AguycalledSimon
pfm Member
InSides said:
"It relies on using springs to maintain horizontality, and said springs can have varying compression rates set with screws. The entire armboard is then connected to the turntable base using POM (Delrin) fasteners of a sufficiently large diameter to facilitate minute changes to the fastening torque."
Kudos - that is a far better description of springs than the poor one i posted, but is effectively what i did with am earlier version of my armboard
I must admit I have not seen a pivoted tonearm with the tonearm wand extending that much past the pivot point in the back - it goes against accepted wisdom that the majority of the balancing weight should be as close to the pivot as possible. I have seen such setups in manually driven linear tonearms, but not a pivoted one - would be very interested to see how it affects effective tonearm mass.
I did try and calculate it once, breaking each cm of the arm in either a + or a - value, and although i got a value (from memory it was around 11gm) i suspect the maths were not really designed so well to this kind of design. similarly there are some methods of weighing the business end with the cart and counterweight removed, but whether the same logic applies to such a long rearward end, i am not sure
When designing (i use the term very loosely), i tried to find anyone who advised against it and could not find anything. My conclusion was that it was at least viable to try an experiment and that the real reason no-one did it was that it made the turntable much harder to fit onto a shelf with any space behind - in the end , my 10.5cm length was more determined by how much space clearance i had at the back of my rack, than it was from a performance choice - i would have preferred 12", as that would potentially have allowed me to ignore anti-skating
TBH, I cannot believe that i prefer this to my SME V, and i hope its not just bias because it want it to be better - one thing i can say with confidence is that its not worse, and with a material cost of about £25, with most parts made from a £200 printer and using very basic bearings, that is pretty eye-opening
I think my best design was an earlier one which used threads for the bearing, however, keeping the tension, especially on the horizontal, was a pain. I suspect my future includes a long stream of further prototype arms............
"It relies on using springs to maintain horizontality, and said springs can have varying compression rates set with screws. The entire armboard is then connected to the turntable base using POM (Delrin) fasteners of a sufficiently large diameter to facilitate minute changes to the fastening torque."
Kudos - that is a far better description of springs than the poor one i posted, but is effectively what i did with am earlier version of my armboard
I must admit I have not seen a pivoted tonearm with the tonearm wand extending that much past the pivot point in the back - it goes against accepted wisdom that the majority of the balancing weight should be as close to the pivot as possible. I have seen such setups in manually driven linear tonearms, but not a pivoted one - would be very interested to see how it affects effective tonearm mass.
I did try and calculate it once, breaking each cm of the arm in either a + or a - value, and although i got a value (from memory it was around 11gm) i suspect the maths were not really designed so well to this kind of design. similarly there are some methods of weighing the business end with the cart and counterweight removed, but whether the same logic applies to such a long rearward end, i am not sure
When designing (i use the term very loosely), i tried to find anyone who advised against it and could not find anything. My conclusion was that it was at least viable to try an experiment and that the real reason no-one did it was that it made the turntable much harder to fit onto a shelf with any space behind - in the end , my 10.5cm length was more determined by how much space clearance i had at the back of my rack, than it was from a performance choice - i would have preferred 12", as that would potentially have allowed me to ignore anti-skating
TBH, I cannot believe that i prefer this to my SME V, and i hope its not just bias because it want it to be better - one thing i can say with confidence is that its not worse, and with a material cost of about £25, with most parts made from a £200 printer and using very basic bearings, that is pretty eye-opening
I think my best design was an earlier one which used threads for the bearing, however, keeping the tension, especially on the horizontal, was a pain. I suspect my future includes a long stream of further prototype arms............