DIY Turntable build with motor and controller

[Impunity]

Do you have any reference turntable available to check your results against or it's rather wherever the chips fall process ?

I do have two Technics turntables and I've owned over the years, Labcraft, Project, Rega, Kenwood and Pioneer TTs so I think I know what I need to hear. I don't own a "high end" TT and so can't compare my DIYs with top gun units. However! - I don't build turntables with the thought that I can in any way compete with the likes of VPI etc. I do it for the love of it, for the challenge and to build something aesthetically pleasing. At the end if it sounds good then I'm happy. I prefer a minimalist turntable although the two I'm currently building are quite large and heavy. I do my best to reduce resonance and any other interference that might deteriorate the sound. My preferred material is straight grain Maple and Walnut. I use lead shot to good effect to dampen resonance.
I will post some pics of the build shortly. I also have built a wooden tone arm from Walnut mated to a technics gimbal that I really like.

 

[Impunity]

Here are two pics of my servo arm lifter.

 

[StevenCrook]

Can I put my two bob's worth in?
I don't know how odippel has configured his operation, but I am controlling my arm using an Arduino Nano with a servo. The servo is mounted so that the output shaft is horizontal, with an arm that will push against a normal tonearm lifter (without the associated mechanism that is redundant) once the arm reaches the record end. In my case, I trigger the Nano via a reed switch magnet attached to an arm at the bottom of the vertical spindle of the tonearm. It's important to have a balanced fitting, so I've used a four arm (cross) fitting with a magnet at opposite sides to prevent yawing. I've tried a simple servo trigger which is simpler than a Nano but It became faulty after a few operations. It may have been something that I did so I don't want to rubbish the trigger. The Nano is very small and easy to install underneath the plynth. I also raise and lower the tonearm via momentary switches for cueing. I'll get around to posting some pics of my TT build. I also made my own tonearm mated to a technics gimbal that's turned out nicely.
Regards Johnno

I'd been thinking along these lines but hadn't settled on the way to get the lift detection. I have a (not entirely logical) aversion to using a magnet for this and had wondered about using the fall of the bias weight on my arm (or the arm itself) interrupting a photocell and using something like this to raise/lower the arm.

I wasn't aware of the existence of servo triggers! I've no problem programming a micro-controller but I've a lot on my plate at the moment so this is going to stay at the notebook stage for now, though I might just order a couple of the motors for the spares box...

 

[Impunity]

I'd been thinking along these lines but hadn't settled on the way to get the lift detection. I have a (not entirely logical) aversion to using a magnet for this and had wondered about using the fall of the bias weight on my arm (or the arm itself) interrupting a photocell and using something like this to raise/lower the arm.

I wasn't aware of the existence of servo triggers! I've no problem programming a micro-controller but I've a lot on my plate at the moment so this is going to stay at the notebook stage for now, though I might just order a couple of the motors for the spares box...

I too am sort of wary about using a magnet but I think it's worth a try. If it's problematic, I can always use a photo transistor to activate the circuit but it will be more complicated. The reed switch is simple and as long as the magnet doesn't interfere with the audio signal in the Cardas wire then that's my preferred method.
Regards Johnno

 

[02GF74]

The most difficult part by far was the motor control. I lost count of how many different threads I've read on this subject. Lots of good ideas out there. In the end, I decided to go with an open-loop system using an Arduino Uno and Adafruit Motor Controller. It's not perfect, but It will do until I learn more, and build a closed-loop system.

Don't get me wrong, I 100% applaud your effort but a microcontroller to control a motor???

You know what they say:
Those that can desgin analogue, do, those that can't, design digital, those that can do neither write software!!!

IMO that is massive overkill. Analogue is not my forte but a £ 2 PIC microcontroller could do of the function required.

How does it play?

 

[jazzboy]

I thought I'd share a project I've been working on for the past few months.
View attachment 1003705

It started when I decided to make some upgrades to my Technics SL-20. I updated the RCA wires to terminals and a new ground connection. Upgraded the cartridge and rewired the tonearm with silver wires. The improvements were eye-opening. But soon after, It began to have some speed issues.

That's when I decided to look into buying a new turntable. I liked the Rega and Fluance offering, but if I was going to upgrade, I really wanted something with a separate motor, and arm board that would allow easy upgrades to the tonearm in the future. Anything I found with features like that was far beyond my price range, so I decided to try to build my own.

Here are the parts I used:

Plinth: MDF (three layers) with walnut veneer View attachment 1003706
View attachment 1003708
View attachment 1003709
View attachment 1003710
Arm board: Curley maple (solid)
View attachment 1003711

Sub platter: Tango spinner with bearing sleeve

Platter: Rega acrylic
View attachment 1003714
Micro Seiki MA-202L tonearm, which I rewired with Cardas 4X33 Tonearm Wire Cryo Treated from Take Five Audio.
View attachment 1003712
Nagaoka MP-110 cartridge with Nagaoka headshell.

Adjustable feet from Amazon

I initially wanted to use a Maxon motor, but I stumbled upon a Portescap 28L28-416E.49 motor for $55 on eBay. It was new-old-stock, so it's Swiss-made, rather than the newer ones made in India.

View attachment 1003713

The spindle for the motor is just a brass motor shaft coupling that I machined a groove into for the belt I made from polyester thread.

How To Make Well Tempered Labs Turntable Belts - YouTube

View attachment 1003715
The most difficult part by far was the motor control. I lost count of how many different threads I've read on this subject. Lots of good ideas out there. In the end, I decided to go with an open-loop system using an Arduino Uno and Adafruit Motor Controller. It's not perfect, but It will do until I learn more, and build a closed-loop system.

View attachment 1003716
View attachment 1003717
View attachment 1003718
I'm posting all my plans, photos, schematics, and Arduino sketch. Hopefully, this post will help someone who wants to take on a project like this.


View attachment 1003719
View attachment 1003720
The green board in the image represents a DC/DC converter used to convert the 12v incoming to 5v to power the Arduino. The 12v feeds off the incoming terminals and goes to the power input of the Adafruit Motor Shield.
View attachment 1003721

Arduino Sketch

===========

#include <Wire.h>
#include <Adafruit_MotorShield.h>
#include "utility/Adafruit_MS_PWMServoDriver.h"

Adafruit_MotorShield AFMS = Adafruit_MotorShield();

Adafruit_DCMotor *myMotor = AFMS.getMotor(2);

int low = 4;
int high = 8;
int off = 13;



void setup() {
// put your setup code here, to run once:
pinMode(low, INPUT_PULLUP);
pinMode(high, INPUT_PULLUP);
pinMode(off, INPUT_PULLUP);

AFMS.begin();


}

void loop() {
// put your main code here, to run repeatedly:

if(digitalRead(low) == LOW)
{

myMotor->setSpeed(131); //0-255 - experiment with this number till you get 33.3 rpm on platter using stribe disc

myMotor->run(FORWARD);
}


// for 45 speed

if(digitalRead(high) == LOW)
{

myMotor->setSpeed(176); //0-255 - experiment with this number till you get 45 rpm on platter using stribe disc

myMotor->run(FORWARD);
}


// for stop

if(digitalRead(off) == LOW)
{

myMotor->setSpeed(0); //0-255

myMotor->run(RELEASE);
}

}

Beautiful aesthetic! I really like the two woods.

 

[DNic]

Hi jazzbou, You should try Mylar tape instead of string. Took my T/T down from 0.09 to 0.06. ( measured with repeat measurement with phone app

Cheers