As famously used by Jah Wobble!  I got it 2nd-hand in 1986, having had experience of playing one that belonged to a friend.  An unusual looking creature ( the bass, that is - though, to be honest, the friend was no oil painting either...)  Beautifully made, of course - as you'd expect from Ovation.

Click the picture to get a PDF of the original User Manual (2.7MB)

It was blessed with a remarkably wide tonal range, thanks to its two very different pickups.  Crammed right next to the bridge was a crisp, cutting Humbucker with unique U-shaped pole pieces; the neck pickup was equally clever in design, having individual gain pots for each pole piece.  I was forced to sell it in 1988, owing to a desperate lack of money.  A good thing I did, really: otherwise, it would have gone in the burglary.

STOP PRESS!! - as of July 2009, I am now once again the owner of a Magnum. Audio samples:

Bridge Pickup, coils in parallel Neck Pickup, coils in parallel Both Pickups, coils in parallel
Bridge Pickup, coils in series Neck Pickup, coils in series Both Pickups, coils in series