good job really....I managed to avoid complete disassembly by soldering micro copper wires at the base of the break after removing the enamel with sandpaper attached to a toothpick; a surgical operation and very delicate having broken 3 wires out of four and only one possibility of repair because if only one of the wires was broken I was with my butt on the ground.
A few drops of insulating paint around the welds and a few drops of melted wax to softly fix the wires at the coil exit as in origin; I finally completely restored the speedometer coil.
before
after
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Stainless Platter update
As many of you will be aware I made 2 Stainless Steel platters one for myself and another for Bon. The one I made for Bon did not quite fit in his plinth I had to put and undercut so it would sit down. Bon gave me one of his old plinths to test fit. So before I ship the platter to him I thought I would do an impulse response test. All tests were done on the unit in pic 1.
Why do a IR test - a TT is a very sensitive vibrometer any resonance in the system however small will modulate onto the audio signal causing a loss of detail in the output (smearing the audio signal).
As can be seen from the scope trace the SS/Delrin platter does an excellent job of damping resonance. It will be interesting to hear Bon's evaluation of this SS/Delrin plattered mk2 against his SP10R.
A description of the pics in order.
Bon's Stainless/Delrin platter in the plinth he gave me.
Impulse response
OEM platter.
My SS platter, designed to fit stock SP10 chassis.
Bon's SS/Delrin platter 19mm thick stainless with 16mm Delrin fixed to the top. NOTE this platter will not fit a stock SP10 chassis.
.
As many of you will be aware I made 2 Stainless Steel platters one for myself and another for Bon. The one I made for Bon did not quite fit in his plinth I had to put and undercut so it would sit down. Bon gave me one of his old plinths to test fit. So before I ship the platter to him I thought I would do an impulse response test. All tests were done on the unit in pic 1.
Why do a IR test - a TT is a very sensitive vibrometer any resonance in the system however small will modulate onto the audio signal causing a loss of detail in the output (smearing the audio signal).
As can be seen from the scope trace the SS/Delrin platter does an excellent job of damping resonance. It will be interesting to hear Bon's evaluation of this SS/Delrin plattered mk2 against his SP10R.
A description of the pics in order.
Bon's Stainless/Delrin platter in the plinth he gave me.
Impulse response
OEM platter.
My SS platter, designed to fit stock SP10 chassis.
Bon's SS/Delrin platter 19mm thick stainless with 16mm Delrin fixed to the top. NOTE this platter will not fit a stock SP10 chassis.
.
Attachments
Yes, it will fit a stock SP10 chassis. Bon's platter was a special order to fit his SP10mk2 Kaneta.
I've have ordered 2 GunMetal blanks and I have some 10mm Delrin. The plan is to make one with and one without Delrin to test the difference. I suspect the Delrin will be better. I will test all 3 platters SS, GM and GM/Delrin.
One of the benefits of the bonded Delrin is flatness of the LP surface which should be better than almost any mat. Bon's platter after a final face measured better than 0.02mm total vertical runout. The motor had more than 10 times this runout.
If the GM is at least as good as the Stainless I will offer these to DIY members as the machining will be much easier. My cost will be about the same as the GM blank will be more expensive but the SS was a PITA to machine and ate tooling and took me 5 days to machine Bon's platter. Drilling the bolt holes in the SS for the Delrin was a nightmare.
I've have ordered 2 GunMetal blanks and I have some 10mm Delrin. The plan is to make one with and one without Delrin to test the difference. I suspect the Delrin will be better. I will test all 3 platters SS, GM and GM/Delrin.
One of the benefits of the bonded Delrin is flatness of the LP surface which should be better than almost any mat. Bon's platter after a final face measured better than 0.02mm total vertical runout. The motor had more than 10 times this runout.
If the GM is at least as good as the Stainless I will offer these to DIY members as the machining will be much easier. My cost will be about the same as the GM blank will be more expensive but the SS was a PITA to machine and ate tooling and took me 5 days to machine Bon's platter. Drilling the bolt holes in the SS for the Delrin was a nightmare.
Motor spindle repair
This is the motor that i rewound the FG coil on. When I assembled it I found the spindle had a very small amount of play. Running the motor the vertical runout was quite bad at 0.5mm.
So in my usual fashion I decided to modify the rotor and insert a brass collar. The rotor was drilled then bored 10mm and the brass was machined for a 0.02mm press fit. I then drilled and bored the brass for a 0.02mm press fit. The spindle is then pressed in. Finally I used the toolpost grinder to grind the platter mounting flange true to the spindle. Checked runout in the lathe and less than 0.01mm TIR. Pretty happy with that.
When I mounted the platter and checked runout it was 0.1mm which is 1/2 what my other SP10 is. I suspect this runout is in the bearing. Next upgrade is to machine PTFE bushes for the spindle.
This is the motor that i rewound the FG coil on. When I assembled it I found the spindle had a very small amount of play. Running the motor the vertical runout was quite bad at 0.5mm.
So in my usual fashion I decided to modify the rotor and insert a brass collar. The rotor was drilled then bored 10mm and the brass was machined for a 0.02mm press fit. I then drilled and bored the brass for a 0.02mm press fit. The spindle is then pressed in. Finally I used the toolpost grinder to grind the platter mounting flange true to the spindle. Checked runout in the lathe and less than 0.01mm TIR. Pretty happy with that.
When I mounted the platter and checked runout it was 0.1mm which is 1/2 what my other SP10 is. I suspect this runout is in the bearing. Next upgrade is to machine PTFE bushes for the spindle.
Attachments
someone has already done it in teflon, delrin and other synthetic materials by testing the noise of friction and rotation with measuring instruments.
Torlon was among the winners, for its silence, robustness and durability.
I used plastic trim tools to prise the magnet carrier out if anything was going to break then it would be the tool not the magnet. I am not going to glue to carrier back in I'm going to use plasticine under the carrier and in the motor housing to damp it.
No need for centering as there are tabs in the rotor that center the magnet.
The other thing you try is to screw M3 bolts into the platter hold down holes these would push on the back of the magnet carrier, I thought about this afterwards.
No need for centering as there are tabs in the rotor that center the magnet.
The other thing you try is to screw M3 bolts into the platter hold down holes these would push on the back of the magnet carrier, I thought about this afterwards.
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Gunmetal platter
Spent yesterday machining one of the Gunmetal platters. A few issues arose mostly to do with the amount of shrinkage in the blanks. I made them 5mm oversize which is not enough. I ended up having to machine more off the radius than I had planned, so this platter is 317mm OD. I'll make another mold insert 10mm larger and 7mm thicker.
I did not put the side chamfer on this platter it has vertical sides. Mass is 7.5kg due to smaller diameter and an undercut on the bottom to accommodate damping material. I have ordered Dynamat Xtreme to fix under the platter.
The difference between the OEM and Gunmetal/Stainless platter is enormous. I have done back to back listening, swapping platters on the same SP10 and there is a clear improvement over the OEM. The difference between the GM and SS is more difficult. I have listened to both and can't really pick any difference.
I am using the stock SP10 rubber mat with a 5mm thick acrylic spacer to lift the mat so my peripheral ring fits.
Once I get the sizing correct, these will be made as a drop in replacement to the OEM platter. I will make these available to DIY members.
Spent yesterday machining one of the Gunmetal platters. A few issues arose mostly to do with the amount of shrinkage in the blanks. I made them 5mm oversize which is not enough. I ended up having to machine more off the radius than I had planned, so this platter is 317mm OD. I'll make another mold insert 10mm larger and 7mm thicker.
I did not put the side chamfer on this platter it has vertical sides. Mass is 7.5kg due to smaller diameter and an undercut on the bottom to accommodate damping material. I have ordered Dynamat Xtreme to fix under the platter.
The difference between the OEM and Gunmetal/Stainless platter is enormous. I have done back to back listening, swapping platters on the same SP10 and there is a clear improvement over the OEM. The difference between the GM and SS is more difficult. I have listened to both and can't really pick any difference.
I am using the stock SP10 rubber mat with a 5mm thick acrylic spacer to lift the mat so my peripheral ring fits.
Once I get the sizing correct, these will be made as a drop in replacement to the OEM platter. I will make these available to DIY members.
