If he can attach bare wire than he should be able to clamp down a spade terminal the same way, unless he has the same kind of terminals that come on cheap mass market stuff like a Best Buy receiver. The plastic gets in the way and prevents the use of a spade. If not that, he may have really big posts on the back of his amp (Like B&W speakers). Then he just needs oversized spade's.
Whatever the case may be, there is a quick fix that will allow your friend to use his system until he gets past this issue. Just get some Monster (Or similiar) mass produced bananas and on the end that you screw down the bare wire, insert the spade in between the actual metal cylinder that you turn with your fingers and the plastic housing (not the same place you put the bare wire, but all the way in the back). Depending on how the terminals are spaced on the back of the amp, you may have to cut the adaptors plastic housing in half.
If all else fails and your only option is banana, Audioquest makes some very good, all metal, spade to banana adaptors that you can use. I've actually used them myself when I tried Magnapan speakers and only had speakers cables with spades. They're good enough that you probably won't lose any SQ unless you have very expensive, revealing equipment.
Whatever the case may be, there is a quick fix that will allow your friend to use his system until he gets past this issue. Just get some Monster (Or similiar) mass produced bananas and on the end that you screw down the bare wire, insert the spade in between the actual metal cylinder that you turn with your fingers and the plastic housing (not the same place you put the bare wire, but all the way in the back). Depending on how the terminals are spaced on the back of the amp, you may have to cut the adaptors plastic housing in half.
If all else fails and your only option is banana, Audioquest makes some very good, all metal, spade to banana adaptors that you can use. I've actually used them myself when I tried Magnapan speakers and only had speakers cables with spades. They're good enough that you probably won't lose any SQ unless you have very expensive, revealing equipment.