I had the same problem when I had the patch volumes set to about 25%.  Almost sounds like a .22 pistol going off!!  Set the patch volumes to at least 50% and it goes away.  I'm very unhappy with that because to get the tubes to saturate, you'd have to crank the master, and it's already crazy loud at like 30%.  I wish you could set the channel volumes to almost nothing and not get the pop!  Something Line 6 needs to fix!!

I have 2.0 and it pops, unless the channel volume is say 12 o'clock or more.

but this way is not a solution at all. there needs to be a update!

Obviously this bug is a common known one for about 1 year and a half.

If you use a pod hd 500 you can't have this valve sound....

Jeff - I understand where you're coming from, and i understand your frustration, but no BS... I have a Mesa Boogie MkIII Simulclass 1x12 combo which has a master volume control which is on a hair trigger and goes from very quiet to ultra loud in the space of just 1mm movement - and it's not the pot that's faulty - that's how the amp is.  It is possible to set it with a little care so that low volume playing is possible, and the same is true of the Spider Valve MkI, Spider Valve MkII, Spider III 150 and Spider IV amps that I own.  I set my channel volume to around 50% and I control my master volume from the Master Volume knob on the amp.  It is a little bit touchy on all those amps for sure, but it is most definitely manageable without too much trouble IME- and with the Channel Volume settings at around 50% I do not experience any popping when changing between presets.

Yes - there is a known issue with this, and yes perhaps Line 6 need to provide a solution, but at the moment there is no fix available except to set your Channel Volume (per preset) to about 50% and to manage the Master Volume, which again is most definitely do-able, and having used my Spider Valve MkII quite a lot at home at low level by managing the Master Volume setting fairly easily, I would have to disagree with your statement that the Spider Valve MkII is unusable at low volume.  I will say it is definitely not a smooth transition from no volume to about 15% on the dial, but it is nevertheless controllable IME - and not only with Line 6 amps, but others which have sensitive MV controls too.

The POD HD500/HD Pro and a DT-xx amp won't fix this problem as they are completely different in terms of architecture and design so they are different animals entirely to the Spider Valve MkII, but I do have an HD500, a DT-25 and a POD HD Pro as well as a DT-50 and they do provide a viable alternative to a Spider Valve MkII if someone wants to go down that road.  The DT-25 and DT-50 actually manage valve amp Negative Feedback Loop topology settings in real time which means switching HT level voltages around and if switching from an amp model on the POD that uses say a class A/B power amp to another amp model that uses a Class A power amp, you may get a pop, but for entirely different reasons to the pop in the Spider Valve MkII.  the DT-25 does seem much quieter in this respect to the DT-50.

Nick