Read 200 times 
  From:   Bob S II   (tubenut@hotmail.com) 
Date:  8/12/2001 5:51 PM 
Subject: Orange Overdrive 120 Schematics? 
 

Hi,
 
Anyone have or know where I can find schematics for either the Orange Overdrive 80 or 120? I already have the non-master schems as published in the Tube Amp Book, but am having a real problem locating the OD schems. 
 
 
Thanks,
-Bob

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Read 223 times 
  From:   Bruce   (MissionAmp@aol.com) 
Date:  8/12/2001 6:05 PM 
Subject: Re: Orange Overdrive 120 Schematics? 
 


They are pretty much the same amps.
Don't see too many master volume ODs but I think the master volume circuit is just a 250K dual gang pot used as variable grid load resistors on the power tubes.
Bruce

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Read 225 times 
  From:   Geert Jacobs   (geertjacobs@yahoo.com) 
Date:  8/12/2001 8:01 PM 
Subject: comparison of 3 Orange MKII Graphics schems 
 


Hi,
 
I have been comparing three Graphic MKII schems (you can find the links at www.geocities.com/geertjacobs/orange_page.htm ) and I was wondering about a few things:
 
1. The '72 circuit doen's seem to have a reference to ground in the bias circuit?
2. The '72 circuit also has a few more resistors around the phase splitter half 12ax7. I think they are some kind of bias but they are simply left out in the '74 schematics?
 
There were also a few minor differences in component values of the tone controls.
 
Were the changes from '72 to '74 simply cost cutting or were they bug fixes?
 
Regards,
 
Geert

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Read 138 times 
  From:   Zouto   (hybridmp@aol.com) 
Date:  8/15/2001 11:31 AM 
Subject: Re: comparison of 3 Orange MKII Graphics schems 
 


Hi Geert,
unfortunately the 
amptext_bestanden\Orange_Graphic_120.jpg link
does not work.Is there any other chance to download this schem?
Thanks,
Zouto

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Read 129 times 
  From:   Rob Strand   (rstrand@ihug.com.au) 
Date:  8/15/2001 2:06 PM 
Subject: Re: comparison of 3 Orange MKII Graphics schems 
 


Here you go:
http://www.geocities.com/geertjacobs/amptext_bestanden/Orange_Graphic_120.jpg

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Read 138 times 
  From:   Steve A.   (steve_ahola@yahoo.com) 
Date:  8/15/2001 2:47 PM 
Subject: Re: comparison of 3 Orange MKII Graphics schems 
 


Rob:
 
    I don't think that you can link to GeoCities JPG's from here anymore, but the original link posted by Geert does work (gotta include the http stuff to make it a live link):
 
http://www.geocities.com/geertjacobs/amptext_bestanden/orange_page.htm
 
--Thanks!
 
Steve Ahola

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Read 128 times 
  From:   Bruce   (MissionAmp@aol.com) 
Date:  8/15/2001 7:37 PM 
Subject: Re: comparison of 3 Orange MKII Graphics schems 
 


Is it AOL or is there something wrong with that site?
I get no picture files no matter where I go there.
Bruce

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Read 117 times 
  From:   MBSetzer   (QualityAna@aol.com) 
Date:  8/15/2001 8:26 PM 
Subject: Re: comparison of 3 Orange MKII Graphics schems 
 


Hi Bruce,
 
I think it may be some settings in AOL or the version, are you using AOL 4.0? I think I remember problems with these same graphics when I use 4.0. Maybe I had to right click & Save Target As, to download direct to disk instead of trying to display in real time. Then still couldn't open the successfully downloaded files until I opened Internet Explorer by itself and that window did OK.
 
Now with AOL 5.0 they are coming through fine for me clicking on the links after getting there from Steve A's post.
 
Also installed AOL 6.0 and quickly reverted back, I don't like the *improvements*, especially the part where you can't see the speed you are connecting at when you first sign on.
 
But I did install 5.0 this time by picking the correct folder from the new 6.0 CDROM, maybe it gave me a newer version of Internet Explorer than I had before.
 
Hope this helps,
Mike

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Read 99 times 
  From:   Geert Jacobs   (geertjacobs@yahoo.com) 
Date:  8/15/2001 10:41 PM 
Subject: Re: comparison of 3 Orange MKII Graphics schems 
 


Hi guys,
 
I'm sorry the link doesn't work as it should. I'll try to find a solution for it tomorrow(it's 0.45am now...). I made the page in word(yeah I know :-) ) and my links are getting screwed up sometimes. Let me know by mail if you want the schematic and I'll mail it to you. 
 
Too bad I didn't save the original link.
 
Geert

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Read 96 times 
  From:   Steve A.   (steve_ahola@yahoo.com) 
Date:  8/16/2001 3:42 AM 
Subject: Re: comparison of 3 Orange MKII Graphics schems 
 


Bruce:
 
    Try this link:
 
http://www.geocities.com/geertjacobs/amptext_bestanden/
 
    With NS4.77 I get a "unix-style" directory listing since there is no HTML file that is recognized as a homepage (i.e., homepage.htm(l), index.htm(l), or whatever).
 
    So what do you get when you click on that link?
 
    Although they call it the "World Wide Web", it seems like our own experiences with a particular site or page are not very "universal" at all, and your mileage may vary depending on your browser, ISP, and choice of plug-ins.      Then again compared to the text-only BBS's from the 80's, it is amazing what can be done with a little HTML and Java...     
 
Steve Ahola

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Read 91 times 
  From:   Zouto  
Date:  8/16/2001 8:55 AM 
Subject: Re: comparison of 3 Orange MKII Graphics schems 
 


Thanks Steve,
your link works!!!BTW:any preamp mods for optimising the FAC switch and a bit more gain available? 
Zouto

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Read 82 times 
  From:   GFR   (gfr@cepel.br) 
Date:  8/16/2001 11:29 AM 
Subject: Re: comparison of 3 Orange MKII Graphics schems 
 


Funny , Toni Iommi says he's _always_ used Laneys or Marshalls. I've seen a few very old Black Sabbath "clips" and he (and Geezer) were using Oranges!

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Read 64 times 
  From:   Stuart  
Date:  8/16/2001 5:12 PM 
Subject: Re: comparison of 3 Orange MKII Graphics schems 
 


Those clips are probably from the German TV show "Beat Club". Every band that played on there in the early '70s used Orange amps, from Black Sabbath to Ike & Tina Turner. They must have been studio props. On the older clips (often mimed), it's usually Selmer amps.

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Read 75 times 
  From:   Rob Strand   (rstrand@ihug.com.au) 
Date:  8/16/2001 1:14 PM 
Subject: Re: comparison of 3 Orange MKII Graphics schems 
 


The link that is on the .html page that someone posted before has a typo. The one I posted is the same link with the typo removed.
 
The link worked for me, I checked it before I posted it.
 
Regards
Rob

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Read 58 times 
  From:   Rick Erickson   (ampdog@wolfenet.com) 
Date:  8/16/2001 10:25 PM 
Subject: Re: comparison of 3 Orange MKII Graphics schems 
 


Note - I tried to post this several days ago but couldn't get through. Just getting around to reposting it today. 
 


The '72 circuit doen's seem to have a reference to ground in the bias circuit?


 
Drawing error. It's grounded, trust me.  
 

Were the changes from '72 to '74 simply cost cutting or were they bug fixes?


 
They only seemed to get worse over the course of time. (See Wishbone Ash interview in June 1974 GP Mag)
The best sounding Orange amps I've heard were the Matamps. They typically used .022uF coupling caps where the later ones used .068. They also had the FAC selector switch circuit first and then the tone stack. The treble cap should be 330pf unless you like your mids real hot. The 1500pf listed on some schematics is just too much midrange for my taste. Maybe that was a bass version. The extra components in the p/i circuit are a coupling cap to block dc from the previous stage and a 1M resistor to bias/balance the p/i circuit. All the Orange amps I've seen used the direct coupled p/i circuit. It looks like this one would work well though. 
Also of interest is the coil in the Punch/Presence circuit of the '72 schematic. Can't say I've ever seen this before. I think the best sounding Matamp I've heard had the FAC circuit right after the input jacks. The first stage coupled to the Volume control through a .022uF cap and was fed to the 2nd stage which then fed the tone stack. This may have been a custom mod to this amp, but it sounded very good. I have a '70's model Graphic 80 which I added two output tube sockets to convert it to a 120. The transformers were the same in both amps, contrary to what I read as a note on one of the schematics. 
The 80W o/t was labeled 8/16/x, whereas the 120W amp used the same ot labled 4/8/16. 
 
RE
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Read 58 times 
  From:   Geert Jacobs   (geertjacobs@yahoo.com) 
Date:  8/17/2001 6:44 AM 
Subject: Orange MKII Graphic transformers 
 


Thanks for the useful info!
 
I've just ordered two transformers to make a DIY Orange Graphic 80. The PT will be a Marshall superlead-like thing(360V-100V-6.3V) and the OT will be a 50W 2*EL34 transformer with 4-8-16 Ohm taps, but it will have a 100W iron core. I asked for this on advice of Bruce from Missionamps and the guy at the transformer shop also said that the Matamp Oranges really had really big transformers.
 
So I'll have to redesign the power supply a bit (no voltage doubling needed with the new PT)but I intend to steal a bit from Bryan James :-) He is designing a 4*EL84 Orange copy.
 
My OT will probably not be suited for use with 4 x EL34's, but that's a bit to loud anyway. 
The shop guy also told me he often uses Marshall 4*EL34 OT's(again super lead I think) to replace broken down Orange OT's and he claimed that his customers were very satisfied!
 
Geert




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