The speaker input on the U5 has a 400 watt max. Is the ohm rating on the amp involved in this? My Ashdown has a rating of about 575 @ 4 ohms. Since 8 ohms may be a little over half that will it be safe to run into the Avalon? The Avalon site says the U5 doesn't pull a load from the amp while using this feature, but then why the 400 watt limit? Thanks!