LGP-30 found in basement, the same model of drum computer programmed by “Mel”
LGP-30 had 113 tubes (for logic switching? or memory?) of mostly type 5687, which elsewhere had industrial uses and were used in hifi audio (I'm unsure how), but are not appropriate for guitar amplifiers. Apparently they take a lot of plate voltage and get pretty hot. I found this brief writeup[1] on them (with pictures) mildly interesting. They can be readily found on eBay in a wide variety of pricing of various brands with NOS pretty expensive, as usual. And there's a neat page dedicated to LGP-30 here.[2][1] http://vinylsavor.blogspot.com/2020/12/tube-of-month-5687.ht...[2] http://ed-thelen.org/comp-hist/lgp-30.html