Hi Tom and welcome:
Guildmark said:
....the moderator here, capnjuan, is likely to know the answer to your question right off. If not, check the names of the other particpants in this and the tech threads. Someone will know!
Sheesh Mark, nothin' like a little pressure...
:wink: Agree w/ Don; the Thuderbass heads came in several configs and prices as did the cabs. The Quantum bass head, except for the elusive Big Bird, was the top (end?) of the line Thunderbass heads. So far, the most reliable distinction we've been able to make is that the the Quantum had an additional 6GF7 tube acting as a screen voltage regular and the 4-tube preamp Thunderbass didn't. I can't say with any certainty that there's a corresponding distinction among or between the cabs other than market-driven model names. The clear suggestion is that Guild pushed this cab with the Quantum head.
As for worth, unfortunately and except among members here, Guild electronics don't get much respect. What would govern value is the condition of those 15" speakers; age, cone condition, presence of voice coil rub that kind of thing and, to some degree, the fact that it's a Guild. 2X15" cabs a little on the rare side. What model are the JBLs? There are a couple 12" models used in the $200-$250 range loose; more for the 15"s. Shredders don't care about the Guild logo; only us LTG BBers do. Otherwise, I'm not sure I could give you a good idea.
Are you going to sell the cab or are you just curious?
Best wishes, cj