Derek....you also must remember that there are 2 iterations of the 10.5 VPI arm. There is an arm wand made of aluminum and therefore light as compared to the stainless steel one that you probably have which is heavier. Higher compliance in a cartridge "likes" a lighter arm. The Stainless arm is new and I would guess that the resonance calculator you used is for the aluminum not s/s arm. Your resonance therefore is worse than you post.
M20FL Super Compliance?
I recently purchased one of the NOS M20FL Super carts from William Thakker on Ebay to use with a VPI Classic. The compliance he states is 20mm/µN. I used Vinyl Engine Resonance Calculator to estimate the resonant frequency in my tone arm (JWM 10.5i SE):
http://www.vinylengine.com/cartridge_database_tools.php#ResonanceCalculator
Arm Effective Mass: 12.3g
Cartridge Mass: 5g
Fastener Mass: 1g
Cartridge Compliance: 20mm/µN
This gave me an estimated Resonant Frequency of: 8.31Hz A little low, but workable.
When I received the cart, I mounted it and aligned it with a MINT Protractor. The VTF was set to 1.5g. And the VTA was up a little in back. (I read that this cart likes a positive VTA setting.)
I tested the M20FL with the Hi Fi News Test Record on the resonant frequency sweep test on side 2, the cartridge would wobble somewhere between the 7 and 5 voice announcements, showing a resonant frequency of around 6HZ! This is too low and the cart was susceptible to footfalls and woofer pumping.
Using the Resonant Frequency Calculator I would need to put in a compliance figure somewhere closer to 35 to get this low of a resonant frequency with this tone arm.
Is the figure quoted by Thakker wrong, or can these NOS cart vary wildly in compliance?
Has anyone else tested their M20fl compliance?
I wanted to make sure I'm not missing something in my calculation before I contact William.
Thanks for any insight.
http://www.vinylengine.com/cartridge_database_tools.php#ResonanceCalculator
Arm Effective Mass: 12.3g
Cartridge Mass: 5g
Fastener Mass: 1g
Cartridge Compliance: 20mm/µN
This gave me an estimated Resonant Frequency of: 8.31Hz A little low, but workable.
When I received the cart, I mounted it and aligned it with a MINT Protractor. The VTF was set to 1.5g. And the VTA was up a little in back. (I read that this cart likes a positive VTA setting.)
I tested the M20FL with the Hi Fi News Test Record on the resonant frequency sweep test on side 2, the cartridge would wobble somewhere between the 7 and 5 voice announcements, showing a resonant frequency of around 6HZ! This is too low and the cart was susceptible to footfalls and woofer pumping.
Using the Resonant Frequency Calculator I would need to put in a compliance figure somewhere closer to 35 to get this low of a resonant frequency with this tone arm.
Is the figure quoted by Thakker wrong, or can these NOS cart vary wildly in compliance?
Has anyone else tested their M20fl compliance?
I wanted to make sure I'm not missing something in my calculation before I contact William.
Thanks for any insight.