I have a question about the MA-15 clamps. I have six sets. The clamps in two sets are heavy, nicely finished, natural metal color underneath and painted black on top, typical JBL product. The clamps in the other four are much lighter, a little smaller and have a sand-cast look under the silver (underneath) and black paint. It's definitely not the same metal. The screws and T-nuts all seem to be the same. Does anyone know if JBL actually made both types or if these second type are a knock-off? The second type I have in boxes with authentic-looking literature from the 70's and the Casitas Ave. address. The heavy, nicely finished ones I got with a pair of 2202 drivers a few months ago.

I have two concerns: One is whether I've bought knock-offs thinking I was getting JBL. The second would be a question about reliability.

Any help on this would be appreciated.

David