Modifying a Technics SL-D2 to play 78rpm

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celt_rock
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Modifying a Technics SL-D2 to play 78rpm

Post by celt_rock » 14 Jul 2015 17:16

Hey all, new member looking for a community to interact with as my wife and kids listen kindly to all my stories but don't really care. :wink:

Yesterday I tried out the mod to make my TT play 78s. It worked though not exactly as I thought it would. I followed the directions of an audiokarma.org member who instructed to lay a 56K resistor across the R7 terminals... or... to wire up a DPDT switch with the resistor so that I can turn the function on and off. The R7 controls only the 45 rpm speed on my TT but what I've found is that if I leave the switch in the ON position and switch my speed to 33 1/3 that it's also faster. Weird. Made for a strange first play on the Spooky Two album I just got! Anyway, it works and soon I'll be getting my new Shure 78rpm cartridge in the mail so I can stop using this AT11E. Here's a video

https://www.youtube.com/watch?v=hw4X2DYT_ZM

BMRR
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Re: Modifying a Technics SL-D2 to play 78rpm

Post by BMRR » 14 Jul 2015 17:28

Nicely done! Great song, too. :D

I came across this video a few months ago of a D1 modded for 78:

https://www.youtube.com/watch?v=VXeicfJ-l3w

celt_rock
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Re: Modifying a Technics SL-D2 to play 78rpm

Post by celt_rock » 14 Jul 2015 17:37

I watched that one as well! I love it, the guy sounds like Hank from King of the Hill but uses much bigger words. For the longest time I only had an old Caliphone school record player to use for my 78s but it took up a bunch of space I just don't have. Being able to use my existing setup means a bunch of music will get play in my house that hasn't seen the light of day in a number of years.

BMRR
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Re: Modifying a Technics SL-D2 to play 78rpm

Post by BMRR » 14 Jul 2015 17:45

celt_rock wrote:the guy sounds like Hank from King of the Hill
I was thinking the same thing! :D I wonder if his day job is selling propane and propane accessories... :lol:

Coffee Phil
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Re: Modifying a Technics SL-D2 to play 78rpm

Post by Coffee Phil » 14 Jul 2015 18:39

Hi Celt_rock,

Congratulations and welcome to the forum. Also welcome to the fast spinning club and the turntable hacking club. My Kenwood KD-500 now plays 78s and Edisons and my Beogram 3000 is on the operating table. My
R-O-K Rondine 2 is going to be more of a challenge since I want to retain the Papst outer rotor motor which I consider a thing of beauty.

R7 in your machine is common to both speeds so what you found is expected. There is a trim pot (VR-2) on the board for 45. I'm guessing that the person who came up with the mod felt he could not get enough reduction in resistance by paralleling VR-2. If the switch speeding up 33 1/3 is egregious I think we can come up with a configuration to avoid that by altering all the resistors in the speed control circuit. Knowing that the seemingly weird result is expected, I wouldn't be bothered.

Phil
celt_rock wrote:Hey all, new member looking for a community to interact with as my wife and kids listen kindly to all my stories but don't really care. :wink:

Yesterday I tried out the mod to make my TT play 78s. It worked though not exactly as I thought it would. I followed the directions of an audiokarma.org member who instructed to lay a 56K resistor across the R7 terminals... or... to wire up a DPDT switch with the resistor so that I can turn the function on and off. The R7 controls only the 45 rpm speed on my TT but what I've found is that if I leave the switch in the ON position and switch my speed to 33 1/3 that it's also faster. Weird. Made for a strange first play on the Spooky Two album I just got! Anyway, it works and soon I'll be getting my new Shure 78rpm cartridge in the mail so I can stop using this AT11E. Here's a video

https://www.youtube.com/watch?v=hw4X2DYT_ZM

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