Oracle AC adventures

[SCD]

Hello all:
I recently purchased a beautiful 1979 Oracle AC turntable with a mission 774 tone arm and a Mission 773lc moving coil cartridge. I am planning on checking the deck out, cleaning it, resetting the suspension, replacing the belt etc.

I plan on keeping the tone arm and using the cartridge. I listened to the set up before I purchased it and it sounded fine to me.

I will submit a few photo's once I get started.

Questions:

How do I figure out if the cartridge is worn out or not?

Are there any specific things I should know about this turntable?

Any helpful / useful comments are welcome. It sure is a beautiful piece of Canadian Engineering History.

I have also ordered up the parts and boards for RJM's Emerald Phono stage to mate with the turn table.

Thanks
I am looking forward to the input

 

[rayma]

How do I figure out if the cartridge is worn out or not?
Are there any specific things I should know about this turntable?

For sure get a spare belt or two. To check the stylus, have a dealer look at it with a microscope.
If not possible, then clean and align it, set the tracking force to the high end of the cartridge mfr
recommended range, and set the antiskating to the lower end of the range. Try it on an LP
that is loud near the end of the side, and compare the sound near the beginning of the side
with near the end. If you hear much difference in quality, the stylus may need replacement,
or else better setup.

 

[ungie]

Hello all:
I recently purchased a beautiful 1979 Oracle AC turntable with a mission 774 tone arm and a Mission 773lc moving coil cartridge. I am planning on checking the deck out, cleaning it, resetting the suspension, replacing the belt etc.

I would strongly suggest getting in touch with Oracle to purchase a maintenance kit for your table. Many of the suspension parts will benefit from being replaced after so many years and the kit also includes a new belt, bearing oil, and acrylic polish. I used the kit on my Delphi Mk.I and it made a noticeable improvement.

 

[SCD]

Hello Ray, and Mr. Ungie

Thank you for the comments. I will contact Oracle right away. Given that it is 40 years old, it needs a tune up and a good clean up and polish.

My bigger questions are about the tone arm, cartridge and cables. Any thoughts or comments on these?

 

[AVWERK]

Before you spend alot of money, You need to look at the bearing and its condition.
If you can feel anything with your fingernail, its going bad.

Slight scuffing is not an issue but check this area first.

Regards
David

 

[SCD]

Hello David:
Which bearing are you referring to, The motor bearing, the platter bearing, the tone arm bearing? Or all of them.

 

[AVWERK]

The spring kit is expensive IMO but if your going for a stock setup and your first time consider your springs dont wear out.
Unless you need a heavier spring and the other goodies with it.

What I would do is purchase the “ black “ dot springs for all 3 posts.
The Oracle has different spring rates for what ever tonearm weight you use to balance it out which can drive you to drink in getting a perfect and equal vertical bounce out of the 3 suspension posts.

Brooks Berdan used a stainless donut underneath and bolted to the underside of the moving 3 spoke chassis. Not sure of its weight, maybe 3 pounds or so, but the goal is to place it along with your chosen tonearm mass so it moves in unison vertically.

I built a complete Oracle tt of my own based on the heaviest springs they offered
but the principle is the same for a stock Oracle.

This might be a little out there for you now but if you go this route and unsure of where to place the weight, you would start by locking the platter and taking the weight and trying different spots on top of the platter until you achieve a perfect bounce and simply transferring that center spot underneath and bolting it there.

Once you get into it, you will see what I am suggesting for an optimum setup based on equal spring tension for all 3 posts and adding weight to compensate
for it.
You would want it damped also so it returns to stop within a couple of bounces

Regards
David

 

[AVWERK]

Sorry platter bearing.

 

[SCD]

Thanks David:
When I strip it down I will make sure to check the platter bearing. If the ssprings do not wear out why would I need to replace them?

Thanks for the help

 

[rayma]

My bigger questions are about the tone arm, cartridge and cables.
Any thoughts or comments on these?

Here's more info on the arm, if you haven't already found it.
Mission 774 (original) - Manual - Rigid Low-Mass Stereo Tonearm - Vinyl Engine

 

[The Peasant]

Thanks David:
When I strip it down I will make sure to check the platter bearing. If the ssprings do not wear out why would I need to replace them?

Thanks for the help

You don't have to replace anything if it is all working fine now, but Oracle improved the suspension system a number of years ago and so you may want to do any upgrades that they recommend. The do (did?) sell an upgrade kit with everything needed, including new springs.

It's unfortunate that the newer DC motor system is not available for upgrading as it is significantly better than the old AC motor and you don't have to move the belt to change speeds. Still, any model of Oracle is an excellent sounding turntable.

Take care,
Doug

 

[SCD]

Thanks for the input fellows.
I am now wondering what cartridge is compatible with mission tonearm. I do not have any idea how to figure this one out. Any help out there? I have about $1000.00 to spend if needed.

 

[vinylkid58]

I am now wondering what cartridge is compatible with mission tonearm.

The 774 is considered (and advertised) as a low mass arm, so high compliance cartridges are the best match. Are you going to stick to high output MC's or MM's? Is the Mission cartridge toast?

I have about $1000.00 to spend if needed.

That's far more than you need, unless you're going to replace the arm.

jeff

 

[SCD]

Hello Jeff:
Right now I am casting a broad net to see what options I should consider. I just ordered up the boards and parts for an RJM Emerald phono stage build. This phono stage has a great range of possibilities.

I think the original 773lc is okay but I do not know, as I have not yet set things up. But right off the top it is 40 years old. Possibly a re-tip is an option as well. but how do I tell?

THe tonearm can take a cartridge between 2 and 10gms There is a lovely Dynavector for sale on CL that got me thinking.

The thing is I am looking at a new toy and thinking about all the possible options. I am quite excited about this. It is getting me to finish a bunch of other home work projects so I can make the time to play with it.

Nuff said for now

 

[vinylkid58]

I think the original 773lc is okay but I do not know, as I have not yet set things up. But right off the top it is 40 years old. Possibly a re-tip is an option as well. but how do I tell?

You need to look at the stylus under a microscope. If the suspension is shot, it's probably not worth rebuilding.

A retip is min. US $250 for a ruby cantilever with LC stylus.

THe tonearm can take a cartridge between 2 and 10gms There is a lovely Dynavector for sale on CL that got me thinking.

Is it the DV-20x2H that's listed? If that's the one, it's not a good match for your arm, as the dynamic compliance is about half what the old Mission cartridge is.

jeff

 

[SCD]

Thanks for the help Jeff.

When I got the TT I listened to it as close as I could. It sounded really good. the price was fair. Hence I bought it.
Perhaps you better come for a visit with your microscope and stable of cartridges to help me figure out what to do?

 

[vinylkid58]

When I got the TT I listened to it as close as I could. It sounded really good. the price was fair. Hence I bought it.

Sounds like it fine.

Perhaps you better come for a visit with your microscope and stable of cartridges to help me figure out what to do?

I know I'm overdue for a visit. Had some health issues that set me back a bit, but I'm doin' ok. Unfortunately, all my cartridges are low compliance, so not much help there.

jeff