In my current project phono pre-amplifier I'm testing how a variable type capacitor and resistor in its input stage works.
Yes, I still have two of them but...,
original styluses for both of my CMK3's suffered of the same issue which turned them useless quite fast (one came to its end in 2 years and the other (which stylus I still have) in 3-4 years) ... I suppose it was the TTDD damper material that perished and made the cantilever flabby (another possible faulty part is the magnet) -> cardridge lays against the record surface all the time. As stylus I still have is used less than 50h, I could try to get the damper fixed ... any suggestions of could this be done and where if it's possible.
Even temperature changes has some effect ...
Here is a Denon DL-160 I had and its response after 10C room ambient delta. Don't ask which trace is for cold or hot ambient temp, its years now and I did not note it down.
Attachments
I've done it with technics 1210, hagerman cornet and about 24pf in the connecting cables, which I reckon gives me about 200pf total per channel. It moves the cart/capacitance resonance higher, probably beyond audible range, so it seems to smooth the high end. With my carts I didn't miss the loss of high freq. peaking. Also added adjustable resistive loading to the preamp, but I couldn't hear a difference at any setting between 10k and 150k or so, and went back to a fixed 51k.... I take the inaudibility of the resistive loading changes to be evidence that the resonant peak is now beyond 15khz.
Steven van Raalte has worked that out in his Linear Audio article. Got completely rid of the mech resonance and a very flat response out to high frequencies.
Jan
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Phono Cartridge Modeling
I'm amazed that listeners can get the same impression of the music on an LP when the "transducer" produces different results based on cartridge make and model, preamp loading, accuracy of RIAA de-emphasis, speakers, listening rooms, listening volumes, and the state of our ears! You'll notice I didn't include the power amp because, in all honesty, that is the least of our problems.
You may wonder what prompted this outburst (or epiphany)? Well, it came from reading an article on Rod Elliott's website (Elliott Sound Products in Australia). Rod's model of a moving magnet cartridge splits the cartridge into two non-equal parts and puts part of the DC resistance of the cartridge in parallel with one of the parts of the inductance. OK, it is quite difficult to envisage what I just wrote, so the easiest thing is to simply go to Rod's website.
I've tried to measure the cartridge inductance. I have a very expensive LCR meter that is really not optimized for this type of measurement. A simple method uses electrical resonance with a suitable parallel capacitor fed through a 1Mohm resistor (feeding 1 microamp into the cartridge does not appear to have any adverse effects).
With 15nF in parallel with the right channel, resonance occurred at 1720Hz. Using w = 1/SQRT(LC) gave L = 570mH. The interesting thing is that the cartridge resistance hardly moves the parallel resonant frequency (I verified that using the eSketch SPICE program).
With a quite accurate estimate of cartridge inductance, it is quite simple to optimize the cartridge loading for the flattest response with the best frequency extension.
As the poster who showed the DL103 response, something else needs to be done to cure some of the upper mid-frequency droop.
I'm amazed that listeners can get the same impression of the music on an LP when the "transducer" produces different results based on cartridge make and model, preamp loading, accuracy of RIAA de-emphasis, speakers, listening rooms, listening volumes, and the state of our ears! You'll notice I didn't include the power amp because, in all honesty, that is the least of our problems.
You may wonder what prompted this outburst (or epiphany)? Well, it came from reading an article on Rod Elliott's website (Elliott Sound Products in Australia). Rod's model of a moving magnet cartridge splits the cartridge into two non-equal parts and puts part of the DC resistance of the cartridge in parallel with one of the parts of the inductance. OK, it is quite difficult to envisage what I just wrote, so the easiest thing is to simply go to Rod's website.
I've tried to measure the cartridge inductance. I have a very expensive LCR meter that is really not optimized for this type of measurement. A simple method uses electrical resonance with a suitable parallel capacitor fed through a 1Mohm resistor (feeding 1 microamp into the cartridge does not appear to have any adverse effects).
With 15nF in parallel with the right channel, resonance occurred at 1720Hz. Using w = 1/SQRT(LC) gave L = 570mH. The interesting thing is that the cartridge resistance hardly moves the parallel resonant frequency (I verified that using the eSketch SPICE program).
With a quite accurate estimate of cartridge inductance, it is quite simple to optimize the cartridge loading for the flattest response with the best frequency extension.
As the poster who showed the DL103 response, something else needs to be done to cure some of the upper mid-frequency droop.
There are mechanical resonances that I have always understood were compensated to some extent by using the recommended load resistance and capacitance.
Probably the safest way to start would be with a pre-amplifier of known good RIAA accuracy and a test record with suitable sweep tones, and adjust cartridge loading for the best (flattest) response above 20Hz.
I have found that there is a whole other world of behavior below 20Hz and that gets messy as you have to factor in the cartridge compliance interaction with the arm mass.
Lots of arms have quite interesting resonances in the audio band as well due to inadequate damping of the arm tube..
I would highly recommend looking at Alex Korf's blog. He's an inquiring spirit, an entertaining writer and a nice guy: Blog Table of Contents
I'm hoping my friend Bill Shurv who is quite knowledgeable in matters turntable related will weigh in soon.
Probably the safest way to start would be with a pre-amplifier of known good RIAA accuracy and a test record with suitable sweep tones, and adjust cartridge loading for the best (flattest) response above 20Hz.
I have found that there is a whole other world of behavior below 20Hz and that gets messy as you have to factor in the cartridge compliance interaction with the arm mass.
Lots of arms have quite interesting resonances in the audio band as well due to inadequate damping of the arm tube..
I would highly recommend looking at Alex Korf's blog. He's an inquiring spirit, an entertaining writer and a nice guy: Blog Table of Contents
I'm hoping my friend Bill Shurv who is quite knowledgeable in matters turntable related will weigh in soon.
I own two TD-124 which at one point were quite similarly equipped except for arms and cartridges. I found they never sounded even similar, and I had marked preferences and a developed a disdain for vinyl despite 6 decades of experience with it.
It will never be accurate, nor even repeatable except on one turntable over one relatively narrow time frame. (When arm and cartridge are in the good performance envelope)
I've had a lot of Ortofon SPUs and moved on to strain gauges and my own strain gauge pre-amp design (still not perfected) and came full circle and now have an SPU A95 on a 12 inch Jelco TK-850L - I believe my reset expectations aside this is the best sounding combination I have owned to date. (Schick, SME3009 Series II, SME3012 SME Series II and a clone)
Cartridges over the past decade have all been MC types such as Benz Ebony H, ZU Denon DL-103, SPU GTE, SPU GME II, Royal N, SPU Silver Meister GMII, SPU A95, Ortofon Windfeld (various generations)
The SPUs as a family have been consistently good, the ZU Denon DL-103 was exceptional as versions of the DL-103 go - my first real taste for LOMCs.
I found that every cartridge is basically giving you its interpretation of what is in the grooves, and for me so far the A95 is by far the best.
All of this means I have no clue how anything is supposed to sound which is I guess really all I was trying to day.
I have decided acting on preference is OK, and have started to enjoy vinyl again, and I have pretty high quality play back, but is it accurate? No, my take would be there is no such thing unless you have the exact original master tape and means to play it to use for comparative testing and fine tuning. Then you will find that tape is better anyway.. LOL (Yeah I have R2R tape too, although not quite good enough yet)
It will never be accurate, nor even repeatable except on one turntable over one relatively narrow time frame. (When arm and cartridge are in the good performance envelope)
I've had a lot of Ortofon SPUs and moved on to strain gauges and my own strain gauge pre-amp design (still not perfected) and came full circle and now have an SPU A95 on a 12 inch Jelco TK-850L - I believe my reset expectations aside this is the best sounding combination I have owned to date. (Schick, SME3009 Series II, SME3012 SME Series II and a clone)
Cartridges over the past decade have all been MC types such as Benz Ebony H, ZU Denon DL-103, SPU GTE, SPU GME II, Royal N, SPU Silver Meister GMII, SPU A95, Ortofon Windfeld (various generations)
The SPUs as a family have been consistently good, the ZU Denon DL-103 was exceptional as versions of the DL-103 go - my first real taste for LOMCs.
I found that every cartridge is basically giving you its interpretation of what is in the grooves, and for me so far the A95 is by far the best.
All of this means I have no clue how anything is supposed to sound which is I guess really all I was trying to day.
I have decided acting on preference is OK, and have started to enjoy vinyl again, and I have pretty high quality play back, but is it accurate? No, my take would be there is no such thing unless you have the exact original master tape and means to play it to use for comparative testing and fine tuning. Then you will find that tape is better anyway.. LOL (Yeah I have R2R tape too, although not quite good enough yet)
Phono Cartridge Modeling
Thanks Kevin, you have a very balanced view and way more experience than me. In 1969 I visited an audio showroom near Swiss Cottage in London called Studio 99. They had the big Bowers and Wilkins speakers with the Ionofane plasma tweeters, the BBC speaker powered by a Radford amp, and some KEFs with the B139. The best sounding by far was the BBC/Radford combo. What did it have that the others couldn't match? It was clarity. And quite honestly, I've been looking for the lost chord ever since! Oh, and the signal source was a Vortexion reel-to-reel. In those days, you could buy pre-recorded tapes.
Going back to vinyl vs CD, I've got The Talking Heads "Stop Making Sense" on both vinyl and CD. The vinyl sounds so much more "alive". The difference is similar to when I rediscovered tube amps. A pal gave me a Dynaco ST70 that he'd stored in his garden shed in Houston. He gave it to me when his garden shed blew away in a tropical storm. It was in miserable condition with rust and corrosion. Some of the caps had split open and some of the resistors had changed value. After a very thorough restoration, when I fired it up, I couldn't stop listening to it. I heard stuff I didn't know was on the record or CD. Everything sounded so much more dynamic.
I've been working on a zero tracking error tone arm made from 3-D printed parts. It certainly sounds better than my SME, Jelco, and Rega tonearms. The single feature I can't quite believe is the bass extension (for example, Neil Young's Harvest). I thought it might be a tonearm/cartridge resonance effect but it measures reasonably flat on my frequency sweep test records. Probably my "best" cartridge is my Grado Green that is easy to use and seems to have a quite flat frequency response. Your experiments are much more serious (and expensive).
The main problem with vinyl is that it is like The Japanese Tea Ceremony. It is a big deal requiring directed attention and purposeful action.
My search for better sound is a race against time. My hearing is not what it once was (12KHz on a good day).
I've started going to a lot more concerts (both rock and classical). Live music is no guarantee that the sound will be any good because of all the venue, seat, and performance variables. There was a cartoon in HiFi News (UK) that showed a man and women sitting at a concert and he says to her, "If I close my eyes, I can almost imagine the speakers".
I have a bad habit of listening to the audio system rather than trying to connect with the music. On days when I can connect, it is like a glimpse of that lost chord!
Thanks Kevin, you have a very balanced view and way more experience than me. In 1969 I visited an audio showroom near Swiss Cottage in London called Studio 99. They had the big Bowers and Wilkins speakers with the Ionofane plasma tweeters, the BBC speaker powered by a Radford amp, and some KEFs with the B139. The best sounding by far was the BBC/Radford combo. What did it have that the others couldn't match? It was clarity. And quite honestly, I've been looking for the lost chord ever since! Oh, and the signal source was a Vortexion reel-to-reel. In those days, you could buy pre-recorded tapes.
Going back to vinyl vs CD, I've got The Talking Heads "Stop Making Sense" on both vinyl and CD. The vinyl sounds so much more "alive". The difference is similar to when I rediscovered tube amps. A pal gave me a Dynaco ST70 that he'd stored in his garden shed in Houston. He gave it to me when his garden shed blew away in a tropical storm. It was in miserable condition with rust and corrosion. Some of the caps had split open and some of the resistors had changed value. After a very thorough restoration, when I fired it up, I couldn't stop listening to it. I heard stuff I didn't know was on the record or CD. Everything sounded so much more dynamic.
I've been working on a zero tracking error tone arm made from 3-D printed parts. It certainly sounds better than my SME, Jelco, and Rega tonearms. The single feature I can't quite believe is the bass extension (for example, Neil Young's Harvest). I thought it might be a tonearm/cartridge resonance effect but it measures reasonably flat on my frequency sweep test records. Probably my "best" cartridge is my Grado Green that is easy to use and seems to have a quite flat frequency response. Your experiments are much more serious (and expensive).
The main problem with vinyl is that it is like The Japanese Tea Ceremony. It is a big deal requiring directed attention and purposeful action.
My search for better sound is a race against time. My hearing is not what it once was (12KHz on a good day).
I've started going to a lot more concerts (both rock and classical). Live music is no guarantee that the sound will be any good because of all the venue, seat, and performance variables. There was a cartoon in HiFi News (UK) that showed a man and women sitting at a concert and he says to her, "If I close my eyes, I can almost imagine the speakers".
I have a bad habit of listening to the audio system rather than trying to connect with the music. On days when I can connect, it is like a glimpse of that lost chord!
I particularly enjoyed your comment about the Japanese tea ceremony, that's pretty much it in a nutshell, and it can be a lot of fun. (Except for of course when you are not in the mood.. lol)
I have pretty much lost my entire top octave and surprisingly find I am not aware of it at all in normal listening, and so far have no inclination to equalize the system to compensate for it. Perhaps one of life's small mercies? For some reason I am still easily able to discern tipped up HF responses, and other anomalies. I do find that I rely more heavily on instrumentation and trust my ears less if there is any question at all. In the end I do try to come up with something that is technically justifiable and sounds good to my ears.
For a while the linear trackers I played with were quite a revelation, their fiddliness (is that even a word) and tendencies to go out of adjustment over time got to me. I owned 2 Southers, and two ET2/2.5 series tonearms, they were good, and the ET arms comparatively well behaved once set up properly, but the need for the quiet air compressor banging away in the back room finally got to be too much.
In an act of absolute desperation last fall I purchased a new Jelco TK-850L and stuck my SPU A95 on it as an expedient after a hasty, but technically accurate set up. To say I was surprised was an understatement, perhaps the old school arm maker through long experience and with access to materials and processes that the boutique makers can't match perhaps can actually build better arms for less money. I've had much more expensive, but I've not had better.
I've struggled to like Grados many times because they have a great backstory and are made less than 200 miles from here. I've owned a Platinum, an 8MR, and have been loaned a black. (My opinion only but I find them warm, soft and altogether too laid back for my tastes, boring. They are among the better tracking and measuring cartridges I have experimented with, but despite this they lacked the palpability and dynamics I was seeking.)
I think you might want to consider an inexpensive HOMC or if you can handle a head amp or transformer maybe an LOMC. I'm thinking specifically of the Hana E, it was mindbogglingly good for the money when I heard it a couple of years ago on a good (Sorane) arm:
Hana - E MC Phono Cartridge | Shop Music Direct
(Just one place of many)
I've found I prefer LOMC, Strain Gauge, HOMC, MI/MM in roughly that order. For a while strain gauge topped that list, but the A95/TK-850L supplanted it for first place. Strangely ancient Shure M3D with a good stylus on a good high mass arm is also quite good. (Part of the reason why it now goes for ludicrous money on eBay, and to think as a naive 17 year old I threw a perfectly good one away and replaced it with something quite inferior - an early M44 IIRC.)
It sounds like you have developed a pretty high performing linear tracker, so some experimentation with higher performance cartridges should complement it nicely.
Would love to see some pictures of your setup at some point.
I have pretty much lost my entire top octave and surprisingly find I am not aware of it at all in normal listening, and so far have no inclination to equalize the system to compensate for it. Perhaps one of life's small mercies? For some reason I am still easily able to discern tipped up HF responses, and other anomalies. I do find that I rely more heavily on instrumentation and trust my ears less if there is any question at all. In the end I do try to come up with something that is technically justifiable and sounds good to my ears.
For a while the linear trackers I played with were quite a revelation, their fiddliness (is that even a word) and tendencies to go out of adjustment over time got to me. I owned 2 Southers, and two ET2/2.5 series tonearms, they were good, and the ET arms comparatively well behaved once set up properly, but the need for the quiet air compressor banging away in the back room finally got to be too much.
In an act of absolute desperation last fall I purchased a new Jelco TK-850L and stuck my SPU A95 on it as an expedient after a hasty, but technically accurate set up. To say I was surprised was an understatement, perhaps the old school arm maker through long experience and with access to materials and processes that the boutique makers can't match perhaps can actually build better arms for less money. I've had much more expensive, but I've not had better.
I've struggled to like Grados many times because they have a great backstory and are made less than 200 miles from here. I've owned a Platinum, an 8MR, and have been loaned a black. (My opinion only but I find them warm, soft and altogether too laid back for my tastes, boring. They are among the better tracking and measuring cartridges I have experimented with, but despite this they lacked the palpability and dynamics I was seeking.)
I think you might want to consider an inexpensive HOMC or if you can handle a head amp or transformer maybe an LOMC. I'm thinking specifically of the Hana E, it was mindbogglingly good for the money when I heard it a couple of years ago on a good (Sorane) arm:
Hana - E MC Phono Cartridge | Shop Music Direct
(Just one place of many)
I've found I prefer LOMC, Strain Gauge, HOMC, MI/MM in roughly that order. For a while strain gauge topped that list, but the A95/TK-850L supplanted it for first place. Strangely ancient Shure M3D with a good stylus on a good high mass arm is also quite good. (Part of the reason why it now goes for ludicrous money on eBay, and to think as a naive 17 year old I threw a perfectly good one away and replaced it with something quite inferior - an early M44 IIRC.)
It sounds like you have developed a pretty high performing linear tracker, so some experimentation with higher performance cartridges should complement it nicely.
Would love to see some pictures of your setup at some point.
Hi Kevin,
My zero tracking error tone arm isn't a cartridge carrier sliding on a tube type but more along the lines of a Garrard Zero 100 or Thales. The original idea is quite old: se, for example, Burne-Jones & Co BJ Tan II from the early 60s. The Achilles heel of all these pivoting headshell tonearms is play and friction. The Garrard was very poorly made - cheap stamped out parts and plastic bits that cracked without much provocation. The Thales is another matter - the engineering is superb.
My arm uses a different idea. One of my hobbies is horology and clockmaking. A smaller wheel driving a larger wheel exactly twice the diameter (and hence circumference) needs to rotate twice for every rotation of the bigger wheel. Applied to the design of a tonearm, if the stylus passes directly over the center of the spindle and there is some means of connecting the larger wheel built into the cartridge carrier with the smaller wheel at the tonearm pivot, then the stylus will always be perfectly tangential to the record groove. Have a look at the photos - in this case, the pictures are worth several hundred words. The setup is actually much simpler than adjusting overhang and offset on a conventional tonearm. The bearings at the headshell are ceramic flanged with no lubricant. The others at the arm pivot are also open type flanged but are steel type. I "borrowed" the Rega test for bearing friction and this arm turns very easily. That thread with the spring is what communicates between the arm pivot and the headshell wheel. The spring provides a light tension that prevents slippage and also takes up the very small amount of slack in the bearings.
The one convenience feature (and potential sanity saver) that is missing is the cueing device. That is on my to-do list.
My zero tracking error tone arm isn't a cartridge carrier sliding on a tube type but more along the lines of a Garrard Zero 100 or Thales. The original idea is quite old: se, for example, Burne-Jones & Co BJ Tan II from the early 60s. The Achilles heel of all these pivoting headshell tonearms is play and friction. The Garrard was very poorly made - cheap stamped out parts and plastic bits that cracked without much provocation. The Thales is another matter - the engineering is superb.
My arm uses a different idea. One of my hobbies is horology and clockmaking. A smaller wheel driving a larger wheel exactly twice the diameter (and hence circumference) needs to rotate twice for every rotation of the bigger wheel. Applied to the design of a tonearm, if the stylus passes directly over the center of the spindle and there is some means of connecting the larger wheel built into the cartridge carrier with the smaller wheel at the tonearm pivot, then the stylus will always be perfectly tangential to the record groove. Have a look at the photos - in this case, the pictures are worth several hundred words. The setup is actually much simpler than adjusting overhang and offset on a conventional tonearm. The bearings at the headshell are ceramic flanged with no lubricant. The others at the arm pivot are also open type flanged but are steel type. I "borrowed" the Rega test for bearing friction and this arm turns very easily. That thread with the spring is what communicates between the arm pivot and the headshell wheel. The spring provides a light tension that prevents slippage and also takes up the very small amount of slack in the bearings.
The one convenience feature (and potential sanity saver) that is missing is the cueing device. That is on my to-do list.
Thanks Mark for those suggestions. Threading some floppy string would definitely help control spring vibrations. The arm tube is a softish aluminum that doesn't go "ping" when it is tapped. I was thinking that if I did have some arm tube resonance, I could squirt some non-hardening foam into the tube after the wires were in place. I seem to remember seeing some, probably exotic, wool stuffed into an arm tube (that has the advantage that you can fish the stuff out if you want to upgrade the wiring). The wire came from Cardas (a good starting point) but is not as flexible as some wire I bought from KAB.
The 3-D printed plastic is PLA which is nice for the first rapid prototyping stages of proof-of-concept but I'll try ABS next (like Lego plastic).
BTW, are you in the "audio" business or a keen hobbyist (like me)?
The 3-D printed plastic is PLA which is nice for the first rapid prototyping stages of proof-of-concept but I'll try ABS next (like Lego plastic).
BTW, are you in the "audio" business or a keen hobbyist (like me)?
It's a bit harder than that, we had a long thread on here that ended up with some of the first accurate cartridge electical models I have seen thanks to Hans Polak and George (Gpapag). I can point you at the thread if you are interested. You have to meaure up to around 1MHz.
Wow - very cool!
I’m not much of a mechanical guy (all thumbs if you get my drift) but I can appreciate a nice bit of engineering.
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