- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
The farmer and his plow - When I set out to build a record cutter
2021_03 The idea
As an old fan of records I would like to introduce myself briefly. I am 55 years old, live in Austria, have a lovely wife, am a technophile and my English is not very good.
So forgive me for that. Also I don't know many technical terms yet, but I will try to do my best with the reports.
I had in March 2021 the inspiration to build a record cutter. So such a thing that cuts the grooves in the blank record. The first trigger for this was an old Bose speaker in my hand. I thought about what I could do with it and my first thought was to put a needle on it and use the vibrations of the speaker to carve a groove into a record.So I did some googling and found little. A few basics regarding cutting and pressing a groove. The V-shaped arrangement of two speakers is also important to get a stereo effect. And the feed must also fit. It is also important that a sound signal is not easy to take over and carve on the plate right away, but needs different audio filters before.The remaining 90% I did not know yet, I had to work hard.
The farmer and his plow - How does the furrow get into the field?
I imagined the following: A farmer and his plow! In order for the farmer to be able to draw a furrow in his field, he first needs a plow (in my case then a cutting needle made of metal, sapphire or diamond). This plow digs into the field and makes a furrow from a smooth surface. At the same time, the plow should be hard and stable and not break at the first approach. So it is important how hard the farmer pushes the plow down. So he gets a furrow that is deep enough to then lay seed in it, but also does not dig too deep that the plow breaks (keep support weight constant). Also the field should not be too hard and dried out, but also not too soft and muddy to get good results (material and temperature of the record blank). Then there is the field horse. It must be strong enough to pull the plow (drive turntable). Finally, the farmer must (should) be sober enough to pull a groove carefully next to the previous one (feed). Thus for me first the bases for a "Silent Cut" were specified. So that sound then still comes into the groove, the farmer must listen loudly to music during the work!
First steps - Microcontroller
Unfortunately I had no idea about microcontrollers and had to teach myself how these things work! After a few weeks I understood it and wrote my first programs (recognize switches and buttons, control LCD and Oled panels, control LED`s and relays, control stepper motors). Before that I did not even know that stepper motors exist - but I am able to learn. I built my first experimental platform (with different voltage sources) and experimented a bit.
Audio filter
Unfortunately, I had little knowledge of audio electronics, but after a few weeks I was a bit wiser.
For cutting records the audio signal must be prepared accordingly. Since I plan to do everything analog, I built three filters as a first try: A LOWCUT (high pass), a HIGH CUT (low pass) and an IRIAA filter. This is important for now, I learned, because too low frequencies make too wide (deep) grooves when cutting, which then causes the needle to bounce out of the groove when playing. Too high frequencies fry the coils of the cutting speakers. With the IRIAA filter, bass ranges are attenuated and highs are boosted, making cutting easier. (In the phono amplifier, basses are then boosted again and highs are attenuated again by means of (standardized) RIAA filters). I made the circuit diagrams for 6th order filters myself and etched the PCBs myself.
As an old fan of records I would like to introduce myself briefly. I am 55 years old, live in Austria, have a lovely wife, am a technophile and my English is not very good.
So forgive me for that. Also I don't know many technical terms yet, but I will try to do my best with the reports.
I had in March 2021 the inspiration to build a record cutter. So such a thing that cuts the grooves in the blank record. The first trigger for this was an old Bose speaker in my hand. I thought about what I could do with it and my first thought was to put a needle on it and use the vibrations of the speaker to carve a groove into a record.So I did some googling and found little. A few basics regarding cutting and pressing a groove. The V-shaped arrangement of two speakers is also important to get a stereo effect. And the feed must also fit. It is also important that a sound signal is not easy to take over and carve on the plate right away, but needs different audio filters before.The remaining 90% I did not know yet, I had to work hard.
The farmer and his plow - How does the furrow get into the field?
I imagined the following: A farmer and his plow! In order for the farmer to be able to draw a furrow in his field, he first needs a plow (in my case then a cutting needle made of metal, sapphire or diamond). This plow digs into the field and makes a furrow from a smooth surface. At the same time, the plow should be hard and stable and not break at the first approach. So it is important how hard the farmer pushes the plow down. So he gets a furrow that is deep enough to then lay seed in it, but also does not dig too deep that the plow breaks (keep support weight constant). Also the field should not be too hard and dried out, but also not too soft and muddy to get good results (material and temperature of the record blank). Then there is the field horse. It must be strong enough to pull the plow (drive turntable). Finally, the farmer must (should) be sober enough to pull a groove carefully next to the previous one (feed). Thus for me first the bases for a "Silent Cut" were specified. So that sound then still comes into the groove, the farmer must listen loudly to music during the work!
First steps - Microcontroller
Unfortunately I had no idea about microcontrollers and had to teach myself how these things work! After a few weeks I understood it and wrote my first programs (recognize switches and buttons, control LCD and Oled panels, control LED`s and relays, control stepper motors). Before that I did not even know that stepper motors exist - but I am able to learn. I built my first experimental platform (with different voltage sources) and experimented a bit.
Audio filter
Unfortunately, I had little knowledge of audio electronics, but after a few weeks I was a bit wiser.
For cutting records the audio signal must be prepared accordingly. Since I plan to do everything analog, I built three filters as a first try: A LOWCUT (high pass), a HIGH CUT (low pass) and an IRIAA filter. This is important for now, I learned, because too low frequencies make too wide (deep) grooves when cutting, which then causes the needle to bounce out of the groove when playing. Too high frequencies fry the coils of the cutting speakers. With the IRIAA filter, bass ranges are attenuated and highs are boosted, making cutting easier. (In the phono amplifier, basses are then boosted again and highs are attenuated again by means of (standardized) RIAA filters). I made the circuit diagrams for 6th order filters myself and etched the PCBs myself.
You do not have the required permissions to view the files attached to this post.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2021_04 Turntable drive
As a turntable drive I have (for now) bought a used Numark TT500 and completely disassembled. This has a relatively strong drive motor. From wood I then quickly built a mount for the platter drive (with RGB LED) and finished the platter drive.
And a short Video:
As a turntable drive I have (for now) bought a used Numark TT500 and completely disassembled. This has a relatively strong drive motor. From wood I then quickly built a mount for the platter drive (with RGB LED) and finished the platter drive.
And a short Video:
You do not have the required permissions to view the files attached to this post.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2021_04 Temperature measurement
I still have a little time in April and used my microcontroller skills to build a temperature measuring unit - with IR sensor and oled display:
2021_04 First control electronics
Still a little time left in April. Therefore I built a first provisional control electronics to test the function. For this purpose I controlled small relays via a couple of optocouplers which then operate the functions for on/off, speed, temperature control and LED control (blue = cold and red = warm). The temperature is displayed on the oled.
After that I built a second provisional (better) control electronics, so that the cables are hidden.
And a short video:
I still have a little time in April and used my microcontroller skills to build a temperature measuring unit - with IR sensor and oled display:
2021_04 First control electronics
Still a little time left in April. Therefore I built a first provisional control electronics to test the function. For this purpose I controlled small relays via a couple of optocouplers which then operate the functions for on/off, speed, temperature control and LED control (blue = cold and red = warm). The temperature is displayed on the oled.
After that I built a second provisional (better) control electronics, so that the cables are hidden.
And a short video:
You do not have the required permissions to view the files attached to this post.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2021_05 Plate heating - first failed attempt
May has come into the country and I really wanted to find a form for heating up the record. (You can already see, I have already forgotten to focus on the essentials). First I tried it with three LED spotlights, which should cover an even surface. The goal was to wrap the lamps in a nice housing and swing them onto the turntable. Unfortunately this didn't work, because the amount of heat was too low.
And a short video:
2021_05 Feed drive system
I decided to move the whole platter and keep the cutting head with holder and suction fixed at the same position.
To do this, I bought a rail system (ball bearing) and a threaded rod with 5mm pitch (with ball screw) from the CAD kit. The whole thing on was mounted on a multilayer wooden plate. The connection from the fixed base plate to the moving platter were made with ribbon cable.
As you can see, I do all this on our kitchen table. My dear wife is not very happy about it, but still she accepts it. When we eat I always have to move everything to the side!
My first attempts to drive the whole thing with a NEMA17 stepper motor failed because of the power of the motor. Due to the necessary high number of steps (necessary to keep the transmission noise low) the performance decreases. A Nema17 with gearbox was also not the solution, because it had too little power at high speeds.
2021_05 Feed drive system 2
In June 2022, I decided on a Nema23 with gear 1:15. It has enough power now! I sat down briefly on the transport plate and he transported me!
...and a short video. (It does not show me sitting on the turntable!)
2021_05 Installation turntable control electronics
Now I have installed the control for the platter and the Arduino for command control under the platter drive.
Additionally I mounted the first aluminum profile strips:
and a short video:
May has come into the country and I really wanted to find a form for heating up the record. (You can already see, I have already forgotten to focus on the essentials). First I tried it with three LED spotlights, which should cover an even surface. The goal was to wrap the lamps in a nice housing and swing them onto the turntable. Unfortunately this didn't work, because the amount of heat was too low.
And a short video:
2021_05 Feed drive system
I decided to move the whole platter and keep the cutting head with holder and suction fixed at the same position.
To do this, I bought a rail system (ball bearing) and a threaded rod with 5mm pitch (with ball screw) from the CAD kit. The whole thing on was mounted on a multilayer wooden plate. The connection from the fixed base plate to the moving platter were made with ribbon cable.
As you can see, I do all this on our kitchen table. My dear wife is not very happy about it, but still she accepts it. When we eat I always have to move everything to the side!
My first attempts to drive the whole thing with a NEMA17 stepper motor failed because of the power of the motor. Due to the necessary high number of steps (necessary to keep the transmission noise low) the performance decreases. A Nema17 with gearbox was also not the solution, because it had too little power at high speeds.
2021_05 Feed drive system 2
In June 2022, I decided on a Nema23 with gear 1:15. It has enough power now! I sat down briefly on the transport plate and he transported me!
...and a short video. (It does not show me sitting on the turntable!)
2021_05 Installation turntable control electronics
Now I have installed the control for the platter and the Arduino for command control under the platter drive.
Additionally I mounted the first aluminum profile strips:
and a short video:
You do not have the required permissions to view the files attached to this post.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2021_06 Creating new audio filter and power supply PCBs
The provisional audio filters from April had the disadvantage that they are not variable. They have only one frequency range each that you can operate. My new audio filters should be able to do more. My goal is to be able to set different frequency ranges using Arduino control. For this I developed new schematics and drew PCB layouts. The analog filters should have highest quality and so I designed the development to use no resistors (1%) higher than 100kOhm and no capacitors with tolerances higher than 1% for the 4th order filters (because of noise). For the production of the print plates, these were exposed by means of altitude sun.
2021_06 Audio filters assembly
The high pass filter (low cut) consists of four circuit boards.
By controlling via the microcontroller -24dB can be selected via the relays for the frequencies 20Hz, 30Hz, 40Hz, 60Hz and 80Hz.
The low pass filter (High Cut) consists of two boards.
The frequencies 9kHz, 12kHz, 15kHz and 18kHz can be selected via the relays.
2021_06 Plate heating - second failure
Since I'm waiting for some parts for further work, I made a second attempt to heat the plate. Of course I could put a light bulb but: I would like to find an elegant solution for heating.
So I removed the heating strips from an old laminator and built a heater. Unfortunately, the device heats up to almost 300 degrees Celsius! By changing the thermosensor I was able to lower the heating temperature to 100°C. Unfortunately, the thermosensor switches off and on permanently whereby in the assembled state of the sensor permantent becomes too warm and no heating power is delivered to the plate. - Failure attempt two!
2021_06 Audio filter control with Arduino
Now I got some components again (touch sensors and LCD display modules).
On a trial basis I assembled the whole thing and tried it out. It took a few tries to program the Arduini correctly. Sometimes the thing doesn't do what I want!
But in the end it worked. With a laminated foil it works quite well. Whether I will stay with the touch buttons or use real buttons I don't know yet.
and a short video
2021_06 Optical position sensors and first control of the stepper motor
Position sensors are installed so that the microcontroller also knows where the platter is. Basically the position can be calculated by counting the steps of the stepper motor. Nevertheless it is necessary to have a starting point for calibration. For experimenting I added a second calibration point and measuring points for 7", 10", 12" and 14" plates.
Now the first calibration process can be done.
Damn, that's a lot of cables already.
and a short video
The provisional audio filters from April had the disadvantage that they are not variable. They have only one frequency range each that you can operate. My new audio filters should be able to do more. My goal is to be able to set different frequency ranges using Arduino control. For this I developed new schematics and drew PCB layouts. The analog filters should have highest quality and so I designed the development to use no resistors (1%) higher than 100kOhm and no capacitors with tolerances higher than 1% for the 4th order filters (because of noise). For the production of the print plates, these were exposed by means of altitude sun.
2021_06 Audio filters assembly
The high pass filter (low cut) consists of four circuit boards.
By controlling via the microcontroller -24dB can be selected via the relays for the frequencies 20Hz, 30Hz, 40Hz, 60Hz and 80Hz.
The low pass filter (High Cut) consists of two boards.
The frequencies 9kHz, 12kHz, 15kHz and 18kHz can be selected via the relays.
2021_06 Plate heating - second failure
Since I'm waiting for some parts for further work, I made a second attempt to heat the plate. Of course I could put a light bulb but: I would like to find an elegant solution for heating.
So I removed the heating strips from an old laminator and built a heater. Unfortunately, the device heats up to almost 300 degrees Celsius! By changing the thermosensor I was able to lower the heating temperature to 100°C. Unfortunately, the thermosensor switches off and on permanently whereby in the assembled state of the sensor permantent becomes too warm and no heating power is delivered to the plate. - Failure attempt two!
2021_06 Audio filter control with Arduino
Now I got some components again (touch sensors and LCD display modules).
On a trial basis I assembled the whole thing and tried it out. It took a few tries to program the Arduini correctly. Sometimes the thing doesn't do what I want!
But in the end it worked. With a laminated foil it works quite well. Whether I will stay with the touch buttons or use real buttons I don't know yet.
and a short video
2021_06 Optical position sensors and first control of the stepper motor
Position sensors are installed so that the microcontroller also knows where the platter is. Basically the position can be calculated by counting the steps of the stepper motor. Nevertheless it is necessary to have a starting point for calibration. For experimenting I added a second calibration point and measuring points for 7", 10", 12" and 14" plates.
Now the first calibration process can be done.
Damn, that's a lot of cables already.
and a short video
You do not have the required permissions to view the files attached to this post.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2021_07 First tests with the feed
A simple mounted pencil and a measuring template (which I created) control the positions.
and a short video
2021_07 Feed control with the microcontroller
First pencil tests on a sheet of paper show that the microcontroller control works.
and the video and the video
2021_07 Plate heating - third failure
Every month again I waste my time trying to find an elegant solution to the heating problem. At the same time, I don't even have any plate blanks, let alone a cutting head (I only have it in my head). Still, the problem won't let me go. Now I'm trying it with an IR heat lamp for reptile terrariums.
Basically it works, but the plate is not heated evenly, because the distance is too small. But I like the approach already quite well and switching it off and on via the microprocessor also works well. Maybe I will try it (later) with an aluminum plate, which should distribute the temperature better under the heat lamp...
and a short video
2021_07 Adhesion mat with Ghekko effect
Looking for a base for the plate so that it does not slip when cutting, I came across this adhesive mat. It is easy to clean and has a ghekko effect. So the mat sticks to both the turntable and the plate itself, making it impossible to slip! Whether it works that way is open to question.
Material: PVC. Non-slip and padded. Effective on both sides, washable, durable. (Found at https://www.carlroth.com/de/de/matten-laborunterlagen/adhaesionsmatte-rotilabo/p/0668.1 )
A simple mounted pencil and a measuring template (which I created) control the positions.
and a short video
2021_07 Feed control with the microcontroller
First pencil tests on a sheet of paper show that the microcontroller control works.
and the video and the video
2021_07 Plate heating - third failure
Every month again I waste my time trying to find an elegant solution to the heating problem. At the same time, I don't even have any plate blanks, let alone a cutting head (I only have it in my head). Still, the problem won't let me go. Now I'm trying it with an IR heat lamp for reptile terrariums.
Basically it works, but the plate is not heated evenly, because the distance is too small. But I like the approach already quite well and switching it off and on via the microprocessor also works well. Maybe I will try it (later) with an aluminum plate, which should distribute the temperature better under the heat lamp...
and a short video
2021_07 Adhesion mat with Ghekko effect
Looking for a base for the plate so that it does not slip when cutting, I came across this adhesive mat. It is easy to clean and has a ghekko effect. So the mat sticks to both the turntable and the plate itself, making it impossible to slip! Whether it works that way is open to question.
Material: PVC. Non-slip and padded. Effective on both sides, washable, durable. (Found at https://www.carlroth.com/de/de/matten-laborunterlagen/adhaesionsmatte-rotilabo/p/0668.1 )
You do not have the required permissions to view the files attached to this post.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2021_08 Test setup loudspeaker with feedback coil
The goal here for me is to learn how a speaker behaves to different frequencies and how to get feedback of the frequencies.
For this I use my old Bose loudspeaker, which had initiated the basic idea of my project.
I have to build the feedback coil first.
From the Bose speaker, first the inner membrane is removed and then a plastic plate is attached with hot glue gun. I stole the plastic plate from my wife's knitting needle area. This part has a receptacle for 3mm diameter knitting needles. (I also stole the carbon knitting needle at the same time).
a video:
2021_08 Construction of a coil winder
To wind the feedback coil, I need a wire, a bobbin and a winding machine that tells me the number of turns.
I built this winding machine from an old Nema17 stepper motor and an Arduino Uno. For the wire I disassembled an old relay and the coil former I built out of papier mâché. The coil former is only one layer of paper thick, light, insulated and easy to work with.
2021_08 Building a feedback coil
By means of a digital microscope and notebook, I can observe the winding process exactly. I have programmed the winding machine so that it makes one revolution per second, but can also be stopped at any time and can also run backwards.
The first attempt failed, because I fixed the bobbin holder too much. When I loosened it, one of the thin wires broke off.
The second attempt was successful.
The coil has 200 turns and a resistance of 10.4 ohms.
and a video to the process:
The coil: 0,16 Gram: 10,4 Ohm:
The goal here for me is to learn how a speaker behaves to different frequencies and how to get feedback of the frequencies.
For this I use my old Bose loudspeaker, which had initiated the basic idea of my project.
I have to build the feedback coil first.
From the Bose speaker, first the inner membrane is removed and then a plastic plate is attached with hot glue gun. I stole the plastic plate from my wife's knitting needle area. This part has a receptacle for 3mm diameter knitting needles. (I also stole the carbon knitting needle at the same time).
a video:
2021_08 Construction of a coil winder
To wind the feedback coil, I need a wire, a bobbin and a winding machine that tells me the number of turns.
I built this winding machine from an old Nema17 stepper motor and an Arduino Uno. For the wire I disassembled an old relay and the coil former I built out of papier mâché. The coil former is only one layer of paper thick, light, insulated and easy to work with.
2021_08 Building a feedback coil
By means of a digital microscope and notebook, I can observe the winding process exactly. I have programmed the winding machine so that it makes one revolution per second, but can also be stopped at any time and can also run backwards.
The first attempt failed, because I fixed the bobbin holder too much. When I loosened it, one of the thin wires broke off.
The second attempt was successful.
The coil has 200 turns and a resistance of 10.4 ohms.
and a video to the process:
The coil: 0,16 Gram: 10,4 Ohm:
You do not have the required permissions to view the files attached to this post.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2021_08 Test setup
I mounted the speaker with drive rod and feedback coil on a base plate. For this I made an adjustable wooden block which holds the magnet for the feedback coil.
By means of signal generator and oscilloscopes I then started to make the first signal measurements
and a short video
2021_09 Measurements and tests in all frequency ranges
Hundreds of signal measurements in all frequency ranges followed. With larger and smaller magnets. With iron and with copper insulators. Different distances between magnets and coils. I also tested double coils.
I posted the test results in another treat at that time. („The best size of a feedback coil?”)
https://www.lathetrolls.com/viewtopic.php?t=9318 .
At that time I thought it was a good idea to plan the feedback coils right away when building my Cutterhead. Today I know that it was too hasty. MARKROB had warned me at that time and suggested to build a perfect non-feedback head first. Today I understand why.
I mounted the speaker with drive rod and feedback coil on a base plate. For this I made an adjustable wooden block which holds the magnet for the feedback coil.
By means of signal generator and oscilloscopes I then started to make the first signal measurements
and a short video
2021_09 Measurements and tests in all frequency ranges
Hundreds of signal measurements in all frequency ranges followed. With larger and smaller magnets. With iron and with copper insulators. Different distances between magnets and coils. I also tested double coils.
I posted the test results in another treat at that time. („The best size of a feedback coil?”)
https://www.lathetrolls.com/viewtopic.php?t=9318 .
At that time I thought it was a good idea to plan the feedback coils right away when building my Cutterhead. Today I know that it was too hasty. MARKROB had warned me at that time and suggested to build a perfect non-feedback head first. Today I understand why.
You do not have the required permissions to view the files attached to this post.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2021_10 Power supply - building a constant voltage source +15V/-15V
During the numerous signal measurements, I have of course also measured my low-cut, high-cut and IRIAA filters. I found out that my cheap +15V/-15V power supply does not provide 100% constant voltage.
Accordingly I built a 100% constant voltage power supply. OK - it may be that it is a little overdimensioned, but I think better than too weak. Finally there is an EQ (elliptic equalizer for monobass), a feedback coil amplifier, a compensation filter for feedback signals, a limiter and who knows what else.
2021_10 All power supplies in one box
After I already have so many power supplies (+15V/-15V power supply for the op-amps; 5V power supply for the microcontrollers; power supply for the turntable drive; 12V power supply for the relays; 24V and 48V power supplies for the stepper motors), the space at the kitchen table is already getting very tight. Therefore I decided to put all power supplies into one case.
2021_10 Loudspeaker for Cutterhead - Selection
For selection I have prepared once a resonance speaker (25W 8Ohm) and a tweeter (25W 6Ohm).
The metal part of the resonance speaker seems to me too stable to transport high frequencies and I don't know yet how to solve the problem of replacing this hard metal part with something elastic. Unfortunately, I don't have a 3D printer that I might be able to use to build a new suspension. Surface grinding (to make the metal plate thinner) would also be a possibility. But I don't have the right tools for that.
With the small tweeter, on the other hand, the machining seems easier to me.
2021_10 Carbon cone construction
In order to connect the coil of the speaker with a drive rod to the torque tube, I need a cone. Creating a light, precise cone from thin aluminum seems very difficult to me at the moment.
Therefore, I have decided to build a cone out of carbon.
I have already posted the process in a treat in October 2021: „Cone made of carbon" https://www.lathetrolls.com/viewtopic.php?f=15&t=9341
2021_10 Purchase of a pillar drilling machine and a milling cutter
Now begins the construction of the cutterhead and its suspension.
Unfortunately, I realize that I won't get anywhere with hand tools, a drill press and a Dremel. The purchase of a pillar drill and a small manual 3D router (Proxxon MF70) is inevitable.
My dear wife was not very pleased about the upgrade in our living room, but I was able to explain the "importance" to her.
During the numerous signal measurements, I have of course also measured my low-cut, high-cut and IRIAA filters. I found out that my cheap +15V/-15V power supply does not provide 100% constant voltage.
Accordingly I built a 100% constant voltage power supply. OK - it may be that it is a little overdimensioned, but I think better than too weak. Finally there is an EQ (elliptic equalizer for monobass), a feedback coil amplifier, a compensation filter for feedback signals, a limiter and who knows what else.
2021_10 All power supplies in one box
After I already have so many power supplies (+15V/-15V power supply for the op-amps; 5V power supply for the microcontrollers; power supply for the turntable drive; 12V power supply for the relays; 24V and 48V power supplies for the stepper motors), the space at the kitchen table is already getting very tight. Therefore I decided to put all power supplies into one case.
2021_10 Loudspeaker for Cutterhead - Selection
For selection I have prepared once a resonance speaker (25W 8Ohm) and a tweeter (25W 6Ohm).
The metal part of the resonance speaker seems to me too stable to transport high frequencies and I don't know yet how to solve the problem of replacing this hard metal part with something elastic. Unfortunately, I don't have a 3D printer that I might be able to use to build a new suspension. Surface grinding (to make the metal plate thinner) would also be a possibility. But I don't have the right tools for that.
With the small tweeter, on the other hand, the machining seems easier to me.
2021_10 Carbon cone construction
In order to connect the coil of the speaker with a drive rod to the torque tube, I need a cone. Creating a light, precise cone from thin aluminum seems very difficult to me at the moment.
Therefore, I have decided to build a cone out of carbon.
I have already posted the process in a treat in October 2021: „Cone made of carbon" https://www.lathetrolls.com/viewtopic.php?f=15&t=9341
2021_10 Purchase of a pillar drilling machine and a milling cutter
Now begins the construction of the cutterhead and its suspension.
Unfortunately, I realize that I won't get anywhere with hand tools, a drill press and a Dremel. The purchase of a pillar drill and a small manual 3D router (Proxxon MF70) is inevitable.
My dear wife was not very pleased about the upgrade in our living room, but I was able to explain the "importance" to her.
You do not have the required permissions to view the files attached to this post.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2021_10 Building an adapter plate with height adjustment for the cutterhead
Armed with a handsaw and Proxxon cutter, I built myself an adapter plate with height adjustment for the cutterhead.
and a short video
2021_10 Construction of an electronic support weight control for the cutterhead - failed test
So that I can control the counterweight to the cutterhead via a microcontroller, I built myself a construction with counterweight and servomotor.
This concept was a total failure. It only cost a lot of time and work. Therefore, I would like to forget this chapter and not go further into it (tears come to my eyes). Now in retrospect this idea seems more than absurd to me.
Armed with a handsaw and Proxxon cutter, I built myself an adapter plate with height adjustment for the cutterhead.
and a short video
2021_10 Construction of an electronic support weight control for the cutterhead - failed test
So that I can control the counterweight to the cutterhead via a microcontroller, I built myself a construction with counterweight and servomotor.
This concept was a total failure. It only cost a lot of time and work. Therefore, I would like to forget this chapter and not go further into it (tears come to my eyes). Now in retrospect this idea seems more than absurd to me.
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- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2021_11 Start of construction Cutterhead
Finally the time has come! I start with the construction of my (first) Cutterhead!
After I have made numerous costruction exercises on the PC I decided to build a cutterhead without V-spring!
The V-spring should hold the torsion bar at the rear end in position and prevent a forward or backward movement by means of a holding wire. The flexible V-spring "swings" allow a small movement, so that finally a 45°/45° cut is possible, which then enables the stereo effect.
In my first design I tried to solve these features in a different way.
The continuation of my story follows. (Today I am already too tired to post further)
Greetings from Austria
Thomas
Finally the time has come! I start with the construction of my (first) Cutterhead!
After I have made numerous costruction exercises on the PC I decided to build a cutterhead without V-spring!
The V-spring should hold the torsion bar at the rear end in position and prevent a forward or backward movement by means of a holding wire. The flexible V-spring "swings" allow a small movement, so that finally a 45°/45° cut is possible, which then enables the stereo effect.
In my first design I tried to solve these features in a different way.
The continuation of my story follows. (Today I am already too tired to post further)
Greetings from Austria
Thomas
Re: The farmer and his plow - When I set out to build a record cutter
Great effort, thanks for the write up and well done.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2021_10 Construction CUTTERHEAD 1
As already mentioned, I did without a V-spring for my first Cutterhead and instead built a construction based on a cardanic suspension.
With the smallest ball bearings, the torsion bar can be moved almost load-free and still remain in its position.
The problem is the exact adjustment of the pressure on the bearings and that this pressure remains constant.
and a short video
2021_10 Construction CUTTERHEAD 1 - The case
After finishing the aluminum plates with my Proxxon router, the assembly begins
2021_10 Construction CUTTERHEAD 1 - The lighting
Of course, a lighting element must not be missing. For this purpose I built a small circuit board with three LEDs and cast it in epoxy resin. When installing the lamp, I covered the aluminum parts of the cutterhead with copper foil. The goal was to dampen the magnetic fields at high frequencies.
2021_10 Construction CUTTERHEAD 1 - The loudspeaker
The construction of the speakers:
The (perforated) carbon cones are connected to the carbon rod. For this purpose, the CNC router is used as a centering unit.
The copper-colored metal rods are made of phosphor bronze and are glued into the carbon rod with epoxy resin.
The carbon cone was then glued (also with epoxy resin) to the speaker.
Finally, the feedback coils are glued to the carbon rod.
2021_10 Construction CUTTERHEAD 1 - The torsion bar
The torsion bar is quite complicated in design:
On the one hand, the angles where the mounts for the speakers are inserted have to be exactly right.
In addition, the drilling angle for the stylus holder must also fit.
There is very little space available, especially when you consider that there is also to be room for an extraction unit.
And then there is also the connection to the gimbal joint.
Therefore, the torsion bar was made of five parts.
The hole in the torsion bar for holding the stylus must have a pitch of exactly 1:10 (1:20 total).
Since I could not buy such a drill, I built it for myself.
I have described the process in another treat: „1:10 conical reamer for Neumann Stylus DIY“
https://www.lathetrolls.com/viewtopic.php?f=15&t=9365
As already mentioned, I did without a V-spring for my first Cutterhead and instead built a construction based on a cardanic suspension.
With the smallest ball bearings, the torsion bar can be moved almost load-free and still remain in its position.
The problem is the exact adjustment of the pressure on the bearings and that this pressure remains constant.
and a short video
2021_10 Construction CUTTERHEAD 1 - The case
After finishing the aluminum plates with my Proxxon router, the assembly begins
2021_10 Construction CUTTERHEAD 1 - The lighting
Of course, a lighting element must not be missing. For this purpose I built a small circuit board with three LEDs and cast it in epoxy resin. When installing the lamp, I covered the aluminum parts of the cutterhead with copper foil. The goal was to dampen the magnetic fields at high frequencies.
2021_10 Construction CUTTERHEAD 1 - The loudspeaker
The construction of the speakers:
The (perforated) carbon cones are connected to the carbon rod. For this purpose, the CNC router is used as a centering unit.
The copper-colored metal rods are made of phosphor bronze and are glued into the carbon rod with epoxy resin.
The carbon cone was then glued (also with epoxy resin) to the speaker.
Finally, the feedback coils are glued to the carbon rod.
2021_10 Construction CUTTERHEAD 1 - The torsion bar
The torsion bar is quite complicated in design:
On the one hand, the angles where the mounts for the speakers are inserted have to be exactly right.
In addition, the drilling angle for the stylus holder must also fit.
There is very little space available, especially when you consider that there is also to be room for an extraction unit.
And then there is also the connection to the gimbal joint.
Therefore, the torsion bar was made of five parts.
The hole in the torsion bar for holding the stylus must have a pitch of exactly 1:10 (1:20 total).
Since I could not buy such a drill, I built it for myself.
I have described the process in another treat: „1:10 conical reamer for Neumann Stylus DIY“
https://www.lathetrolls.com/viewtopic.php?f=15&t=9365
You do not have the required permissions to view the files attached to this post.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2021_11 Construction CUTTERHEAD 1 - Completion
Here I have shown the assembled cutterhead. The cabinet with the gimbal. Both speakers are installed and connected to the torque tube. The aluminum parts to hold the magnets for the feedback coils are also installed. The last picture also shows the stylus attached.
Here I have shown the assembled cutterhead. The cabinet with the gimbal. Both speakers are installed and connected to the torque tube. The aluminum parts to hold the magnets for the feedback coils are also installed. The last picture also shows the stylus attached.
You do not have the required permissions to view the files attached to this post.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2021_11 The first cut
I was already very excited when I placed the needle on the plate blank for the first time. I didn't have suction at that point!
The stylus was a Sapphire and the plate blank was PGP plastic. The professionals among you already know, this can't go well. But I didn't know any better at the time and was very surprised that I couldn't get a clean groove together.
Shown here is the first cutting pattern (silent cut). The surface is just a pure scratch! The groove spacing is 80µm and the cut width is about 40µm.
VIDEO 1 CUTTERHEAD in motion: VIDEO 2 CUTTERHEAD in motion:
2021_11 Further cutting attempts (Silent Cut)
No matter what I tried, it was always scratching! No matter whether I increased or decreased the contact force. Only with very low tracking force a "relatively smooth" cut could be detected. However, due to the slightest unevenness of the record, a uniform tracking force is not feasible!
It was a disaster!
2021_11 Further cutting attempts (Silent Cut)
In between, I kept checking the stylus to see if it was still sharp or broken. But it was OK (only one of the heating wires was broken)
In addition, I then mounted a suction tube, which I connected to my house vacuum cleaner. But the suction hadn't worked, especially since I couldn't get any cutting thread together. It was rather small snippets that I scratched from the plate blank.
And it went on like this for the whole month of December!
I was already very excited when I placed the needle on the plate blank for the first time. I didn't have suction at that point!
The stylus was a Sapphire and the plate blank was PGP plastic. The professionals among you already know, this can't go well. But I didn't know any better at the time and was very surprised that I couldn't get a clean groove together.
Shown here is the first cutting pattern (silent cut). The surface is just a pure scratch! The groove spacing is 80µm and the cut width is about 40µm.
VIDEO 1 CUTTERHEAD in motion: VIDEO 2 CUTTERHEAD in motion:
2021_11 Further cutting attempts (Silent Cut)
No matter what I tried, it was always scratching! No matter whether I increased or decreased the contact force. Only with very low tracking force a "relatively smooth" cut could be detected. However, due to the slightest unevenness of the record, a uniform tracking force is not feasible!
It was a disaster!
2021_11 Further cutting attempts (Silent Cut)
In between, I kept checking the stylus to see if it was still sharp or broken. But it was OK (only one of the heating wires was broken)
In addition, I then mounted a suction tube, which I connected to my house vacuum cleaner. But the suction hadn't worked, especially since I couldn't get any cutting thread together. It was rather small snippets that I scratched from the plate blank.
And it went on like this for the whole month of December!
You do not have the required permissions to view the files attached to this post.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2022_01 Further cutting attempts (Silent Cut)
A new year, a new happiness!
To change the cutting angle, I built various torsion bars with different geometries. From 90° (perpendicular to the plate) up to 105° (+15° against the cutting direction). But this did not bring the desired success.
Then I built an auxiliary construction to more easily test different cutting angles.
Only at negative angles (85° corresponds to embedding) a somewhat better cut could be brought together.
2022_01 Further cutting tests (test frequencies)
With an inverted stylus (embedding) I pressed first frequencies. The signal is not clean but visibly better. I had to readjust the gimbal regularly to compensate for play in the bearings:
In the meantime, I have found out that a diamond stylus is required for cutting in PGP plastic. I have cut with a sapphire up to now, but it can only be used for lacquer.
A new year, a new happiness!
To change the cutting angle, I built various torsion bars with different geometries. From 90° (perpendicular to the plate) up to 105° (+15° against the cutting direction). But this did not bring the desired success.
Then I built an auxiliary construction to more easily test different cutting angles.
Only at negative angles (85° corresponds to embedding) a somewhat better cut could be brought together.
2022_01 Further cutting tests (test frequencies)
With an inverted stylus (embedding) I pressed first frequencies. The signal is not clean but visibly better. I had to readjust the gimbal regularly to compensate for play in the bearings:
In the meantime, I have found out that a diamond stylus is required for cutting in PGP plastic. I have cut with a sapphire up to now, but it can only be used for lacquer.
You do not have the required permissions to view the files attached to this post.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2022_01 The "Sir" Caruso Board
I have ordered a diamond stylus, but I still have to wait some time for it. Therefore I decided to build a circuit in the remaining time that uses the feedback signal to counteract the resonances of the cutting head. Thereby I came across the Caruso board.
I changed the circuit diagram a little bit. First I separated the amplifier for the feedback coil from the rest of the circuit. The reason for this was to not transport the weak signal of the feedback coil over too long cables. The rest of the boards could end up being far away from the cutting head. And I equipped the main board with variable (switchable) capacitors to be able to do different simulations.
2022_01 Construction of a new control panel
Since I'm still waiting for the diamond stylus, I decided to build a better, clearer control panel.
With a wooden base plate, various pushbutton switches, LED's and LCD displays, all covered with a foil.
I have ordered a diamond stylus, but I still have to wait some time for it. Therefore I decided to build a circuit in the remaining time that uses the feedback signal to counteract the resonances of the cutting head. Thereby I came across the Caruso board.
I changed the circuit diagram a little bit. First I separated the amplifier for the feedback coil from the rest of the circuit. The reason for this was to not transport the weak signal of the feedback coil over too long cables. The rest of the boards could end up being far away from the cutting head. And I equipped the main board with variable (switchable) capacitors to be able to do different simulations.
2022_01 Construction of a new control panel
Since I'm still waiting for the diamond stylus, I decided to build a better, clearer control panel.
With a wooden base plate, various pushbutton switches, LED's and LCD displays, all covered with a foil.
You do not have the required permissions to view the files attached to this post.
- farmersplow
- Posts: 422
- Joined: Thu Jun 17, 2021 3:43 am
- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
2022_02 The exhaust system
The diamond stylus is still not there. But because I assume that this new stylus will also cut and a magnificent cutting thread will result, I still have to take care of the suction. The household vacuum cleaner is too weak for this and shuts down after 30 seconds due to overheating!
Therefore, I have implemented the suction by means of a rotary blower. In addition a voltage transformer and a silencer. Later, the whole thing will be installed in a sound-absorbing housing.
2022_02 The stylus heater
Additionally, I built a small controller to regulate the current for the stylus heater.
2022_02 Cutting tests with the new diamond stylus
Finally the diamond stylus arrived. I have installed it immediately. How the results look like I will report tomorrow.
The continuation of my story follows.
Greetings from Austria
Thomas
The diamond stylus is still not there. But because I assume that this new stylus will also cut and a magnificent cutting thread will result, I still have to take care of the suction. The household vacuum cleaner is too weak for this and shuts down after 30 seconds due to overheating!
Therefore, I have implemented the suction by means of a rotary blower. In addition a voltage transformer and a silencer. Later, the whole thing will be installed in a sound-absorbing housing.
2022_02 The stylus heater
Additionally, I built a small controller to regulate the current for the stylus heater.
2022_02 Cutting tests with the new diamond stylus
Finally the diamond stylus arrived. I have installed it immediately. How the results look like I will report tomorrow.
The continuation of my story follows.
Greetings from Austria
Thomas
You do not have the required permissions to view the files attached to this post.
- Fela Borbone
- Posts: 280
- Joined: Thu Mar 07, 2013 5:22 pm
- Location: Valencia, Spain