Aaaahhh... I didn't realize that the switch didn't have an "8 Ohm" position.

And I thought it possible that despite your hearing the issue in the "mids and highs" of the violin, that it might be an overall crescendo where other instruments (read: More "Bassy") were sucking up wattage that was just showing itself more clearly in the violin.
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::::::: No disrespect to Axiom, but my favorite woofer is my yellow lab :::::::