Would be fun to know what's inside, though.

I have a plexi OR120 I have tried to find out more about - take a look at my thread here: http://forum.orangeamps.com/viewtopic.php?t=27984

That looks almost like mine! It is a bit different from the one (GRO) at Orange Field Guide, both internally and on the front. Mine has not the four screws that the GRO has, but it has the same plexi front panel. It is not really easy to see in the picture, but it seems that your amp does have the s...

Very interesting info about the biasing, Andy H. Thank you. However, I do not have a bias pot in my '72 OR 120, so the question is: What valves would work for me? Or is it really a good idea to modify the amp to have a bias pot?

I have a couple of the new ones (Daredevil 290 and Flatroc) and I must say they are a real bang for the buck. The Daredevil is my main guitar now, it gets played a lot more than my Gibson SG. Lots of grunt, growl and punch. Can be creamy, too.

Excellent! I just stumbled upon this thread and it is quite a read.

Amoun, There are no bias pot on these. They are fixed bias, but it is not adjustable! I have more or less the same amp (pics here: http://www.flickr.com/photos/22488102@N00/sets/72157605005879389/ ) and it too lacks a bias pot. Just out of curiosity: Are you sure it is a '72? My OR120 has a plexi fa...

Thanks! There it is, before my eyes.

The only difference is that I don't have the four screws in the faceplate. That seems to be a heritage of the Matamp era. I would like to see the intestines of this amp, and compare with my amp.

Hi again. It's definately a plexi - see the photos at the end of this post. What's puzzling me, is that I find some things atypical, and that they don't belong to the same time period, but that is relatively common, I have heard. Anyway, what I find a bit strange is: <ul> <li>Model number OR120 (72-...

Don't know - I didn't get it from there. It has as far as I know never been sold on the bay, but it could have been listed, of course.

Hmm, you made me think. I am at work now, but I can get some better pics when I get home. There is undoubtedly a layer of transparent plexi there, on top of the whatever it is that the graphic is on. You can even see the cracking on the top left.

Hi all! new to this forum, and fairly new to Orange amps as well, although I've been curious for some time. Anyway, I recently bought this beauty: http://flickr.com/photos/22488102@N00/sets/72157605005879389/ However, the seller couldn't tell me the year it was built. I have looked around at orangef...