Test results with damping of speaker drive rods:
Here are the test results in comparison:
ABOVE: Speakers with epoxy-resin impregnated coil spiders (without damping).
BOTTOM: Speakers with epoxy-resin impregnated coil spiders (with damping of the drive rods)
The main resonant frequency has dropped from 820Hz to about 790Hz!
Probably because of the additional weight of 0.5g damper weight per speaker. - (I save: 0.5g corresponds to about 30-40Hz loss of main resonance -- at 800Hz).
The "secondary resonance" at 1.8kHz has remained about the same.
The resonances (~9kHz) were visibly further attenuated!
Music test with the modified Spider speakers:
After removing the damping elements on the drive rods again, I wanted to hear how the whole thing sounds with music.
Of course a "new" set of speakers with a new frequency band also needs an adjusted equalizer. Therefore I adjusted the input EQ a little bit on the computer in the sound program (still Cakewalk). For this I needed several attempts (15x) so that my music sounds halfway good. Unfortunately, I still have a little too much volume in the range between 3kHz and 7kHz.
Nevertheless, I think the result sounds quite good for "Spider" speakers - what do you think?
My dear wife thinks "Honey, there is a little bit missing volume". She's not a professional, but she's my strongest critic - and she's right. (Now where do I get the volume?)
TEST MUSIC MIX (Six excerpts of music pieces)
DUMP QUESTION TO THE TROLLS:
Do you play your music "directly" to the cutterhead?
Of course you use an EEQ, a low and high cut filter and maybe a limiter and a feedback coil amplifier (if you have a feedback coil) - I do that too.
But in your case, is the frequency line of the cutterhead flat enough that you don't need an equalizer?
(Because I'm afraid I'll never get a cutterhead like that).
So do you use an EQ to compensate the characteristic curve of the cutterhead?
If so, which one? A digital one from the sound program, or an analog one?
Please give me some hints, because I haven't found enough on this topic.
(I suspect that in the coming week the new tweeters will finally arrive...).
See you soon and best regards from Austria
Thomas
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farmersplow
- Posts: 376
- 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
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Re: The farmer and his plow - When I set out to build a record cutter
Hi,
If you close the feedback loop, the servo action takes care of much of the EQ needed to flatten the head response. You will always need to apply RIAA, but that is typically outside of the feedback loop. Depending on the amount of feedback applied, you might still need a bit of corrective EQ to flatten the head response at the frequency extremes as the feedback will not be in effect at those points.
See the attached pdf from an Ortofon brochure that shows the open loop response of their head with no feedback. Notice how nice and smooth and free of extra resonances it is. Not so easy to do, but this response allows the head feedback loop to be closed easily over a wide range.
In the case of an open loop moving coil head design, you will always require some heavy amounts of EQ to flatten the response of the head. This is true even for a head that is "textbook" perfect in its behavior. The basic physics of the
mechanical system dictates its response. In terms of velocity response, you have two basic regions of operation defined by the main system resonance. Below resonance, the system is controlled by stiffness and rises at 6db/oct. On the other side of resonance, the response falls at -6db/oct. Any deviation from "textbook" adds additional EQ requirements. On the RIAA front, you can use the fact that some of the RIAA curve matches the response in the stiffness region and fold this into your overall EQ. If you choose to look at the response from an excursion point of view, the head is flat up to system resonance and then falls at -12db/oct beyond.
You can see that even in the best case, you need some very large amounts of EQ in the system to make this work. That why you need such large reserves of power for the high frequencies. The head only needs to dissipate 5-20 Watts on a long term average to cut at reasonable loudness, but you need tons of extra power reserve to make the head accelerate at high frequencies.
Moving Iron heads are a different beast. They need less power, are quite stiff, have very high main resonances (8-10Kz) and require less EQ. For examples see the Presto 1C/D and Grampian designs.
Hope you find this helpful,
Mark
If you close the feedback loop, the servo action takes care of much of the EQ needed to flatten the head response. You will always need to apply RIAA, but that is typically outside of the feedback loop. Depending on the amount of feedback applied, you might still need a bit of corrective EQ to flatten the head response at the frequency extremes as the feedback will not be in effect at those points.
See the attached pdf from an Ortofon brochure that shows the open loop response of their head with no feedback. Notice how nice and smooth and free of extra resonances it is. Not so easy to do, but this response allows the head feedback loop to be closed easily over a wide range.
In the case of an open loop moving coil head design, you will always require some heavy amounts of EQ to flatten the response of the head. This is true even for a head that is "textbook" perfect in its behavior. The basic physics of the
mechanical system dictates its response. In terms of velocity response, you have two basic regions of operation defined by the main system resonance. Below resonance, the system is controlled by stiffness and rises at 6db/oct. On the other side of resonance, the response falls at -6db/oct. Any deviation from "textbook" adds additional EQ requirements. On the RIAA front, you can use the fact that some of the RIAA curve matches the response in the stiffness region and fold this into your overall EQ. If you choose to look at the response from an excursion point of view, the head is flat up to system resonance and then falls at -12db/oct beyond.
You can see that even in the best case, you need some very large amounts of EQ in the system to make this work. That why you need such large reserves of power for the high frequencies. The head only needs to dissipate 5-20 Watts on a long term average to cut at reasonable loudness, but you need tons of extra power reserve to make the head accelerate at high frequencies.
Moving Iron heads are a different beast. They need less power, are quite stiff, have very high main resonances (8-10Kz) and require less EQ. For examples see the Presto 1C/D and Grampian designs.
Hope you find this helpful,
Mark
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farmersplow
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Re: The farmer and his plow - When I set out to build a record cutter
Hello Mark,
thank you very much for the answer. With this information I am reasonably reassured. I already thought I was completely off track.
My EQ curve looks really bad!
The information is very helpful for me and motivates me to create a (according to my possibilities almost) resonance-free head.
I will take care of the closed loop later - if I should be ready at some point I might need some support (I have some questions about this) - but much much later.
So I'm off on my journey.... and the search for resonances and their hidden causes....
Thanks for the support
Greetings from Austria
Thomas
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farmersplow
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Re: The farmer and his plow - When I set out to build a record cutter
New speakers:
I am back.
After spending a few days of vacation on the Italian Adriatic with my dear wife (before she leaves me due to neglect and kitchen block), I have arrived back home.
Likewise, the speakers have also arrived. (Both the tweeters and the resonance speakers).
I would love to test both right away, but unfortunately, I have to build one after the other.
Because I already have the cutterhead enclosure for the resonant speakers, I'll start with that.
The goal is to make the mount for the voice coils much more stable and at the same time reduce the weight of the moving masses. First, I separate the coil from the metal ring (as I did a few times before) and then I separate the aluminum plate from the metal ring.
Now I use my 3D milling cutter again and mill away everything I don't need.
From the aluminum plate I make a very thin aluminum ring (that centers the coil later).
From the metal plate I mill a big hole from the center - just as big as the aluminum ring.
And then I glue the two parts together.
The weight saving is great! Especially when you consider that the outer stabilizer ring is still attached to the "new" metal ring. (Moving mass is a little less than half because the outer part is fixed).
Here in comparison the metal rings (original, first version and new version):
With the coil the part weighs 5.3 grams (I estimate the moving mass to be 3.5g)
Installation in the casing:
When I installed them in the chassis, I moved the two speakers slightly inward. The goal is to keep the drive rods shorter to reduce any resonances and to reduce the weight (even if only slightly).
I coated the carbon parts with epoxy resin to increase the hardness.
Tomorrow I will then make a cutting test. I expect the main resonance to rise above 1kHz and hope for lower secondary resonances.
We will see.
Greetings from Austria
Thomas
I am back.
After spending a few days of vacation on the Italian Adriatic with my dear wife (before she leaves me due to neglect and kitchen block), I have arrived back home.
Likewise, the speakers have also arrived. (Both the tweeters and the resonance speakers).
I would love to test both right away, but unfortunately, I have to build one after the other.
Because I already have the cutterhead enclosure for the resonant speakers, I'll start with that.
The goal is to make the mount for the voice coils much more stable and at the same time reduce the weight of the moving masses. First, I separate the coil from the metal ring (as I did a few times before) and then I separate the aluminum plate from the metal ring.
Now I use my 3D milling cutter again and mill away everything I don't need.
From the aluminum plate I make a very thin aluminum ring (that centers the coil later).
From the metal plate I mill a big hole from the center - just as big as the aluminum ring.
And then I glue the two parts together.
The weight saving is great! Especially when you consider that the outer stabilizer ring is still attached to the "new" metal ring. (Moving mass is a little less than half because the outer part is fixed).
Here in comparison the metal rings (original, first version and new version):
With the coil the part weighs 5.3 grams (I estimate the moving mass to be 3.5g)
Installation in the casing:
When I installed them in the chassis, I moved the two speakers slightly inward. The goal is to keep the drive rods shorter to reduce any resonances and to reduce the weight (even if only slightly).
I coated the carbon parts with epoxy resin to increase the hardness.
Tomorrow I will then make a cutting test. I expect the main resonance to rise above 1kHz and hope for lower secondary resonances.
We will see.
Greetings from Austria
Thomas
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farmersplow
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Re: The farmer and his plow - When I set out to build a record cutter
Cutting tests :
The results of the cutting tests with the harder speakers (solid metal ring) with lower weight are unfortunately very frustrating.
Although the results are better than the resonances with the ground-machined "softer" metal ring, I am not satisfied.
The main resonance increases from 280Hz to 520Hz, but the secondary resonances at 2kHz, 8kHz and 12kHz are much worse than before.
Picture above: the new metal ring (harder and lighter)
Picture below: the old metal ring (softer and heavier)
Especially when I compare the results with the "Spider" suspension.
Picture above: the new metal ring (harder and lighter)
Picture below: the old "Spider" suspension
Why is that? Is it because of the mechanical construction of the resonant speakers? Is it because of the carbon cone? Is it the torsion bar?
The results of the cutting tests with the harder speakers (solid metal ring) with lower weight are unfortunately very frustrating.
Although the results are better than the resonances with the ground-machined "softer" metal ring, I am not satisfied.
The main resonance increases from 280Hz to 520Hz, but the secondary resonances at 2kHz, 8kHz and 12kHz are much worse than before.
Picture above: the new metal ring (harder and lighter)
Picture below: the old metal ring (softer and heavier)
Especially when I compare the results with the "Spider" suspension.
Picture above: the new metal ring (harder and lighter)
Picture below: the old "Spider" suspension
Why is that? Is it because of the mechanical construction of the resonant speakers? Is it because of the carbon cone? Is it the torsion bar?
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farmersplow
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Re: The farmer and his plow - When I set out to build a record cutter
New speakers :
To further narrow down the resonance issue, I'm now trying new tweeter speakers.
They have a diameter of about 50mm and are 8 ohm speakers. I could not find a quality 4 ohm speaker in a suitable size. Maybe someone has a good suggestion?
First I cut out the plastic part in the middle.
The cone:
I am trying to create cones from different materials. On the one hand, I have built a cone from carbon, one from aluminum and one from brass foil. The three versions show different characteristics.
In terms of weight, the carbon cone is the heaviest and the brass foil one is the lightest.
In terms of stability, the carbon cone is by far the best. Although it is somewhat elastic, I can compress it only slightly at the edge. If I did that with the aluminum/brass cones, they would be flat as paper!
But when I drop the cones from a height of about 50cm onto the stone plate, the carbon cone sounds far more muffled than the two metal cones.
Therefore, I will first test the cone for the new speaker with the brass foil.
Since the coil diameter of these speakers is only about 12mm, I built slightly longer/pointed cones for this purpose to get closer to the torque tube. They weigh 0.14 grams.
Next, I need to rebuild the cutting head so that the speakers can be installed as well. I will get back to you.
Greetings from Austria
Thomas
To further narrow down the resonance issue, I'm now trying new tweeter speakers.
They have a diameter of about 50mm and are 8 ohm speakers. I could not find a quality 4 ohm speaker in a suitable size. Maybe someone has a good suggestion?
First I cut out the plastic part in the middle.
The cone:
I am trying to create cones from different materials. On the one hand, I have built a cone from carbon, one from aluminum and one from brass foil. The three versions show different characteristics.
In terms of weight, the carbon cone is the heaviest and the brass foil one is the lightest.
In terms of stability, the carbon cone is by far the best. Although it is somewhat elastic, I can compress it only slightly at the edge. If I did that with the aluminum/brass cones, they would be flat as paper!
But when I drop the cones from a height of about 50cm onto the stone plate, the carbon cone sounds far more muffled than the two metal cones.
Therefore, I will first test the cone for the new speaker with the brass foil.
Since the coil diameter of these speakers is only about 12mm, I built slightly longer/pointed cones for this purpose to get closer to the torque tube. They weigh 0.14 grams.
Next, I need to rebuild the cutting head so that the speakers can be installed as well. I will get back to you.
Greetings from Austria
Thomas
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farmersplow
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- 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
The speaker cone:
Short information how I built the cone with brass foil. First I marked the brass foil with compasses and cut it out with nail scissors:
Then I rolled the film over a steel cone for a long time (very long). Until it remained almost without holding in the mold. Only then were the slightly overlapping surfaces glued with superglue under pressure.
In the same way I made a thin connection tube (1mm). The one end I have then slightly brushed with the steel cone. (Do you say brushed? I mean conically expanded).
Here is a first (test) fitting:
Because it fit so well, I used the 1mm wire from phosphor bronze to center and glue the two parts. I rubbed the transitions with a thin metal rod.
Looks better right away:
Now to the weight: The cone with attachment weighs only 0.16 grams glued together.
That is a low weight, especially if you measure the weight with the phosphor bronze wire glued. There it is already 0.30 grams. So the piece of wire weighs almost as much as the whole rest of the cone.
To check - both together weigh 0.60 grams.
As a reminder, the very first cutting head (the small one) had a perforated carbon cone with carbon rod and phosphor bronze wire - together they weighed 0.70 grams. So if weight is a decisive feature, then I'm on the right track.
Whether the stability and resonance fidelity of the new cone is better, only the tests will show.
Cone with weight with the phosphor bronze wire glued
Two cones together
Compare: the first carbone cone with wire
Short information how I built the cone with brass foil. First I marked the brass foil with compasses and cut it out with nail scissors:
Then I rolled the film over a steel cone for a long time (very long). Until it remained almost without holding in the mold. Only then were the slightly overlapping surfaces glued with superglue under pressure.
In the same way I made a thin connection tube (1mm). The one end I have then slightly brushed with the steel cone. (Do you say brushed? I mean conically expanded).
Here is a first (test) fitting:
Because it fit so well, I used the 1mm wire from phosphor bronze to center and glue the two parts. I rubbed the transitions with a thin metal rod.
Looks better right away:
Now to the weight: The cone with attachment weighs only 0.16 grams glued together.
That is a low weight, especially if you measure the weight with the phosphor bronze wire glued. There it is already 0.30 grams. So the piece of wire weighs almost as much as the whole rest of the cone.
To check - both together weigh 0.60 grams.
As a reminder, the very first cutting head (the small one) had a perforated carbon cone with carbon rod and phosphor bronze wire - together they weighed 0.70 grams. So if weight is a decisive feature, then I'm on the right track.
Whether the stability and resonance fidelity of the new cone is better, only the tests will show.
Cone with weight with the phosphor bronze wire glued
Two cones together
Compare: the first carbone cone with wire
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farmersplow
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- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
The rebuilt cutterhead (version 5):
After I cut the tweeter speakers a bit, they also fit into the existing cabinet. (Back of the speakers to d=50mm circular ground and cut on the sides).
However, I had to completely disassemble the cabinet and make threaded holes for the speakers.
All assembled looks quite nice again.
I reinstalled the cutterhead in my lathe and rebuilt the mount a bit because of the weight adjustments. - Finally, this cutterhead is much lighter than the last one.
Now I'm going to let all the glue set until tomorrow. I'm already very curious how the tests turn out. - Hopefully not another setback....
Greetings from Austria
Thomas
After I cut the tweeter speakers a bit, they also fit into the existing cabinet. (Back of the speakers to d=50mm circular ground and cut on the sides).
However, I had to completely disassemble the cabinet and make threaded holes for the speakers.
All assembled looks quite nice again.
I reinstalled the cutterhead in my lathe and rebuilt the mount a bit because of the weight adjustments. - Finally, this cutterhead is much lighter than the last one.
Now I'm going to let all the glue set until tomorrow. I'm already very curious how the tests turn out. - Hopefully not another setback....
Greetings from Austria
Thomas
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Re: The farmer and his plow - When I set out to build a record cutter
I have used those large surface transducers before - they worked surprisingly well...my theory was that I could to offset the extra mass of the drivers by dampening and stiffening the construction, I did this by mounting them on the top side of the aluminum angle, they were then coated in a thin layer of sealant. In my mind this stiffer assembly could be better for a dynamic cutting head as it means the head is more rigid and controllable. The layer of sealant theoretically provides another spider/spring to stop coil rub. I don't think I even maxed out the coils, so it may have required a beefier amplifier.
I haven't tried using the head for a long while, at some point once I figure out how to sharpen these stylus I might give it another crack. I've also procured a spot/tig/pulse welder which could mean it would not require glue.
I was quite impressed with how well it worked, considering it was assembled from piano wire, sealant and glue. There's a pink noise sample at the beginning of the track.
This is a sample cut with a unpolished diamond - Since the diamond is essentially blunt, I was cutting at something like 20g of weight...I think it muted the volume and top end a little and it's a little noisy.
https://drive.google.com/file/d/1aEz7EYOFOz8VQStTTlT3k3njb14TCVDh/view?usp=sharing
I've attached some photos.
I plan to release the STLs at some point, as I was quite happy with how easy construction was.
It's based on the Souri/Bachman style cutting head.
I haven't tried using the head for a long while, at some point once I figure out how to sharpen these stylus I might give it another crack. I've also procured a spot/tig/pulse welder which could mean it would not require glue.
I was quite impressed with how well it worked, considering it was assembled from piano wire, sealant and glue. There's a pink noise sample at the beginning of the track.
This is a sample cut with a unpolished diamond - Since the diamond is essentially blunt, I was cutting at something like 20g of weight...I think it muted the volume and top end a little and it's a little noisy.
https://drive.google.com/file/d/1aEz7EYOFOz8VQStTTlT3k3njb14TCVDh/view?usp=sharing
I've attached some photos.
I plan to release the STLs at some point, as I was quite happy with how easy construction was.
It's based on the Souri/Bachman style cutting head.
You do not have the required permissions to view the files attached to this post.
Record Lathe Embossing Supplies - http://www.supplies.johnnyelectric.co.nz/
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farmersplow
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- Location: Austria - Vienna
Re: The farmer and his plow - When I set out to build a record cutter
Hi jjwharris,
thank you for your contribution.
I was also very surprised how well the resonant transducers work - especially compared to the tweeters.
Thanks for the suggestion to coat the aluminum parts with sealant. I wouldn't have thought it would have any effect on the resonance curve.
What I don't understand is how can the coating simulate another "spider/spring" and stop the coil rubbing?
Is the test cut created by embedding or cutting?
By the way, this cutting head looks really good.
Greetings from Austria
Thomas
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farmersplow
- Posts: 376
- 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
One step forward and two steps back:
When I made the first test cuts with the modified tweeters, I was a little demotivated and decided to take a week's vacation by the sea with my lovely wife. I had to calm down.
But now the vacation time is over and I would like to report briefly what had happened.
First, I had the cutting head installed in my lathe and had to realign the geometry as reported earlier.
I also had to renew the diamond needle because the "old" one was damaged during the rebuild (my carelessness).
I took a new plate blank and tried a first "silent cut". In doing so, I produced a lot of cutting thread, which I only got a handle on after several adjustments (support weight, adjust positioning...). In the process, the entire side A of the plate blank was consumed.
The "Silent Cut" was anything but "Silent"! It sounds: "windy"; "loud"; "crashing"; "high frequency". I had all this under control before!
[/b]
On the second cut attempt (White Noise without IRIAA) I had to turn the plate (side B). But the plate then had a vertical runout of almost 2mm!
[/size][/b]
I suspect that I did the flipping of the record when it was still too warm and warped it?!
I then played back the signal (white noise). Regardless of the resonance band, I had a terribly loud background noise! It sounds: "even more windy"; "even louder"; "even more crashing"; "and high-frequency".
[/b]
The only positive thing is that I had the extraction of the thread under control again (see picture and video)
[/size][/b]
Here is the signal image of the White Noise:
It is immediately noticeable that there is only one yellow line! (RED = right channel; GREEN = left channel; YELLOW = when both channels are identical).
This can mean two things: First, both speakers work so accurately that there are no differentials and both work exactly the same at all frequencies. Or two, the stereo effect is completely lost and any signal that one of the two speakers sends out directly affects the other speaker.
The probability for case two is unfortunately much too high.
(When I also cut my test music, it proved true: No more stereo signal!)
Signal comparisons: Tweeter version v.s. resonance loudspeaker with metal ring
First the signal comparison of this tweeter version with the version of the resonance loudspeaker with metal ring. The main resonance could be raised from 520Hz to 610Hz. The other resonances were also raised a bit.
Signal comparisons: Tweeter version v.s. resonance loudspeaker with spider (epoxy)
Now the signal comparison of this tweeter version with the version of the resonance speaker with spider (epoxy). The main resonance of 820Hz of the "Spider" could not be reached.
Parametric Equalizer for Tweeter-Version
I sat down at the PC and tried to get the white noise signal reasonably straight by generating an insane parametric equalizer curve. And yes, it works. But the EQ curve looks accordingly "creative".
So after diamond needle was destroyed, suction was faulty, the plate blank was wavy, Silent Cut was loud, resonance image was below my expectations and the stereo effect was also gone --- I just had to take some vacation.
Now I'm back stronger and rolling up my sleeves to turn all those flaws and weaknesses into strengths. (I already sound like my own motivation trainer).
So first I'm going to realign the geometry of the suspension. The squeaking of the graver is probably because of an incorrect angle - or just because it's new?
And the stereo effect? Don't know. Maybe I have to weaken the V-spring a bit because the weight of the moving masses has become so low now???
I will get back to you.
Greetings from Austria
Thomas
When I made the first test cuts with the modified tweeters, I was a little demotivated and decided to take a week's vacation by the sea with my lovely wife. I had to calm down.
But now the vacation time is over and I would like to report briefly what had happened.
First, I had the cutting head installed in my lathe and had to realign the geometry as reported earlier.
I also had to renew the diamond needle because the "old" one was damaged during the rebuild (my carelessness).
I took a new plate blank and tried a first "silent cut". In doing so, I produced a lot of cutting thread, which I only got a handle on after several adjustments (support weight, adjust positioning...). In the process, the entire side A of the plate blank was consumed.
The "Silent Cut" was anything but "Silent"! It sounds: "windy"; "loud"; "crashing"; "high frequency". I had all this under control before!
[/b]
On the second cut attempt (White Noise without IRIAA) I had to turn the plate (side B). But the plate then had a vertical runout of almost 2mm!
[/size][/b]
I suspect that I did the flipping of the record when it was still too warm and warped it?!
I then played back the signal (white noise). Regardless of the resonance band, I had a terribly loud background noise! It sounds: "even more windy"; "even louder"; "even more crashing"; "and high-frequency".
[/b]
The only positive thing is that I had the extraction of the thread under control again (see picture and video)
[/size][/b]
Here is the signal image of the White Noise:
It is immediately noticeable that there is only one yellow line! (RED = right channel; GREEN = left channel; YELLOW = when both channels are identical).
This can mean two things: First, both speakers work so accurately that there are no differentials and both work exactly the same at all frequencies. Or two, the stereo effect is completely lost and any signal that one of the two speakers sends out directly affects the other speaker.
The probability for case two is unfortunately much too high.
(When I also cut my test music, it proved true: No more stereo signal!)
Signal comparisons: Tweeter version v.s. resonance loudspeaker with metal ring
First the signal comparison of this tweeter version with the version of the resonance loudspeaker with metal ring. The main resonance could be raised from 520Hz to 610Hz. The other resonances were also raised a bit.
- Main resonance tweeter slightly higher than the resonance speaker.
The tweeter speaker cut louder at the same amplifier power.
Tweeter speaker has lost its stereo effect.
The tweeter speaker has a big resonance problem at 3kHz.
The tweeter speaker has a slightly flatter resonance curve overall.
The tweeter speaker is more "stable" in the upper frequency range (>10kHz)
Signal comparisons: Tweeter version v.s. resonance loudspeaker with spider (epoxy)
Now the signal comparison of this tweeter version with the version of the resonance speaker with spider (epoxy). The main resonance of 820Hz of the "Spider" could not be reached.
- Main resonance tweeter nedrer than the resonance speaker.
The tweeter speaker cut louder at the same amplifier power.
The tweeter speaker lost its stereo effect.
The tweeter speaker has a major resonance problem at 3kHz.
The tweeter speaker is more "stable" in the upper frequency range (>10kHz)
Parametric Equalizer for Tweeter-Version
I sat down at the PC and tried to get the white noise signal reasonably straight by generating an insane parametric equalizer curve. And yes, it works. But the EQ curve looks accordingly "creative".
So after diamond needle was destroyed, suction was faulty, the plate blank was wavy, Silent Cut was loud, resonance image was below my expectations and the stereo effect was also gone --- I just had to take some vacation.
Now I'm back stronger and rolling up my sleeves to turn all those flaws and weaknesses into strengths. (I already sound like my own motivation trainer).
So first I'm going to realign the geometry of the suspension. The squeaking of the graver is probably because of an incorrect angle - or just because it's new?
And the stereo effect? Don't know. Maybe I have to weaken the V-spring a bit because the weight of the moving masses has become so low now???
I will get back to you.
Greetings from Austria
Thomas
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Re: The farmer and his plow - When I set out to build a record cutter
Hello farmersplow, you've done a lot of work!
I wrote about my project because I've seen professional metal cutting and turning machines, surely vinyl recording is also high accuracy machining, so the machine for this process should be made of very rigid materials, don't be mad at me for telling you that.
Your recordings sound very good.
You record on plastic, it is much harder than varnish plates and plastic has a heterogeneous structure, which can cause crackling and noise.
If you have the opportunity to buy an original Apollo master lacquer plate, try to record Apollo master on this disc using your recording lathe, certainly the sound quality and volume of the recording and the depth of the grooves will be much better with less noise, sapphire, ruby knives will last much longer than a diamond knife in plastic plates that's what my engineers say.
I am greatly and positively impressed by Michael Jakson's recordings. Your work is a great inspiration for me.
greetings Zdenek
Hallo farmersplow , Sie haben viel Arbeit geleistet!
Ich habe über mein Projekt geschrieben, weil ich professionelle Metallschneide- und -drehmaschinen gesehen habe. Vinylaufnahmen sind sicherlich auch eine hochpräzise Bearbeitung, daher sollte die Maschine für diesen Prozess aus sehr steifen Materialien bestehen. Seien Sie mir nicht böse, wenn ich es Ihnen sage Das.
Deine Aufnahmen klingen sehr gut.
Sie nehmen auf Kunststoff auf, dieser ist viel härter als Lackplatten und Kunststoff hat eine heterogene Struktur, die zu Knistern und Geräuschen führen kann.
Wenn Sie die Möglichkeit haben, eine originale Apollo-Master-Lackplatte zu kaufen, versuchen Sie, mit Ihrer Aufnahmemaschine Apollo-Master auf dieser Disc aufzunehmen. Die Klangqualität und Lautstärke der Aufnahme sowie die Tiefe der Rillen werden mit Sicherheit viel besser und mit weniger Rauschen sein. Saphir- und Rubinmesser halten viel länger als Diamantmesser mit Kunststoffplatten, sagen meine Ingenieure.
Ich bin sehr und positiv beeindruckt von den Aufnahmen von Michael Jakson. Ihre Arbeit ist eine große Inspiration für mich.
Grüße Zdenek
I wrote about my project because I've seen professional metal cutting and turning machines, surely vinyl recording is also high accuracy machining, so the machine for this process should be made of very rigid materials, don't be mad at me for telling you that.
Your recordings sound very good.
You record on plastic, it is much harder than varnish plates and plastic has a heterogeneous structure, which can cause crackling and noise.
If you have the opportunity to buy an original Apollo master lacquer plate, try to record Apollo master on this disc using your recording lathe, certainly the sound quality and volume of the recording and the depth of the grooves will be much better with less noise, sapphire, ruby knives will last much longer than a diamond knife in plastic plates that's what my engineers say.
I am greatly and positively impressed by Michael Jakson's recordings. Your work is a great inspiration for me.
greetings Zdenek
Hallo farmersplow , Sie haben viel Arbeit geleistet!
Ich habe über mein Projekt geschrieben, weil ich professionelle Metallschneide- und -drehmaschinen gesehen habe. Vinylaufnahmen sind sicherlich auch eine hochpräzise Bearbeitung, daher sollte die Maschine für diesen Prozess aus sehr steifen Materialien bestehen. Seien Sie mir nicht böse, wenn ich es Ihnen sage Das.
Deine Aufnahmen klingen sehr gut.
Sie nehmen auf Kunststoff auf, dieser ist viel härter als Lackplatten und Kunststoff hat eine heterogene Struktur, die zu Knistern und Geräuschen führen kann.
Wenn Sie die Möglichkeit haben, eine originale Apollo-Master-Lackplatte zu kaufen, versuchen Sie, mit Ihrer Aufnahmemaschine Apollo-Master auf dieser Disc aufzunehmen. Die Klangqualität und Lautstärke der Aufnahme sowie die Tiefe der Rillen werden mit Sicherheit viel besser und mit weniger Rauschen sein. Saphir- und Rubinmesser halten viel länger als Diamantmesser mit Kunststoffplatten, sagen meine Ingenieure.
Ich bin sehr und positiv beeindruckt von den Aufnahmen von Michael Jakson. Ihre Arbeit ist eine große Inspiration für mich.
Grüße Zdenek
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farmersplow
- Posts: 376
- 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
Hello Zdenek,
thank you for your comment. It's been almost a year since I posted about my progress. This year I have progressed about another 2500 hours on the machine. When I am ready, I will post about it again and present my developments. I'm working on the "next level" project, so to speak.
It is of course well known that cutting on lacquer offers many advantages and in any case provides better recording quality than cutting on plastic. The only disadvantage is that I can't play back this great quality. My goal is not to produce top quality for galvanizing processes. I want to produce the best possible quality on plates that I can then play back without further processes.
I can post a short video of my device on this occasion. It is generation 5 (I am currently on gen. 7). Means the fifth cutting head and the fourth device. It is a feedback cutting head with 5 degree pre-cutting angle and diamond for PETG. The unit still has the direct drive (which I have since changed to belt drive and sleeve bearings). The stepper drive has a feed rate of 0.21µm per step. The control is adjusted via 7" touch display (cutting width, cutting depth, record speed and variable pitch, intensity suction, intensity stylus heating, temperature for record heating, laser calibration, filter (lowpass highpass), EEQ, IRIAA, feedback amplifier...
VIDEO:
See you soon and best regards from Austria
Thomas
thank you for your comment. It's been almost a year since I posted about my progress. This year I have progressed about another 2500 hours on the machine. When I am ready, I will post about it again and present my developments. I'm working on the "next level" project, so to speak.
It is of course well known that cutting on lacquer offers many advantages and in any case provides better recording quality than cutting on plastic. The only disadvantage is that I can't play back this great quality. My goal is not to produce top quality for galvanizing processes. I want to produce the best possible quality on plates that I can then play back without further processes.
I can post a short video of my device on this occasion. It is generation 5 (I am currently on gen. 7). Means the fifth cutting head and the fourth device. It is a feedback cutting head with 5 degree pre-cutting angle and diamond for PETG. The unit still has the direct drive (which I have since changed to belt drive and sleeve bearings). The stepper drive has a feed rate of 0.21µm per step. The control is adjusted via 7" touch display (cutting width, cutting depth, record speed and variable pitch, intensity suction, intensity stylus heating, temperature for record heating, laser calibration, filter (lowpass highpass), EEQ, IRIAA, feedback amplifier...
VIDEO:
See you soon and best regards from Austria
Thomas
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Re: The farmer and his plow - When I set out to build a record cutter
Cool! Good you engineer! Beautiful work!
I'm very impressed !
I'm making a slightly different machine, but this one will come soon... [I prefer not to show pictures for now because it's embarrassing ...]
Tell me Farmer, does this tt500 motor have enough power, doesn't it slow down from time to time when cutting? I am thinking about buying this turntable.
Can you give me the details of where to buy this device to which the cutting head is attached, this large metal device?
The whole performance is great!
Cool! Gut, Ingenieur! Schöne Arbeit!
Ich bin sehr beeindruckt !
Ich baue eine etwas andere Maschine, aber diese wird bald kommen ... [Ich zeige vorerst lieber keine Bilder, weil es peinlich ist ...]
Sag mir, Farmer, hat dieser TT500-Motor genug Leistung, wird er beim Schneiden nicht von Zeit zu Zeit langsamer? Ich denke darüber nach, diesen Plattenspieler zu kaufen.
Können Sie mir sagen, wo ich dieses Gerät kaufen kann, an dem der Schneidkopf befestigt ist, dieses große Metallgerät?
Der gesamte Auftritt ist großartig!
I'm very impressed !
I'm making a slightly different machine, but this one will come soon... [I prefer not to show pictures for now because it's embarrassing ...]
Tell me Farmer, does this tt500 motor have enough power, doesn't it slow down from time to time when cutting? I am thinking about buying this turntable.
Can you give me the details of where to buy this device to which the cutting head is attached, this large metal device?
The whole performance is great!
Cool! Gut, Ingenieur! Schöne Arbeit!
Ich bin sehr beeindruckt !
Ich baue eine etwas andere Maschine, aber diese wird bald kommen ... [Ich zeige vorerst lieber keine Bilder, weil es peinlich ist ...]
Sag mir, Farmer, hat dieser TT500-Motor genug Leistung, wird er beim Schneiden nicht von Zeit zu Zeit langsamer? Ich denke darüber nach, diesen Plattenspieler zu kaufen.
Können Sie mir sagen, wo ich dieses Gerät kaufen kann, an dem der Schneidkopf befestigt ist, dieses große Metallgerät?
Der gesamte Auftritt ist großartig!
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farmersplow
- Posts: 376
- 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
Glad you like it. It's far from finished - I guess it will take until the end of the year.
But I dare to say, then it's a cool thing! (I'll add a small picture to give you an idea how it should look like when finished).
The TT500 engine is fine up to a certain limit, has a lot of torque. But it is indeed not good enough when high demands are made. I have changed to a motor drive from Reloop RP7000MK2. This motor has a better bearing and higher as well as more stable torque (16-pole; starting torque 4.5 kg/cm; 0.01% WOW/Flutter). Furthermore, half-speed is also possible with this motor.
As for that big metal thing on which the cutting head is mounted: You can't buy it like that, it's my design that I developed and built myself. It contains the lifting mechanism, the dashpot, electronic contact force sensors, counterweight, tension springs and an electromagnetic contact force regulation. And some sensors and actuators. And the adjustment screws for the suction tube.
As soon as I find a little more time, I will report on the development progress.
Greetings from Austria
Thomas
But I dare to say, then it's a cool thing! (I'll add a small picture to give you an idea how it should look like when finished).
The TT500 engine is fine up to a certain limit, has a lot of torque. But it is indeed not good enough when high demands are made. I have changed to a motor drive from Reloop RP7000MK2. This motor has a better bearing and higher as well as more stable torque (16-pole; starting torque 4.5 kg/cm; 0.01% WOW/Flutter). Furthermore, half-speed is also possible with this motor.
As for that big metal thing on which the cutting head is mounted: You can't buy it like that, it's my design that I developed and built myself. It contains the lifting mechanism, the dashpot, electronic contact force sensors, counterweight, tension springs and an electromagnetic contact force regulation. And some sensors and actuators. And the adjustment screws for the suction tube.
As soon as I find a little more time, I will report on the development progress.
Greetings from Austria
Thomas
You do not have the required permissions to view the files attached to this post.
Re: The farmer and his plow - When I set out to build a record cutter
Farmer, how much would you pay for making me a cutting head like yours?
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farmersplow
- Posts: 376
- 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
My cutting head version 8 is ready (not for sale) and has a main resonance of 1560Hz and a nice characteristic curve, but it is not yet perfect.
Version 9 should then remove the last doubts and have an even better characteristic curve.
First tests with the hopefully last cutterhead version 9 will take place next week and will be subjected to a long term test and a stress test (4 weeks).
Only if this goes well, I will build some heads.
As for the price, I have not yet decided. But if the version 9 (CH9) works well I will give details and data about it and offer it. Until then I ask for a little patience.
So far, I have only tested my cutting heads extensively on PET-G blanks.
However, if you are cutting on lacquer or PVC, for example, it would be necessary to know this beforehand. Because depending on the hardness of the blank, the angle of the cutting graver to the plate blank should be set accordingly.
What do you want to cut on?
Greetings from Austria
Thomas
Version 9 should then remove the last doubts and have an even better characteristic curve.
First tests with the hopefully last cutterhead version 9 will take place next week and will be subjected to a long term test and a stress test (4 weeks).
Only if this goes well, I will build some heads.
As for the price, I have not yet decided. But if the version 9 (CH9) works well I will give details and data about it and offer it. Until then I ask for a little patience.
So far, I have only tested my cutting heads extensively on PET-G blanks.
However, if you are cutting on lacquer or PVC, for example, it would be necessary to know this beforehand. Because depending on the hardness of the blank, the angle of the cutting graver to the plate blank should be set accordingly.
What do you want to cut on?
Greetings from Austria
Thomas
Re: The farmer and his plow - When I set out to build a record cutter
Hello Thomas, I have no place to buy masters' plates, so I decided to make a machine for cutting metal, it is a tin alloy, such sheet metal is heavy, so it has a lot of mass and looks like aluminum, but it cuts great, i.e. it cuts or processes, my friends have already designed a machine for me and it is in the process of being made, they will finish it soon, I would like to try cutting an empty, non-modulated groove next Saturday, but I don't know if they will be able to do it by Saturday, maybe...
The head will be for soft metal, maybe I can buy an original steel one with a galvanized copper surface, such as for DMM, I ordered one, I'll see. Videos and photos coming soon. How much can a DMM head cost?
The head will be for soft metal, maybe I can buy an original steel one with a galvanized copper surface, such as for DMM, I ordered one, I'll see. Videos and photos coming soon. How much can a DMM head cost?
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farmersplow
- Posts: 376
- 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
My developments have focused primarily on cutting directly into plastic sheets, and my knowledge regarding DMM is limited. I think it will be difficult to impossible to buy a DMM head. It should also be noted that with DMM, the extraction system and the cutting stylus are also different from all other cutting systems (lacquer, Pet-G, PVC...). Maybe you could check with Sillitoe. (sillitoeaudiotechnology).
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farmersplow
- Posts: 376
- 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
...rr you can contact flokason in switzerland directly, if you have not reached him yet...farmersplow wrote: ↑Wed Sep 13, 2023 2:02 pmMy developments have focused primarily on cutting directly into plastic sheets, and my knowledge regarding DMM is limited. I think it will be difficult to impossible to buy a DMM head. It should also be noted that with DMM, the extraction system and the cutting stylus are also different from all other cutting systems (lacquer, Pet-G, PVC...). Maybe you could check with Sillitoe. (sillitoeaudiotechnology).