Advance Balls

[ilovethelawrencearms]

Hey guys! This is my first post ever!

I was just curious what every ones thoughts were on Advance Balls.

Are they good to have?
Do they complicate things at all (do they make excess noise etc.)?
If you don't have an advance ball, how do you make sure you are cutting at the same depth consistently?

I'm just curious because some heads have them, and some don't. To me, it seems like a great way to control your depth, but maybe not?

Thanks in advance for your replies. This forum is the best thing in the world.

[tragwag]

Hey! I love the lawrence arms too!

I've never cut with an advance ball, I use Presto 6Ns and the Vinyl Recorder.
With depth, I've found that it's mostly based on the blank condition.
If you're cutting a quality, good condition lacquer you shouldn't have depth fluctuation.

Sometimes embossing plastic, less than perfect blanks can still be used but create variable depth if the blank is warped.
Those just require more listening after cutting to make sure they track properly, but in my experience are usually fine.
I think it's due to the extra weight applied for the embossing process, which is not used when cutting.

The VR does this with the use of an oil filled dashpot, to keep vertical fluctuation at a minimum.

[EmAtChapterV]

I've tried using an advance ball on my Presto 1D, and had nothing but problems with it - it was too far ahead of the stylus and caused an uneven cut with out-of-phase clinking and chattering especially near the edge of the lacquer. Chip pickup and keeping the heating wires away from the advance ball support became a pain too. IMHO if you're using anything smaller than a Westrex or the ginormous vertical-lateral Fairchild stereo head... let it float. As long as your turntable is smooth and runs quietly, your cut will sound better.

[Fatrecco]

How does the advance ball working ? How is the ball mounted? I got big problems with warped discs out of polycarbonat. I try to glue them on the platter, so I searching für a better solution. I think ball bearings, shouldn't work for that.

[rsimms3]

The advance ball on the Presto is a fixed location, smooth nub that rides ahead of the cutterhead stylus. The idea is that it rides on the surface of the blank and when their is a warp the head is raised during this area so that the same depth of cut is maintained through the hill instead of potentially the stylus cutting deeper on the peaks. On a Presto this is a fixed distance from the stylus, the stylus is supposed to cut in the same areas where the advance ball preceded it on the blank so that if the ball dented the blank, that area would later be cut by the stylus on later passes. On the Fairchild lathes I've seen with the carriage and Fairchild cutterhead, they use a polished stone for the advance ball that is mounted to a pivot so you can adjust the distance between the advance ball and the stylus to better compensate for how precise the advance ball rides ahead of the stylus. If the advance ball is too far ahead of the stylus it could raise the head in a section where the stylus does not need to be raised.

Presto Advance Ball (no stylus in the head)


Fairchild

[Fatrecco]

Thanks, thats very interesting. I thought that the ball rolls on the surface of the disc, but now I understand that it's fixed, or not? I try to build it.

[ilovethelawrencearms]

Thanks everyone for your replies!!! This is great!

[grooveguy]

A Presto 1D head that I got many years back came with the advance-ball cover, just like the one shown in rsimms3 picture above. I tried using it but never had good results. Best just to have a well-balanced head. Any cutterhead needs a spring with an adjustment to control depth of cut, and to be properly counterweighted as well. You can cut with either just a spring, or with just a counterweight, but the best results (meaning no vertical oscillations) always uses the right combination of the two. There's probably a quadratic equation that defines this relationship, but that's beyond me.

The Presto had a sapphire ball, just like in rsimms3 picture. By the way, note that his advance ball is screwed into the right-hand threaded hole on the adjustment yoke. That would be for inside-out cuts. For traditional outside-in recordings, the ball would be screwed into the other hole to ride on the unrecorded part of the blank... hence "advance" ball.

An alternative to the ball is a felt pad. Not only does a pad ride on a larger area of the disc, but it does not create a pattern on the disc surface as the sapphire ball does. Also, the closer you can get the ball or pad to the stylus, the better. I think the problem I had with mine was that the turntable stem was bent. It was an old RCA lathe, and you could see the turntable wobble up and down with each revolution. Unless the space between the advance ball and the stylus is zero, any unevenness like that will result in a variable depth of cut. Even with the proper balance between spring and counterweight, that turntable always made records that had shallow grooves on one side and deep ones on the other.

[Fatrecco]

My selfmade advance ball is 13mm away from the stylus and its sometimes to far away for the wobblediscs. I'm interestet in a picture of the felt pad.


Here is my low budged solution:

Photo0559.jpg

Bad picture.
I can adjust it with the wheel at the top of the head.

Photo0560.jpg

But I made only a few cuts to test materials with theese russian saphire stylus. This means, at the moment, I won't calling it a working system.

[grooveguy]

Hey, Fatrecco,

You do have the ball pretty close to the stylus, at least the photo appears that way, but is it on the right side? Does the ball run on the unrecorded part of the blank? This is important. I can't help with a photo of the felt pad, but from what I was told by the late Bob Morrison (see references to his book elsewhere here), it was about a quarter of an inch square and rode just next to the stylus, and on the spindle side, of course.

[Gridlock]

Haha I just realized i have a little advance ball on my k8. I never knew what it was before and it is always getting in the way or screwing something up and I hate it

[grooveguy]

I'd get rid of it then. On the portable recorders, like your K8, the advance ball may have been a safety precaution against cutting through the lacquer into the aluminum if the recorder were bumped in a schoolroom or similar setting. That could have ruined the stylus, not just the recording, but setting the advance ball properly would have saved the stylus tip at least, as the ball would bear-down on the lacquer. I've similarly tried using an advance ball, but never found it of any use at all. It seems more like a Band-Aid®; best to get rid of whatever shortcoming calls for its use.