SL-1200 MK2 project complete!

[Trackside]

SL-1200 MK2 with a DL-103
List of mods in no particular order to create a reasonable price/performance source for recording my vinyl collection;
KAB tonearm Damper
DIY 5mm 'achromat' between plater and thick technics rubber mat
12"Cardas tonearm twisted wire running outside the tonearm from cart to V-LPS phonostage attached to side of plinth.
Transformer moved to external housing.
Feet replaced with 50mm sorbothane 1/2 domes
3mm aluminium spacer/ weight between cart and Sumiko headshell
Heatshrink on armtube
Engineering nut glued to rear of counterwieght and whole lot damped with O rings and section of bike inner tube.
Bearing shaft and particularly the tip polished to a mirror finish, DIY bottom plate holding a Delrin thrustpad and incorporating an oil bath , all lubed with Redline 0w10 race oil.
The kind of mods to take it above this level get expensive and it's now good enough with no obvious sonic flaws.

[missan]

A very good effort, I guess the KAB damper has made the biggest difference.

I have suggestions on a couple of cheap tweaks I find really good. I uploaded some pics of a way to damp the platter, it has really surprised me how audible this is.

Another one is to fix the lower part of the bearing to the plinth. This can be done in different ways, one way is to fix the bearing with silicone, another is to fill the whole space under the bearing with oil.

The counterweight stub´s connection to the pivot is another issue IMO.
I have done this connection much more rigid, and this has made the bass resonance peak cleaner and more defined.

missan

[Trackside]

Yes the KAB damping trough is the biggest sonic improvement and if I had to mod another SL-1200 I'd probably do this and the armtube heatshrink and it would be 90% of what I'd have now. I'd probably also just get a good MM cart so I didn't have to mess around with all the mass loading and VTA mods to run my DL-103. I have a blob of blutack under the bearing to couple it with the plinth - missed that from my list and also stuffed some blutack into the voids around the magnet but the biggest damping success was sandwiching the acromat under the rubber mat. Any other way of platter damping and I'm all ears! I looked at the CW stub to pivot and it's decoupled but couldn't see an obvious way of making this rigid - any advice on this would also be welcome

[missan]

Hi
I have a Dynamat under the rubber mat, but the damping I have done on the underside of platter was surprisingly good. Pictures are in the Technics section. One removes the magnet and fill up the whole space with a high loss factor compound, I used Silicone. The key is to form a, in principle, constrained layer.
missan

[Trackside]

Seen the pics and will have a go. Any problems aligning the magnet assembly correctly as I would have thought it's essential it's precisely aligned with the center of rotation to prevent WOW. Was the silicone just standard bathroom sealant?

[missan]

Seen the pics and will have a go. Any problems aligning the magnet assembly correctly as I would have thought it's essential it's precisely aligned with the center of rotation to prevent WOW. Was the silicone just standard bathroom sealant?

No, there is no problem in aligning, it fits snugly and only in one way. Yes, standard bathroom sealant.
missan

[Trackside]

Thanks Missan - I've just looked at some damping compound called 'Green Glue' http://www.greengluecompany.com/
This may offer better performance than silicone sealant? Could be useful in quite a few places in a TT or a layer between 2 MDF boards may make an effective isolation platform........

[missan]

Thanks Missan - I've just looked at some damping compound called 'Green Glue' http://www.greengluecompany.com/
This may offer better performance than silicone sealant? Could be useful in quite a few places in a TT or a layer between 2 MDF boards may make an effective isolation platform........

Looks interesting, yes probably has a more direct design for high losses. Well it´s easy to remove the silicone and test another compound if one wants to.
missan

[Trackside]

this was supposed to be a post to report the end of my tweaks........

[missan]

It looks to me You have just begun...., then You have plinth.....
missan