I have just recently bought some excellent volume controllers from American Syscom inc, and what a difference it has made to my KING CAMEL , and FIRE DRIFT, and can now play those two without waking the dead!, anyone in the uk thinking buying some volume controllers,i can't recommend these people highly enough. I bought 2 packs of 5 piece volume control, the TWO SAMMY machines had FOUR different volume controls for the upper speakers (103) , and the other SIX (501) for the rest of the speakers. used six in total 4 x 103 upper, 2 x 501 lower (sub). The total cost to me in the UK was $32.00, $2.00 was for shipping. Bargain I dont know what the difference in the two types are but it works!