The longest I have is 50ft.
I am concerned about the abundant use of ahoustondj's 1/4 connectors. You really should check into switching over to speakons!
The reason you should use speakons is because they have much more conducting surface to let the signal get to the speaker without as much resistance.
Take 2 butter knives. Lay one on the table, and take the point of the other one and touch it to the side of the blade of the one laying on the table. That tiny place of contact is all you have attaching your speaker cable to the cabinet! Trust me, it's not enough when you are pushing more than 50 watts even!
A friend of mine didn't think it mattered much. After a show when we shut the amps off, I had him go unplug the speaker within a couple minutes of shutting down. These were 12G cables with the large metal barrel type 1/4" connectors on them, and the ENTIRE plug was warm, while the tip was almost too hot to touch!
This is because the connctor got hot with such a small area of contact. Now, when the contact area gets hot, it increases the resistance of the connection, sort of creating an analog compressor. The hotter it gets, the less signal will get to your speaker.
that sucks. Get speakons and get more signal to your speakers, especially the subs!