I've been considering buying an older Ampeg combo lately and I'm curious if tube availability will be an issue. It seems like the older Ampeg's seem to contain tubes that are less common in amp designs now, and I'm somewhat hesitant to buy an older amp that would present problems with sourcing parts for maintenance. For instance, I was looking at a Gemini VI today and read that it takes a pair 7159A power tubes. That tube turns up 0 results at the tube store. I'm betting there's some supply out there, but what about in 10 years..and a what cost? The prices are reasonable (IMO) on older Ampegs, and I realize it all comes down to risk assessment, but I'm curious if TGP has any input on this I hadn't considered. Or possibly alternate amps that sound like an old Ampeg Gemini that use more widely available tubes. I've really been enjoying Heath Fogg's (Alabama Shakes) tone lately for some context on what I'm hoping to get from the amp.