Vintagear: Man o man would that be helpful! I really appreciate it. Another fellow on here is looking for the same piece. I, and I am sure others, will appreciate your help!!!!!
Vintagear: Man o man would that be helpful! I really appreciate it. Another fellow on here is looking for the same piece. I, and I am sure others, will appreciate your help!!!!!
Brilliant help Vinta! Are you an engineer? Your photos and descriptions are amazingly good!The width of the channel that the o-ring rests in is ~2mm wide and ~1.5mm deep. I did not want to remove the o-ring (which is a very tight fit) to measure the depth of the channel so I inserted an X-Acto blade and then measured the portion of the blade that fit into the groove.
I also measured the opening on the rear of the tonearm and it is ~8.5mm so you can see it coincides very closely with the previous measurements (were talking micrometers here) of the section of the sub-weight that is inserted into the tonearm. This is probably the most important measurement because if you make it too big it will not fit. I would err on the side of caution and let the o-ring you install make up the difference. As is it is a very snug fit and yes, the o-ring provides the compliant friction for a secure fit but it is also there to mitigate any resonance. If you look at the tonearm there is another o-ring in the tube section between the bearing and the large counter-weight which is also there to damp resonance.
I hope this helps.
Width of O-ring channel.
Depth of O-ring channel.
https://i.imgur.com/ZAhjlzQ.jpg[/img]']
Width of rear opening on tonearm.
The width of the channel that the o-ring rests in is ~2mm wide and ~1.5mm deep. I did not want to remove the o-ring (which is a very tight fit) to measure the depth of the channel so I inserted an X-Acto blade and then measured the portion of the blade that fit into the groove.
I also measured the opening on the rear of the tonearm and it is ~8.5mm so you can see it coincides very closely with the previous measurements (were talking micrometers here) of the section of the sub-weight that is inserted into the tonearm. This is probably the most important measurement because if you make it too big it will not fit. I would err on the side of caution and let the o-ring you install make up the difference. As is it is a very snug fit and yes, the o-ring provides the compliant friction for a secure fit but it is also there to mitigate any resonance. If you look at the tonearm there is another o-ring in the tube section between the bearing and the large counter-weight which is also there to damp resonance.
I hope this helps.
Width of O-ring channel.
Depth of O-ring channel.
https://i.imgur.com/ZAhjlzQ.jpg[/img]']
Width of rear opening on tonearm.
Thank you again Vintagear! You've been so very helpful!
Putting this in here as this was the original thread. If you are a Sansui SR-838 TT user, and wish to have the hard to secure, and seemingly always lost, subweight, please let me know. The subweight is used when you have a heavier cart (12 grams or greater, if memory serves) and need to counterbalance arm. The subweight came with the 838 model, but are almost always lost. My friend has now made me four copies of increasing dimensions (each +0.005") over spec for male bit that fits into back of tone arm. Smallest three of four fit as is. I am going to secure some O rings for final, more secure, fitment. Once that is done, I'll have him make more, if anyone would like one. He didn't charge me anything (as I sold him some minty speakers cheap). This weight is used when you use a 'heavier' cart (more than 12 grams total weight, if memory serves). I run a Soundsmith Zephyr Mk III, which is right at that threshold. Pics below. Major thanks to @Vintagear, without whom this fabrication would have never happened! Thank you!
Thank you! I can't take any credit! Vintagear provided all the information and my new friend did all the work! I am just the go-between!
