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replacing tonearm question?

Hey,
I have a VPI HW-19 MK4 which I love dearly. My existing Sumiko FT-3 tonearm is 20 years old and on its last legs and I want to replace it with a Jelco 750 or 850. Both arms are 9". Would I have to have a new armboard made and drill new holes? Or could I use the existing armboard and hole and just drill new screws? I know I'd havr to factor in the tonearm radius and all the millimeter differences.

I've never done this before so please excuse my ignorance on this.
128x128simao
simao's avatar
simao OP
1,831 posts
 
@noromance Not yet. It just came in today and I won't have time until this weekend. Will post an update then.
@best-groove: Thanks for the Sumiko tonearm picture - that'll help!
best-groove's avatar
best-groove
843 posts
 
@simao 

the photo is of a standard lifter that I have restored (it is not a Sumiko or Jelco that is exactly the same) but they are practically all the same and simple to disassemble.
noromance's avatar
noromance
9,860 posts
 
@best-groove  In much the same way a 1% THD tube amp sounds better than a 0.05% THD solid state amp, the friction measurements are so low as to not matter. What does matter is how it sounds. The Jelco 850 is radically different from the other gimbal bearing models in that it uses a hardened precision knife edge. My Jelco 750 bested the Sumiko and the 850 is far better than the 750.
best-groove's avatar
best-groove
843 posts
 
@noromance 

If what you say is true, then the manufacturers could use stone bearing balls carved by Fred Flinstones himself if friction isn't important.
The friction heavily affects the suspension of the head, the cantilever, the tracking, going to compromise several elements.
Every detail of an arm is important, but the bearings and clutches they possess must be taken seriously.
noromance's avatar
noromance
9,860 posts
 
That is not what I said or implied. Some false equivalence in your example. My argument is that at 25mg, the amount of friction ceases to be a primary concern. Stability and control of resonance is also important. It should also be noted that these Jelco arms are relatively inexpensive so the value-performance ratio is high.
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