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DIY Turntable.....is....finished?

vinyldavid

vinyldavid

Collectorius Giganticus
Subscriber
No. It will probably never be finished.

but it does most of the things that a turntable is supposed to do. :banana::banana::banana:

It will play a record, but the arm is only working in one channel-will have to address that ASAP- and the lack of a bearing makes it skip every revolution when the arm's near the outside of a record.


But the sound is good. VERY good, IMO. :music::thmbsp:


However, the speed is off. Little fast at about 4v. So I'll have to work on that being more stable. Also, the motor is just not powerful enough to drive that big platter, so the wow and flutter is insane.


All of this was achieved using found parts, and a total cost of $0.


I think that the project suceeded beyond my wildest expectations, as it actually works, and if the motor was stronger, it would actually be a fully working turntable with a low wow and flutter spec.

Next motor: Dual 1218, soon as I get a power supply worked up for it where I an change the AC freq to match the platter.

Parts used:

Motor from a Marantz TT (BPC, 1989 or so)
Shure M232 arm from a Russco CueMaster that I was given
platter/mat/bearing assmebly from a Elac XS-200 that I was given
Shure M93 with original stylus that came with the XS-200
Barrier strip that I have no idea where is came from
RadioShack semi-variable power supply, no idea where IT came from, either
Assorted wires that were laying around.

The wiring going in:
1220210971.jpg



The (semi)finished project:
1220210975.jpg



The lovely and talented dulcimerlex with the turntable:
1220210979.jpg


The first record played, Simon and Garfunkel's Concert at Central Park:
1220210982.jpg


Dulcimerlex cuing a record:
1220210988.jpg



Just because the other pic of Alexis did not come out so good:
1220215783.jpg
 
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Hey, David, that's an excellent project. It looks more turntable-like with a record on it. Let's hope you can get the bugs out.

Is that an anti-grounding device that Dulcimerex is holding as she cues up?

Rick
 
Tapehead47 said:
Hey, David, that's an excellent project. It looks more turntable-like with a record on it. Let's hope you can get the bugs out.

Is that an anti-grounding device that Dulcimerex is holding as she cues up?

Rick
Click to expand...

Nope, just the wood that we were using to support the turntable until we saw that it was uneven, then we switched to identical campbells tomato soup cans.

tensleep said:
I'll bet that is her highly technical David whacker.
Click to expand...

Were you secretly in chat last night or something????????
 
Nice going! One thing I know for sure is I learned a lot more about how stuff works and how to improvise when I didn't have much money. That's a pretty cool project! :yes::thmbsp:
 
So it works great.......... just on one channel, and skips everey revolution, and the wow and flutter is off the chart, sounds like a Craigslist ad in dollars and sense :D

Nah, just pullin yer chain, nice work
 
Here's what it needs:


New motor (should be worked with tonight)

5 new bearings to put into the bearing housing. (takes 5 bearings)

Check out the arm...it worked in both channels last time I used it, so I'll clean all of the connections and see where to go from there. That one channel sounded GREAT (barring everything else), so I'm excited to hear it when it's fully working.
 
vinyldavid said:
5 new bearings to put into the bearing housing. (takes 5 bearings)
Click to expand...

David,

Are you referring to the balls that go into the ball bearing? Post pictures of the bearing so I can see. If the balls are all that you need, you may find them at a bicycle shop.

The balls are precision, so you need to measure your old ones with a caliper. Get to know your shop teacher at school - he/she should be able to help you out with both measuring and possibly procuring what you need.

Lemme know what size they are, and I can check on sourcing them for you, too.
 
tensleep said:
David,

Are you referring to the balls that go into the ball bearing? Post pictures of the bearing so I can see. If the balls are all that you need, you may find them at a bicycle shop.

The balls are precision, so you need to measure your old ones with a caliper. Get to know your shop teacher at school - he/she should be able to help you out with both measuring and possibly procuring what you need.

Lemme know what size they are, and I can check on sourcing them for you, too.
Click to expand...

yea, just the balls.

I dunno about precision, and they might be pretty worn down since they were made in 1959. They're kinda small, I think....the platter rotates very smoothly except for that one little dip, and I would think that the Dual motor would be sufficient for driving a platter of slightly less mass than the Dual...

yes, i am friends with the shop teacher, and he should be able to help me.
 
High-precision ceramic bearing balls are now available, which rotate without so many "stiction" problems as compared to steel balls. All owners of turntables with ball-bearing platters should take note of this.
 
Splatter Pak said:
High-precision ceramic bearing balls are now available, which rotate without so many "stiction" problems as compared to steel balls. All owners of turntables with ball-bearing platters should take note of this.
Click to expand...

what's the pricing like on those?
 
Splatter Pak said:
High-precision ceramic bearing balls are now available, which rotate without so many "stiction" problems as compared to steel balls. All owners of turntables with ball-bearing platters should take note of this.
Click to expand...

David,

Ya gotta get your ball bearings from a bike shop - it goes with the theme of the whole project!

Just kidding, of course.
 
Just got the motor system out of the base of the Elac that this all started with. This time, I was smart enough to take the entire wiring set out of the turntable, and bypass the on/off switch.

I wired it up to the 70v output of my Realistic MPA-35 (or 40, I forget which), and turned up a 60hz signal fed from my iPod, and it turns with nice torque.

Just gotta get the stepped pulley (I guess that's what it's called...) off so that the motor shaft is driving the belt. I would think that doing that would give a better ratio to the platter speed.

Or do you think that the original 33RPM diameter would be better?
I'd have to make a baffle so that the belt does not come off, but I think that it would be workable. It's about the correct size, height wise for the belt.
 
That's really cool! I love the idea of driving the motor with an amplifier. The best thing about that is you can adjust the platter speed easily by slightly adjusting the frequency of the sine wave. You could do that instead of working with the pulley, although I don't know what the recommended RPMs are for that motor.

You're probably right in keeping the pulley, though. The gear ratio will provide some type of matching to keep the motor in the correct RPM range.
 
tensleep said:
That's really cool! I love the idea of driving the motor with an amplifier. The best thing about that is you can adjust the frequency easily by slightly adjusting the frequency of the sound wave. You could do that instead of working with the pulley, although I don't know what the recommended RPMs are for that motor.

You're probably right in keeping the pulley, though. The gear ratio will provide some type of matching to keep the motor in the correct RPM range.
Click to expand...

Yeah. Going from driving the inside of the rim of the platter to the outside....Hopefully getting the 33RPM pulley going at 33RPM would give me 45 and 78RPM, too.....


That would be nice.

It would be cool to have a 120V tap from that amp. THAT would be perfect.
 
My prior response was full of typos. You should be able to adjust your platter speed by changing the frequency of the sine wave. The voltage is the amplitude of the sine wave. If 70vac is enough to power the motor, all you should have to do is change the frequency up or down and the platter speed will directly follow the change.
 
tensleep said:
My prior response was full of typos. You should be able to adjust your platter speed by changing the frequency of the sine wave. The voltage is the amplitude of the sine wave. If 70vac is enough to power the motor, all you should have to do is change the frequency up or down and the platter speed will directly follow the change.
Click to expand...

Yep. Understood that completely.

And once I get a strobe that I can READ, I'll connect the amp+turntable to the computer and start from a 60hz sine wave and start adjusting it.

I also have to somehow get the arm fixed.....I might just have to glue it...:scratch2:
 
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