The farmer and his plow - When I set out to build a record cutter

[lulu]

Cutting music again at last

I still had to fix a few signal problems, which I will write about in the next reports. After I had finally fixed the interference, I was able to make a music cut again.
An old friend from school visited me in Austria again. He now lives near San Francisco (California) and is currently studying music. So he was able to help me with the mastering. Thank you Bernhard.

Here is an excerpt from the Whitney Houston cutting. In my opinion, very difficult to cut because there are many very quiet spots that show every mistake of the setting and the material.
I think I managed to get a good shot.

TESTCUT: Whitney Houston - I will always love You

45rpm 7" +1dB (5cm/sec) no post-processing!
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cutted whitney houston.mp3
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Greetings from Austria
Thomas

Hi Thomas,

as always, your work is very inspiring. It seems that the tweaking never ends, I am too still working on my DIY lathe, now fighting witch vibrations from the steper motor driving the cutting arm, but hopefully i am on to something, I am now using 3d printed magnetic coupling to connect the motor to the leadscrew. Variable groove spacing is the next thing on the list So thank you for inspiration.

Is it possible that I hear a bit of wobble in your cut? is the platter motor stable? But soundwise it is very nice, really...

Lu.

[farmersplow]

Hi Thomas,

as always, your work is very inspiring. It seems that the tweaking never ends, I am too still working on my DIY lathe, now fighting witch vibrations from the steper motor driving the cutting arm, but hopefully i am on to something, I am now using 3d printed magnetic coupling to connect the motor to the leadscrew. Variable groove spacing is the next thing on the list So thank you for inspiration.

Is it possible that I hear a bit of wobble in your cut? is the platter motor stable? But soundwise it is very nice, really...

Lu.

Hello Lu, thank you very much. The turntable has undergone many “stressful” tests over the years. Maybe I should replace it soon. At the moment I'm still testing it and will postpone the replacement.

[farmersplow]

Editing music

Last week we had roadworks. Jackhammers and road rollers outside the door made recording impossible.

Now I've edited some more.

TESTCUT: SADE - Why can't we live together

(again, only excerpts from the cutted record - recorded in the DAW. This is the mp3 version 48000 16bit, because the wave format requires 180MB)

33 rpm 7" +1dB (5cm/sec) no needle heating, blank at 30°C room temperature, 50% humidity
no post-processing!
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2025_08_12b cutted SADE - Why cant we live together 48000 16bit.mp3

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Greetings from Austria
Thomas

[farmersplow]

Editing music


TESTCUT: SKRILLEX - BANGARANG

(again, only excerpts from the cutted record were recorded in the DAW. This is again only the mp3 version 48000 16bit)

45 rpm 7" +1dB (5cm/sec) no needle heating, blank at 30°C room temperature, 50% humidity
no post-processing!
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2025_08_12d cutted Skrillex - Bangarang.mp3

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Greetings from Austria
Thomas

[farmersplow]

Eliminate humming noise:

I had a variety of interference noises that were stronger at times and then less strong again. There was a 50Hz hum, a hiss, a crackling and grinding, a noise from 1kHz to 20kHz that increased slightly with the frequency (and was already +10dB at 15kHz). And interference above 20kHz up to 80mV.

First the 50Hz hum. It was quite easy to fix. All audio signal lines in my device are equipped with shielding. After I had finally connected the shields at both ends to the device ground, the problem was solved.

Eliminate noise from 1kHz to 20kHz:

I had noticed that there was always a slight amount of noise in the silent cut recordings. As the frequency increased, so did the noise. In some cases, it rose from -90dB to -75dB during the analysis (silent cut). But only on the right channel! Earthing the shielding did not solve the problem. I didn't have this “grinding” noise before, but I do now. After a long search, I was able to find the cause. It was due to the positioning of the cutting stylus. Somehow I had forgotten an important factor when testing my cutting heads and the different contact forces that result from testing. The contact point of the cutting stylus must be exactly on the line that leads to the center of the record. If the contact point is too far below the line, then this noise will occur on the right channel. If the touchdown point is too far above the line, the left channel will be noisier.
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Bild1.jpg

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That's why I installed the laser (but unfortunately forgot about it). Correct positioning solved the problem.
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D40.jpg

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The (short) video shows that the diamond is positioned exactly in the laser beam:
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Laser positioning compr.mp4

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Greetings from Austria,
Thomas

[spinnertownblanks]

Cutting dead central to the spindle is essential, we made a little tool for this exact task

[SONARC]

Hi Thomas -

This is interesting to me, although I’m not certain it relates to my own lathes.
I work with Presto 6N units, which natively emboss monaural grooves, so there may or may not be much correlation to what you are describing.

Still, it seems that the mechanics of various lathes are all driven by the same basic principle - that a cutting head travels along the lead screw to the center of the disc being cut. It would seem that regardless of where the head makes contact with the disc, it would have no other option than to follow a straight line to the center.

For example, with the Presto 6N, as well as the Rek-O-Kut shown in Joe’s photograph, there can only be one path from the outside to the center - the head can only be lowered in one stationary postion, and from there it follows the lead screw in a straight line to the center.

My question in this case would be: what might cause a stylus to fall outside a direct line to the center? Does this somehow relate to the type of overhead assembly being used?

What might I be missing here?

Thanks in advance for any information you might be able to provide to help me undertsand this.

Eliminate noise from 1kHz to 20kHz:

I had noticed that there was always a slight amount of noise in the silent cut recordings. As the frequency increased, so did the noise. In some cases, it rose from -90dB to -75dB during the analysis (silent cut). But only on the right channel! Earthing the shielding did not solve the problem. I didn't have this “grinding” noise before, but I do now. After a long search, I was able to find the cause. It was due to the positioning of the cutting stylus. Somehow I had forgotten an important factor when testing my cutting heads and the different contact forces that result from testing. The contact point of the cutting stylus must be exactly on the line that leads to the center of the record. If the contact point is too far below the line, then this noise will occur on the right channel. If the touchdown point is too far above the line, the left channel will be noisier.

That's why I installed the laser (but unfortunately forgot about it). Correct positioning solved the problem.

Greetings from Austria,
Thomas

[farmersplow]

Hi Thomas -

This is interesting to me, although I’m not certain it relates to my own lathes.
I work with Presto 6N units, which natively emboss monaural grooves, so there may or may not be much correlation to what you are describing.

Still, it seems that the mechanics of various lathes are all driven by the same basic principle - that a cutting head travels along the lead screw to the center of the disc being cut. It would seem that regardless of where the head makes contact with the disc, it would have no other option than to follow a straight line to the center.

For example, with the Presto 6N, as well as the Rek-O-Kut shown in Joe’s photograph, there can only be one path from the outside to the center - the head can only be lowered in one stationary postion, and from there it follows the lead screw in a straight line to the center.

My question in this case would be: what might cause a stylus to fall outside a direct line to the center? Does this somehow relate to the type of overhead assembly being used?

What might I be missing here?

Thanks in advance for any information you might be able to provide to help me undertsand this.

This usually affects overhead-mounted lathes. However, the principle applies to all machines (including the Presto 6n).
Many people experiment and modify existing machines (especially here in the experimentation area). A different (similar) cutting head or a different adapter for the cutting head. This changes the geometry and must be corrected.
For example, if you use a different needle shaft that is longer or shorter than the original shaft, not only does the angle of the entire head change, but also the contact point.

Example:
Unfortunately, I have no idea about Presto 6N – let me say that up front.
But I briefly read through the description and, from a technical point of view, this is how it looks to me:

IMAGE 1: Angle adjustment
The screw shown can be used (when loosened) to adjust the angle of the cutting head – now at -5°.
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Presto 6N Pic1.jpg

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IMAGE 2: Setting the angle to 0°
Presto has solved this perfectly because the combination of the holding arm (red) and cutting head (blue) is aligned in such a way that when you change the cutting angle, the contact point remains the same. This is not so well designed in all devices.
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Presto 6N Pic2.jpg

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IMAGE 3: Longer cutting shaft
If the cutting tool protrudes only 1 mm longer from the cutting head than the original (yellow tool), then you have an offset of 1 mm from the center line. The same applies if the cutting tool is 1 mm shorter, then there is an offset in the other direction.
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Presto 6N Pic3.jpg

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I don't know if Presto has small spacer plates between the cutting head and the holder that could be used to adjust this. Someone familiar with Presto 6n will certainly be able to help.

hope that helps
Thomas

[farmersplow]

Noise 50kHz to 200kHz:

Who cares? These frequencies cannot be heard and certainly cannot be cut!
But they still have a very disruptive effect on my device.
Here's why:
My analog level meter is very sensitive and connected to the signal from the cutting head. So it's directly connected to the output of the power amplifier. An interference signal at the analog input, which then runs through the feedback amplifier and is then (strongly) amplified in the high frequencies by the IRIAA equalizer, generates strong high frequencies. An interference signal at 20kHz is then amplified so strongly that the analog display shows noise, even when no sound is playing. You can't hear anything in the recording either. But you can't rely on the display. And who can say whether the interference will remain at 20kHz or 30kHz?
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112_A.jpg

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But where did this interference come from? As long as I didn't have any cables connected to the input, there was no interference. As soon as I connected the audio interface (SSL2+) and supplied it with USB power, the interference signal appeared.
The interference was clearly visible on the oscilloscope. The sine wave input signal (green 1600Hz from the signal generator) is relatively good. The output signals (blue & yellow) were not smooth but showed interference. At higher frequencies, it is even worse.
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112_B.jpg

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I also had this problem with other D/A converters from other audio interfaces. You need expensive studio equipment with linear power supplies to avoid this problem. The cause of such problems is switching power supplies, which always have high-frequency components.
So I installed an 18 kHz low-pass filter (which I built a few years ago) at the signal input. It is powered by a “linear power supply.”
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112_C.jpg

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Now the problem is finally solved, the signal display on the oscilloscope is as smooth as a baby's bottom, and my analog displays remain completely stable and where they should be.
Here is a comparison with and without the filter. The left channel (blue) is without the filter and the right channel (yellow) is with the filter.
(P.S.: The RC filter causes a signal shift of 25µs. Since the filter is ultimately installed on both channels, this does not matter).
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112_D.jpg

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Greetings from Austria,
Thomas

[farmersplow]

18kHz low-pass Butterworth filter, 4th order, -80dB:

I have redesigned the low-pass filter mentioned above for my lathe.
I chose an analog “Butterworth filter” to filter the audio input signal. (4th order -80dB). This means that filtering is performed in two stages (-20dB per frequency decade/order). Minus 3dB at 18kHz.
Stage 1: 1st order -20dB; 2nd order -40dB
Stage 2: 3rd order -60dB; 4th order -80dB

To avoid distortion and noise, I opted for high-quality components. I chose the LT1357 as the op-amp because it is one of the “quietest” and “fastest” op-amps. I chose the RC (resistor capacitor) ratio so that the largest resistance is 7.15kOhm (resistance noise can occur from 10kOhm). The capacitors were selected with 1% accuracy. This selection is a little more expensive, but the quality is right.

The calculated characteristic curve of the low-pass filter:
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113_A.jpg

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And the calculated dispersion based on the component selection. This is really good:
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113_B.jpg

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The simplified circuit diagram:
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113_C.jpg

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And here is my circuit diagram for the (stereo) implementation:
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113_D.jpg

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Of course, I also produced the corresponding printed circuit board:
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113_E.jpg

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And assembled the components in 45 seconds. (Video)
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113_F_video.mp4

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I have now measured it again with the oscilloscope and cannot detect any signal loss. And since I don't want any frequencies above 18kHz on my cutting head anyway, I'm glad that I have now installed this filter.

Greetings from Austria,
Thomas

[farmersplow]

3D printer parts:

Since my lathe is almost complete, I used the 3D printer to make a few more parts.
There are only three parts. Two for the microscope, which needs better cable routing, and one part to cover a mounting hole between the housing and the mounting plate for the cutting head suspension.

Here are the top and bottom parts for the microscope...
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114_A.jpg

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114_C.jpg

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...and the cover for the mounting hole:
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114_E.jpg

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Greetings from Austria,
Thomas

[farmersplow]

LED strobes and speed controllers:

My previous (temporary) strobe lamp was not only ugly, but also too high. So whenever I moved my microscope over it, I bumped into it. So I made an aluminum housing using a CNC milling machine, installed LEDs, and encased it in blue resin. Now it fits perfectly and is lower than the blank plate.
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115_A.jpg

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It works perfectly and looks good too. It was about time I remedied this problem!
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115_B.jpg

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Greetings from Austria,
Thomas

[FILMTOOLS]

Loved every second of reading from page 1 to page 22 and learned a lot Your dedication and attention to detail is incredible. Can't wait to see it in person! Just listened to Sade and Skrillex you cut and the dynamics is so nice I am listening on mastering headphones with RME interface. I can hear a lot of background noise but I think you have cleaned that with the filters you made. It would be nice to cut some drum'n'bass/jungle and house tracks to hear the performance now after the filters. USB interfaces are almost always full of hum/noise without the USB filter.

Greetings from Ried im Innkreis (Austria),
Edin

[farmersplow]

Loved every second of reading from page 1 to page 22 and learned a lot Your dedication and attention to detail is incredible. Can't wait to see it in person! Just listened to Sade and Skrillex you cut and the dynamics is so nice I am listening on mastering headphones with RME interface. I can hear a lot of background noise but I think you have cleaned that with the filters you made. It would be nice to cut some drum'n'bass/jungle and house tracks to hear the performance now after the filters. USB interfaces are almost always full of hum/noise without the USB filter.

Greetings from Ried im Innkreis (Austria),
Edin

Hi Edin, I'm looking forward to your visit, then we'll get the plow out and plow a furrow! See you in two weeks.

[farmersplow]

The power supply:

I had been using my “temporary” power supply for many years, and it had served me well. I had installed it in an old PC case with various switching power supplies (non-linear) from China for the supply voltages 24V, 12V, and 5V (stepper motor control, servo motor, pull magnet, lighting, heating, display, and processors). In addition, I had my own complex linear power supply for the +/-15V of the audio preamplifiers, filters, feedback amplifiers, and EQs.
Tests and measurements have shown that the Chinese power supplies are of poor quality and that the connection cables also need improvement.
So now I'm doing this part properly too:

By installing high-quality switching power supplies with switch-on delay, switch-off relays, and 47,000µF capacitors, I can now ensure safe and stable voltages. I have also made the linear power supply a little more stable against mains interference with filters.
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117_A.jpg

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117_B.jpg

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I also included the power supply for my turntable drive and a super-quiet cooling fan.

I installed everything in a neat and sturdy 19" rack enclosure.
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With an illuminated power switch and indicator lights for the different voltage ranges. This isn't absolutely necessary, but otherwise the front would look too empty. A little design is allowed, right?

On the back, I installed the 14-pin power connector next to the power plug (with fuse). The power cable then leads directly to my lathe (also with a 14-pin power connector).
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117_H.jpg

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I also installed a switched power connection for the heating lamp at the rear. A cable is also routed to the lathe to supply power to the temperature control. This allows me to switch everything on or off with one switch on the power supply unit.
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117_J.jpg

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Greetings from Austria,
Thomas

[diy_cutter]

Thomas, once again, I take my hat off to your professional approach.

I would also like to participate in the challenge by recording a Whitney Houston track. I'll be at the machine tomorrow.

Our approach as a team is more practical. The goal we have set for ourselves is to donate a significant portion of our income to help our country. We have been recording as a service for over a year now and have recorded about 2,000 records. We now have two machines and I like the results of our recordings. However, I need to write about all this in my (long-forgotten) thread.

I admire you and your perseverance!

Yevgeniy

[farmersplow]

Thomas, once again, I take my hat off to your professional approach.

I would also like to participate in the challenge by recording a Whitney Houston track. I'll be at the machine tomorrow.

Our approach as a team is more practical. The goal we have set for ourselves is to donate a significant portion of our income to help our country. We have been recording as a service for over a year now and have recorded about 2,000 records. We now have two machines and I like the results of our recordings. However, I need to write about all this in my (long-forgotten) thread.

I admire you and your perseverance!

Yevgeniy

Yevgeny - Great! If you have time, please tell us about your successes and work in your post. I'm already curious; it seems to be working!

And please do cut Whitney too; I think an interactive challenge like this is great. Thanks for the idea to Joe (displacednail).

And thank you for your praise.

Thomas

[zdenda.jircik]

Hello Farmer,
I'm newbie here. I'm going into building my own lathe for cutting vinyls. So, I decided start at this forum and absorb theory and experiences as much as possible.

You topic here is one of most inspiring to me. I really appreciate so much effort and sharing it here. I already have ordered turntable as a base for the project. I'm looking forward for such a build.

I still have a lot of questions, but quite all answers are already in this forum. Maybe I could also report my progress in new topic. Also seems to be really heplful to know others opinion.

BR
Zdenda

[zdenek]

The power supply:

I had been using my “temporary” power supply for many years, and it had served me well. I had installed it in an old PC case with various switching power supplies (non-linear) from China for the supply voltages 24V, 12V, and 5V (stepper motor control, servo motor, pull magnet, lighting, heating, display, and processors). In addition, I had my own complex linear power supply for the +/-15V of the audio preamplifiers, filters, feedback amplifiers, and EQs.
Tests and measurements have shown that the Chinese power supplies are of poor quality and that the connection cables also need improvement.
So now I'm doing this part properly too:

By installing high-quality switching power supplies with switch-on delay, switch-off relays, and 47,000µF capacitors, I can now ensure safe and stable voltages. I have also made the linear power supply a little more stable against mains interference with filters.
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.
117_A.jpg
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117_B.jpg
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I also included the power supply for my turntable drive and a super-quiet cooling fan.

I installed everything in a neat and sturdy 19" rack enclosure.
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117_C.jpg
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117_D.jpg
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117_E.jpg
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117_F.jpg
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117_G.jpg
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With an illuminated power switch and indicator lights for the different voltage ranges. This isn't absolutely necessary, but otherwise the front would look too empty. A little design is allowed, right?

On the back, I installed the 14-pin power connector next to the power plug (with fuse). The power cable then leads directly to my lathe (also with a 14-pin power connector).
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117_H.jpg
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117_I.jpg
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I also installed a switched power connection for the heating lamp at the rear. A cable is also routed to the lathe to supply power to the temperature control. This allows me to switch everything on or off with one switch on the power supply unit.
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117_J.jpg
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117_K.jpg
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Greetings from Austria,
Thomas

Hello,
Nice work, remember to GROUND [yellow mains center pin to ground].
Your entire device is metal, so it's no joke [although they say that electricians won't be affected by current, or that electricians are immune to current, etc.]
I have a question for you, Farmer. You have a power output socket there. What overloads can it withstand, and who is the manufacturer of this socket?
I'm currently on vacation and starting to build a new lathe from scratch, starting with the power supply, unfortunately...
Greetings from a war veteran...

[farmersplow]

Hello Farmer,
I'm newbie here. I'm going into building my own lathe for cutting vinyls. So, I decided start at this forum and absorb theory and experiences as much as possible.

You topic here is one of most inspiring to me. I really appreciate so much effort and sharing it here. I already have ordered turntable as a base for the project. I'm looking forward for such a build.

I still have a lot of questions, but quite all answers are already in this forum. Maybe I could also report my progress in new topic. Also seems to be really heplful to know others opinion.

BR
Zdenda

Hi Zdenda, thank you so much for your feedback. I'm glad my post inspired you; that was the goal.

I wish you all the best on your journey. It may be challenging at times, but ultimately it's very rewarding (especially when the first furrows you cut are filled with music).