Straight tonearms without offset angle
In the October issue of Stereiphile, there was an article on a tonearm that had no offset angle and therefore had no skating force. The disadvantage of this is at the beginning and end of the record, the tracking angle error was much greater than what you get with an offset angle. For conventional tonearms that have an offset, and require anti-skating, which can never be perfect, the typical tracking error has a supremum of about 2 degrees, and according to online Lofgren calculators, this imposes a second-order harmonic distortion less than 2%.
I have a single-ended triode amplifier consisting of vintage globe 45 triodes transformer coupled to 833A SETs which drives Magnepans. Such SETs typically have second-order harmonic distortion as high as 10% which does not hurt the sound. A straight tonearm without an offset would have a maximum, or supremum tracking error of just under 10 degrees. If this causes a second-order harmonic distortion of less than 10%, would not this be irrelevant in a SET system? Is there any way of calculating this, or has this ever been studied?
Even with a straight arm with no offset angle, the tracking angle error could have been lessened by making the arm longer and not underhung. The reason for this design is not only to minimize skating force, it is designed to be extremely rigid by being short. I have to say I was surprised, but it does sound good. |
Stax and Micro Seiki both produced Straight Arms, but not Zero Offset . When looking at the Models it does seem a Zero Offset can be created, a little thought for a Headshells Cart' Mounting Mounting would be the ideal place to modify. Both Stax and Micro Seiki has a removable Headshell of the Flag on a Flagpole Type. There are simplistic alternative methods to attach a removable Headshell to the Wand that are a substantial improvement. The Zero Offset seems to make this as a option even easier to achieve. As made known in other Threads, I am at some point in the future to be demonstrated a friends TA Design as a Underhung Geometry, with them producing a alternate Headshell for their TA. https://www.monoandstereo.com/zero-offset-full-straight-tonearm-project/ https://www.hifispeaker.wiki/item/micro-seiki-cf-1 There are Headshell designs in the following link that will attach to the Wand, these designs enable a rigidity not usually achievable from a Bayonet attachment, the ones in the link are much closer to a formed Headshell on the Wand @mijostyn would make easy work of producing one of these alternate removable Headshells if the OD of the Wand is supplied. There will also be a need for getting over any confliction held with Underhung Geometry http://www.schiller-phono.de/de/tonarm-diy
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As well as the thread here on the Viv Labs Rigid Float, I can recommend studying a couple of others elsewhere: At Audiokarma At diyaudio It's a fascinating subject, not least for the love for underhung arms exhibited by owners contrasting with the hatred exhibited by those who do not own them. |
As Stated on many occasions: "There is a principle which is a bar against all information, which is proof against all arguments and which can not fail to keep a man in everlasting ignorance-that principle is contempt prior to investigation." Where investigation and experiences off are not easily attained, an open mind is also a wonderful companion and failsafe against everlasting ignorance . |
