Pickup SRA - starting from a 500x microscope

Hi Ralph: No, I missed that post of yours, but it is a good one. Much of my knowledge of the LP cutting process comes from Takawa-san and his boys who were responsible for all of the King Super Analog series, and also Joe Harley, who has produced many a LP, but it is nice to be able to check my information against yours.

Guys, Ralph owns and operates an LP cutting lathe, and when he writes something about LPs and the LP mastering and cutting process, his words are based on first-hand experience!

BTW, I have absolutely no desire to dissuade anyone from using a USB microscope. As a firm believer in the importance of correlating objective measurements with subjective listening impressions (or at least seriously trying), I strongly encourage the use of azimuth checkers, digital scales, USB microscopes and anything else which can attach numbers to what we hear.

My prime suggestion in this case is that the ear be used as the principle guide, and the microscope used to translate the optimal setting into numbers that can be replicated or independently confirmed.

I'd love to see a database containing the SRA findings of hundreds of audiophiles. The greater the number of SRA reports, the more the outlier cases will be down-prioritized, leading to more meaningful results for us cartridge manufacturers. It would also be nice to have cantilever rake angles (which the microscope software should be able to supply) as well as the SRA, since the cantilever rake angle must also affect how the cartridge responds to the LP groove (as I wrote in my previous post).

kind regards to all, jonathan

Some months ago an audo friend of mine, visiting and listening to my system, adjusted my SME V arm upwards - he felt that the Atlas sounded better that way. It went as far up as possible, 6-8 mm in my case (Hanss T30 player). I thought, well perhaps he is right, at least it does not sound worse. Today I tried again, adjusting the arm down to parallel, listening, a bit up, listening again, and then up to the highest postion. Well yes, vaguely (my old non-golden ears), once more I did prefer the highest position, quite a bit above parallel. Now, what I should do (before I throw away my microscope), is to take some good pictures. Since my friend borrows it, they will come, later. Perhaps a core matter here, is that the Lyra pickups are made to be fairly - dare I say it - robust regarding VTA/SRA? In a sense, their "goodness" is their own worst enemy? I mean, if any of these adjustments had sounded BAD we would all have heard it, right, including Michael Fremer, who reviewed a lot of equipment with his Lyra Titan FAR TOO LOW on his LPs. I have a Meade telescope. It "clicks into place" when the focus is right. There is no question, one thing is RIGHT, all the rest is WRONG. My impression of Lyra pickups, unless you are really out of tune, there is seldom a WRONG, there is only a QUITE GOOD. And this often sounds mighty good too. So I am not sure if the "click into place" applies. Although I do believe in getting the best possible - going most of the way.

Hi O_holter. When you raise the SME pivot by 6-8mm, you are not only changing the SRA, you are also increasing the VTF, and reducing the overhang along with the tonearm effective length.

In order to isolate your findings to SRA only, you need to compare the VTF before and after raise and add the difference in VTF to the before raise position, or subtract the difference in VTF from the after raise position.

Also, you need to quantify how much the stylus position has moved and either pull the Atlas back a skosh in the before raise position, or nudge it forward a skosh in the after raise position.

I am not poo-poohing your findings at all, but good science demands that only one variable is changed at a time - even though you will have to fight the tonearm design to accomplish this.

Once you have confirmed the above and hopefully pinned the reason for the sonic improvement down to SRA increase and nothing else, I would be very interested in knowing what SRA and CRA (cantilever rake angle) your USB microscope reveals.

kind regards, jonathan

Thank you, JCarr. I will do it when I get the microscope back (may take some time). Very grateful for this help.
Let me assure everyone reading this, that I enjoy my Atlas a lot, each day - this is why I have used Lyra cartridges for almost twenty years.

If I can add my 2 paise worth. If the broad range for acceptable SRA is 90-95 deg, it doesn't require too much geometry to figure out that the cartridge body or tone arm underside will be parallel to the record surface. That's the starting point for most non SRA aficionados to start tweaking for optimal results. IOWs junk the usb microscope and NJoy the music.
Cheers