Tube Amps / Music Electronics
For current discussions, please visit Music Electronics Forum. New: view Recent Searches.
New: visit Schematic Hell!
The sunn still shines online!

Listen to great tunes streaming live right now!

ampage archive

Vintage threads from the first ten years

Search for:  Mode:  

Why does my RI Orange sound better than my vintage one?

3/20/2004 3:51 AM
Why does my RI Orange sound better than my vintage one?
I have a 90's era Orange OR-120 that i've owned for a while now. The amp sounds great, it always has. But after hearing so much vintage hype about the 70's models, I broke down and picked one up.  
Now, the second Orange I have is a '71 GRO100. I didn't know if until I got the head. But the pre-amp circuit is different. Basically, the gain stages were in a different order, the pre-amp voltage lowering resistors to the pre-amp were different (different voltages, but same plate/cathode resistors as the 90's head), and two of the coupling caps are different values.  
I played the 70's head a bunch of times and decided I like the 90's head much better. I figured it was because I liked the circuit in the 90's head more, so I decided to switch the pre-amp around in the 70's head. I switched the gain stages and made it the EXACT same circuit as the 90's head. I changed the voltage divider resistors and got the pre-amp voltages about the same.  
The heads are now exactly the same, with the exception of 2 couling caps. They're .068mfd's in the 90's head, and .047's in the 70's head.  
OK...My question is...  
Should I just give up on the vintage mojo and accept the fact that the 90's head sounds better, even though the 70's head has better components and transformers? Or should I go a little deeper into it and change those last 2 caps. Would it even make a difference? Is there something going on here that i'm missing? Does it need a recap?  
The 90's head just has more clarity and more depth to it. The 70's head sounds flat and kind of muddy in comparision. It just doesn't have the same cool sonic character.  
Any suggestions are appreciated. Thanks guys.  
3/20/2004 10:09 AM
Two Tone
Interesting,could you post a schematic of the 90´s model?
Book Of The Day The Ultimate Tone, Volume III by Kevin O'Connor
Have you ever wondered if there is a better way to build a Bassman, Champ, Plexi, an 800, AC-30, Bulldog or Portaflex? Or you wanted to build an SVT with off-the-shelf parts? How about a master-volume amp that doesn’t change tone with the master setting? Everything you need to know is right here, including: proper grounding techniques, wiring methods, and mechanical considerations. Eighteen chapters cover the “iconic” amps everyone knows and loves, with schematics and layouts for each, along with the technical history of the product. Eyelet-board and chassis-mounted tube socket construction is used throughout, for easy servicing and modding. TUT3 is very accessible even if you cannot fully read a schematic and is a "must have" if you are going to build an amp for your self.

Note: The Ampage Archive is an Amazon Associate site. A small commission is paid to the site owner on any qualified purchase made after clicking an associate link such as the one above.
3/20/2004 2:30 PM

What kind of caps did you use when you switched preamp circuts?  
3/20/2004 2:44 PM

Richie, I didn't switch out any caps yet. The 70's head is loaded entirely with old WIMA's.  
I should mention that there is some motivation behind my madness. ;) My other guitar player has a 70's head that completely floors both of mine in terms of tone. My 90's head sounds fantastic, but his 70's one has something more that I cann't really put my finger on.  
His was rebuilt from the ground up by Plexi Palace, and he's got a MM OT in it. The head sounds amazing.  
He's actually got a 90's OR-120 also. We have 4 Orange heads between the 2 of us. His 70's model sounds the best, followed by my 90's, followed by his 90's, and my 70's head is noticably less exciting than the other 3.  
3/20/2004 2:38 PM
That's the 90's head. It's the same exact circuit as the late 70's models. The only difference are the transformers and the actual components used.  
The 70's one that I bought is now wired up exactly like that schematic. The only difference is that coupling caps C9 and C15 are .068's in the 90's head...and I still have 2 .047's in the 70's head.  
If anything i'd think that would add a little clarity and take some low end away. But the 90's head is more clear, and the 70's head is more muddy and actually has a bit more low end.  
Switching the pre-amp around a bit was no big deal. Then I noticed I needed to switch out the voltage dividers...ok, no problem. But i'm just wondering if i'm taking this too far because I think the 70's head should sound better by default, and it doesn't.  
Then I thought it may just need a recap.  
I guess i'm just looking for some opinions from the experts, so to speak. Am I wasting my time, or if I get things right with this 70's head, will it level the 90's unit and my work will pay off?  
Thanks for the reply...any suggestions/comments anyone?  
3/20/2004 9:26 PM
Two Tone
Those 2 caps don´t make no difference,did you compare the amps with the same tubes and plate current?I have a 70´Orange/Matamp and a 74´Matamp with ´reversed´pre-amp stages,I actually like them much better than any Orange I know,the only mod is the plate resistor of V2a ,390k is way too much,I prefer 100k and the Paul C. mod.My Orange/Matamp has only 420v on the plates,breaks up earlier,which I like
3/21/2004 4:40 PM

Both amps have SED EL-34's in them, both running at about 65% max plate dissipation. The plate voltage is a tad higher in the 70's head (by about 12V), so the specs aren't exactly the same. But they're running as proportional as I could get them.  
Yeah, the 70's head had the PI with the 390K plate resistor. Which I was surprised of because I thought that was just a post '74 thing. The schematics dated '72 that i've seen have a different PI. I guess they used that for a year or 2, and went back to the one with the 390K. I've tried both in my 90's head and I liked the 390K one a bit better. It was more fuzzy, and a bit less dymanic, but seemed to have more punch and a tighter sound.  
At any rate, do you think that head may need a recap?  
It had been sitting a while before it came to me. I wasn't really getting any hum. But for the first hour or so, if I REALLY cranked it, you could hear the voltage swing dropping. It would take a second to catch up. That went away just from rocking it at high volumes for about an hour and it's been flawless ever since. My meter isn't strong enough to measure the big electrolytics to see how far they've drifted. But the amp is either a '70 or a '71 and every component in it is original. In cluding the filter caps.  
I'd hate to track down the 100mfd 500V cans, and fork over another $50-60 and do all that work, and still have it sound not up to par.  
   Page 1 of 3 Next> Last Page>>