Search found 11 matches

by thedudear
Thu Jun 10, 2021 1:54 am
Forum: Serial Numbers
Topic: ~1972 Orange OR-80
Replies: 12
Views: 4882

Re: ~1972 Orange OR-80

Sorry for late reply, yes there is a star ground system on these for the power supply, one of which includes the electrostatic screen from the PT. So the "SCR" tap is an electrostatic screen for the power transformer, I wasn't aware. Thanks, that's very valuable info and might be the last unidentif...
by thedudear
Sun May 02, 2021 5:33 pm
Forum: Technical
Topic: 1972 OR80 - Restored on Turret Board - My First Build
Replies: 10
Views: 1243

Re: 1972 OR80 - Restored on Turret Board - My First Build

Looks good. My only real criticism would be to try and get those big filter caps secured a little better. The small width turret board isn’t ideal for longer cals and bending the wire underneath like that and having them raised makes them susceptible to movement and weakening on the solder joint. M...
by thedudear
Wed Apr 28, 2021 3:37 am
Forum: Technical
Topic: 1972 OR80 - Restored on Turret Board - My First Build
Replies: 10
Views: 1243

Re: 1972 OR80 - Restored on Turret Board - My First Build

Here are some photos of the final build. This forum seems sort of quiet at times, I hope to get some feedback! This is my first "build". I've done repairs on other amplifiers here and there, but have had plenty of experience with projects of the high voltage sort in my past. What a joy it is to actu...
by thedudear
Sat Apr 24, 2021 11:15 pm
Forum: Technical
Topic: 1972 OR80 - Restored on Turret Board - My First Build
Replies: 10
Views: 1243

Re: 1972 OR80 PT Wiring "SCR"

I wound up (Har Har) connecting that point to ground as it was when I got it. That, and grounded the positive side of the bias supply (which also is not grounded according to the schematic) and the amp is powered up and working great. Biased the KT77s to 42mA and this thing shouts!! I'll have some v...
by thedudear
Fri Apr 23, 2021 1:27 am
Forum: Serial Numbers
Topic: ~1972 Orange OR-80
Replies: 12
Views: 4882

Re: ~1972 Orange OR-80

https://i.imgur.com/QwjyJgZ.jpg Hey LD50, I'm doing a complete rebuild of my OR80. Does the pair of green transformer wires in the bottom right of the image go to the ground? I'm having trouble identifying these on any schematic and I'm not sure it was wired correctly when I got it. Just double-che...
by thedudear
Fri Apr 23, 2021 1:06 am
Forum: Technical
Topic: 1972 OR80 - Restored on Turret Board - My First Build
Replies: 10
Views: 1243

Re: 1972 OR80 PT Wiring "SCR"

Hi Jondog, thanks for the reply! I have repeatedly referenced the schematic, the 72 circuit schematic makes no reference to this connection. The DC negative side of the bridge is connected to the ground, not the transformer (as it was previously wired). However, the 74' schematic does show a ground ...
by thedudear
Wed Apr 21, 2021 2:14 am
Forum: Technical
Topic: 1972 OR80 - Restored on Turret Board - My First Build
Replies: 10
Views: 1243

1972 OR80 - Restored on Turret Board - My First Build

Hello All! A few years ago, I picked up a "working" OR80 off Reverb. With my luck, it was junk. Had a horrible parasitic oscillation, and when I opened it up, I discovered it was a 72 OR80 converted halfway into a 74+ circuit. I say halfway because it was really poorly done and hacked together. Perm...
by thedudear
Mon Apr 15, 2019 1:50 am
Forum: Serial Numbers
Topic: ~1972 Orange OR-80
Replies: 12
Views: 4882

Re: ~1972 Orange OR-80

Thanks for the insight LD50. Accepting that this thing has had a hard life, how should I move forward to getting it back to original glory? Even knowing what it's state is, I'm not ready to give up on it. I'd like to have this amp in my collection. Are there any techs you know who could perform a re...
by thedudear
Sun Apr 07, 2019 11:49 pm
Forum: Serial Numbers
Topic: ~1972 Orange OR-80
Replies: 12
Views: 4882

Re: ~1972 Orange OR-80

Hey Guys, I just got back from a 3 month holiday in SE Asia, sorry for the late response. Feeling slightly rejuvenated, I disassembled the OR80 again and took some photos. The album is here: https://imgur.com/a/XJxNTgK I haven't learned much about it since then, my tech handed it back and said it wa...
by thedudear
Mon Nov 12, 2018 3:14 am
Forum: Serial Numbers
Topic: ~1972 Orange OR-80
Replies: 12
Views: 4882

Re: ~1972 Orange OR-80

Hey LD50, Ill get some internal shots soon enough. I also suspected parasitic oscillation, but my tech was unable to reproduce this. Is this a problem that could react differently with a resistive dummy load? It's puzzling since its such an obvious problem, turn the volume up, the amp output clicks ...
by thedudear
Sun Nov 11, 2018 12:32 am
Forum: Serial Numbers
Topic: ~1972 Orange OR-80
Replies: 12
Views: 4882

~1972 Orange OR-80

Hey all, just got my OR-80 that I purchased over the summer back from my tech. A myriad of issues with it (mostly) sorted out, I'm looking to get some input on dating this thing. It was sold as a 72' OR-80. Looking at the Orange Field Guide, that seems to match up. I'm still not quite sure it's work...