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Re: not another 2nd pivot question

PostPosted: Tue Jan 01, 2019 8:20 pm
by mitchlim
Brf wrote:Over the last couple of months I have been theorizing as to what would be the optimal force applied on the skate plate by the dual pivot. I then tested my theory with extensive listening test and my conclusions are listed below

1) The dual pivot point force should be 60-70% of the cartridge’s vertical tracking force.

2) A dual pivot force 1.0 grams less than the cartridge vtf may result in audible dual pivot bearing chatter in heavily modulated grooves

3) A dual pivot force 0.5g greater than the cartridge vtf will result in compressed micro dynamics and loss of high end extension.

The above results were based on a 12” arm


Hi, Just would like to confirm that by adding dual pivot unit I need to reduce the VTF, i.e. if I am using Dynavector XV-1s at 2.5 gram (without Dual pivot), then after adding the dual pivot, the VTF has to be reduced by 40-30% (your point 1 above) from the 2.5 gram to approx. 1.65 gram

Thank you

Re: not another 2nd pivot question

PostPosted: Tue Jan 01, 2019 9:15 pm
by Mr_Putty
The force in Brf reply #1 below is for the second pivot contact only, not the stylus force. #1 is a percentage of your desired stylus force determined before adding the second pivot. AIUI (as I understand it).

Re: not another 2nd pivot question

PostPosted: Tue Jan 01, 2019 10:16 pm
by mitchlim
Ah. I see

Thank you

Re: not another 2nd pivot question

PostPosted: Tue Jan 29, 2019 2:29 pm
by gar
Brf wrote:

Over the last couple of months I have been theorizing as to what would be the optimal force applied on the skate plate by the dual pivot. I then tested my theory with extensive listening test and my conclusions are listed below

1) The dual pivot point force should be 60-70% of the cartridge’s vertical tracking force.

2) A dual pivot force 1.0 grams less than the cartridge vtf may result in audible dual pivot bearing chatter in heavily modulated grooves

3) A dual pivot force 0.5g greater than the cartridge vtf will result in compressed micro dynamics and loss of high end extension.

The above results were based on a 12” arm

I am new to the forum and owning a VPI turntable, having recently purchased a Classic Signature along with a second pivot. Using information from this forum I have been dialing in my new Classic which has been going very well. Just wanted to say that following Brf's guidelines above I adjusted the loading on the second pivot. This was by FAR the single best improvement in sound yet! The separation and clarity just jumped out! Amazing.

Thanks to Brf for sharing your research!

-GAR

Re: not another 2nd pivot question

PostPosted: Thu Jan 31, 2019 10:18 am
by Johnny
gar wrote:Brf wrote:

Over the last couple of months I have been theorizing as to what would be the optimal force applied on the skate plate by the dual pivot. I then tested my theory with extensive listening test and my conclusions are listed below

1) The dual pivot point force should be 60-70% of the cartridge’s vertical tracking force.

2) A dual pivot force 1.0 grams less than the cartridge vtf may result in audible dual pivot bearing chatter in heavily modulated grooves

3) A dual pivot force 0.5g greater than the cartridge vtf will result in compressed micro dynamics and loss of high end extension.

The above results were based on a 12” arm

I am new to the forum and owning a VPI turntable, having recently purchased a Classic Signature along with a second pivot. Using information from this forum I have been dialing in my new Classic which has been going very well. Just wanted to say that following Brf's guidelines above I adjusted the loading on the second pivot. This was by FAR the single best improvement in sound yet! The separation and clarity just jumped out! Amazing.

Thanks to Brf for sharing your research!

-GAR


Yes, Brf is very helpful on this forum. Tweaking my dual pivot has yielded a huge benefit in performance.