I found that Home Depot and Lowes both carry the expansion nut (trade name Well-Nut). This is the standard part of the fastening system for SUNN Studio Lead/Studio Bass combo amps. May work well with other solid state amps too (Concert, Coliseum, etc).
It's a black rubber mounting device with a brass nut inside that secures the chassis to the cabinet, but provides some isolation from vibrations. Need four of them. Has the brand name "WELLNUT" and what appears to be a part/size A-1024
It's a black rubber mounting device with a brass nut inside that secures the chassis to the cabinet, but provides some isolation from vibrations. Need four of them. Has the brand name "WELLNUT" and what appears to be a part/size A-1024