silverhead

The X3 forum is here:
http://line6.com/support/forum/19-pod-x3/

There is no firmware v2.21 for the Pod HD. That version number exists for Pod HD Edit. They are two different software products whose version numbers are not necessarily synchronized.

The battery is being used (drained) whenever there is a cord/plug in the 1/4" connector jack. That plug acts as the power switch on the JTV, and it is "ON" (using battery charge) whether the modeling is being used or not. It's like powering your computer on with the battery then walking away from the computer - the computer is still using its battery to patiently listen for any commands. Your computer has a 'sleep' setting that you can use to let it rest when you are not there for a while. The JTV has no such sleep mode or setting; it is either on (cable plugged in) or off (cable disconnected). Like any battery it has a shelf life - it will eventually discharge even when disconnected for a long period of time.
 
If you want to use only the magnetic pickups of the JTV and don't want to drain the battery, just remove the battery.

1) Yes - no problem
 
2) In the preset set your Input to Variax Mags when you want to use the JTV pickups instead of a model.

The Looper has no sense of tempo. You must start/stop it exactly 'on the beat', but the beat is only in your head. It sounds like you are stopping it early - by exactly the amount of pause that you are hearing. It records the silence until you tap the footswitch, and then plays back the silence at the end of each cycle.
 
Here's an old thread that may help.
http://line6.com/support/message/451813#451813

Use HD500 Edit - not Line 6 Edit. Run Line 6 Monkey with your HD500 connected to get HD500 Edit.

Since a Wah pedal is typically used early in the signal chain there are basically two good ways to do this, I think.
1) Put your Wah pedal before the HD500 in the signal chain, i.e. guitar -> Wah pedal -> HD500. In this case it will not show up in the HD500 signal chain because it precedes it.
2) Place your Wah pedal in the FX Loop of the HD500. The FX Loop (and hence the Wah pedal) will show up in the HD500 signal chain and you can place it where you want with respect to other FX and pedals.
 
In either case you can assign your HD500 EXP-1 and EXP-2 to do other things.
 
If you want to experiment with placing the Wah pedal later in the signal chain you could place it in the FX Loop of your DT50.

No - you can't do this effectively. The Variax model stored in an HD500 preset is used (when VDI connected) to set the Variax to the specified model, regardless of the current status of the Variax Model Selector knob and Pickup Selector switch. As soon as you physically move the knob/switch, you override the stored preset selection and the Variax model changes to reflect the current status of the knob/switch. There is no concept of a 'like' guitar.
 
I suggest you abandon the idea of using both HD500 presets and the Variax itself to simultaneously control your Variax settings. You can use the HD500 and its stored presets, or you can use the Variax controls manually. You can choose one or the other at different times during your gig. As you say, you can set up your HD500 patches so that you always use them to control the Variax setting. Or you can not store Variax settings in the preset and set the Variax manually when you like. But you can't avoid the potentially harsh contrast if you use an HD500 preset to specify a model that does not correspond to the physical settings of the guitar, and then manually change the physical setting. If you do this mid-song you are inviting trouble.
 
Workbench is just another way of using the Variax in conjunction with either HD500 preset control or manual control; it doesn't really affect or alter the above situation. In your Chime example, you could do what you want without using Workbench - you just have to make sure your Model Selector knob was set to the Chime Model Bank before selecting the HD500 preset that selects Chime 2. But unless your physical Variax Model Selector setting corresponds to the HD500 preset's Model Bank selection you are in trouble when you change the pickup selector switch because that will automatically change the Variax model to the currently selected Model Selector position also.
 

What you describe is normal. The HD500 Studio/Direct output is line level, and best for the L3t PA/Reference mode. The L3t mixer inputs expect instrument/mic level. It's best to use the L3t rear panel inputs for your HD500 outputs. You can also experiment with changing the HD500 output mode to one of the  Combo/Stack modes (instrument level output) for the |L3t mixer and perhaps changing the L3t mode.

Yes. To do this you must create a dual-path preset with no Amp or FX appearing before the path split. Here is a sample preset that I posted in Customtone some time ago, designed for an acoustic guitar and a mic/vocal:
http://line6.com/customtone/tone/215659
 
Of course you will need to customize the Inputs, the Amp/FX selection in the paths, and perhaps the Mixer panning. The important part is to NOT put anything before or after the path split. This will keep the processing of your 2 inputs completely separate and independent.
 
Please come back with more questions if this doesn't help you do what you want.

You will get more reliable performance with the digital AES/EBU cable. Standard analog XLR cables have been known to work OK, but some have reported problems. Line 6 recommends the AES/EBU.

Perhaps the four-cable method of connecting your amp and HD500 is what you want:
http://line6.com/support/docs/DOC-2504
 
I think this will let you do what you want by using an HD500 preset with no amp, some FX placed before the HD500 FX Loop, and some after.