I remember one of my first “Ah Ha” moments in audio. This was in the time period of about 1970. Equipment: A Thorens TD-124 turntable (bought new in about 1965) and an SME 3009 tone arm (bought used but pristine). Issue: Pivot bearing resonance. Design: A gimbal pivot bearing.
Like most audiophiles of the time, I subscribed to all of the major Hi Fi Mag’s which I read avidly. In those days, tone arm reviews appeared regularly. The SME 3009 was certainly considered to be at the top of the heap. I was content that I had one of the best arms around, maybe THE best. One performance issue that was given attention was bearing resonance. Some arms were downgraded because of bearing resonance. The 3009 was not one of them. It was the performance benchmark.
I did not know what bearing resonance sounded like. I had never seen it described. I wondered….. But, why should I worry? I had the “perfect” tone arm.
Then one day I was listening to a familiar record and I HEARD IT!! Only for an instant. I replayed the passage and again I heard it. There must something wrong. This led to a complete review of the arm set up. The set up was fine. Must be mistracking, right? What is this, I thought. This set up never mistracked! I increased the VTF. No help.
Since I have a typical audiophile mind, the idea was in place and could not be ignored. Once I had an idea of what to listen for, I heard this same sonic signature often. Not obvious, not loud, occurred for only an instant then was gone, like a mirage. I realized the signature had always been there but I had ignored it. I changed to another cartridge. It sounded different but the anomaly was still there with the same characteristic signature. I don’t remember the cartridges but they were TOL MM’s. After some experience, I began to be able to predict when the recorded matter would produce the signature. I began to suspect bearing resonance was the culprit. It sounded like what I would imagine bearing resonance to sound. After enough time passed, I was sure of it. Well, the 3009 was not “perfect” after all. I was shaken.
There is a saying that declares a pick pocket only sees pockets. Similarly, audiophiles only hear the latest problem. I only heard bearing resonance. I know you know what I mean.
Before continuing, I should note that the 3009 is not a typical gimbal design. The vertical pivot is a knife edge which I believe is not the resonance culprit. No, I think the offending item is the horizontal pivot which is a ball bearing design.
I concluded that all gimbal bearing designs were flawed and would resonate. It’s the nature of the beast. Some are worse than others.
I could not ignore the problem. Once I was programmed to hear it, I heard it often and it grated. In time I had another turntable and arm. It was a B&O 4004 linear tracking turntable. I loved it. And the bearing resonance had disappeared.
Since I made the change to the 4004, I have never had a pivoted tone arm-until recently. Eventually, I settled on the Eminent Technology ET-2 (and ET-2A) linear air bearing arm. I am convinced that linear tracking is the best solution for a tone arm design. I have good reasons to think this. I have had my ET-2 (A) for over twenty years. Obviously, I love the arm. There is never a hint of resonance which really can't be an issue due to the air gap.
However, I wondered about unipivot designs. But, I had never owned one. I basically liked the idea because the design should eliminate bearing resonance. A couple of years ago I bought a used Oracle Delphi V, fully optioned. It came with a Graham 2.2 Deluxe arm, my first unipivot. It was very impressive in so many ways. I could see right away why the 2.2 was so highly regarded. But, how would it sound? I mounted a Clearaudio Discovery cartridge and proceeded to set up. After so many years using, setting up, and listening to the ET-2, I had definite expectations. After quite a lot of time spent setting up the 2.2 I found myself frustrated. The arm was clearly incapable of establishing a perfect relationship between the groove and the stylus such as was possible with the ET-2. I settled for the best I could get and decided to just listen.
I had proven to myself that a linear design was superior in terms of set up. But, set up is not listening. I listened. I was very impressed. The 2.2 was a gorgeous sounding arm. No hint of bearing resonance. In fact, if I had not had so much experience with the ET-2, I could have lived happily. In truth, the ET-2 was a better sounding arm but the difference was not stark. The 2.2 lacked a little in resolution, detail, and dynamics (but these are the items I pay the big bucks for, so they are significant). But, it was never, never, hard to listen to. In fact it was most enjoyable.
So, what had I learned? Well, first, I found that the 2.2 unipivot bearing did not resonate. This was a big step in the right direction. Next, I concluded that beyond the benefits of the unipivot, a pivoted arm had enough geometrical errors to prevent the cartridge from aligning with the groove perfectly. This causes a loss of detail and dynamics. It has nothing to do with the unipivot bearing which, I thought, performed brilliantly. Rather it is totally because of the pivoted geometry. All pivoted arms would suffer the same lack because they share the same geometry.
However, not all linear arms are created equal. All (except Souther) linear arms that do not use air bearings (the servo types), have a pivot bearing and they are typically gimbals. I would expect all gimbaled arms to have resonate modes, even the best of them (SME V?). The gimbals are the bad guys in this design game.
The Souther linear arms are a mess. When they work they can work well. But, they have enough ball bearings to create a symphony of resonances. They have other problems as well. These are beyond our discussion here. I have never owned a Souther (Clearaudio) but I have worked on and mounted them. I really hate the design.
The remaining pivot design that I know of is the suspended pivot such as used by Well Tempered. I have no personal experience with these in that I have never owned one. However, I have spent many hours listening to the Well Tempered Turntable owned by a friend. It sounded good, no doubt. But, the periodic listening session is not the same as living with it. The design is odd enough to warrant an entirely different discussion. The only comment I have is it uses a pivoted geometry and will have the typical pivoted drawbacks. I truly admire the design because it is so out of the box. Is it equal to or better than a unipivot design? I don’t know.
BTW, I replaced the Graham 2.2 Deluxe arm on the Oracle with a brand new ET 2.5. The 2.2 is now mounted on my pristine Thorens TD 125 Mk1 with an Audio Techinica OC9/2 mounted. This is actually a very nice combo. I use it for the dirty work of auditioning new/used unheard records.
Sparky
Like most audiophiles of the time, I subscribed to all of the major Hi Fi Mag’s which I read avidly. In those days, tone arm reviews appeared regularly. The SME 3009 was certainly considered to be at the top of the heap. I was content that I had one of the best arms around, maybe THE best. One performance issue that was given attention was bearing resonance. Some arms were downgraded because of bearing resonance. The 3009 was not one of them. It was the performance benchmark.
I did not know what bearing resonance sounded like. I had never seen it described. I wondered….. But, why should I worry? I had the “perfect” tone arm.
Then one day I was listening to a familiar record and I HEARD IT!! Only for an instant. I replayed the passage and again I heard it. There must something wrong. This led to a complete review of the arm set up. The set up was fine. Must be mistracking, right? What is this, I thought. This set up never mistracked! I increased the VTF. No help.
Since I have a typical audiophile mind, the idea was in place and could not be ignored. Once I had an idea of what to listen for, I heard this same sonic signature often. Not obvious, not loud, occurred for only an instant then was gone, like a mirage. I realized the signature had always been there but I had ignored it. I changed to another cartridge. It sounded different but the anomaly was still there with the same characteristic signature. I don’t remember the cartridges but they were TOL MM’s. After some experience, I began to be able to predict when the recorded matter would produce the signature. I began to suspect bearing resonance was the culprit. It sounded like what I would imagine bearing resonance to sound. After enough time passed, I was sure of it. Well, the 3009 was not “perfect” after all. I was shaken.
There is a saying that declares a pick pocket only sees pockets. Similarly, audiophiles only hear the latest problem. I only heard bearing resonance. I know you know what I mean.
Before continuing, I should note that the 3009 is not a typical gimbal design. The vertical pivot is a knife edge which I believe is not the resonance culprit. No, I think the offending item is the horizontal pivot which is a ball bearing design.
I concluded that all gimbal bearing designs were flawed and would resonate. It’s the nature of the beast. Some are worse than others.
I could not ignore the problem. Once I was programmed to hear it, I heard it often and it grated. In time I had another turntable and arm. It was a B&O 4004 linear tracking turntable. I loved it. And the bearing resonance had disappeared.
Since I made the change to the 4004, I have never had a pivoted tone arm-until recently. Eventually, I settled on the Eminent Technology ET-2 (and ET-2A) linear air bearing arm. I am convinced that linear tracking is the best solution for a tone arm design. I have good reasons to think this. I have had my ET-2 (A) for over twenty years. Obviously, I love the arm. There is never a hint of resonance which really can't be an issue due to the air gap.
However, I wondered about unipivot designs. But, I had never owned one. I basically liked the idea because the design should eliminate bearing resonance. A couple of years ago I bought a used Oracle Delphi V, fully optioned. It came with a Graham 2.2 Deluxe arm, my first unipivot. It was very impressive in so many ways. I could see right away why the 2.2 was so highly regarded. But, how would it sound? I mounted a Clearaudio Discovery cartridge and proceeded to set up. After so many years using, setting up, and listening to the ET-2, I had definite expectations. After quite a lot of time spent setting up the 2.2 I found myself frustrated. The arm was clearly incapable of establishing a perfect relationship between the groove and the stylus such as was possible with the ET-2. I settled for the best I could get and decided to just listen.
I had proven to myself that a linear design was superior in terms of set up. But, set up is not listening. I listened. I was very impressed. The 2.2 was a gorgeous sounding arm. No hint of bearing resonance. In fact, if I had not had so much experience with the ET-2, I could have lived happily. In truth, the ET-2 was a better sounding arm but the difference was not stark. The 2.2 lacked a little in resolution, detail, and dynamics (but these are the items I pay the big bucks for, so they are significant). But, it was never, never, hard to listen to. In fact it was most enjoyable.
So, what had I learned? Well, first, I found that the 2.2 unipivot bearing did not resonate. This was a big step in the right direction. Next, I concluded that beyond the benefits of the unipivot, a pivoted arm had enough geometrical errors to prevent the cartridge from aligning with the groove perfectly. This causes a loss of detail and dynamics. It has nothing to do with the unipivot bearing which, I thought, performed brilliantly. Rather it is totally because of the pivoted geometry. All pivoted arms would suffer the same lack because they share the same geometry.
However, not all linear arms are created equal. All (except Souther) linear arms that do not use air bearings (the servo types), have a pivot bearing and they are typically gimbals. I would expect all gimbaled arms to have resonate modes, even the best of them (SME V?). The gimbals are the bad guys in this design game.
The Souther linear arms are a mess. When they work they can work well. But, they have enough ball bearings to create a symphony of resonances. They have other problems as well. These are beyond our discussion here. I have never owned a Souther (Clearaudio) but I have worked on and mounted them. I really hate the design.
The remaining pivot design that I know of is the suspended pivot such as used by Well Tempered. I have no personal experience with these in that I have never owned one. However, I have spent many hours listening to the Well Tempered Turntable owned by a friend. It sounded good, no doubt. But, the periodic listening session is not the same as living with it. The design is odd enough to warrant an entirely different discussion. The only comment I have is it uses a pivoted geometry and will have the typical pivoted drawbacks. I truly admire the design because it is so out of the box. Is it equal to or better than a unipivot design? I don’t know.
BTW, I replaced the Graham 2.2 Deluxe arm on the Oracle with a brand new ET 2.5. The 2.2 is now mounted on my pristine Thorens TD 125 Mk1 with an Audio Techinica OC9/2 mounted. This is actually a very nice combo. I use it for the dirty work of auditioning new/used unheard records.
Sparky
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