JVC Victor UA-7045 arm on the way... Thoughts?
- Thread starter gary7
- Start date
Never actually mounted a tonearm from scratch. Since the hole for the Kenwood arm was drilled at 220mm center, instead of 222mm to spec, I need to add 10mm to meet the 230mm spec for the 7045, correct. Can I just move it lateral right by 10mm or would I need to adjust it back to front any to be in alignment?
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You can't just move it 10mm back, it'd have to be 10mm outwards along the vector through the table's axis.
If you want to keep the same fore-aft position you'll have to do some trig.
If you want to keep the same fore-aft position you'll have to do some trig.
That's what i said. VE does have a mounting template, but I don't read Japanese.You can't just move it 10mm back, it'd have to be 10mm outwards along the vector through the table's axis.
If you want to keep the same fore-aft position you'll have to do some trig.
When you said lateral right I was thinking directly to the right of the current hole as you look at it from the front. That won't be right. You'd need to go back at an angle so that the two holes are in a straight line as viewed from the line intersecting the spindle and the tonearm pivots.
That was what I was asking. That's what I figured so it would be in line looking at the VE template. But anyway, whoever made this armboard did nice work.
You can get the right distance a number of different ways, but if you want to base the measurement off of the old hole that's the easiest one and only one that doesn't require trig.
You can get the right distance a number of different ways, but if you want to base the measurement off of the old hole that's the easiest one and only one that doesn't require trig.
Works for me, never that good at high math.
I'd like to see a side by side comparison of the two. If the only difference the nice VTA on the 7045 or is the whole arm a step up?
Blue Shadow
Waiting for Vintage Gear from this century
Let me correct this mess. Previous post here deleted.
The template shows how to measure in English to locate the mounting hole. The numbers are all you need to know. There is a measurement from the spindle to the armboard, parallel to the front of the turntable and then a measurement from that line toward the rear to locate the spot for the center of the arm mounting hole. fortunately the Japanese language uses regular numbers which we can read. Since I prefer metric measurements it makes it easy for me to use that template to mount the arm.
The template shows how to measure in English to locate the mounting hole. The numbers are all you need to know. There is a measurement from the spindle to the armboard, parallel to the front of the turntable and then a measurement from that line toward the rear to locate the spot for the center of the arm mounting hole. fortunately the Japanese language uses regular numbers which we can read. Since I prefer metric measurements it makes it easy for me to use that template to mount the arm.
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You only need trig if you want to base the location of the new hole off of the old hole and not go along the vector through the spindle centreline or if you don't want to use the template. OP asked about using the old hole to measure.
Marking the arc at the right distance from the spindle is the obvious solution. You just need a protractor that can pick up the spindle or a preprinted template at the right scale.
Marking the arc at the right distance from the spindle is the obvious solution. You just need a protractor that can pick up the spindle or a preprinted template at the right scale.
Blue Shadow
Waiting for Vintage Gear from this century
Magnepan did it differently because the arm mounting post is NOT the location of the pivot. They provided a two piece mounting template, one to hang on the spindle and the other that has the pivot point located with a pin that goes into the first template. This allowed one to rotate the contraption to find where it would look best on the table. Then a hole center location was marked through that second template. Magnepan specified a correct angle to have between the two templates but also said that those that know tonearm set up can use a slightly different angle.Marking the arc at the right distance from the spindle is the obvious solution. You just need a protractor that can pick up the spindle or a preprinted template at the right scale.
I think he just need a chunk of cardboard with a spindle hole and a small hole 212.5mm away that he can use a marking device through it to mark the position of the line to measure back to the hole center. Be aware that the cardboard will probably be well above the armboard so that marking device needs to be perpendicular to the armboard and cardboard. Removing the platter to get the cardboard closer to the armboard can help make this marking more accurate.
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I don't think 212.5mm is the correct measurement for his arm. His arm effective length is 245mm so minus the overhang of 15mm that should be a mounting distance of 230mm.
Why are we talking about magnepans all of a sudden?
Why are we talking about magnepans all of a sudden?
Blue Shadow
Waiting for Vintage Gear from this century
I was just using the info in the mounting template on VE. and I screwed that up so I edited my post on how to do the measuring.
Magnepan mentioned to show how to handle the step from the platter to the arm board and that there are more complicated ways used to set up an arm, that this one isn't so bad.
Magnepan mentioned to show how to handle the step from the platter to the arm board and that there are more complicated ways used to set up an arm, that this one isn't so bad.
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OK. Tried that. The Arc is right at the inner edge (By the platter) of the current hole. If I drilled a hole there, it would brake the outer edge of the board. ?
Looks like some trig did bite us. Or some geometry at least.
212.5 mm isn't the arc distance, it's the straight line distance between their recommended mounting location and the spindle. The arm is also 88 mm back from the spindle, so the arc is actually the hypotenuse of that triangle, so sqrt(212.5^2+88^2) = 230 mm.
212.5 mm isn't the arc distance, it's the straight line distance between their recommended mounting location and the spindle. The arm is also 88 mm back from the spindle, so the arc is actually the hypotenuse of that triangle, so sqrt(212.5^2+88^2) = 230 mm.
Do not drill at 212.5mm, that's not the correct measurement! See my previous post.
