Yeah I know and that's why deep down I'll keep it and schlep it to every gig I can. I was gigging at the weekend and every time I hit an F note on one particular song the room vibrated.. used the parametric eq and notched out the troublesome frequency in seconds between songs, added back a little bass and problem solved.
The 680 has the Jensen out, the tubes just a wee bit bigger and maybe not so pedal board friendly 😉