Stylus Rake Angle

Csontas: If we must continue:

John, have you read this article in it's entirety yourself? It corroborates every single point I've made without fail! I'm now wondering what your motive is in participating in this discussion.

Yes I have. I read it when it was published. I understand the difference between SRA and VTA. My motive in contributing to this thread was to try and help those who obviously thought SRA and VTA were the same thing, see that they were different and had different effects. I have provided links which is more than you have. Make of them what you will.

John goron. I don't see why you should feel insulted. But I certainly have been. To suggest that those participating in this thread don't understand the terms borders on an insult to them as well. We all understand the terminology and what's clear is that you've been just playing semantics.

If everyone understood the terminology there would be no thread.

You reckon the difference between VTA and SRA is a semantic one and so adjust the height of your arm on the fly and find it sounds better. Good for you. However, some might wish to know why it is the case in order to improve their understanding.

From what you have posted anyone who knows the subject (some of the previous posters) will see that you are confused about why that is so. You are not alone Don't feel insulted.

I don't know why you are so concerned with what I have posted and why. I simply post when I feel I can contribute to what appears to be a misunderstanding or a confusion regarding vinyl replay.

I don't care what your motives are, and I will leave it there.

But when the cutting stylus records any signal other than a pure mono one it must move more and less deep into the lacquer, otherwise how can the signal be cut? That was what I was getting at and confused by your answer. I didn't mean the whole mechanism moved, solely the cutter itself

John, you might want to re-read my prior posts as my answer here will be very similar. But to be clear, part of the groove does show variable depth with the signal.But regardless of what that signal is doing, if you look at the center of the groove it will be the depth described by the adjustments on the cutterhead, and not related to the signal, and that is what is called 'groove depth' in the parlance of the field. The only exception is if out-of-phase information is being recorded, which I covered previously- that will cause the center of the groove to seem to change in depth.

Atmasphere:
Thanks for that. I was obviously on a different track regarding the terminology of record cutting lathes- the meaning of groove depth, cutterhead, centre, etc.

It is a good example of why familiarity with specific terms in unfamiliar areas is beneficial. Which type of lathe do you have?

John

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There is some confusion here due to terminology, I believe, as well as a lack of clarity, in some cases, of what is really happening.

An attempt to clarify:

1. The cutter head height is constant across the lacquer, an therefore, the final pressed record.

2. The "no signal" actual groove depth is a constant due to #1, if we ignore slight differences in thickness of the lacquer, slight vertical error of the lathe platter, and other such imperfections.

3. Groove depth at any point, when stereo signal is present, will vary if there is any difference between the left and right channel recorded information. This MUST be the case, as this is how stereo records work: the vertical modulation of the groove (which indeed represents changing depth) represents left minus right channel information.

4. If we define "groove depth" as the actual measurement of the the distance from the bottom of the groove to the top of the record at any point on the record, #3 above is true. IT DOES CHANGE.

Now, if we define "groove depth" as a no-signal SETTING based on the height of the cutter head when cutting a particular record, that does not change during the cutting of any one particular lacquer after the cutting process begins.

To sum up: as I read this thread I perceive that some are talking about a SETTING with no signal going to the had when referring to groove depth, while others are talking about the ACTUAL measured groove depth at a given point on the record. They are two difference concepts.

The actual measured depth, if one physically cut a record and looked at the grooves on end with a powerful microscope, would indeed be a changing measurement on a given stereo record when there is indeed a difference in left and right channel information. This change will be small, as bass information is not recorded in stereo, but vertical modulation (and modulation means a changing parameter!) is indeed there.

Confusion like this often exists when one party with experience in a given field sticks to the terminology used in that field, instead of trying to put himself in the place of someone who is not in that field and not experienced wiht the typical jargon of the field. In technical teaching situations I have always found that it is best for the experience person to not get hung up on the "insider terminology", but rather to put himself in the position of the inexperienced person to try to understand exactly what that person is trying to ask.

Trying to help clarify, not criticize.

Although my own experiments and experiences cause me to doubt some of the charts and statements on Yosh's webpage about VTA, overall it remains worth reading.

http://www7a.biglobe.ne.jp/~yosh/vta.htm

I will add that speaking as a cartridge designer, I find SRA and VTA to be different. For example, designing a cartridge with increased VTA will allow a shorter cantilever to be used, but doing so has the side-effect of stiffening the suspension vertically while leaving the horizontal compliance more or less unaffected.

As a rough guide, at 0 degrees VTA, horizontal compliance and vertical compliance of the suspension wire will be the same. At 90 degrees VTA (which no cartridge does), the vertical compliance will be 0, while the horizontal compliance will remain the same as it was at 0 degrees. For all angles in between, you can figure out how the ratio of horizontal to vertical compliance changes in the suspension wire by calculating the cosine of the VTA angle.

Note that I have deliberately not included compliance of the suspension dampers, therefore you should not jump to conclusions from the above. Some suspensions have linear characteristics, while other types have progressive characteristics, making it impossible to generalize.

kind regards, jonathan