electromagnetic, not mechanical
They probably don't until the price gets up there. The shielding is necessary in many cases, or else there is a lot of hum. Perhaps an advantage of the moving coil type is that the low signal level doesn't interact much with the shield.
Very good engineering tutorial, George. I have had enough math and physics to see clearly what you mean. I have never really considered this. I have wondered for a long time if the changing field in the coil has an effect on the magnet. It would cause eddy currents in the magnets? I recall reading that the Supertrack III had improved magnets, they were laminated.
I recall that you used the term "energy pool." I assume that this refers to the summary situation of all mechanical factors in a mechanical system.
I thought that possibly, aside from the EM characteristics, that the shield may have been a factor in the energy pool.
You are probably right about the post. The guy was getting rid of the shield and hearing an electromagnetic improvement.
Actually the poem was a parody of lofty verse. Mark
They probably don't until the price gets up there. The shielding is necessary in many cases, or else there is a lot of hum. Perhaps an advantage of the moving coil type is that the low signal level doesn't interact much with the shield.
Very good engineering tutorial, George. I have had enough math and physics to see clearly what you mean. I have never really considered this. I have wondered for a long time if the changing field in the coil has an effect on the magnet. It would cause eddy currents in the magnets? I recall reading that the Supertrack III had improved magnets, they were laminated.
I recall that you used the term "energy pool." I assume that this refers to the summary situation of all mechanical factors in a mechanical system.
I thought that possibly, aside from the EM characteristics, that the shield may have been a factor in the energy pool.
You are probably right about the post. The guy was getting rid of the shield and hearing an electromagnetic improvement.
Actually the poem was a parody of lofty verse. Mark
Hi hailteflon and all
Engineering-wise, this is true.
Yes. Eddy currents are induced into the magnets as well as into the cantilever.
Both are made out of electrically conductive material.
The higher the electrical conductivity, the more intense the eddy currents into the conductor, thus the higher the secondary magnetic field.
Also, the higher the magnetic permeability of the conductor, the stronger the secondary magnetic field (for a given eddy current intensity).
Now, think of this:
Electrical conductivity of known materials and alloys ranges from 0 to 105 (span: 105).
Magnetic permeability (mu) ranges from -0.9 to approx. +30000 (span:30000). (this is the "bulk" permeability of materials. In real applications, mu, varies wildly, depending on the intensity of the external magnetic field, past and present)
This indicates that, the resultant secondary magnetic field is much more strongly influenced by the magnetic permeability of the conductor rather than from it's electrical conductivity (all other variables held constant).
Up to now we are talking about how eddy currents induced in any conductor placed near the coils can influence momentarilly the shape and the amplitude of the current that flows into the coils.
There is another way to look at this.
Eddy currents are energy dissipative.
The dissipated energy appears as:
A. Heat produced by the circulating currents into the conductor B. Electromagnetic energy of the secondary magnetic field.
The energy equaling the sum of these two, (dissipated energy) is drawn from the primary magnetic field, thus it is subtracted from the electrical energy that is (or can be) produced by the cartridge's motor.
I hope that I didn't confuse you.
No. Please go to post#44 (page 5)
Regards
George
Engineering-wise, this is true.
Yes. Eddy currents are induced into the magnets as well as into the cantilever.
Both are made out of electrically conductive material.
The higher the electrical conductivity, the more intense the eddy currents into the conductor, thus the higher the secondary magnetic field.
Also, the higher the magnetic permeability of the conductor, the stronger the secondary magnetic field (for a given eddy current intensity).
Now, think of this:
Electrical conductivity of known materials and alloys ranges from 0 to 105 (span: 105).
Magnetic permeability (mu) ranges from -0.9 to approx. +30000 (span:30000). (this is the "bulk" permeability of materials. In real applications, mu, varies wildly, depending on the intensity of the external magnetic field, past and present)
This indicates that, the resultant secondary magnetic field is much more strongly influenced by the magnetic permeability of the conductor rather than from it's electrical conductivity (all other variables held constant).
Up to now we are talking about how eddy currents induced in any conductor placed near the coils can influence momentarilly the shape and the amplitude of the current that flows into the coils.
There is another way to look at this.
Eddy currents are energy dissipative.
The dissipated energy appears as:
A. Heat produced by the circulating currents into the conductor B. Electromagnetic energy of the secondary magnetic field.
The energy equaling the sum of these two, (dissipated energy) is drawn from the primary magnetic field, thus it is subtracted from the electrical energy that is (or can be) produced by the cartridge's motor.
I hope that I didn't confuse you.
No. Please go to post#44 (page 5)
Regards
George
After reading my last posts, some more questions arose into my mind.
So, I would like your help on this:
Let’s say that we are riding a bicycle on some terrain. We are providing some work through the pedals to attain a certain speed.
We then engage the dynamo, so we can operate front and rear lights.
We assume that the dynamo is designed for max output of 20Watts and the light bulbs are consuming 10 watts total.
For to attain the same speed on the same terrain, we observe that we have to increase our work supplied to the pedals, if we can.
This indicates (the obvious) that dynamo draws some energy.
Now in relation to the above, I would like to ask the following:
1. When we keep the bulbs consumption to 10Watts and we feed them through a more powerful dynamo designed for 40Watts max. output (but with the same efficiency), will we have to further increase our work on the pedals?
2. When we keep the 20 watt dynamo, but we increase the wattage of the light bulbs to 15 watts total, will we have to further increase our work on the pedals (in relation to the initial 20W dynamo/10W bulbs)?
The above may sound off-topic, but I used it as a crude analogous model - under the context of energy flow within the system – of the record groove, cartridge, preamplifier, as follows:
Our feet are replaced by the modulated record grooves of the rotating record.
The pedals is the cartridge needle/cantilever assy.
The dynamo is the motor of the cartridge.
The bulbs is any load to which cartridge supplies it’s energy.
Regards
George
So, I would like your help on this:
Let’s say that we are riding a bicycle on some terrain. We are providing some work through the pedals to attain a certain speed.
We then engage the dynamo, so we can operate front and rear lights.
We assume that the dynamo is designed for max output of 20Watts and the light bulbs are consuming 10 watts total.
For to attain the same speed on the same terrain, we observe that we have to increase our work supplied to the pedals, if we can.
This indicates (the obvious) that dynamo draws some energy.
Now in relation to the above, I would like to ask the following:
1. When we keep the bulbs consumption to 10Watts and we feed them through a more powerful dynamo designed for 40Watts max. output (but with the same efficiency), will we have to further increase our work on the pedals?
2. When we keep the 20 watt dynamo, but we increase the wattage of the light bulbs to 15 watts total, will we have to further increase our work on the pedals (in relation to the initial 20W dynamo/10W bulbs)?
The above may sound off-topic, but I used it as a crude analogous model - under the context of energy flow within the system – of the record groove, cartridge, preamplifier, as follows:
Our feet are replaced by the modulated record grooves of the rotating record.
The pedals is the cartridge needle/cantilever assy.
The dynamo is the motor of the cartridge.
The bulbs is any load to which cartridge supplies it’s energy.
Regards
George
What a fascinating thread and very informative on so many levels, I would just like to add something in support of Georges original posting. I have tried many cartridge tweaks with cheap sacrificial carts and the gluing of the stylus into the cart was one that made an amazing difference, sound became cleaner overall, the highs much sweeter, grain was almost eliminated and interestingly the tracking on the inner grooves was far better and bass was also stronger and tighter. I found the improvement somewhat surprising as I thought the bond would have been tight enough normally.
Additionally and bear in mid these carts were cheap I found that using a fine screwdriver tip to bend the mounting plates inside the cart a little inwards so it clamped the holder better inside the cart also helped.
I didn't make any attempt to measure anything but as I had a std cart mounted on a headshell and the modded one on another headshell it was very easy to A/B and hear the difference.
I do feel there was an increase in output as well though not huge
In my case I used araldite instead of superglue, I really don't know if that would make a difference.
I tried many other mods as well and a great many of them worked nicely but the soild mounting was probably the best single mod for my money.
In my mind I came to view the whole concept as a bit like car suspension and chassis design, a chassis that lacks rigidity and a suspension that is poorly mounted makes for a very poor handling vehicle regardless of how good the springs and tyres are, the vehicle doesn't follow the intended path at all well and makes for a pretty mushy ride. Its a rough analogy I know but if we think of the steering wheel as the tip of the stylus and you as the record groove I know what I would I rather be steering.
I suppose it is easy for use to overlook what can happen in terms of high frequency vibrations but when I really sat down to think about it I realised that such vibrations can be quite destructive, I well remember how many times I have had nuts and bolts come loose on vibrating mechanical gear that were perfectly tight when assembled (without lock washers) and some pretty stiff torque settings, obviously there must be some samll movements happening somewhere for it to work loose.
Anyhow thanks George for your efforts and enlightening information.
Additionally and bear in mid these carts were cheap I found that using a fine screwdriver tip to bend the mounting plates inside the cart a little inwards so it clamped the holder better inside the cart also helped.
I didn't make any attempt to measure anything but as I had a std cart mounted on a headshell and the modded one on another headshell it was very easy to A/B and hear the difference.
I do feel there was an increase in output as well though not huge
In my case I used araldite instead of superglue, I really don't know if that would make a difference.
I tried many other mods as well and a great many of them worked nicely but the soild mounting was probably the best single mod for my money.
In my mind I came to view the whole concept as a bit like car suspension and chassis design, a chassis that lacks rigidity and a suspension that is poorly mounted makes for a very poor handling vehicle regardless of how good the springs and tyres are, the vehicle doesn't follow the intended path at all well and makes for a pretty mushy ride. Its a rough analogy I know but if we think of the steering wheel as the tip of the stylus and you as the record groove I know what I would I rather be steering.
I suppose it is easy for use to overlook what can happen in terms of high frequency vibrations but when I really sat down to think about it I realised that such vibrations can be quite destructive, I well remember how many times I have had nuts and bolts come loose on vibrating mechanical gear that were perfectly tight when assembled (without lock washers) and some pretty stiff torque settings, obviously there must be some samll movements happening somewhere for it to work loose.
Anyhow thanks George for your efforts and enlightening information.
George, I'll make this quick and get back later.
About the bicycle; Aside from such factors as friction from the cog on the rubber tire. questions: (1) no (2) yes.
As before, I agree with your electro-mechanical analysis, but this is an energy transducer with such mechanical characteristics by necessity, not by choice.
The ultimate purpose is not energy conversion, but fidelity.
The ideal situation of just moving the diamond is a gross oversimplification. With 20X magnification one can only see the lo-freq waves in the groove. We're talking about super-small dimensions here.
You have consequently raised the issue of moving iron versus moving magnet. Probably easier to laminate iron than high-mu magnet stock.
There is also the problem of the variability of the cutting angle. It is 15 degrees nominal, but is more like 20 degress at high velocity.
I'll get back later tonight, Mark
About the bicycle; Aside from such factors as friction from the cog on the rubber tire. questions: (1) no (2) yes.
As before, I agree with your electro-mechanical analysis, but this is an energy transducer with such mechanical characteristics by necessity, not by choice.
The ultimate purpose is not energy conversion, but fidelity.
The ideal situation of just moving the diamond is a gross oversimplification. With 20X magnification one can only see the lo-freq waves in the groove. We're talking about super-small dimensions here.
You have consequently raised the issue of moving iron versus moving magnet. Probably easier to laminate iron than high-mu magnet stock.
There is also the problem of the variability of the cutting angle. It is 15 degrees nominal, but is more like 20 degress at high velocity.
I'll get back later tonight, Mark
Results of...
Hi George, Hailteflon & Zero
It won't be the magnets which would be laminated, but the coils' cores - surely?
@ George, you've got me all fired-up now, hehe😀 I've never wound coils for an mm cart and won't try that anyway as there's just too much wire. I've got a couple of mm carts laying around perishing and oxidising. I'm tempted to take a can-opener to a Shure M75ED, remove the coils and transplant them into a new milled alu body (with tapped threads, of course) and mill and drill a proper, secure mounting block which can be screwed down below the coils. My own proprietary damper would go ahead of the magnet (and at the rear of the cantilever). The magnet, I will also fabricate from rare earth material I have here. Then, I'll replace the Shure cantilever/stylus assembly with say a Gyger FG11 alu or ruby job. In other words, the replacement generator would have the appearance of that of an mc cart, but the grooves driving a small magnet, instead of the coils.
To again illustrate the dividends of small, intelligently chosen mods to mm carts (and also to mc's), I recently repaired a humble Excel cart for a friend. The cart had a whacked cantilever and I asked him if I could implement some of my ideas in the repair.
The cantilever/stylus assembly was replaced with a Gyger FG11 which is much lighter and thinner than the original. At the back of the original cantilever, was a small steel tube to hold the magnet. I replaced the steel tube with a titanium replacement, which I turned on my lathe. As luck would have it, I found a slightly longer and thicker magnet which fitted into the new titanium tube.
The last mods were to replace the hardened suspension rubber with that of my material, cut to size with an NT cutter blade, and to replace the anchoring wire with a 9-strand cable - even thinner than the original wire and much more flexible.
The difference in sound was profound - sounding like a cross between a Grace F-9 and a moving coil.
OK, this is a recipe. Check out your parts bins 😉 . Just remember, small magnets fly away, never to be found again.
bulgin
Hi George, Hailteflon & Zero
It won't be the magnets which would be laminated, but the coils' cores - surely?
@ George, you've got me all fired-up now, hehe😀 I've never wound coils for an mm cart and won't try that anyway as there's just too much wire. I've got a couple of mm carts laying around perishing and oxidising. I'm tempted to take a can-opener to a Shure M75ED, remove the coils and transplant them into a new milled alu body (with tapped threads, of course) and mill and drill a proper, secure mounting block which can be screwed down below the coils. My own proprietary damper would go ahead of the magnet (and at the rear of the cantilever). The magnet, I will also fabricate from rare earth material I have here. Then, I'll replace the Shure cantilever/stylus assembly with say a Gyger FG11 alu or ruby job. In other words, the replacement generator would have the appearance of that of an mc cart, but the grooves driving a small magnet, instead of the coils.
To again illustrate the dividends of small, intelligently chosen mods to mm carts (and also to mc's), I recently repaired a humble Excel cart for a friend. The cart had a whacked cantilever and I asked him if I could implement some of my ideas in the repair.
The cantilever/stylus assembly was replaced with a Gyger FG11 which is much lighter and thinner than the original. At the back of the original cantilever, was a small steel tube to hold the magnet. I replaced the steel tube with a titanium replacement, which I turned on my lathe. As luck would have it, I found a slightly longer and thicker magnet which fitted into the new titanium tube.
The last mods were to replace the hardened suspension rubber with that of my material, cut to size with an NT cutter blade, and to replace the anchoring wire with a 9-strand cable - even thinner than the original wire and much more flexible.
The difference in sound was profound - sounding like a cross between a Grace F-9 and a moving coil.
OK, this is a recipe. Check out your parts bins 😉 . Just remember, small magnets fly away, never to be found again.
bulgin
George, Here is an extract from a Shure magazine article. The Ultra 500 was an up-grade of the Supertrack type V-MR, no longer available.
“The greater weight of the ultra 500 is due to the metal mounting block that couples the encapsulated cartridge body to the tonearm. It is widely held in high-end audio circles that a cartridge must have extremely tight mechanical coupling to its headshell to avoid resonances that can color the sound”
Would you say that the theory behind the rigid tonearm-cartridge assembly is to channel all vibrations into a mechanical system with a very low resonant frequency?
The Ultra 500 stylus angle is 20 degrees instead of 15 degrees.
The Supertrack type III (1979) brochure is on the Shure website. One of the improvements was a laminated core, not a laminated magnet.
When I worked part time at a stereo store in 1972 they sold a Toshiba turntable with a Toshiba Photoelectric cartridge. I have never located any technical info. other than a listing in a cartridge index, but no useful info on operating principles.
Bulgin, where do you get your cartridge rebuilding supplies? Mark
“The greater weight of the ultra 500 is due to the metal mounting block that couples the encapsulated cartridge body to the tonearm. It is widely held in high-end audio circles that a cartridge must have extremely tight mechanical coupling to its headshell to avoid resonances that can color the sound”
Would you say that the theory behind the rigid tonearm-cartridge assembly is to channel all vibrations into a mechanical system with a very low resonant frequency?
The Ultra 500 stylus angle is 20 degrees instead of 15 degrees.
The Supertrack type III (1979) brochure is on the Shure website. One of the improvements was a laminated core, not a laminated magnet.
When I worked part time at a stereo store in 1972 they sold a Toshiba turntable with a Toshiba Photoelectric cartridge. I have never located any technical info. other than a listing in a cartridge index, but no useful info on operating principles.
Bulgin, where do you get your cartridge rebuilding supplies? Mark
Results of...
Hi hailteflon
Styli come from Fritz Gyger Hartstofftechnik SA. For how long still, I don't know as I read that part of the biz has been sold off.
I'm not really into repairs. I try to make mc carts.
regards
bulgin
Hi hailteflon
Styli come from Fritz Gyger Hartstofftechnik SA. For how long still, I don't know as I read that part of the biz has been sold off.
I'm not really into repairs. I try to make mc carts.
regards
bulgin
Hi all
Zero One, thank you for your kind words.
My knowledge has been benefited by the contribution of posters in this site.
Each one is providing what he (she) can, so I am trying to follow.
Your reporting of the mods is encouraging.
Now that you have two cartridges of the same model, one modified and one unmodified, you may like to produce two recordings via a sound card into your PC and compare the waveforms on each. This is the first step you can do to quantify the differences.
High freq vibrations.
You touched a very sensitive area, in fact a situation difficult to analyze.
Let me explain myself:
Although the definition of the term “frequency” is something we can take for granted, what we mean by “high frequency” when we are referring to a vibrating body, is a bit unclear.
The way I see it, when the wavelength of the vibration frequency approaches the smallest of the dimensions of the vibrating body, then we are have to use two analysis methods.
One is the analysis using mechanical motion terms (mass, stiffness, springiness, mechanical impedance) and think of the body as a vibrating element (that is, the bulk of it’s mass is being displaced in synchrony with the vibrations).
The other is the analysis using acoustic wave terms (modes of acoustic waves, sound velocities, density, specific acoustic impedances, transmition coefficients, reflection, diffraction, refraction effects) and think of the body as a non vibrating element (that is, the bulk of it’s mass not being displaced in synchrony with the vibrations, but the molecules into part of it’s mass to vibrate).
I hope that I will be able to come to this again, but not really soon, due to lack of time.
Hailteflon.
Your quick reply (post#65) finds me in agreement, except from this.
Fidelity is a composite term at least. I would call it a qualitative and loose term.
If we place it under the magnifying lens, we will find ourselves in a situation similar to a cynic trying to analyze what an ordinary man means when he says “What an attractive woman!” .
Bulging
My best wishes for the results of your endeavor. Please report back.
Regards
George
Zero One, thank you for your kind words.
My knowledge has been benefited by the contribution of posters in this site.
Each one is providing what he (she) can, so I am trying to follow.
Your reporting of the mods is encouraging.
Now that you have two cartridges of the same model, one modified and one unmodified, you may like to produce two recordings via a sound card into your PC and compare the waveforms on each. This is the first step you can do to quantify the differences.
High freq vibrations.
You touched a very sensitive area, in fact a situation difficult to analyze.
Let me explain myself:
Although the definition of the term “frequency” is something we can take for granted, what we mean by “high frequency” when we are referring to a vibrating body, is a bit unclear.
The way I see it, when the wavelength of the vibration frequency approaches the smallest of the dimensions of the vibrating body, then we are have to use two analysis methods.
One is the analysis using mechanical motion terms (mass, stiffness, springiness, mechanical impedance) and think of the body as a vibrating element (that is, the bulk of it’s mass is being displaced in synchrony with the vibrations).
The other is the analysis using acoustic wave terms (modes of acoustic waves, sound velocities, density, specific acoustic impedances, transmition coefficients, reflection, diffraction, refraction effects) and think of the body as a non vibrating element (that is, the bulk of it’s mass not being displaced in synchrony with the vibrations, but the molecules into part of it’s mass to vibrate).
I hope that I will be able to come to this again, but not really soon, due to lack of time.
Hailteflon.
Your quick reply (post#65) finds me in agreement, except from this.
Fidelity is a composite term at least. I would call it a qualitative and loose term.
If we place it under the magnifying lens, we will find ourselves in a situation similar to a cynic trying to analyze what an ordinary man means when he says “What an attractive woman!” .
Bulging
My best wishes for the results of your endeavor. Please report back.
Regards
George
Ok I have got a little inspired here from this thread and thought I'd see what would happen if I re-bodied one of my cheap $10.00 carts, so this afternoon I managed to disect it and cut away the steel housing successfully, having never seen inside a cart this was interesting. Using bits from the cart I can keep everything aligned so thats good. If I stuff up it won't break the bank so I can afford to experiment.
The question is now how to best re-body the cart and control interference, I was thinking making a body out of balsa and then gluing aluminium foil to the outside casing and earthing it of course and then painting it black or some other finish..is this likely to work OK. I would love to do a machined aluminium body but I don't have the gear so it needs to be wood or plastic.
It looks like I can get things much more rigid internally as the original assembly was glued to the cart casing at the front only so I imagine there would have been some vibration of the whole assembly under pressure.
The wiring behind the motor assembly has quite a lot of extra lenght in there, I imagine to make assembly easier but I wonder how this effects things as it was a bit of a tangled mess.
I imagine embedding the whole motor assembly in epoxy is not a good idea, as it might effect capacitance? This would make for a solid structure though with little weight penalty.
Any ideas guys?
The question is now how to best re-body the cart and control interference, I was thinking making a body out of balsa and then gluing aluminium foil to the outside casing and earthing it of course and then painting it black or some other finish..is this likely to work OK. I would love to do a machined aluminium body but I don't have the gear so it needs to be wood or plastic.
It looks like I can get things much more rigid internally as the original assembly was glued to the cart casing at the front only so I imagine there would have been some vibration of the whole assembly under pressure.
The wiring behind the motor assembly has quite a lot of extra lenght in there, I imagine to make assembly easier but I wonder how this effects things as it was a bit of a tangled mess.
I imagine embedding the whole motor assembly in epoxy is not a good idea, as it might effect capacitance? This would make for a solid structure though with little weight penalty.
Any ideas guys?
Hi George.
Yes yes, thankyou for those pearls on high frequency vibrations that give me a little more to ponder, makes great sense. I had not thought of it quite like that.
Yes yes, thankyou for those pearls on high frequency vibrations that give me a little more to ponder, makes great sense. I had not thought of it quite like that.
Yes, I think that this is the theory behind rigid coupling.
Very well expressed hailteflon. Spot on.🙂
I like it. Any photos Zero One?
Balsa is excellent for prototyping the cartridge body.
You can use the constraint layer method, to produce whatever shape you wish, very easily.
I don’t know though if it is good material for a final version.
Balsa has a spongy construction.
It will work as a vibration dissipative element.
You will also face the problem of proper rigid coupling to the headshell.
You may try to harden balsa by immersing it into a hot varnish (or into a two-part diluted varnish). Hopefully it will soak varnish into it’s pores and become harder and stiffer when dry.
Also, instead of sticking aluminum foil on the outside, you may use a conductive coating in spray-can.
Both aluminum foil and conductive coating, will provide some shielding for HF (RF) but not for 50Hz electromagnetic fields. In your turntable, you may have no 50Hz hum problem though, so HF shielding may be adequate for you.
Try first with no shielding, then paint and compare.
Again, try to make recordings (even with a cassette recorder), so you will have a way to compare, not by memory.
Electronic components and switching (HF) hybrid boards are often coated with Epoxy(embedded in epoxy). Some X-former varnishes are also epoxy based. I don’t think that there is a problem there.
If you pour-in epoxy to make a mould, always remember that curing is an exothermic process.
The released heat, may deform some delicate structures.
So proceed in steps.
Add a small amount of epoxy, let cure, then add some more and so on.
Is it pearls or sea-urchins actually?😀
Regards
George
to remove super glue...
use a little acetone. works great. you can also use heat around 275 F if the part will stand that temp.
use a little acetone. works great. you can also use heat around 275 F if the part will stand that temp.
Hi George, here is a pic of the cart with the metal case removed, it is actually quite easy to use the plastic bits left as a supporting chassis, so this is now the plan, embed the coils in epoxy, mount the motor into the plastic chassis and then glue mount the stylus holder with stylus in place and than add the exterior balsa shell and foil coating, finish with black paint and laquer.
Attachments
George and others. I am still following your engineering activites. I'm still short on time so I don't post much.
I did read George's posts 62 and 63 and fully understand. The energy pool is the record and platter motor, the source of energy.
By the word "fidelity" I meant faithful reproduction of the waveform on the groove wall.
The mechanical aspect of the stylus in the groove requires deep consideration of the aspects that you are all concerned with. That is, the generation and transmutation of energy.
I am still waiting for someone to steer the conversation into my original concern. That is, the rigid cartridge assembly will send energy into the tonearm and it will return out of phase and often of a different frequency. This is what I meant by "misdirected energy" in a former post. I suspect that the main advantage of a proper choice of wood is that is does not transmit sound as metal does.
There is dilemma here. One does not want the cartridge to vibrate in relation to the tonearm, but one also does not want the cartridge to send acoustical energy up into the tonearm. Seems like the ultimate material would be a rigid material that does not transmit mechanical energy.
The reason I assume that this is a factor is because of the following. I have a 1973 B&O 3000 turntable. It has an SP-12 cartridge that plugs in firmly into the tonearm socket. This is a very good cartridge that can track any record that I have put it on. A kind fellow in the Chicago warehouse sold me one of the last OEM stylii available in the world. There is an audible difference when a damping ring is removed from the gap between the stylus and the tonearm (you would have to see a picture of it to understand). The point here is that considerable mechanical energy makes its way up into the tonearm if there is a rigid mechanical linkage. This energy can return to the cartridge motor as unwanted signal components.
From a different perspective, if mechanical energy was not escaping from the cantilever through the elastomer suspension (and also the anchor wire) then tonearm/cartridge design would not be such an issue. Mark
I did read George's posts 62 and 63 and fully understand. The energy pool is the record and platter motor, the source of energy.
By the word "fidelity" I meant faithful reproduction of the waveform on the groove wall.
The mechanical aspect of the stylus in the groove requires deep consideration of the aspects that you are all concerned with. That is, the generation and transmutation of energy.
I am still waiting for someone to steer the conversation into my original concern. That is, the rigid cartridge assembly will send energy into the tonearm and it will return out of phase and often of a different frequency. This is what I meant by "misdirected energy" in a former post. I suspect that the main advantage of a proper choice of wood is that is does not transmit sound as metal does.
There is dilemma here. One does not want the cartridge to vibrate in relation to the tonearm, but one also does not want the cartridge to send acoustical energy up into the tonearm. Seems like the ultimate material would be a rigid material that does not transmit mechanical energy.
The reason I assume that this is a factor is because of the following. I have a 1973 B&O 3000 turntable. It has an SP-12 cartridge that plugs in firmly into the tonearm socket. This is a very good cartridge that can track any record that I have put it on. A kind fellow in the Chicago warehouse sold me one of the last OEM stylii available in the world. There is an audible difference when a damping ring is removed from the gap between the stylus and the tonearm (you would have to see a picture of it to understand). The point here is that considerable mechanical energy makes its way up into the tonearm if there is a rigid mechanical linkage. This energy can return to the cartridge motor as unwanted signal components.
From a different perspective, if mechanical energy was not escaping from the cantilever through the elastomer suspension (and also the anchor wire) then tonearm/cartridge design would not be such an issue. Mark
Hi Hailteflon, your comments/questions on the cartridge tonearm interface etc are interesting to me and bring up a couple of issues I have grappled with a few months ago.
(There is dilemma here. One does not want the cartridge to vibrate in relation to the tonearm, but one also does not want the cartridge to send acoustical energy up into the tonearm. Seems like the ultimate material would be a rigid material that does not transmit mechanical energy. )
Like many I noted with interest the idea and concept of the cartridge isolator, which I feel is highly overpriced, but that is another issue, the point is that it is quite controversial as it flies in the face of accepted wisdom regarding the mounting of carts and how the issue of vibrations etc are dealt with.
But.....
Intrigued by this I decided to concoct my own interpretation and see what would happen, this was simple enough I used some double sided thinnish foam tape to attach the cart to the headshell and then ran a bead of bluetac around the perimeter of the tape. The tricky part was aligning it all up as bear in mind there are no mounting bolts used at all in my set-up, but I sorted it all out OK.
I must also point out that the cart was longhorn modded to so that I feel helps with stability.
Now I had two identical carts and headshells, one mounted via foam with a longhorn mod and the other normally, the VTA was the same for both as in the case of the normally mounted one it had a spacer which was removed on the foam mounted version.
I remember at the time when I posted on a couple of forums a few folk claimed the whole idea to be unsound and likely to be problematic, though I wasn't really interested in arguing, my knowledge is pretty limited, but my ears are fine.
What I found was that in my case the sound was vastly better, in summary the result was far less surface noise yet uncannily far better micro detail and much clearer treble, basically there was far more air in the sound. Many felt that bass would be anemic yet I found the total opposite. This I add was no small change it was of the order of putting an entirely different cart on the TT.
Granted the results are probably very much dependent on the cart and the quality of the tonearm but I know my ears were not decieved, and in fact many others have heard this set-up since then and the comments are always along the lines of "wow that sounds good"
I tried to reason why this might work, to my mind I felt it was three things.
One, high frequency info was not feeding into the tonearm and reflecting back out of phase, (which is what you are commenting about)
Two, the foam damps vertical impacts which are caused by debris in the bottom of the grooves but does not effect the side ot side movement of stylus in the modulations as the foam does not flex laterally.
Three, thefoam helped damp vibrations within the cart itself so that it might oscillate only for a very brief time in reaction to the stylus input.
I could be totally wrong on all the above counts, but it proved the idea has merit and the wooden bodied cart I am working on now will be mounted in this way, so I have no doubts for my system. I still find the idea couterintuitive, and I would like a better understanding of it so I will research futher.
I feel there are many other aspects of cart design that might also have an effect, such as how large is the internal cavity, how rigid is the motor mounting, does the cart have any flat hard surfaces or is it smoothly countoured all over, how heavy is the cart and what effect does mass itself have on damping given the restrictions on cart weight. These are all issues I am trying to come to grips with. Obviously cart makers have looked at all this and really put a lot of work into their designs, you just wonder where it all ends and just how far can things be taken, given a big enough budget. Isn't analogue great!
(There is dilemma here. One does not want the cartridge to vibrate in relation to the tonearm, but one also does not want the cartridge to send acoustical energy up into the tonearm. Seems like the ultimate material would be a rigid material that does not transmit mechanical energy. )
Like many I noted with interest the idea and concept of the cartridge isolator, which I feel is highly overpriced, but that is another issue, the point is that it is quite controversial as it flies in the face of accepted wisdom regarding the mounting of carts and how the issue of vibrations etc are dealt with.
But.....
Intrigued by this I decided to concoct my own interpretation and see what would happen, this was simple enough I used some double sided thinnish foam tape to attach the cart to the headshell and then ran a bead of bluetac around the perimeter of the tape. The tricky part was aligning it all up as bear in mind there are no mounting bolts used at all in my set-up, but I sorted it all out OK.
I must also point out that the cart was longhorn modded to so that I feel helps with stability.
Now I had two identical carts and headshells, one mounted via foam with a longhorn mod and the other normally, the VTA was the same for both as in the case of the normally mounted one it had a spacer which was removed on the foam mounted version.
I remember at the time when I posted on a couple of forums a few folk claimed the whole idea to be unsound and likely to be problematic, though I wasn't really interested in arguing, my knowledge is pretty limited, but my ears are fine.
What I found was that in my case the sound was vastly better, in summary the result was far less surface noise yet uncannily far better micro detail and much clearer treble, basically there was far more air in the sound. Many felt that bass would be anemic yet I found the total opposite. This I add was no small change it was of the order of putting an entirely different cart on the TT.
Granted the results are probably very much dependent on the cart and the quality of the tonearm but I know my ears were not decieved, and in fact many others have heard this set-up since then and the comments are always along the lines of "wow that sounds good"
I tried to reason why this might work, to my mind I felt it was three things.
One, high frequency info was not feeding into the tonearm and reflecting back out of phase, (which is what you are commenting about)
Two, the foam damps vertical impacts which are caused by debris in the bottom of the grooves but does not effect the side ot side movement of stylus in the modulations as the foam does not flex laterally.
Three, thefoam helped damp vibrations within the cart itself so that it might oscillate only for a very brief time in reaction to the stylus input.
I could be totally wrong on all the above counts, but it proved the idea has merit and the wooden bodied cart I am working on now will be mounted in this way, so I have no doubts for my system. I still find the idea couterintuitive, and I would like a better understanding of it so I will research futher.
I feel there are many other aspects of cart design that might also have an effect, such as how large is the internal cavity, how rigid is the motor mounting, does the cart have any flat hard surfaces or is it smoothly countoured all over, how heavy is the cart and what effect does mass itself have on damping given the restrictions on cart weight. These are all issues I am trying to come to grips with. Obviously cart makers have looked at all this and really put a lot of work into their designs, you just wonder where it all ends and just how far can things be taken, given a big enough budget. Isn't analogue great!
Hi all
Excellent participation. You are real diyers🙂
It is two hours now that I am formulating a reply trying to expand on my writing found in post#26 (page3).
It turned very long and complicated
, so I will summarise it with the following 
:
Keep in mind the concept of Conservation of Momentum
and think of the whole system as a Newton’s cradle.
Concentrating to what will happen when the “back wave” reaches the first ball (needle), try to visualize the action, with balls of successively increasing mass (1st lightest, last heaviest) and with stiffness in the inverse order (1st stiffest, last most compliant).
The aim is to have the back wave reaching the first ball with as much reduced amplitude and as much delay as possible.
Regards
George
Excellent participation. You are real diyers🙂
It is two hours now that I am formulating a reply trying to expand on my writing found in post#26 (page3).
It turned very long and complicated
, so I will summarise it with the following :Keep in mind the concept of Conservation of Momentum
and think of the whole system as a Newton’s cradle.
Concentrating to what will happen when the “back wave” reaches the first ball (needle), try to visualize the action, with balls of successively increasing mass (1st lightest, last heaviest) and with stiffness in the inverse order (1st stiffest, last most compliant).
The aim is to have the back wave reaching the first ball with as much reduced amplitude and as much delay as possible.
Regards
George
yes, analog is great
Zero, the result of the sticky tape experiment says a lot.
Decoupling noise is essential. The proper name for the phenomenon being discussed is probably “acoustic feedback.” It is directly related to the problem of vibrations caused in the tonearm when the speaker volume is loud.
I won’t go too far with this issue because it relates to some problems that become quite technical. The flexing of the vinyl is a problem that is similar to acoustic feedback. It inserts energy into stylus motion that is not constructive to the program material in the groove wall. I will also avoid the friction on the diamond.
---------------------------
(1) I began to better understood the issue of noise and distortion when I did away with a feedback equalizer and built a passive equalizer. For those who may not know, in a passive equalizer the RIAA equalization network is not in a feedback loop. The difference is very great. Years later I removed the metallized polycarbonate capacitors and substituted hermetically sealed teflon/foil. This was another surprising improvement. Thus, I get a much better picture of what the diamond is actually encountering in the groove. Feedback equalizers intensify noise and distortion.
(2) Pictures of the current production SME tonearm indicate that it may be made of some sort of carbon fiber compound. It is solid black. Research on the web will answer this question.
(3) My concept of a material that does not transmit sound would be a nylon or wood spacer. I took some 1/8-inch neoprene gasket sheet and used it as a shim between cart and headshell. I don’t recall the results, but it surely didn’t sound worse (I have about 15 cartridges so it is hard to recall).
(4) Inspection of many cartridges revealed that the rake angle of the stylus ( the VTA is supposedly something a little different) is no where near 15 degrees. I began to put a few layers of index card in front of the cartridge to give it more rake angle. Nylon screws had to be used so that they would bend a little. These nylon screws may be a good decoupling method. Number 4 is a little to big, 3 or metric would be ideal if I could find them, but number 2 works OK. I suspect that cart manufacturers intentionally avoid sufficient rake angle so that their lower-priced carts will sound like the price.
(5) There was a storm here yesterday and a neighbors maple tree lost a branch in our back yard. When cutting it up I noticed how soft the wood was. Maple may be a good material for decoupling vibrations.
(6) An analogy: Using a two foot long steel plumbing pipe to represent the cantilver..... If one hits it with a wrench it will ring long after the impact. If one hits a wood or nylon two foot long pipe, it will make more of a thud. Materials that have strength yet do not transmit sound well would probably suffice for a shim between the cart and headshell.
(7) There are some LPs that sound superior to most. One must ask if the engineer did something special to them. I have heard the term “curvature limiter” used in relation to the cutting electronics in LP production. The stylus/cantilever system does not like certain curvature patterns. My theory is that, in part, the cartridge is at a disadvantage when encountering difficult curvatures due to acoustic feedback destabilizing the tracing of the groove. The difficult curvatures probably initiate torsion on the cantilever which is loaded on the hidden end by magnet mass. If you have had any calculus.....once the derivative of the motion of the tip reaches too high of a degree then the cantilever cannot take the stress. The elastomer suspension bushing may exacerbate the problem (this is a hypothesis).
Zero, the result of the sticky tape experiment says a lot.
Decoupling noise is essential. The proper name for the phenomenon being discussed is probably “acoustic feedback.” It is directly related to the problem of vibrations caused in the tonearm when the speaker volume is loud.
I won’t go too far with this issue because it relates to some problems that become quite technical. The flexing of the vinyl is a problem that is similar to acoustic feedback. It inserts energy into stylus motion that is not constructive to the program material in the groove wall. I will also avoid the friction on the diamond.
---------------------------
(1) I began to better understood the issue of noise and distortion when I did away with a feedback equalizer and built a passive equalizer. For those who may not know, in a passive equalizer the RIAA equalization network is not in a feedback loop. The difference is very great. Years later I removed the metallized polycarbonate capacitors and substituted hermetically sealed teflon/foil. This was another surprising improvement. Thus, I get a much better picture of what the diamond is actually encountering in the groove. Feedback equalizers intensify noise and distortion.
(2) Pictures of the current production SME tonearm indicate that it may be made of some sort of carbon fiber compound. It is solid black. Research on the web will answer this question.
(3) My concept of a material that does not transmit sound would be a nylon or wood spacer. I took some 1/8-inch neoprene gasket sheet and used it as a shim between cart and headshell. I don’t recall the results, but it surely didn’t sound worse (I have about 15 cartridges so it is hard to recall).
(4) Inspection of many cartridges revealed that the rake angle of the stylus ( the VTA is supposedly something a little different) is no where near 15 degrees. I began to put a few layers of index card in front of the cartridge to give it more rake angle. Nylon screws had to be used so that they would bend a little. These nylon screws may be a good decoupling method. Number 4 is a little to big, 3 or metric would be ideal if I could find them, but number 2 works OK. I suspect that cart manufacturers intentionally avoid sufficient rake angle so that their lower-priced carts will sound like the price.
(5) There was a storm here yesterday and a neighbors maple tree lost a branch in our back yard. When cutting it up I noticed how soft the wood was. Maple may be a good material for decoupling vibrations.
(6) An analogy: Using a two foot long steel plumbing pipe to represent the cantilver..... If one hits it with a wrench it will ring long after the impact. If one hits a wood or nylon two foot long pipe, it will make more of a thud. Materials that have strength yet do not transmit sound well would probably suffice for a shim between the cart and headshell.
(7) There are some LPs that sound superior to most. One must ask if the engineer did something special to them. I have heard the term “curvature limiter” used in relation to the cutting electronics in LP production. The stylus/cantilever system does not like certain curvature patterns. My theory is that, in part, the cartridge is at a disadvantage when encountering difficult curvatures due to acoustic feedback destabilizing the tracing of the groove. The difficult curvatures probably initiate torsion on the cantilever which is loaded on the hidden end by magnet mass. If you have had any calculus.....once the derivative of the motion of the tip reaches too high of a degree then the cantilever cannot take the stress. The elastomer suspension bushing may exacerbate the problem (this is a hypothesis).
Here is a pic of the outer shell for the cart I have I dissected, it has a built on longhorn stabilizer, still lots of finishing to do but so far it is going OK.
Thinking about some peoples comments regarding decoupling the cart, I recalled one of the comments was that it would lead to less dynamics, now thinking about it perhaps what is interpreted as dynamics is actually vibration being fed back into the system, which would mean what is really being heard is a type of colouring of the sound rather than a true dynamic effect.
A while back I wondered if the weight on the end of the tonearm could be better utilised, most are very solid and probably redirect a lot of energy back into the system, I thought that a weight that consisted of sand and leadshot might do a better job, though I have not got around to trying this.
I also have thought that most tonearms being some sort of tubular contruction are not perhaps the ideal appraoch, a non tubular wooden tonearm with light weight and carbon fibre or similar covering might be a lot better.
And while I'm on the subject, might bass dynamics actually be effected by having a tonearm that actually is too easily moved in the horizontal plane, many makers pride themselves on having main tonearm bearings with almost no resistance at all, but is this really a good thing?
Ah so many questions?
Thinking about some peoples comments regarding decoupling the cart, I recalled one of the comments was that it would lead to less dynamics, now thinking about it perhaps what is interpreted as dynamics is actually vibration being fed back into the system, which would mean what is really being heard is a type of colouring of the sound rather than a true dynamic effect.
A while back I wondered if the weight on the end of the tonearm could be better utilised, most are very solid and probably redirect a lot of energy back into the system, I thought that a weight that consisted of sand and leadshot might do a better job, though I have not got around to trying this.
I also have thought that most tonearms being some sort of tubular contruction are not perhaps the ideal appraoch, a non tubular wooden tonearm with light weight and carbon fibre or similar covering might be a lot better.
And while I'm on the subject, might bass dynamics actually be effected by having a tonearm that actually is too easily moved in the horizontal plane, many makers pride themselves on having main tonearm bearings with almost no resistance at all, but is this really a good thing?
Ah so many questions?
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