Technics SL-1100. One turntable, two motor runs

[thedelihaus]

AK post on technics

Did some research and have proof of two different motors used in the Technics SL-1100.#

Ofcthe motors,#one will be marked DIRECT DRIVE PHONOMOTOR MJL-9A

The other, DIRECT DRIVE PHONOMOTOR MJL-12A.

The 9A has the name cast in it with raised letters, and features a low cut groove in the upper part of the body and a straight "tongue" that fits in the groove to lock it into position with the lower motor assembly.

The 12A has the name printed on it, and features a higher positioned cut groove in the upper part of the body and a stepped (upwards) "tongue" that fits in the groove to lock it into position with the lower motor assembly.

Otherwise they look basically the same. Same width, height, design.

The motors- Amy insight between the differences of 9a and 12a ?

And the motors- do you think they're interchangeable with each other without causing any conflict with the internal boards? ##

 

[Panotaker]

I checked both of my 1100A's and they are both MJL-9A's. I never knew they made two different motors. Where did you find that info at? Although both of mine work perfectly, I am going to modify them a little one at a time. I already polished one platter and now it looks like it is chrome plated. I am now going to make some new legs for them out of aluminum with pointed feet and then polished the legs up to match the platter. I then am going to remove the light grey long flat piece of metal that the tone arm is bolted to and make a new piece out of aluminum and polish that up until it shines like chrome. I thought about polishing the original piece, but I want to save it just incase I want to change it back to original. I'll post some pictures when I get the first one done. Eventually I plan on making some new plexiglass covers for them too.

 

[MelodyMaster]

I checked both of my 1100A's and they are both MJL-9A's. I never knew they made two different motors. Where did you find that info at? Although both of mine work perfectly, I am going to modify them a little one at a time. I already polished one platter and now it looks like it is chrome plated. I am now going to make some new legs for them out of aluminum with pointed feet and then polished the legs up to match the platter. I then am going to remove the light grey long flat piece of metal that the tone arm is bolted to and make a new piece out of aluminum and polish that up until it shines like chrome. I thought about polishing the original piece, but I want to save it just incase I want to change it back to original. I'll post some pictures when I get the first one done. Eventually I plan on making some new plexiglass covers for them too.

An Aluminum armboard will have considerably worse acoustic properties than the cast metal original. So will Walnut but only slightly, and it looks really pretty! I'm getting a walnut toneboard for mounting my Opera-Consonance arm on the SL-110A, and keeping the SME 3009 and factory OEM armboard intact.

In my wildest nightmares I wouldn't consider grinding down the original armboard... (Shudder!) In fact I wouldn't imagine touching the look of the SL-1100 at all, and your doing so has just made your deck valueless..If one must pimp the look of a turntable, and ruin its sound, do so with a cheap unit that isn't collectible. There ARE mods that can somewhat improve the sound of the 1100, but yours don't do that in any way.

 

[thedelihaus]

The motor in mine is the 9A, and a partially parted out 1100 has the 12A motor.

Research before this, including on Vintage Knob, discusses this but with no detail and more questions than answers.

 

[Panotaker]

An Aluminum armboard will have considerably worse acoustic properties than the cast metal original. So will Walnut but only slightly, and it looks really pretty! I'm getting a walnut toneboard for mounting my Opera-Consonance arm on the SL-110A, and keeping the SME 3009 and factory OEM armboard intact.

In my wildest nightmares I wouldn't consider grinding down the original armboard... (Shudder!) In fact I wouldn't imagine touching the look of the SL-1100 at all, and your doing so has just made your deck valueless..If one must pimp the look of a turntable, and ruin its sound, do so with a cheap unit that isn't collectible. There ARE mods that can somewhat improve the sound of the 1100, but yours don't do that in any way.

Well I have been looking at my two 1100's for over 30 years now, so I figured I will try to change the looks of them a little. I am not really ruining the tables since I can put the pieces back and change them back to original since I am not modifying the original pieces. If it doesn't sound good, I'll just put the original toneboard back. Is't the original toneboard also made out of aluminum, it sure looks like it to me. It looks to be cast aluminum. I am machining mine on a mill.

 

[MelodyMaster]

Is't the original toneboard also made out of aluminum, it sure looks like it to me. It looks to be cast aluminum. I am machining mine on a mill.

It's apparently a rough hgoneycomb type of structure, with no resonance, in the same way that particle board is preferred over solid wood for speakers.

I love the SL-1100, it's one of my favourite two tables, along with my TD-124, that's why I'm sounding protective, my apologies. Imagine grinding down the deck of a Garrard 301 or painting a TD-124 hot Pink...

 

[Panotaker]

I can machine the bottom of it and give it the same honeycomb structure and make it look just like the original one. My original one looks like crap from many years of using it while I was a disco DJ. That is why I want to try the polish look. I don't want to repaint the old one since it has the lettering on it. I guess I will just have to try it and see how it sounds.