Noise question

[carter]

Can anyone offer insights into noise variations on a cut disc being stronger/louder in one part of the disc, associated with the rotation? I've had this problem lately and I just can't figure out what's wrong.

I don't think it's caused by a damaged stylus. Wouldn't a damaged stylus produce a cut that is consistently noisy throughout the cut?

What other factors can contribute to noise or periodic noise?

If the disc plane is not perfect, i.e. the cutting head has to track through some slight vertical variations, is this is a possible problem during the points where the cut gets deeper?

Anyone ever notice more noise during deeper cuts?

[Angus McCarthy]

It depends on what you're cutting. I can tell you the nature of the plates I've cut on changes greatly depending on evenness of heating across the entire band. Basic velocity differences as well can have a great bearing on noise level from the outside to the inside of a cut.

[carter]

Thanks - I'm just seeing your answer... still frustrated with noise lately.

[piaptk]

AlSo depends on the type of lathe you are using. If a presto 6n isnt set up correctly on the collar to the right, it can cause the cut to get deeper or shallower as it goes across the plate.

What type of lathe?
What type of blank?
What type of stylus?

[Serif]

Is the noise in a once-around sort of pattern, happening always during lateral crossings of the same pizza slice of the disc (as it were)? Or is it that between, say, effective radius of 3 and 4.5", all the way around the revolution, through all the pizza slices of the disc (pie), that the noise is louder?

The former would tend to implicate the run-out of the turntable - as in, the vertical up and/or down from true flat (horizontal) spin.

The latter would tend to implicate the feedscrew in some way.

Another source of noise could be coming from a loose connection or otherwise intermittent current in the stylus heat circuit.

Please give more details. What type of head - floating? Advance ball?
What type of noise? Shwoosh? hum? buzz? pfffffffftttttssssss? etc...


I have just heard from our comrade in Scandinavia that Apollo are going to discontinue supplying advance balls (in the near future).


Good luck, and keep on shootin at trouble - you'll hit it eventually - even if it seems that one has been in the Minotaur's labyrinth for a Season....


- Andrew

[petermontg]

I have just heard from our comrade in Scandinavia that Apollo are going to discontinue supplying advance balls (in the near future).

Let the panic buying commence

[piaptk]

I didn't even know they sold advance balls!

[flozki]

well. i see no reason why i could not find a 2nd source for advanced balls if apollo stops.
shouldnt be that much of a problem. so no panic....

its just a ball. not a stylus....and not even laquers... then we have a problem..

[audadvnc]

I bought an advance ball from Apollo recently; its construction is not trivial. It's a precision machined jewel. I think we'll put in an order for a couple spares, just in case.

[carter]

Serif,

Sorry I didn't see your reply until now. It's across the same 'pizza slice' as you say, once per revolution. when it's cutting, i can see the head floating up and down during each rotation.

This is a vinylium on a technics 1200. i've had instances where the noise is barely audible, and instances where it's unbearable.

I'd describe the noise as the same as cause by a damaged stylus, but not continuous around the whole circumference of the cut, just once per revolution.


--Carter

[studiorp]

Is my the same problem in this period.
The cause is the platter of dd turntable, that is not precise as a platter of a true lathe ( Neumann, or other ).
I am thinking many solutions, in these days, but at this moment nothing...

[tragwag]

i've run into a similar problem, that has gone away slightly due to different blanks.
what are you all cutting on?
also I've found that the neumann stylus perpetuate this noise, while the capps stylus are more even throughout. (though are still noisy sometimes)

[Serif]

Might be, as studiorp suggests.... Check the platter runout. First use a spirit level, for coarse confirmation that the table is level... Then, use a depth feeler, for fine measurement of runout while slowly moving the platter through an entire revolution by hand... (and, if possible, adjustment thereof)... For what's worth, with advance ball support, there is more tolerance for plaTTer runout, but for floating head, even with a good spring for support and silicon(e) fluid for dampening, there should be ideally no more than 2 mil p-p runout...


- Andrew

[mossboss]

Hi All
A good way to find out run out or the cutting head not in the right spot is as follows
If you where first to place a lacquer on the TT, while it is stationary, with vacuum on, if you have it, or screwed down, if that is your system
you can easily check it out as follows
Lower the head down so as to just touch the lacquer at its outer edge but on the flat face
Adjust the height so as to leave just a very faint cut on the face of the lacquer plastic whatever you are cutting on
Move the cutting head across the lacquer by hand or by using the lead screw handle
The stylus should leave a faint line which At the end of it's travel should be in the very center of the TT spindle
Lift the head, spin the TT 180 Degrees, Repeat the above step
The lines either side of the spindle should match/meet, dead center
If not the head has to be aligned so as to do so
Adjust it accordingly than the next step is this
Repeat so as to make sure you got it right than do the same at quadrants of say 90 or 45 degrees
This will indicate very quickly where you have unevenness run out or any other issues
What steps would be required so as to resolve the issue are of course quite different for each system so we are not going there
But the above works well for all types of cutting lathes
It will be very clear if there is any run out as the cut will be uneven
It will also indicate if the head is not in the right position in its mount
Mark the lacquer to the TT to have a reference so you know what spots have run out
Easy with some TT that have a second hole
With a vacuum type of hold down or a screwed down style TT a couple of marks on the lacquer and the TT will do it
Cheers

[carter]

While I think the issue discussed here (lack of a totally flat lathe/cutting surface) was a contributor to my noise problem, it was secondary to a misadjustment I had made when I changed out the piece where the head mounts. (I had a custom piece made to try to get my cutting angle close to perpendicular so I could cut with a diamond and had to change it out with the factory piece).

When I reinstalled the factory piece, I think I had the pivot pins too tight, ever so slightly. When I loosened them and retested earlier today, the noise decreased drastically, essentially disappearing. I can still hear a background swoosh in every revolution but it's really feint and would be totally masked by music. I've been testing with silent cuts or I might not have even noticed this 'swoosh.' I think the swoosh is most likely related to the slight change in the vertical position of the head each revolution.

I'm also now wondering how the spring tension on the SC-99 with the Kingston overhead can contribute to noise in a cut. Thoughts, Flo? it seems like the cut takes on every possible vibration in the environment and in the various mechanics.

I would love Flo's thoughts on any of this, esp. how the pin (mis)adjustment could create noise.

Finally, I wanted to test the integrity of the diamond I have by cutting silence on a lacquer. I did it next to a cut I had done with a sapphire. The noise characteristics of each is noticeably different. It made me wonder if some of the noise qualities people describe when cutting PVC with diamond is partially about the diamond itself. The diamond cut I made in lacquer was a little noisier than the sapphire (not to the point that I feel the diamond is bad, it's just different.) Is this because the diamond doesn't have burnishing facets? I don't even know what burnishing facets are supposed to do, but if they produce a smoother quieter cut, then it makes sense that a diamond produces a little noisier cut.

[piaptk]

I definitely have this problem when my stylus is leaning either right or left, due to the head being slightly askew.

[carter]

On the topic of noise, I feel like I'm also getting noise due to material buildup on my styluses. How much of a factor can this be in signal clarity?

I'm sure this is discussed elsewhere but I can never find topics quickly enough. There has to be a thread on cleaning diamonds and sapphires - where is it? I need some recommendations.

I read somewhere that ammonia solutions are good for cleaning diamonds. How does this affect the heating wire cement?

Thanks

[opcode66]

I use acetone to clean my stylus. Doesn't affect the cement for the heating wire.

[carter]

thanks opcode, and i'll assume it works equally well for both gem types.

[carter]

in reference to my post from Sept. 18, I'd really appreciate thoughts and comments from anyone here who owns a vinylium dubcutter and has messed with the pivot pins where the head rotates. (the cutting head mounts onto a metal block that rotates on two pins, adjustable on each side, then on the top/back of the block, the tension spring attaches and allows the cutting depth to be adjusted.

Since the post above, I switched out the factory mounting piece to the custom piece and then back to the factory piece, and I can't get it readjusted the way I did the other day that eliminated the noise - it must have been dumb luck that time, even though I thought it was a methodical adjustment.

For what it's worth, I've noticed that the point of the pins are not the point of contact/friction, i.e. the point of the pins don't actually touch anything. the rotational contact happens along the circumference where the edge of the hole touches the cone of the pins. that's a fair amount of metal on metal action, so it seems intuitive that friction there could easily translate into noise in the cut. that's what i've been led to believe.

i can't figure out if there's any margin for error on this adjustment. i would love love love to know how this is set in the factory... Flo?

i have not tried any lubrication on the pins.