Jl 1000/1 keeps blowing up subs

If the shop is reputable, and it blew the subs on their settings the subs are on them unless they can prove the amp is bad. You can have them ship the amp back to jl and they will put a new board in the amp eliminating the amp as the potential problem

My question is where is the gain knob set when this happens and where is the bass boost?

Are you using bass boost on the radio?

if a JL Audio certified dealer done the work then it is certainly backed up but not sure how the subwoofers would blow up as one have to drive the subwoofers into distortion for a few minute for the effect to take place!!!

JL Audio gear is pretty tough and well known brand so there is no question about their products but if you keep blowing subwoofers then something is the cause.

If possible for you, try another amp (from a mate as well as a single subwoofer and use it for a week to see if any issues arise.

You may need to take the JL Audio amp out and get it bench tested from a knowledgeable person before you take it to a repair shop.  This action is to get a second opinion on the amp and to rectify the amp is definitely the cause of the subwoofer blowing up.

Let us know how you go mate, as some components can fail over time and with amps, its hard to determine unless it is thoroughly tested by a reputable person who knows what they are doing. 

Good luck and let us know how you go, mate! :veryhapp:

blown subs is from sh*t settings. The shop fked you with improper gain settings.   

Using a meter check the DC voltage from power ground to the + and - sides of the speaker terminals. You should measure about 57VDC on BOTH sides of the speaker terminals. Also measure across the speaker terminals. You should measure less than 1 VDC. If you measure more than that then it's not balanced and you have a DC offset problem with the amp. If you measure several volts or more that DC voltage will just heat up and slowly cook  your voice coils in your subs and permanently damage them. 

i can almost guarantee the gains were "turned up to eleven" and your subs have died the unfortunate deal of being clipped as fu¢k

Winkychevelle is on point. After blowing a few sets of subs, I wouldn't continue trying other brands and buying more subs until I look into the problem/issue. My guess is the same thing winky has already stated. That said, get back to us for proper gain setting on the amp or search for a tutorials online or youtube. It'll save your 5th set of subs from being blown.