I don't actually own a solo so I can't verify this myself, but from what I am reading, the solo needs either around 7-9v or 12v depending on whether you're charging or just using it for pass-through heating. The VK can definitely provide the 7-9v or 12v, the real question is how much current it needs. From what I'm reading, charging might be OK with 12v @ 1.5A, which the VK should be able to do.
However, the "pass-through" power seems like it requires a lot of amperage. I saw this supply below being recommended as an alternative for the pass-through (requires an adapter for the jack on the solo)
http://www.jameco.com/webapp/wcs/st...0001&productId=206529&catalogId=10001&CID=PDF
However, that adapter is over 5 amps @ 7.5v, which is definitely more than the VK could provide. The funny thing is, that adapter looks nearly the same as the one from my arizer extreme-Q. I'm guessing it needs a similar level of power to that in order to do the pass-through function. That said, I don't think I'd try using the VK for the pass-through, but as a charger it'd probably be OK. You'd need about 37.5 watts to be the equivalent of that pass-through adapter above, and the VK peaks at 25w.
I've considered making a higher-powered VK for people with more specialized uses, it would likely require a larger circuit board with higher rated parts, so it definitely wouldn't be fitting into any smaller cases, but, it could potentially power many more higher powered devices. If there's enough interest in that, I can definitely look into ordering some higher powered boards.
Oh yeah, and I'd definitely recommend the vernier if you were using the VK for this, so you can lock the voltage in place and not have to worry about an accidental bump frying your device.
BTW, these are the adapters you would need in either case, you can get it in right angle or straight:
http://www.amazon.com/Super-Power-Supply®-5-5x2-1mm-4-0x1-7mm/dp/B00EA4GL3W/ref=pd_cp_pc_1
http://www.amazon.com/Barrel-Converter-2-1mm-5-5mm-1-7mm/dp/B009AZ84YA
You could use this for charging with a standard VK.
That is an awesome response! With how much more complex it is as a pass thru I think I would opt against a custom one.... For now. Heh. Though later I may talk to you about a fixed voltage unit to be used in one setting for charging, and with a switch flip (possibly?) for pass thru use.
Me and my damn custom jobs huh?
=)