End Float
I like that thought.
The inside diameter of the platter is machined in a lathe, using a fine longitudinal feed, amounting to what is essentially a very fine pitch thread. This "thread" could lift the pulley until its end-play is taken up, resulting in a thump. However, I have no idea how the pulley would move down again to repeat the cycle. If the pulley indeed has end-play, try putting a shim washer onto the pulley shaft.
Sincerely,
Ralf
I like that thought.
The inside diameter of the platter is machined in a lathe, using a fine longitudinal feed, amounting to what is essentially a very fine pitch thread. This "thread" could lift the pulley until its end-play is taken up, resulting in a thump. However, I have no idea how the pulley would move down again to repeat the cycle. If the pulley indeed has end-play, try putting a shim washer onto the pulley shaft.
Sincerely,
Ralf
I assumed I was hearing a flat spot or hard spot on the idler, which is why I ordered one from Simone. Unfortunately there was more to it than that. I'm hoping my washers show up tomorrow so I can continue working toward solving this issue.
Have you auditioned both the black o-ring and the red with Simone's idler?
If there is undamped end float in a rotating mechanism, then slight disturbances can initiate a "rattling" of the rotating device.
reducing the end float might control the rattling.
Damping the resonance will reduce the rattling.
Oil in the rotational axis will help.
Oil in the end float clearance will help.
very small gaps in both will help to hold the oil in the gaps by capillary action.
Try shimming out the end float, but without making it tight.
reducing the end float might control the rattling.
Damping the resonance will reduce the rattling.
Oil in the rotational axis will help.
Oil in the end float clearance will help.
very small gaps in both will help to hold the oil in the gaps by capillary action.
Try shimming out the end float, but without making it tight.
I cannot see that happening at all, the decks were not handmade so should all be the same.
Perhaps the idler shaft and the stepped pulley shaft are not parallel to each other causing a toe in effect thus distorting the idler wheel?
That's interesting. I'd expect the rhythmic noise to be synchronous to the rotation of the step pulley, which is virtually unchanged regardless of what speed is selected, if the step pulley is the culprit, rather than being synchronous to the rotation of the idler, which changes in frequency depending upon which speed is selected.
I suppose a bad bushing in the step pulley could make a noise sympathetic to a problem with the idler, in which case I'd want to address both the idler and the step pulley.
Simone's idler wheel
http://www.theanalogdept.com/images/spp6_pics/wheel_audiosilente/DSC_3407.MOV
Above link to a .mov video clip file I have up on my site showing Simone's idler wheel shifting through the speeds on the stepped pulley. The video is in 1080p and does take a bit of bandwidth. however my site should be able to cope with some demand....I think. It is a Quicktime movie. Windows Media Player does play it.
Above is one of many images I put up today on a page that will become a review of this O-ring idler wheel.
LINK to Page: O-ring wheel
At present I can't think of a solution to Terrya's snag I figure it would be apparent if we saw all of the associated parts in close-up detail.
-Steve
http://www.theanalogdept.com/images/spp6_pics/wheel_audiosilente/DSC_3407.MOV
Above link to a .mov video clip file I have up on my site showing Simone's idler wheel shifting through the speeds on the stepped pulley. The video is in 1080p and does take a bit of bandwidth. however my site should be able to cope with some demand....I think. It is a Quicktime movie. Windows Media Player does play it.
Above is one of many images I put up today on a page that will become a review of this O-ring idler wheel.
LINK to Page: O-ring wheel
At present I can't think of a solution to Terrya's snag I figure it would be apparent if we saw all of the associated parts in close-up detail.
-Steve
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I'm hoping a new idler and washer and fresh spindle will be the solution.
I'll be interested to hear what you think of the Audio Silente idler. I'm trying to decided whether to start with the red or black o-ring.
It is almost always something simple that was overlooked that will snag ya on these little beasts. Something you've already seen and disregarded.
I can say that Simone's wheel is working very well for me. I'm getting an improvement in sq over my old original wheel. Spins true. Runs quiet. Sound is quite good. I hear the improvement, so far in the bass.
I'm still using the black rubber o-ring that came installed to it. I'll try the silicone o-ring next in a couple of days. Right now, I'm liking what I hear.
-Steve
If there were some change in the compliance in the idler pulley around it's circumference, then when that change passes the step pulley it gives the necessary impulse to trigger the step pulley into rattling. That repeats at the idler rotation.
I may reassemble with the black o-ring as well.
I hope to have a chance to work on the table this afternoon.
I was thinking that this was a possibility, and I will look at the step pulley if a noise still exists after addressing the idler, but I was compelled to address the idler first.
That's very reasonable. One change at a time.
But it was the assertion that is could not be the step pulley because it was in sync with the idler that I felt it necessary to post.
Take the analogy (not a good one) of the pistons going up and down and rotating the crankshaft. The end float on the crankshaft should never be affected by the piston movement.
But guess what: The end float shims are set up with a clearance and are available in alternative thicknesses.
They are faced on one side only.
Put them in back to front and the steel galls against the crank face. Brought about by the pistons going a quite different direction.
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I'm not sure I get the analogy but it's clear to me that I have to start at the idler, then move to the step pulley if the problem, or a similar problem still exists.
How about this for an analogy. The tire is low. I add air. The tire is low again. Why? I addressed a symptom, not the source of the problem, which is a nail in the tire. Fix the hole first, then add air.
The lack of concentricity in the movement of the idler may be causing a rattle in a worn step pulley bushing, but replacing the step pulley bushing first isn't what I would instinctively do. I know there's a problem with the idler, I don't yet know there's a problem with the step pulley. If there is I'll know once I address the idler and take care of it.
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To be clear, I appreciate the suggestion that there may also be a problem with the step pulley. I hope it's only an issue with the idler, but if I still have the same or a similar noise, it won't take me totally by surprise, and I'll move to the step pulley.
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Andrew, all you say makes sense and I have noticed the same in other idler designs. The Sony SQP20 music centre ( Father Ted song for Europe ) had an idler with from memory 3 plastic/fibre washers. My boss of the time was an engineer at Smiths ( Hypertac, he brought it to production and cured production problems ) before buying Wstwoods of Oxford. He worked out that the washers were not correctly fitted at the factory and should be 2 bottom and 1 on top. At the time I laughed as he was very serrious about the smallest detail, it was only a music centre. I have to say it transformed it from dreadful to very OK. If I remember Japan had fitted them 3 to the bottom and none on top. I now realise those washers work very well when correct. It's too easy to see simple engineering as bad engineering. Often the simple part is still to a tight spec.
That much said, you've replaced the idler wheel with another and the noise continues. You've replaced the thrust washer and the noise continues.
With the platter off and the TT drive train running with idler wheel engaged, see if there is any lateral runout whether it be the wheel or the stepped pulley in a way that might cause a slight rub. Just a reach.
Other thoughts. Belt noise. The Td124 belts, particularly the factory approved ones, tend to shed and leave parts of themselves on pulley surfaces. Solution: remove belt, clean all surfaces with alcohol/Q-tip. A visual examination of the pulley surfaces should suffice to determine clean versus gummed-up with rubber deposits..
Noises can migrate from one part of the player to another and in that way be hard to trace.
-Steve
Steve,
I'll clean the belt and surfaces since I'm under the hood, but I'm still convinced it's something with the idler. The stethoscope screams "Here I am!" when I touch the spindle. No other area of the table comes close.
I've watched the movement at the step pulley and see nothing that would indicate the source of the noise.
I have a few ideas I'm going to look into in the next few minutes.
I'll report back if I find success.
Here's a short video of my new idler not moving in a concentric fashion.
I'm stumped.
https://youtu.be/9IsFiZW2c5Q
I'm stumped.
https://youtu.be/9IsFiZW2c5Q
that's wrong
ok we've isolated the problem to the idler wheel.
Since both of your wheels exhibit this behavior (I presume) what's left is that pin (bearing axle) that the idler bushing fits over and/or the carrier bracket that holds the wheel into position.
First thing:
axle pin diameter: should be .1965 inches
The bushing ID will offer some clearance in size over the pin size. You said earlier that you had a set of calipers. digital calipers should be close enough to identify if you have the right pin installed. does it measure anywhere close to .1965 inches?
-Steve
ok we've isolated the problem to the idler wheel.
Since both of your wheels exhibit this behavior (I presume) what's left is that pin (bearing axle) that the idler bushing fits over and/or the carrier bracket that holds the wheel into position.
First thing:
axle pin diameter: should be .1965 inches
The bushing ID will offer some clearance in size over the pin size. You said earlier that you had a set of calipers. digital calipers should be close enough to identify if you have the right pin installed. does it measure anywhere close to .1965 inches?
-Steve