mayware formula 4 type

[david counter]

heres a picture of my formula4 I think it's a mkIII, but is it?, could it be a mkIV, it makes a difference because I've been faffing around trying to get it to work at 215mm and the mkIV has a different spindle to pivot distance

[Greg.]

Hi David,

Yours looks identical to my Mk3 in every respect, unless of course mine isn't a Mk3 also

Best wishes,

Greg

[Richard]

Hi David,

Yes it looks like my Mk3 also. I couldn't find the Mk4 data but the Mk5 is longer.

I put a rule across mine and it is 224mm stylus to pivot. I then checked the headshell angle with one of those plastic semicircle protractors and a small rule against it and it came out at 22 degrees as far as I could see.

Near the bottom of this page is a spreadsheet calculator you can download,

http://www.enjoythemusic.com/freestuff.htm

Forget the Baerwald input and use the three tan boxes top left. For your 215mm mounting, enter 224 for effective length and 9 for overhang and press enter. Try a few different angles for angular offset and watch the graphs. You'll see 18 degrees gives about the best result. At that the null point is 98.2mm.

So, if you want to use this arm at 215mm spindle to pivot the cart will need turning approx 4 degrees in the headshell (more towards the line of the armtube) and you need to make an alignment protractor to set the cart square at 98mm from the spindle.

This still gives a far worse result than mounting it at 209mm with 15mm overhang. Enter those figures and you'll see that at 21.7 degrees (I measured approx 22 degrees remember) the null points are 63.7mm and 101.9mm and the distortion graph pretty low. This agrees well with the provided protractor with its single point at 63.5mm.

Conclusion for me is that the 215mm mounting position is not good. It will work if you turn the cart in the headshell but not as well as the 209mm mounting so I can't see the point.

Of the 3 set-up sheets I found, the Mk3 sheet was the only one to mention this 215mm mounting and as there is nothing magic about the arm (adjustable headshell angle for instance) I really cannot see why it is mentioned. An error I think otherwise there'd be another protractor included and a note to turn the cart in the shell.

Rich

[david counter]

beats me then why they suggest 215 mm and a null point of 63.5mm, from what you've worked out it was never going to work, interestingly vinyl engine give an effective length of 229 +/-3mm,( holding a tape to my arm this is roughly what I've got)

anyway it looks like further woodwork is required to mount it at 209mm, trouble is it puts it very close to the t/t,

unfortunately I haven't got excel so I can't play with that programme,

[soulminer]

Originally Posted by david counter

unfortunately I haven't got excel so I can't play with that programme,

Hi David.

If you download Open Office, that has an Excel (.xls) compatible spreadsheet program included. I think it's only about 140MB download.

Cheers

[david counter]

ta Lee

[Richard]

Originally Posted by david counter

beats me then why they suggest 215 mm and a null point of 63.5mm, from what you've worked out it was never going to work, interestingly vinyl engine give an effective length of 229 +/-3mm,( holding a tape to my arm this is roughly what I've got)

anyway it looks like further woodwork is required to mount it at 209mm, trouble is it puts it very close to the t/t,

unfortunately I haven't got excel so I can't play with that programme,

Hi David

I still can't find a pic of the Mk4 but found a description of it having a bigger diam armtube than the 3 and the headshell has a cast-in finger lift as used in the Mk5.

Rich

[david counter]

I think I've sorted the problem, I got myself a Clearaudio alignment gauge,using that I've ended up with 215mm, overhang of 17mm and an effective length of 232mm, to make it work the cartridge is right forward in the h/shell which is hanging right at the end of the arm tube

to be fair it would have been much easier to mount the arm at 209mm which I think would have perhaps produced better results