The amp that I use and have used since the mid 90's is the Adcom 545 mk2. Its in my opinion one of the best sounding amps Adcom ever made and if you look around I have seen them go for around 150 to 200 bucks. They sound as good or better than allot of amps costing well into the thousands and is rated at 100 wpc into 8 ohms. This amp can drive very hard to drive speakers without problem and has a smooth and transparent quality that will do most speakers well. I have hooked it up to 3000 dollar mirage m3's which are somewhat difficult to drive and it made them sound great. I have run the big cerwin vega dx 9's with it and it hammered them. I'm not a vega fan but this amp made them sound probably the best you could make them sound. Very good buy and I think you could hook this amp to your JBL's or any other of the speakers mentioned and it would make them sound good.