I've run into a frustrating limitation when using the tone knob to control parameters on the HD500. Setting it to lock the tone control doesn't do so completely. The HD500 firmware is 2.2 and the JTV firmware is 2.0. Here's an example I ran into:
I have the tone knob set to control the amp drive control. At maximum knob value the gain is at 60% and at minimum knob value it goes to 100%. Tone knob lock is set to preset not global, but I've found this happens in both instances. When playing and turn the tone knob everything behaves as it should. However whenever I change pickup positions or banks on the JTV the tone is rolled off. Even if I turn the tone knob back up the tone stays rolled off, but the amp parameter is still affected. I have to run the tone knob back up to maximum and change pickup position or bank to get it to tone back to maximum.
So what is happening is that whenever I change pickup positions or bank the guitar recalls the tone setting for where the physical knob is set. However I'm then unable to change the tone setting because the tone knob is locked.
The only slight work around I've found is going into workbench and saving the tone knob position to 10 on each model. The problem here is that now when I change pickup position and/or bank the amp gain setting follows the preset saved value. So if I have the knob at minimum and the amp gain is at 100 when I change to another pick up position it goes back to 60.
This is very frustrating! I don't mind if the HD500/JTV don't have the ability to work together like this, they didn't when I bought the HD500. But don't add a "feature" that only half way works. I've wasted the last hour trying to get this to work in the way it logically should. I can see no good reason for designing this feature to work this way.
If this is just something I'm doing wrong PLEASE someone point out how I need to set it up and I will gladly recant my anger with Line 6 programmers.