Removable headshells 101

Timeltel ... TA?

Also the use of wood as a damping/vibration modification material is interesting.
I have some mpingo wood shims I had made up for the Revox (where cartridge mounting requires shims for adjustment)

They are usually sold/advertised as "cartridge dampers"...

I have to admit to not having experimented with these other than using them as shims on the Revox (where they do an excellent job)

Wood has a couple of interesting properties:
Different speed of sound along grain vs across grain
This results in quite complex reflection/refraction patterns of vibration movement - with the potential for frequencies being altered/spread (refraction) resulting in damping...
Add to that the shear influences at the material boundaries.

The potential may indeed be there - but like any of these vibration related issues, the environment is so complex as to make it intractable other than as a black art. (frustrating that!)

bye for now

David

Pryso - yes interesting isn't it, Henry's comments amount to "this emperor has no clothes" :)

I don't know how I missed this thread!....

Perhaps the fact that I was not (yet) focused on the headshell side of things.

My switch back to the Revox yesterday highlighted a resonance at 300Hz that I had assumed (wrongly) was a property of the test tracks....

I have a suspicion that the 300Hz resonance (bell curve centered around 250 to 300Hz extending roughly 1 octave each way to around 150Hz and 600Hz - center/peak and width varies a little with cartridge/headshell) is caused by the movement between arm/headshell.

Has anyone done any analysis/work on this?

The Revox 1 piece arm fitted with a p-mount adapter, shows the same effect but with around half the amplitude (1db as opposed to 2db on the JVC S-Arm).

Do any specific headshells reduce/control this better than others?

What about the two pin headshells? (one above, one below - like the Orsonic AV-1)

I also have a couple of AT headshells for which I need those very short screws.... anyone out there have some ideas as to where one might find some?

Although I have a wide variety of headshells now - primarily focused on lightweight models, as most of my cartridges are high compliance - I have normally chosen a headshell for a cartridge based on rigidity and mass considerations - without experimenting with differing headshells. It appears I may need to take my experimentation down the headshell path as well.

Bye for now

David

Thanks guys,

I have been eyeing off some of the wooden HS's but have held off as they are a bit pricey....
I have some experiments to do with damping the headshell join.... -replacing the washer with a bit of plasticine - which will mold itself into the join and form a CLD layer.

The other thing I need to try is wrapping the tonearm.

I just cannot imagine that this particular anomaly would be affected by a wooden HS. - My gut feeling being that the Wood would be good for damping some of the higher frequency grunge.... (and I will stick with that until I can justify the expense of a wooden HS or two to myself...)

Also good to get some trusted feedback on the Orsonic headshells...

bye for now

David

Well my experiments with resonance damping on arm & headshell have failed miserably...

Not because it doesn't work, but because my current test track/measurement method has accuracy that is around +/- 0.25db....

That results in variations of up to 0.5db between two readings of the same setup....

My gut feeling looking at the plotted results is that I can see a shift, but it is small (less than 0.5db) and not demonstrably repeatable...

Bye for now

David