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Oberheim OB-X full restoration with pictures
Old 4th January 2010
  #1
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Don Solaris's Avatar
 
4 Reviews written
🎧 10 years
Oberheim OB-X full restoration with pictures

Oberheim OB-X my story

Intro
It was an early March of 2008 after about a year of desperate searching, i've finally found it - an Oberheim OB-X. One of the two synths that inspired me the most as a kid (the other synth was a Pro One). The OB-X record in question was Jean Michel Jarre: Magnetic Fields which was his main synth for the whole album and which i really liked to listen. Many many years later to find out which synth was behind all those fantastic lush and fat sounding pads. If you want to know what i'm talking about, load Magnetic Fields Part 1 to your player and listen to the intro.

Although the purchase was made on ebay via Kevin Kelley, the unit itself originates from the famous Audio Playground keyboard museum on Florida. The price was all right, but the cosmetic condition was horrid. To be honest, the only thing that interested me was the fact that it was an 8 voice version and that all 8 voices have recently been checked at their service. I wasn't much worried with the rest aside the fact the unit will be shipped from Florida to Chicago and something might go wrong during transport.

Arrival and inspection
Well, as expected the unit was in terrible cosmetic condition (part of the reason why Audio Playground decided to get rid of it). Keys were in bad condition as well, dirty as hell with broken / damaged bushings that would make them wobble and give that nasty "clack" sound when pressed. I was very nervous, TBH.

Restoration
The first thing i did was replace the bushings on the keyboard. I also washed all the keys, and aligned key backs (check the photo to see what i mean by non aligned keys!). Each key is held by a screw and it takes a while to take them all down. Then to remove the holders as well, and a spring from each of them, clean everything and then approach the bushings, remove the old ones and install new ones. Cleaning of the keyboard contacts is assumed, for each key several times. Though summarized in just 4 pics, that was a lot of work actually!

Next thing was replacing old capacitors in the PSU and cleaning all the switch contacts and potentiometers. I also replaced all the electrolyte and tantalum caps while the boards were out. While open, i did small pimpn' by installing a green led for the Tape check. Some of the original red leds were dead, so replaced them as well. There was one dead CMOS chip that would regulate turning LEDs on and off, and that was the only chip i had to replace (it cost me $3 or less).

Paint work
There was no much to think. If you look at the condition of the metal surface all the scratches and marks, only one thing to do, repaint the whole thing. I secured the parts which should be protected and hit the rest with standard matte black spray. Applied total of three layers to ensure proper results.

Custom side panels
With the courtesy of Chris K. aka The Wasp, he made a pair of nice side panels for OB-X based on those of OB-8 which i gave him. Material was cherry wood but we decided to modify it to mahogany (using special transparent paint) which worked like a charm. I also restored the rusty screws, cleaned them fully and painted in black for 'some pimpin'.

Calibration and tuning
The rest of the work was to calibrate all the voltages to original factory specs and tune the machine. Tuning was pain in the a** given a lot of response changes once once you put down the upper motherboard. But in the end somehow i've managed it.

Final results and impression
In my book, Oberheim OB-X is one of the best sounding polyphonic synthesizers ever. I was lucky get one right on time before the bubble. It is hard, and perhaps unfair to compare a discrete based design to a chip based one, but there is definitely a difference in sound. For example, while OB-8 will cut through most dense mix, its oscillators do not have this softness and width of an OB-X. This is perhaps where this synth's beauty lies, in its discrete VCOs. Luckily, the design incorporates a 12dB filter slope (which is a crucial thing for polyphonic synths) and in combination with it, some magnificent and wonderful sounds can be created on this machine. Not many people know of the OB-X which is in fact a good thing. It's definitely not as famous as Jupiter 8 or CS-80 but that goes for your benefit (cheaper price!).
Old 5th January 2010
  #2
Moderator
 
Don Solaris's Avatar
 
4 Reviews written
🎧 10 years

When i removed the keyboard this is what i found. A lot of mess and a bunch of dead / broken bushings.



As noted before, the unit was pretty beaten up.



And here as well.




Pretty nasty, isn't it?




Just horrid.




Look at the dirt of the keyboard and the "alignment" of individual keys.




After removing all the keys, time to reach the bushings and also to do some aligning of those little hooks.




Dead bushings in many cases were easily removed. You can see why.



After removing the springs i prepared the bag of new bushings.




And installed them.
Old 5th January 2010 | Show parent
  #3
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Don Solaris's Avatar
 
4 Reviews written
🎧 10 years

Keys sent to where they belong to.




In the meantime i prepared for the paint job.




First layer on. Looks better.




After three layers looks much better.




Switches cleaned with contact cleaning spray.




To ensure proper voltages, the PSU has been recapped. I also removed the notorious tantalum caps.




Chris K. aka The Wasp provided me with those. I did the drilling and some finishing to the wood (spot the sandpaper).




When restoring something, don't forget the small things like screws. It does make a difference once you clean them and paint for some sexy look.
Old 5th January 2010 | Show parent
  #4
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Don Solaris's Avatar
 
4 Reviews written
🎧 10 years

So. Before...




...and after. heh (one month later)



It was worth the trouble.
Old 15th October 2012
  #5
Lives for gear
 
🎧 10 years
nice work, don. the bulging you see on the original end pieces is likely due to moisture damage. this unit might have been in a flood.
mini
Old 15th October 2012
  #6
Lives for gear
 
🎧 10 years
Hello Don, I do not mean to hi jack but I have a question regarding the re-bushing job that you did. It appears that you have a Pratt & Ried keyboard. I recently re bushed my ARP Odyssey with an Identical Keybed. However after finishing my keys have uneven spacing side to side in between keys, they even wiggle side to side, and idea what is going on here?
Old 15th October 2012
  #7
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Odey's Avatar
 
🎧 10 years
Awesome job on the keyboard Don. Looks like new!

This thread really makes me think about owning one of these.
Old 15th October 2012 | Show parent
  #8
Gear Addict
 
🎧 5 years
Great story Don! Very interesting read.

Quote:
Originally Posted by sctt_stone ➑️
Hello Don, I do not mean to hi jack but I have a question regarding the re-bushing job that you did. It appears that you have a Pratt & Ried keyboard. I recently re bushed my ARP Odyssey with an Identical Keybed. However after finishing my keys have uneven spacing side to side in between keys, they even wiggle side to side, and idea what is going on here?

I can offer some amateur advice based on my experience of restoring a few Pratt Read keybeds...

After rebushing, I firstly check there is no excess side-to-side play in the part of each key channel where the bushing sits. You can gently tighten by squeezing the two sides together with pliers or loosen with a fine screwdriver in the slot.

Next, I check the key comb is aligned to ensure equal spacing between the keys. You can do this by adjusting the little hooks as Don describes above - be very careful not to break any of the hooks! You will also want to ensure the keys are level, again by adjusting the hooks. Note that the height of the white keys needs to be correct relative to the black keys or it will feel odd to play, and if all the keys are set too high you might get key triggering issues. There are correct specifications for key height, but I'm not totally sure what they are.

If in doubt, take it to a professional, as it would be easy to make things worse or do irreparable damage if you bend things too far.
Old 15th October 2012
  #9
Lives for gear
 
🎧 10 years
My God. The work and just pure love that went into that project is making me feel guilty about not having more analog synths (even if I do only purchase them lol). I'm going to have to remedy that. Great work Don.
Old 16th October 2012 | Show parent
  #10
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Don Solaris's Avatar
 
4 Reviews written
🎧 10 years
Quote:
Originally Posted by minime123 ➑️
nice work, don. the bulging you see on the original end pieces is likely due to moisture damage. this unit might have been in a flood.
mini
I was never told the whole story though i talked with Kevin from Audio Playground (synth museum) and he just mentioned one service prior to selling it to me.

The only problem the unit had afterwards was one dead multiplexer, hence some of the front panel LEDs not indicating programs selected. This was the only fault after i bought it. Good thing is: I've inspected all the PCB contacts, no rust. At this moment voice boards are out, decided to recap them, at least the power rails, i won't touch the audio path. So it's near 90% completed.
Old 16th October 2012
  #11
Lives for gear
 
🎧 5 years
Awww, that almost made me weep, like seeing some kitty recused from the dump....

Good work.
Old 16th October 2012
  #12
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TheBrightSide's Avatar
 
🎧 5 years
Those finished photo's look stunning.
Though I get pretty embarressed when I see people here doing work like that. I'm not competant enough to change a fuse.
Old 16th October 2012
  #13
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tyler477's Avatar
 
1 Review written
🎧 10 years
Amazing job Don, *clap clap clap* you always are so meticulous with your work!
Old 16th October 2012
  #14
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teamsterjim's Avatar
 
1 Review written
🎧 10 years
I had mine all the up until '85 when the Matrix/XPanders starting coming.
I actually regret not keepin it.
Looks beautiful.

It's been so long since I have seen the innards but I thought I remembered 8 voice cards, yours looks like 4 or is my memoty shot...?
I use to tune them all of the time so I had the screws off, and also great place to hide my stash from the old lady....
Old 16th October 2012
  #15
Gear Maniac
 
🎧 10 years
EXCELLENT JOB!

Good for you.
Old 16th October 2012 | Show parent
  #16
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by Don Solaris ➑️
So it's near 90% completed.
I cant wait to hear some samples when its done Don.
Old 16th October 2012
  #17
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gruvsyco's Avatar
 
🎧 5 years
Very nice. I had an OB8 back in the day, I always thought Oberheim really got the Pitch/Mod "wheels" right.
Old 16th October 2012
  #18
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Teknobeam's Avatar
 
🎧 10 years
WOW.. Awesome work !
Old 16th October 2012 | Show parent
  #19
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Don Solaris's Avatar
 
4 Reviews written
🎧 10 years
Quote:
Originally Posted by gruvsyco ➑️
Very nice. I had an OB8 back in the day, I always thought Oberheim really got the Pitch/Mod "wheels" right.
Someone's probably going to punch me in the face for this, but i actually "corrected" the layout. Those who played OB-X will probably understand what i did, those who didn't, let's say that as of now on, bender and mod wheel are finally like on the other synths.




Quote:
Originally Posted by teamsterjim ➑️
It's been so long since I have seen the innards but I thought I remembered 8 voice cards, yours looks like 4 or is my memoty shot...?
It's and 8 voice. Other 4 cards are below the lid. Cool patent from Oberheim.
Old 16th October 2012
  #20
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alexp's Avatar
 
🎧 10 years
Don well done! Thats one happy synth! :D


alexP
Old 16th October 2012
  #21
Deleted cda76ca
Guest
Nice work don, I think I understand what you mean about the layout, as my matrix 6 has identical levers, is the mod wheel is on the left, and the pitch wheel is on the right, AND the pitch wheel responds in the opposite direction you'd expect, is, you pull it down and the pitch goes up!

Did you just turn the whole lever box upside down? There's a menu option to invert the levers on the matrix, but I am tempted to just open her up and rotate them wheels 180 degrees
Old 16th October 2012
  #22
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flat's Avatar
 
🎧 10 years
Fantastic work Don.

I'm surprised this thread didn't get more attention when you originally posted it.
Old 16th October 2012 | Show parent
  #23
Deleted 8456dd3
Guest
I always thought the levers were great, pulling the lever towards you for modulation seemed a lot more natural and easy. Same on the Chroma iirc, its been a few years since i had a Chroma keyboard.

Quote:
Originally Posted by Don Solaris ➑️
Someone's probably going to punch me in the face for this, but i actually "corrected" the layout. Those who played OB-X will probably understand what i did, those who didn't, let's say that as of now on, bender and mod wheel are finally like on the other synths.




It's and 8 voice. Other 4 cards are below the lid. Cool patent from Oberheim.
Old 16th October 2012 | Show parent
  #24
Moderator
 
Don Solaris's Avatar
 
4 Reviews written
🎧 10 years
Quote:
Originally Posted by flat earth ➑️
I'm surprised this thread didn't get more attention when you originally posted it.
The thread was locked as a part of Gear service help and modifications thread. But the things started to clutter up in that thread, so i've separated each article to its own thread now. I also realized it is more useful to have those threads open for public discussion, tips and tricks sharing. This is now the parent:

https://gearspace.com/board/electron...ns-thread.html
Old 16th October 2012
  #25
KT1
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KT1's Avatar
 
🎧 10 years
Congratulations and thank you for a great thread!

The OB is also one of my fav synths of all time! I have serious lust right now .

I have to say I wouldn't be as brave as you in this respect. Clearly the risk paid off..BIG TIME!

Enjoy - now let's hear her!
πŸ“ Reply

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