I got a Sansui SR-2050C record player that was given to me in 2017. I restored it and noticed the speed was slightly slow. I tried a new belt given the one on it was a little loose and that didn't help.
The motor spins as free as it should and the platter does as well.
I figured the slight speed difference must be within some tolerance, however it's a difference I can easily hear.
My cure was to take a Bogen CHS-60A amplifier and make a variable frequency AC supply out of it then set the frequency to where the platter spins at 33 1/3 RPM and the speed is correct on the 45 RPM setting. Needed a frequency of 61.75Hz.
Anyways I'm thinking of moving the record player to my bedroom and I don't have any space for the supply nor do I need another heat generator in my room as the tube amp does a good enough job by itself of heating the room up.
I was looking at doing this to my RCA 45 player.
I then thought why not do it to the Sansui.
Here's the schematic.
The relay looks like it operates on 50Vrms and the auto shut off arm raiser operates on 100V. So in order to keep those circuits intact I'd need a transformer with dual 50V secondaries or a 100V center tapped secondary. That said would it be possible to use the 200V tap on the 120V line and use the 100V tap to power the relay?
Also if I use that motor controller I'd need to figure a way to make the 33/45 buttons actuate a switch that changes the motor speed as currently the switch moves the belt to a different motor pulley step.
What easily sourced motors are out there that would work for this or is there a cure for the speed issue using the stock motor?
Now if I could find another small function generator kit I could use a small amplifier that puts out 45Vrms at about an amp or so then connect it to the 100V tap while moving the circuit connection to the 250V tap.
The motor spins as free as it should and the platter does as well.
I figured the slight speed difference must be within some tolerance, however it's a difference I can easily hear.
My cure was to take a Bogen CHS-60A amplifier and make a variable frequency AC supply out of it then set the frequency to where the platter spins at 33 1/3 RPM and the speed is correct on the 45 RPM setting. Needed a frequency of 61.75Hz.
Anyways I'm thinking of moving the record player to my bedroom and I don't have any space for the supply nor do I need another heat generator in my room as the tube amp does a good enough job by itself of heating the room up.
I was looking at doing this to my RCA 45 player.
I then thought why not do it to the Sansui.
Here's the schematic.
The relay looks like it operates on 50Vrms and the auto shut off arm raiser operates on 100V. So in order to keep those circuits intact I'd need a transformer with dual 50V secondaries or a 100V center tapped secondary. That said would it be possible to use the 200V tap on the 120V line and use the 100V tap to power the relay?
Also if I use that motor controller I'd need to figure a way to make the 33/45 buttons actuate a switch that changes the motor speed as currently the switch moves the belt to a different motor pulley step.
What easily sourced motors are out there that would work for this or is there a cure for the speed issue using the stock motor?
Now if I could find another small function generator kit I could use a small amplifier that puts out 45Vrms at about an amp or so then connect it to the 100V tap while moving the circuit connection to the 250V tap.
Well I just learned something today.
Decided to try the phono and checked the belt noticing the inside part of the belt looking like it had seen some use which likely came from using the phono over the last several years. I decided to flip the belt inside out then tried it and dang if the speed isn't near perfect just running straight from the power outlet.
I confirmed it with a strobe disk where with the belt as it originally was the speed was slow and with the belt inside out the speed is near perfect.
I never knew flat belts were not the same on both sides, however I do not know when the belt was actually made so could time have an effect on it or is there a specific side to the belt and it got packaged inside out?
So therefore I will not be needing to do any modification to this record player.
Decided to try the phono and checked the belt noticing the inside part of the belt looking like it had seen some use which likely came from using the phono over the last several years. I decided to flip the belt inside out then tried it and dang if the speed isn't near perfect just running straight from the power outlet.
I confirmed it with a strobe disk where with the belt as it originally was the speed was slow and with the belt inside out the speed is near perfect.
I never knew flat belts were not the same on both sides, however I do not know when the belt was actually made so could time have an effect on it or is there a specific side to the belt and it got packaged inside out?
So therefore I will not be needing to do any modification to this record player.
Listened to another record today of music I know well and the slight slow speed was very noticeable so I am using the variable frequency AC supply temporarily. To lighten the load on the supply I have the Sansui set to 130V and run the supply at 120V. I use a power strip with it which has one of those Radio Shack analog AC voltmeters that can plug into an outlet plugged into it so that I can set the voltage properly. I also have the 45 player power transformer and the phono preamp power transformer plugged into it. They don't need to be plugged into it, however that saves me from having to get a power strip just for those things and the AC supply to plug into.