Leave it in standby mode and hook up the xlr out to your mixer or audio interface and there you go.Make sure to set your DI output to "Studio" mode and don't bump the standby switch by accident.

*Never run any tube amp with the speakers disconnected! The electricity created needs to go somewhere and it is drained into the speakers.You could seriously damage your amp by trying to run it with no speaker load.

I have the SpiderValve mkii HD 100 head and have read to never run it with out a cabinet(speaker load) or there will be serious damage.There is a cheat if people so wish but be fore warned about the dangers.One can put the amp in standby mode and run it with no speaker load because the power output tubes aren't on and only the pre-amp tubes are fired up,but....one false move by you,little kids or a dog or something bumping that switch out of standby mode and your amp is frazzled.So I suggest always keeping speakers or a "hot plate" connected at all times.

A Line 6 expert can tell you for sure but for now I'd stick to what I'm saying

Hey jesuscares,

  I would suggest to use the Direct Out XLR output for home recording.

  I would suggest to use the live mode for the Direct Out so that it can take advantage of the Power amp's tone. Make sure not to disconnect any of the speaker leads. I would say you could take the amp out of standby and keep it at a low volume so that the amp can be used to monitor your sound, try to use as much master volume as you can.

  For more information on how to adjust the Direct Output modes, reference page 3-4 of the Spider Valve MKII Advanced Users guide at the link below:

  http://l6c.scdn.line6.net/data/l/0a060072bd264aca7babf058d/application/pdf/Spider%20Valve%20MkII%20Advanced%20Guide%20(Rev%20A)%20-%20English.pdf