About used tube gear: I have no experience with tube gear; are there any considerations or risks when buying it used aside from possible warranty issues? Thanks.IMO, buying used from Audiogon sellers is pretty safe. There's no trick to buying used tube gear versus any other gear.
Actusreus (Answers)
Do some research about the seller. See if he/she has feedback, and is he/she has contributed to the discussions.
Ask specific questions about the gear. For example, ask the seller to describe specifically any cosmetic flaws and operational issues rather than to provide just a general description of condition.
Get serial numbers and check them with the manufacturer to see when the components were sold and if they have been serviced.
Obviously, most used gear is not warrantied, but in my experience, I have never had a single issue with a unit failing or requiring servicing within what would have been the remaining warranty period (and beyond).

