MM Cartridge Loading Capacitance - More or Less?

[Wakefield Turntables]

I'm in the process of fine tuning my Lenco L75 deck and I want to get the best of it, so I have a wee question regarding MM loading Capacitance. I have a Shure M55E at present I'm probably "showing" it somewhere between 200-300pf (tonearm cable, PCA plugs, interconnects etc). It needs somewhere between 400-500pF, now to me this is a huge discrepancy. So, should I be "showing" the M55E 400pf or 500pf, or somwhere in the middle? Generally is less or more better for Capacitance loading to a MM cart.

Thanks in advance

A

[NRG]

Do you know the cartridge inductance? You can mess about with this loading calculator to get an idea how the response will change...also try different resistance loading it has an effect as well.

http://www.hagtech.com/loading.html

[Wakefield Turntables]

M55e inductance is 720 millhenries and I've worked out the capacitance of my system to be around 400pf, I get a calculation of 9.4 mHz, which means nothing to me! So, next question is, is a higher or lower value better or worse? What's ideal?

[Wakefield Turntables]

ok, done some more research and according to Ortofon :-

"
Cartridge and tonearm systems resonance frequency
To maintain a cartridge/tonearm system resonance frequency within the acceptable range of 7 to 12 Hz, whereas 10 Hz recommended, it is necessary to choose a cartridge with the mass and compliance matching the tonearm "
So its looks like I've accidentally hit upon the correct Hz.

[disarmamant]

M55e inductance is 720 millhenries and I've worked out the capacitance of my system to be around 400pf, I get a calculation of 9.4 mHz, which means nothing to me! So, next question is, is a higher or lower value better or worse? What's ideal?

It’s actually 9.4KHz. There is a resonant peak at that frequency. Adding more capacitance will lower the frequency of the resonant peak and reduce the bandwidth by rolling off the HF sooner.


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[Wakefield Turntables]

It’s actually 9.4KHz. There is a resonant peak at that frequency. Adding more capacitance will lower the frequency of the resonant peak and reduce the bandwidth by rolling off the HF sooner.


Sent from my iPad using Tapatalk

Martin, I've done a little more work and have found the total pF in the system to be 383-400pf and the inductance of the m55E is actually 630mH, so I'm now sitting around 10.3 Khz. Which according to Ortofon is a little suboptimal but at those levels I'm ok.

[NRG]

But u r missing the critical load resistance should now be 40k ish with those numbers. Rule of thumb: the lower the capacitance the better.

[sq225917]

Andy it seems like you're mixing up tonearm/cart/compliance resonant frequency with the resonant peak of the carts electrical loading. Tonearm/ cart resonant frequency is a product of effective mass, canti compliance and arm length.

Electrical loading for the carts hf peak is a totally separate issue.

[Wakefield Turntables]

Andy it seems like you're mixing up tonearm/cart/compliance resonant frequency with the resonant peak of the carts electrical loading. Tonearm/ cart resonant frequency is a product of effective mass, canti compliance and arm length.

Electrical loading for the carts hf peak is a totally separate issue.

Yep I stand corrected. Thanks Si, well at least I know my Tonearm resonance is now around 10.3 Khz, so a result of sorts.

[Aerobat]

I've been playing around with capacitance and resistive loading on a very very bright Signet TK7LCa with an inductance of 550mH. Using the Hagerman calculator, at 70pf capacitance (the lowest I could get) the loading should be 88.6kOhm. Loading it that high made the cart sound unbearably thinner and brighter, so I don't put much stock in the calculator. Loading the cart per the mfg recommended 150pf the calculator says I need 60k loading, again not right.

I settled on 32K and 170pf loading which rolls it off a bit but not too much. I also tried 22K and that was too much of rolloff affecting the music. So my point is listen to it rather than assume the math will make it sound best.

[Wakefield Turntables]

I've been playing around with capacitance and resistive loading on a very very bright Signet TK7LCa with an inductance of 550mH. Using the Hagerman calculator, at 70pf capacitance (the lowest I could get) the loading should be 88.6kOhm. Loading it that high made the cart sound unbearably thinner and brighter, so I don't put much stock in the calculator. Loading the cart per the mfg recommended 150pf the calculator says I need 60k loading, again not right.

I settled on 32K and 170pf loading which rolls it off a bit but not too much. I also tried 22K and that was too much of rolloff affecting the music. So my point is listen to it rather than assume the math will make it sound best.

very valid thanks.