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Posted: Thu Jan 29, 2009 11:24 pm
by shai-hulud
i recently purchased what i THINK is an OR120 from the early 70's, with a vintage Orange 4x12 cab. i've got the serial number as OA7177 and can't seem to find the exact model on the catalogue scans. also the does not seem to be working, at least not from my work computer. any help identifying this groovy amp would be greatly appreciated!

Posted: Thu Jan 29, 2009 11:42 pm
by bclaire

Posted: Fri Jan 30, 2009 7:47 am
by Orphin
or this: even better has never worked for me..

Posted: Mon Feb 02, 2009 2:49 am
by shai-hulud
so i know it's from 71, 72 or 73... but i can't find any reference to the OA before the serial number. anybody know what that means?

Posted: Mon Feb 02, 2009 2:50 am
by bclaire
I don't think anyone has ever explained that... might just be OA= Orange Amp.

Posted: Mon Feb 02, 2009 3:00 pm
by shai-hulud
alright so this is getting a bit more confusing, especially because i don't physically have the amp in my possesion. anyway the face plate seems to be plexi, indicating that it is not an OR120 but an ORS100 or a GRO100 (what the difference is besides maybe wiring i don't know). however on the back of the head it clearly has 4/8/16 Ohms.

GRO100 3.75/7.5/15 Ohm
ORS100 3.75/7.5/15 Ohm
OR120 4/8/16 Ohm

perplexing. i can live not knowing whether its a GRO or an ORS at the moment, but i'd like to determine exactly how many watts she has pumping through her. btw all your resources have been really key and i've learned a helluva lot over the past week, but in the grand scheme of things i'm a total n00b when it comes to tube amps, so do bear with me.

Posted: Mon Feb 02, 2009 7:46 pm
by evergud
I have a plexi OR120 I have tried to find out more about - take a look at my thread here: