Phono cartridge self resonance

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I'm not sure anyone knows*! We never got many hints of inband cantilever resonances when we went looking for them other than the most Clydesdale** of cantilevers. As LD says so many loose ends to tug. I think we are closer now than before though.



*well people did know, they just never told and the knowledge is dying with them.
**A popular breed of heavy horse. weighs 800-1000kg
 
We never got many hints of inband cantilever resonances when we went looking for them
I think that, for all the wrong reasons, cartridges with low effective tip mass don't have audioband resonances.

Tip mass was worked backwards from observation of the 'top resonance' assuming a certain vinyl spring constant, which value I've lost and can't find again. Now whether that is right or wrong I suppose is a moot point: what matters is that the resonance is clear of the audioband. Tip mass is a restatement of that.

LD
 
The super OM I have is very flat; the Shure V15VxMR is not (while the V15V-MR was flat, split pole pins). Having the SAS stylus gives a different response on the V15Vx
 

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Yes, R Comp needs to be selected based on the specific MM cartridge inductance and DCR. Not consumer friendly, for sure. I think the PA6 did offer it initially for MM cartridges, but it was likely dropped.

It had plug in phono card options.
 
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Actually I'm the one who's no fun at parties!


I will say that, for me, for whom these things are not always obvious seeing how he got the 50Hz pole was interesting. Same topology, two approaches. But there is something that feels right about getting the pole there and needing less correction downstream. I can't tell what is lost this way over the 2L-R approach without thinking about it.
 
I'm not sure anyone knows*! We never got many hints of inband cantilever resonances when we went looking for them other than the most Clydesdale** of cantilevers.

Maybe so, if one simulates the three loadings, 100pF||47k, open circuit, short circuit the coil currents are orders of magnitude different. Should this not show up some how in the magnitude of eddy current effects?
 
I mis-spoke a little yesterday, what I meant was that the midrange dip has a 1-3dB per decade slope which is (small) fractional f and I don't see modeling it except with some broad distributed time constant mechanism. So I didn't mean cantilever resonance per se but something else mechanical possibly.

EDIT - I might be in the wrong thread. :)
 
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I've had another bash at this. I've 'modelled' the mechanical resonance with V2 which gives deep dip at 30 kHz - obviously this can be moved around within reason with the judicious adjustment of parasitic L and C.

I can only get a significant resonant peak at ~20 kHz if I increase the cart load from 47k to 100-200k which hardly representative of reality. More work needed.

R3 and C2 crudely model the RIAA corner f at 2120Hz.

I need to find a way to sum to two curves. Anyway, my 2 cents worth.

Keantoken, where are you? :D
 

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I mis-spoke a little yesterday, what I meant was that the midrange dip has a 1-3dB per decade slope which is (small) fractional f and I don't see modeling it except with some broad distributed time constant mechanism. So I didn't mean cantilever resonance per se but something else mechanical possibly.

EDIT - I might be in the wrong thread. :)
Yup, it's still a mind melt to work out which thread applies ;)

Bending mechanics and wave propagation theory yields equations in fractional powers in fourths.

Here's a plot from a while back on calculated cantilever impedance as seen from the pointy end which sort of has an interesting and familiar profile. Only certain modes of cantilever bending resonance are permissible without mistracking.

Cantilevers bend!

LD
 

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