start-up inrush current of the Krell most electrical panel manufactures make breakers with a longer inrush current lag time.
Here is some info.
Jim