For those who search this topic and the phrase Egnater Renegade, you don't need a stereo Y cable. If you just want to channel switch, a simple stereo cable will do. I can't believe how many things I tried before landing on that solution.
I have this same problem now on my JTV59. All 3 magnetic pickups are barely putting out sound. Same results connecting with an instrument cable. First of all, has anyone besides the thread starter experienced this? Was there a solution apart from sending to Line 6. I have a tour coming up and don't know that they could turn it around in time. Thanks, all