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Vintage Orange Amp Experts?
Old 22nd October 2013
Lives for gear
Vintage Orange Amp Experts?

Have a chance to buy a few Orange amps from the 70s and I found a few things that make me wonder...

1. What's the difference between ORS, GRO and just an OR?

2. Besides plate voltage, is there any essential difference in sound between an OR100 and an OR120? Between a pics only (early 70s) and a pics and text (78 or so)? Between a plexi panel and a metal panel pics only?

3. What speakers did they deliver with in the 70s? I've heard Celestion, Fane and CTS (square magnet like the ones in the Ampeg V4/Sunn cabs)?
Old 22nd October 2013
Gear Addict
AwTAC's Avatar

Ive had several of the old 70's amps over the years and they were all similar enough. At some point they changed phase inverter design, and while I dont think they were truly ultralinear in a snooty hifi sense, they did have a feedback tap on the transformer that was fed from the phase inverter, you want one with that circuit, which has you covered for the 70's. THAT is the orange sound, Im not too sure the new amps are using that feedback arrangement much.

Id be on the lookout for a head with partridge transformers, this certainly would be in an older head.

Buying any orange, youd want to pull the chassis and look at the circuit, the common failure mode for these amps typically includes a ball of fire, so you'll want to make sure there is no evidence of a bunch of burned up stuff in there.
Old 22nd October 2013
Lives for gear
A ball of fire... that would make a spectacular end to a world tour, but not so helpful when the bills come due! Yeah, I'd heard something about the pi design, I think from the early 70s they were all the "concertina" design, so a more complex clean and gradual onset of distortion compared to a Marshall, say. Beyond that, I don't know when and how the feedback thing came in. There's remarkably little info out there.
Old 22nd October 2013
Gear Addict
AwTAC's Avatar

I just looked through what I had and I cant find a single schem that shows the circuit Im talking about. Perhaps Im remembering wrong, but I dont think so. Im almost certain there was an ultralinear thing happening in those amps, everything I searched w google just shows a feedback arrangement similar to what youd see in a marshall- just taken from the speaker output. Admittedly, last time I looked at an orange was in the mid 90's, I could very well be wrong.

Orange amps were in fact big clean amps which I think comes as a surprise to most people who went and bought one after the first time they saw black sabbath on beat club Shoulda got that laney, dude.
Old 23rd October 2013
Lives for gear
Well, having played an OR80 in anger, I can attest that if you're willing to sacrifice your hearing they'll crunch with the best Laney (I've got a Supergroup 60 as well). It's just that they're DAMN loud when they do it. All the schematics I've found from 74-78 or so include the straight forward negative feedback, but that's pitifully few...
Old 5th November 2013
Lives for gear
Travst's Avatar
I had a Hustler 125 in the late seventies. 100 watts with 2x12 Fanes. Heavy as hell but sounded like the hammer of the gods with my '70 335 or a Strat. I wish I still had it. The one thing I hated about it was that the plastic knobs broke off very easily and weren't protected well. What a beast.

It was wired very much like a Twin as I recall and had EL34s. Very fat, big, and clean unless dimed.
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