First post here (though I was lurking this forum for some time:) )
A while ago I got on repair an unusual Orange head,the SuperBass.
Facts:
1.The amp(as it came) beared clear signs of unaware modifications (for the n-th time,amateur hands) and unusable judging by the wrong wirings/wrong replacements/worn components.For these reasons,I didn't have the courage to "see how it works" but I proceeded immediately to a total re-capping job and overall cleaning.As you can see from the pictures,the ressurection is in progress (but not finished yet).
2.I'm confused about this amp's original config.
The "SuperBass" schematic doesn't show anywhere on the Net...accordingly,so far,I'm only speculating/guessing what's it all about.
The chassis says "SuperBass" on the front panel.It has two inputs (Normal-Deep) and the controls are Vol.-Bass-Mid-Treble-Presence-Contour (?!?).Also,it has both switches:Mains and Standby.
The back panel states "Model OR",serial No.12270 and nothing more.
I looked for some mfg.codes on trannies' bells but I didn't see nothing there.However,the two original bigger chassis-mounted HV electrolytics are Plessey from 1974 (I mentioned this in case if it might mean something).
The underside of the PCB says "Orange Graphic MKIII"....what the heck's going on?
Because of the front panel controls' config,I assumed that,despite of the "OR" imprinted on the chassis' back,the schemo is a later AD with FMV tonestack.Nothing wrong with that but I'll have to dig up the preamp's scheme just to be sure wether is a real FMV or a weird Baxandall,as marked on the PCB.
3.What puzzles me the most is the "contour" control.The worst of all is that on the 5-position switch,prior modifications made it unidentifiable.Before cleaning the switch completely,I carefully inspected the "made-up" line of small caps and resistors (sorry for not having a picture of it...you might laugh all day) and I concluded that there's no way that THAT components'arrangement would EVER work (this was one of the primary main reasons for not lit it up and clean it to the bone).
Back to the "contour" control itself:as I said,it has 5 positions instead of the classic "F.A.C".The positions are,from the left to the right:
Lo2 - Lo1 - Direct - Hi1 - Hi2
Does anyone know what are the original components and their values for this arrangement? (for some reason,I doubt that it has the classic small caps' sequence as found in a "F.A.C.").
Here are the pics:
Any help greatly appreciated!
Regards,
Le Basseur
)