I'm an old school tube amp stomp box guy by nature and never used midi before.So here are my questions(I have studied what midi can do somewhat).
If I purchase a POD HD 500 and hook it into my SV mkii HD 100 amp head using midi will I still have complete access to my SV presets and have them show up on the HD 500 display window?
NOT exactly, no. The HD500 will change presets on your SV using MIDI either by just following the MIDI program change messages that the HD500 send when you change patches or by you programming the HD500 switches FS1 - FS8 with MIDI commands which can include Program Change/ You would see the name of the HD500 patch in the HD500 LCD. The HD500 doesn't pick up the names of SV presets. It may clutter the stage somewhat but you will still get full control over the amp's amp and FX models by using an FBV Shortboard MkII. You may experience issues in trying to get the HD500 expression pedal to control the Wah and Volume pedal functions in the SV
Will the Wah still work exactly how it does on my FBV Shortboard Mkii? But on the HD 500(Eliminating the use of the shortboard)
I haven't tried this personally, but there are users on this forum who have and there does appear to an issue with the MIDI CC controls and the Wah functionality from what i have read in this forum including Line 6's responses.
Is there a button on the HD 500 that will let me quicky switch between HD 500 presets and SV presets?
Yes. If you use the 4 cable method of connection between your amp and the HD500, you can set up a 'null' patch in the HD500 with no amp models or FX except the HD500's FX loop and you can then use the amp's DSP section and the amp's power amp section. You will be feeding the amps's DSP pre-amp into the HD500 circuitry and then out and into the power amp. This may affect the sound very slightly, You can enhance the amp's FX by adding FX from the HD500. You can completely bypass the amp's DSP section by NOT including an FX Loop effect in some of your HD500 presets and this effectively sends the guitar signal through the POD and its amp and FX models as configured by you straight to the SV's power amp. You can assign a footswitch on the HD500 on a per patch basis to turn the HD500 FX loop ON and OFF.
Can I update the SpiderValve with the HD 500?
No. The HD500 is not a computer MIDI interface
Can I use SpiderValve Edit on my PC with the HD 500 hooked up to the head and computer?
Not using the HD500 as the interface, but you can still use your FBV MkII to connect the amp to Spider Valve MkII Edit
Can I play the guitar and sing at the same time through the HD 500 into the SV mkii HD 100 and have a vocal level and reverb/delay adjustments on the HD 500 on the fly? *(Still hooked up with only midi cables)
Yes. The HD500 will process two signal chains. Both signal chains are summed to mono if you use only one 1/4" output rrom the HD500
I'm kinda guessing that I will only be able to use one pre-amp at a time so I figure the HD 500 connection will defeat the SV pre-amp and presets and render them basically useless.
Not necessarily. If you utilise the 4 Cable Method (4CM) you can combine all the modelling form both devices if you wish. There are certain things that you probably wouldn't want to do such as using amp modelling from the SV and from the HD500 too at the same time, but nothing's stopping you from doing that if you want to.
I know this is a lot to ask but any help would be greatly appreciated.I live fairly far away from all the big music stores and most pimply faced salesmen newbs would't know these answers anyway lol.
The HD500 can work very flexibly with a number of different amps including your Spider Valve MkII, but there are limitations. In all honesty, if you have an HD500 plugged in to your Spider Valve's power amp it's very likely that you might not actually have a need to use the amp's own DSP section in practice, but the fact is you can by using the 4CM if you wish. There's plenty of info on this forum and in the Documents section of the POD HD forum as well as elsewhere about the 4 cable method and how to do it, so I won't repeat it again for now.