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 Post subject: Tracking Weight of acoustic gramophones.
PostPosted: Fri Apr 10, 2020 7:36 pm 
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Victor II
Joined: Wed Dec 04, 2019 9:31 pm
Posts: 259
What is a good tracking weight for an acoustic gramophone and a bamboo needle for example? Not to heavy to avoid wearing records and not to light to avoid bouncing and inaccuracy.


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 Post subject: Re: Tracking Weight of acoustic gramophones.
PostPosted: Mon Nov 30, 2020 8:16 pm 
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Victor II
Joined: Wed Dec 04, 2019 9:31 pm
Posts: 259
Grams 130 HMV#4 Brassback Mica Diaphragm no counterspring
Grams 105 HMV#4 Brassback Mica Diaphragm with Counter Spring
Grams 102 HMV#4 Alloy Back Alloy Diaphragm no counterspring
Grams 74 HMV#4 Alloy Back Alloy Diaphragm with Counter Spring
Grams 134 Palliard Steelback Alloy Diaphragm no counterspring
Grams 95 Palliard Steelback Alloy Diaphragm with counterspring


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 Post subject: Re: Tracking Weight of acoustic gramophones.
PostPosted: Tue Dec 01, 2020 6:47 am 
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Victor IV
Joined: Sun Mar 15, 2009 6:18 am
Posts: 1266
Location: Luxembourg
Hi Daithi, in my experience setting the optimum weight has been a trial-end-error process, and specific to the machine to which the soundbox is connected. With all the other factors like arm alignment, friction, planarity of the turntable etc, whenever I find the best weight for the soundbox, it does not translate to another machine.

It is interesting to see how much lighter is the pot metal soundbox compared to the brass-backed. That probably explains all the bunk about pot metal performing better (or worse) than brass-backed soundboxes, when in reality it is not the material, but the weight that makes the difference, making it sound better or worse depending on the machine you use.


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 Post subject: Re: Tracking Weight of acoustic gramophones.
PostPosted: Tue Dec 01, 2020 7:02 am 
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Victor II
Joined: Wed Dec 04, 2019 9:31 pm
Posts: 259
Hi Carlos, thanks for your reply. Not pot metal, aluminum alloy, new made from John Sleep.


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 Post subject: Re: Tracking Weight of acoustic gramophones.
PostPosted: Tue Dec 01, 2020 8:06 am 
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Victor II
Joined: Wed Dec 04, 2019 9:31 pm
Posts: 259
When you measure soundbox weight do you measure on or off the tonearm?


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 Post subject: Re: Tracking Weight of acoustic gramophones.
PostPosted: Tue Dec 01, 2020 9:02 am 
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Victor IV
Joined: Sun Mar 15, 2009 6:18 am
Posts: 1266
Location: Luxembourg
Daithi wrote:
When you measure soundbox weight do you measure on or off the tonearm?


I adjust the whole thing together, i.e. the soundbox installed on the arm, but I don't measure it directly, what I do is to add the counterweight and play a record, and adjust the counterweight force until I get a satisfactory play, without jumping or distortion. When the counterweight is a spring, I adjust the force by changing the length of the wire that ties the spring to the arm. I have other counterweights that are more sophisticated, with a weight that slides on a rod, like the old scales. See the photo below. Unfortunately this kind of counterweight only fits a small number of tone arms, in this case this is an English Expert, and are quite hard to find today, although you could make one with modern materials.


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counterweight.jpg
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 Post subject: Re: Tracking Weight of acoustic gramophones.
PostPosted: Tue Dec 01, 2020 4:09 pm 
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Victor VI
Joined: Mon Aug 24, 2009 3:08 pm
Posts: 3446
Location: Southeast MI
Daithi wrote:
When you measure soundbox weight do you measure on or off the tonearm?



If all you care about is the weight of the reproducer, then off the arm. If you really care about stylus pressure, then on the tone arm, which then also includes the weight of the tone arm, (or u-tube), as well.


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 Post subject: Re: Tracking Weight of acoustic gramophones.
PostPosted: Tue Dec 01, 2020 8:25 pm 
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Victor II
Joined: Wed Dec 04, 2019 9:31 pm
Posts: 259
JerryVan wrote:
Daithi wrote:
When you measure soundbox weight do you measure on or off the tonearm?

If you really care about stylus pressure, then on the tone arm, which then also includes the weight of the tone arm, (or u-tube), as well.


I'm interested in the combined weight so all the measurements above are with the soundbox mounted on an HMV swan neck and a 25mm thorn needle.


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 Post subject: Re: Tracking Weight of acoustic gramophones.
PostPosted: Tue Dec 01, 2020 8:30 pm 
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Victor II
Joined: Wed Dec 04, 2019 9:31 pm
Posts: 259
CarlosV wrote:
Daithi wrote:
When you measure soundbox weight do you measure on or off the tonearm?


When the counterweight is a spring, I adjust the force by changing the length of the wire that ties the spring to the arm.


Instead of a counterweight I use a spring which takes some of the weight from the soundbox. About 25 grams reduction but its not very adjustable. I have plans for a modification that would make it adjustable. Maybe someday.


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 Post subject: Re: Tracking Weight of acoustic gramophones.
PostPosted: Tue Dec 01, 2020 8:49 pm 
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Victor II
Joined: Wed Dec 04, 2019 9:31 pm
Posts: 259
CarlosV wrote:
Daithi wrote:
When you measure soundbox weight do you measure on or off the tonearm?

I don't measure it directly, what I do is to add the counterweight and play a record, and adjust the counterweight force until I get a satisfactory play, without jumping or distortion.


I'd love if you could measure the weight every time you found a satisfactory play just to see how they group and within what range they fall?
Would that be possible, am I asking too much?


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