Released in February 1974, Humble Pie’s seventh studio album, ‘Thunderbox’ was pivotal for the seminal hard rock group led by legendary vocalist and guitarist Steve Marriott. But not in a good way, as it signaled their commercial fall from grace.

Starting with their modest 1969 debut, ‘As Safe as Yesterday,’ Humble Pie had grown from strength-to-strength, quickly earning their reputation as one of the world’s first supergroups (along with Small Faces alum Marriott, they featured former Herd lead guitarist Peter Frampton and ex-Spooky Tooth bassist Greg Ridley — plus teenage drummer Jerry Shirley), and achieving a career milestone with 1971’s exuberant ‘Performance: Rockin’ the Fillmore’ live album.

But then Frampton quit, promptly signed a solo deal with Humble Pie’s record company, A&M, and while Marriott efficiently replaced him with the more-than-capable Clem Clempson, things would never be the same.

Subsequent offerings like 1972’s ‘Smokin’’ and ’73’s ‘Eat It’ (a four-sided behemoth, split between studio rockers, acoustic fare, and live cover material) did manage to capitalize on 'Performance's' breakthrough with Top 20 chart showings, but their sales were still no match for those of competing stadium-filling titans of the day like Led Zeppelin or The Who.

Fairly or not, A&M Records expected more, and after indulging Humble Pie’s grand ambitions on ‘Eat It,’ the last thing they were expecting from the band’s next studio venture was a rush-recorded follow-up boasting seven cover tunes (out of twelve total tracks), named after a 17th century slang term for toilet.

This was 1974’s ‘Thunderbox,’ which A&M nevertheless packaged in a lavish sleeve (boasting a keyhole view into the water-closet of some scantily clad models) and trotted out to record stores and radio stations, in the hopes that its powerful title cut and many soulful remakes — including the Rolling Stones-like ‘Ninety-Pounds’ — would prolong Humble Pie’s relative career winning streak.

Instead, they saw ‘Thunderbox’ fall short of the U.S. Top 50 (stalling just outside, at No. 52) and miss the U.K. charts completely. But in Humble Pie’s defense, they had dutifully worked their butts off to promote this and every prior album, undertaking some 20 tours over the previous four-year span, only to find themselves exhausted, broke and with precious little else to show for their efforts.

As a result, Marriott and co. would delay their return to both the studio and the road in late-’74 in an attempt to recharge their batteries. But this sadly prompted A&M and manager Dee Anthony to backstab the band, heist whatever working demos they could from Marriott’s proposed solo LP, and release the rough and substandard contents in early-’75 as the much-maligned ‘Street Rats’ LP.

By doing so, they effectively killed the golden goose and derailed Humble Pie’s once high-flying career, while leaving an emotional toll that the band members and leader Steve Marriott, in particular, would never fully recover from.