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Re: Orange Model RO 100? Serial Number 752

Posted: Fri Oct 05, 2018 6:15 am
by LD50
Wow
Does it work?
Fender OT,
I cannot make anything else out in there of any structure!

Re: Orange Model RO 100? Serial Number 752

Posted: Fri Oct 05, 2018 10:40 am
by FranktheTank
He works.....and he sounds great. But I have no Idea what kind of amp i'am playing.

Re: Orange Model RO 100? Serial Number 752

Posted: Fri Oct 05, 2018 11:30 am
by bclaire
FranktheTank wrote:
Fri Oct 05, 2018 10:40 am
He works.....and he sounds great. But I have no Idea what kind of amp i'am playing.
My guess is, someone got ahold of an Orange chassis and sleeve and built something in there. If it plays well that's awesome, but if you ever need any work, it might be difficult to work out what's going on.

Re: Orange Model RO 100? Serial Number 752

Posted: Fri Nov 16, 2018 9:39 am
by Ruptor
It looks like a prototype unit to me and been built by someone dyslexic. Not only is the OR round the wrong way but the hand written PRES has the S back to front. Having been a design engineer building prototype medical electrical equipment for most of my life you use what you have like a chassis off a previous pilot production unit. As a private amp builder it wouldn't make sense to scrap all the electrical connections but doing a new prototype design would require a bare chassis with just the valves and transformers mounted to begin.The unit has all the notes in English so probably not built by a German and probably built in Britain. Looking at later models the presence control was added and that is the knob on the back of this unit so I put forward that it is a prototype from Orange of a unit with the presence control like the OR80R. The components look like 70s parts with the blue capacitors and the toroidal transformer. There is writing on the toroidal that could identify the year it was done and if it predates the amps with presence controls it surely must be an Orange prototype.
Looking further the chassis is an Orange Matamp OR100 because of the 3.75 ohm capability on mine and the front panel is off an OR120. I don't know the chronological order of the amps but if the OR120 came before the OR80R units or the units with presence controls it might be the prototype for those units. If it is it could be worth a packet as an historical unit and probably works the best since prototype units tend to be tuned to the best state as the bench mark for production to match.