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VTF on Garrard Type A

gillsev

gillsev

Well-Known Member
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After adjusting the counterweight for static balance, I then set the the tracking force to 3 grams. I have verified it on the Shure SFG-2 Stylus Force Gauge and was exactly 3 grams.

However if you put it on 5 or 7 grams on the pointer, you would assume the force would be heavier, right? But the opposite happens. The higher you go, the more the spring is being stretched underneath the arm which makes the tracking force even lighter.

Was this the way they read it back in the 50's?
"3" being the heaviest, and "7" being the lightest? :scratch2:
 
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Odd question, but is your stylus force guage close to the platter when you're making your measurement?

The reason is that if the arm is below horizontal (as it will be when playing) then the spring will pull it downwards, as it should do. However, if you move it much above horizontal then it will start to pull the arm upwards and appear that it's getting lighter the higher a figure you dial in.
 
Yeah, the stylus force gauge is on the platter when I take the measurement.
I never thought that the spring would pull it downwards below the horizontal, and upwards above the horizontal. I thought it just pulled it up no matter what position it is.

I will verify your theory by putting it back on the gauge at various positions. Thanks.
 
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My Bad (I haven't given it much thought), your theory is right Beobloke! :thmbsp:

As illustrated above, the Red Dashed Line is the Horizontal at Zero degree (True Level). No force exerted by the spring at zero deg. since that is the neutral position.

Above the Horizontal is the Angle of Elevation at (+) degrees. At this position, the force exerted by the spring is to pull the arm upwards thereby resulting in a lighter VTF.

Below the Horizontal is the Angle Of Depression at (-) degrees. At this position, the force exerted by the spring is to pull the arm downwards thereby resulting in a heavier VTF. This is the ideal position for the arm to maintain the indicated VTF that corresponds to the pointer.
 
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Now that makes me curious of something. When you have the max number of records on the stack, whatever that number is, does the tonearm remain below horizontal ? I also wonder how much the VTF changes as the machine goes through a stack, highest on the first record and decreasing as the stack grows.
 
Well, yeah but...

The horizontal center line of the spring is quite a bit below the center line of the arm, could it ever apply a lifting force? The pivot end of the spring would have to be above the tonearm.

Damn, now I have to dig out my Type A70 (similar setup).
 
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gadget73 said:
Now that makes me curious of something. When you have the max number of records on the stack, whatever that number is, does the tonearm remain below horizontal ? I also wonder how much the VTF changes as the machine goes through a stack, highest on the first record and decreasing as the stack grows.
Click to expand...

The Type A only allows a maximum of 6 in a stack. I am not sure whether it goes beyond the horizontal. I sure hope not. But yes, VTF changes as it goes through the stack. The most ideal and accurate VTF is the first record.
 
Does it change enough to be a problem though? Just curious as I'm sort of looking to acquire an A for something. I'd imagine this also applies to my RC88 and the RC121 that I'd like to replace with an A since they have spring VTF loading, though the spring attaches to a different point on those machines.
 
gadget73 said:
Does it change enough to be a problem though? Just curious as I'm sort of looking to acquire an A for something. I'd imagine this also applies to my RC88 and the RC121 that I'd like to replace with an A since they have spring VTF loading, though the spring attaches to a different point on those machines.
Click to expand...

As the arm moves towards the horizontal it gets heavier;
At the horizontal, only the counterweight is effecting the VTF;
Past the horizontal, it gets lighter.

To be safe, I'd set it at the minimum for 3 grams (for the first record). Then as you move up, you'll just be gaining 0.5 g.
At the horizontal, you're on static balance; and past it, you'll be going down to 2.5 g.
I think it's manageable. :thmbsp:
 
My stylus for 78 rpm finally came in today from Garage-a-records.com (they are the only ones carrying 3 mil for the Shure M7D), so I was able to test it.

At full stack on the 6th record, the arm is exactly at the horizontal!
I had to increase VTF to 4 grams on the pointer. Three grams is just too light for this arm and it keeps on skipping. At 4 grams, everything works fine. :thmbsp:

The M7D has a range of 3 to 6 grams anyway.

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gillsev said:
Three grams is just too light for this arm and it keeps on skipping. At 4 grams, everything works fine.
Click to expand...

Let me guess, it skips about an inch from the end of a side. My type AII doesn't like much less than 3.5g for the same reason. There are things you can do to the arm trip mechanism to get it to work at 3 grams but I took the lazy way out and only use cartridges that can run above 3.5g. For 78 use I generally prefer to use cartridges in the 4-6g range anyway.
 
Just for info..

The trip mechanism of the Type A can be made to function down below 2,5 grams tracking weight with the stock parts...maybe even 2 grams...but only if everything is absolutely perfect.

The best way to upgrade it USED to be by substituting parts from the Type A70 and 70 Mk II. In a hi-fi shop I frequented when I was in college, the technician used to order those A70 parts from Garrard so he could do the upgrade. Under the platter, the Type A70's trip operating lever was made of aluminum, replacing the heavier steel one in the Type A. The auto trip friction plate was made of Delrin®, which was lower in mass and more "slippery" than the steel part in the Type A. Finally, a transfer lever under the chassis in the Type A70 was made of aluminum AND had Delrin® pivot sleeves, replacing an all-steel part in the Type A. With all the Type A70/70 Mk II parts installed, the Type A trip mechanism became equivalent to those newer models. They could then operate at 1.5 grams...maybe a smidgen lighter.

Of course, since Garrard is gone, the only way to get those parts now is to strip them off a Type A70 or 70 Mk II, which would not be practical to upgrade a Type A unless the newer machine were heavily damaged beyond repair. Better to cannibalize a Type A to fix an A70 or 70 Mk II.

Many years ago, I went a step farther on my own Type A. I substituted the Type A70's trip operating lever and friction plate; and made my own transfer lever under the platter, out of plastic, with the A70's Delrin® pivot sleeves. This made the transfer lever much lighter; with it installed, my Type A could operate at one gram...but alas, there were no cartridges around in that era that could ACTUALLY track that lightly.
 
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