A cheap and accurate way to adjust VTA of JMW arm
We all know that accurate tone arm VTA adjustment is very important. But I found that the usual eyeballing method is very difficult to be accurate and it requires both a 20/20 eyesight and a arm tube that is straight from the head shell to the arm base. Of course I can invest 100 for a Wally tool but there is a very cheap and accurate alternative.
I learnt about this method two decades ago but I may not be the first to think of it. It worked well 20 years ago with my MA505s and it works very well with my new JMW 10.5.
What you need is a small tube level. Mine was given to me by a picture-framing store. It is about 1 ½ inch long, made of plastic, very light – lighter than my Helikon. It is used to level hanging pictures.
If you cannot find it in store, you can buy a small carpenter level, take it apart, and use only the glass tube. Make sure the carpenter level you buy can be easily taken apart. Don’t buy the expensive all metal ones. They are very well built and virtually unbreakable. Also try to find the one with a smaller tube, which is lighter. You want it as light as possible.
Now you got the tool here are the steps to make VTA adjustment:
1. Make sure your turntable is absolutely leveled. We should all do this anyway. But in case yours is out of alignment for some reasons, now is a good time to make the adjustment. This is the most important step. If your turntable is not perfectly leveled, my method will not work.
2. Place the tube level on the head shell along the direction of (not across) the arm tube. If you mount cartridge with washers, make sure the tube level is clear of them. Otherwise you won’t be able to get the right reading. The tube level may roll around and does not stay put, you can fix it with a small piece of scotch tape.
3. With the level on the shell, adjust the counter weight such that the tracking force is the same as it was before. If you have a heavy tube level and the counter weight is not heavy enough, tape some coins at the end of the counter weight. Don’t worry about the ugliness. You are not going to play record with that. You just need to add enough weights to balance out the added weight of the tube level.
4. Place a 120g record on the turntable and lower the cartridge on to the middle of the record.
5. Turn the VTA tower until the tube level is leveled. The tube level is quite sensitive; you can see the bubble moves when you make a 1/4th of a turn. Write down the VTA reading and this is your low water mark.
6. Repeat the last two steps with an 180g and a 200g record. Write down the VTA readings and these are your high water marks.
7. Remove the tube level, any extra coins you taped, and readjust the tracking force to the original value.
Now you have it, three technically correct VTA values for different weight records. They may not be the perfect settings but these are the base lines. From here on you can fine turn them by ear. If you are willing to take the trouble, you can change the VTA to best match the thickness of the record you play. I am too lazy to do that. I just set it in the middle between the 120g and 180g marks.
Comments and suggestions are welcome