Resonance testing of new tone arm

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Hello All,

I have just finished assembling my new 2017 tangential tone arm. It functions as expected and I need to test it for resonance. I have several LPs that contain test tones for that purpose, but I don't know what to look for or how to interpret the tone arm's reaction to the tones. Has someone done this test before? Can you tell me what to look for?

Sincerely,

Ralf
 
Interesting topic. I recently did some tests for my air bearing arm and want to see the difference of lateral resonance frequency and vertical resonance frequency, but the results are not what I expected. I may post the results later on under my air bearing thread.
 
Hello billshurv,

I was referring to the frequencies between 7 Hz and 12 Hz.
When knowledgeable individuals discuss tone arms, they always stress that a tone arm's self resonance frequency should be in the above mentioned range of frequencies. I wanted to know how to test my tone arm without lab equipment.

Sincerely,

Ralf
 
Then you are interested in the mass of your arm and the proper cartridge compliance combination that puts the range above low sub frequencys like you mention 7-12 Hz range.

You can in a pinch, put a high efficiency woofer on the floor unmounted and just watch it move as the tonearm traverses a record.
In alot of ways, this real world test will give a better feel on whats going on since the end result is all that matters.

If the woofer is moving like crazy on quiet passages then you have a severely mismatched cartridge compliance to TA mass ratio. It should be fairly stable if matched.

For Self resonance of the tonearm itself, I would use a strain gauge taped to the arm shaft in some way and not certain how you would find this out without test equitment

Regards
David
 
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> 7-12 Hz range. ..... woofer on the floor

If a 'scope is available: set the horizontal sweep to happen twice a second. Watch as you tap lightly on the top of the headshell. If you get 5 full waves per sweep, that is 10Hz. 4 or 6 waves (8-12Hz) is cool also.
 
Hello everyone,

I just realized that my original post was missing some information. I should have mentioned that the test I am trying to perform includes the cartridge! The cartridge is on long term loan to me from a kind gentleman who was adamant that I not disclose the brand. It is a cartridge that retails for $2,800 when it is not loaned. I do have an old Philipps dual beam oscilloscope but otherwise I am operating on the proverbial shoestring.

Sincerely,

Ralf
 
Once I had an idea to do that kind of testing using a CDP pick up.
Making a small hole in the plastic optic with a heated needle for the stylus to seat in.
Mount the optical pick up assembly on a flat block of aluminum ,use the focus coil for vertical and the tracking coils for lateral excitement. Never built it because I'm finished with LP-s in the early eighties, but it could work 🙂
 
revelation is imminent.

Hello Doug.

I would love to introduce my tone arm to the DIY community immediately. But if I do, I am certain I would loose it to some copy cat out there as I have no patent or other protection.

I am currently negotiating with a company east of here, to market my tone arm. If nothing comes of that, I'll probably make it public at the end of 2017.

It is nothing less than revolutionary.

If you ever come this way, I'll demo it to you if you are willing to sign an NDA.

Sincerely,

Ralf
 
The cost of defending a patent could easily make you miserable and cost you incredible dollars with no guarantees
Better off just selling as many as you can because a copy cat will change it just enough to get away with it.
Small ticket item anyway and not worth the legal hassle.
 
Hello AVWERK,

I agree 100% with what you wrote, but how else can an inventor protect his intellectual property?

I happen to know quite a bit about patents. Back in 1984 I patented my first tangential tone arm without the aid of a patent attorney. It takes a lot less money doing it yourself, but still requires some cash.

"Changing a patent just enough to get away with it" is a common misconception. That depends on how well the patent claims are written. Writing the claims is the part of an application that requires the most skills.

Sincerely,

Ralf
 
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