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Lyra Kleos: tracking force/VTA/azimuth questions

I just bought a Lyra Kleos and I'm mounting it on a VPI JMW 12.7 (HRX turntable). I've done a bit of research, including Jonathan Carr's many posts here), so I know VTF is critical. I've done a trial set up to Lyra specs, and it doesn't sound right - piano in particular is distorted as if the cartridge is approaching break-up. I suspect the way I've set VTF. VPI recommends measuring VTF at the level of the record, which is impossible with the electronic scale I currently use - I simply put it on the platter and took readings, after first calibrating the scale, of course, and left it at 1.75 g. VPI says that simply measuring tracking force that way will under-represent actual VTF at the level of the record by a substantial amount because of the height of the gauge over the platter. Could that be the source of the problem I'm hearing? With other carts, I've done a couple of tests that seem to verify VPI's advice, so I plan to carefully measure the plinth to platter-top height, remove the platter, and build a temporary platform lower by exactly the thickness of the scale's pan. I'll put the scale on that, and then set VTF to Lyra's specs. This will result in VTF at the level of the record measuring correctly, when I put the scale on the mock-up platter, but NOT when I just slap the scale on the platter - it will measure higher. So my question is: does anyone see any potential problems flowing from my use of this process? I plan first to set VTA slightly tail high to approximate the magic 92 degrees SRA that seems to be the consensus of opinion these days.

Also, I'd like a bit of advice on using a fozgometer to measure azimuth. In my trial set up, I've never been able to get exactly the same readings left vs. right channel with the Foz; the best is a two-division difference, right higher in level than the left. I also get a one division reading, rather than zero, on the channel balance test, with both channel lights very faintly lit. Could this be a function of insufficient tracking force, or is there something else at play?

Thanks to any and all who might feel the spirit to respond (hopefully including you, Mr. Carr).
zachteich

Showing 3 responses by stops

stops
56 posts
 
If you believe the 92 degree angle for VTA as pushed by the audio press. I have a very simple way to get you close to this angle.
I use a ruled 3 by 5 index card.

Set the anti skating to zero and get out an old LP.

PLace the stylus carefully on the STATIONARY record away from any raised record edge. Place the card with the lines parallel to the tone arm on the spindle side and mark the position of the tonearm so you can see the mark when you look at the card from the non spindle side'

Remove the card.
Draw a horizontal line where you marked the card (the lines on the card help). Make this line a convenient length say 4 inches. Now at the end of the line (closest to the arm pivot) draw a vertical line of 0.1397 inches (for a 4 inch line). Draw a second line from the starting point of the 4 inch line to the top of the 0.1397 inch line.( 0.1397 is 2.23/16 inches)

This new line is exactly 2 degrees to the horizontal one. Place the card back on the record and adjust the back of the arm till you can see that the arm and new line are parallel.

Hope this helps

You can do small adjustments on the arm height by ear but this will bring you very close
stops
56 posts
 

It is the angle made by the stylus axis to the record. Is that more clear?
You will get closer using my method.

I have assumed that the playing weight has already been adjusted prior to this.

Believe me it works VERY well on my Rega arm and is a lot better than setting the arm at some arbitrary height and guessing at what the "correct" sound should be
stops
56 posts
 
I noticed while doing the measurement using the analogue test record that I was picking up surface noise that threw the measurement. I estimated this by getting a reading between the test tracks. Ideally you should subtract this from your minimum reading.This will much improve the separation of course.

I did however have to shim my cartridge (Benz Glider SM) to get both readings in the un-driven channel lower and reasonably matched. My Rega arm has no azimuth adjustment but I have added a VTA adjustment to it.

The improvement I got was quite staggering. I had thought I was already there....
Hope this helps.
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