Cartridge Loading- Low output M/C

Wynpalmer4 5-25-2018

The non-inverting amplifiers used in an RIAA stage never have a gain below unity unless an additional pole is added. It’s hard to see why adding a capacitance of significant value to the input of a phono stage helps when the self resonant frequency of most larger value caps is well below the RF region of interest. Indeed, if that is your concern, then adding several caps of scaled value 1-2 orders of magnitude apart, say 0.1uF//3300pF//100pF as the cartridge load would be the way to go, and who does that- except as an extra pole in a non-inverting RIAA stage.
I’m a believer in fixing the problem where it exists and not by adding an additional parameter to an already over-constrained problem.

Thank you for your responses. I must say, though, that despite being a highly experienced electrical engineer myself (in my case analog and digital circuit design for defense electronics), I don’t see the relevance of this statement.

What I, Atmasphere, and Jonathan Carr have said in regard to load capacitance, and which the Hagtech calculators you referred to will confirm, is that in the case of LOMC cartridges **minimizing** load capacitance will increase the frequency and reduce the amplitude of the resonant peak which occurs at RF frequencies as a consequence of the interaction of cartridge inductance and load capacitance. Both of which are desirable goals, although it presumably won’t matter much if at all in the case of **some** phono stages (such as my Herron and I would assume the phono stages that are built into Atmasphere’s preamps).

But in the case of phono stages whose design is such that RF energy received at their inputs may have audible consequences keeping that resonant peak as small as possible and at as high a frequency as possible will mean that less resistive loading will be necessary to tame that peak. Which in turn can often be beneficial sonically, as has often been attested to by many highly experienced and astute audiophiles. A notable example being Larryi, who posted earlier in this thread.

So I’m not understanding why your statement that I quoted refers to adding capacitance, rather than minimizing it, or what the relevance of that statement’s concluding sentence may be.

Regards,
-- Al

^ I agree.......I have followed pretty much everything JCarr has stated in other forums about loading and all I can attest is my listening experience is much better for it.
The part that I focus on is that your LOMC should not be tasked to work so hard that it stiffens compliance, I can't see any good from that.

Unless you like buying a new cart sooner, much sooner, than normal.

@catcher10:  " stiffens compliance "?, you or any one but the cartridge designer can change cartridge compliance, certainly load can't do it.

R.

Dear @almarg : My " worry " here is not whom is rigth but more if things are pratically to any one of us, if we can do a easy as to load impedance changes. Normally cable manufacturers does not gives cable capacitance. I put the KK example but if you go to Audience ( OP cables. ) you can find out nothing.

Many times you can't know the ps fixed capacitance and the ones that comes with capacitive loading switch this works only when using MM but not when LOMC.

Ok, what's the problem to tame the peak ( as you said. ) loading at 100 ohms?

In the times of that TAS LOMC cartridges evaluations the specific cartridge loading never was associated to capacitance .

The advise is almost useless because we don't have or can have control on it to make any kind of changes about.

The cable manufacturers does not give the capacitance value but the tonearm manufacturers neither with the tonearm internal wires.

I don't think that that kind of advice from your part is of any help but only making more " noise " in the audiophile minds.

I always read your posts because always have very good contributions but for me not this time .

Now, always is good to have contributions as the wyn one. Don't you think?
I'm not technical oriented at your level but I always try to make things in the best way and in an easy way because at the end what I and we want is to enjoy the MUSIC and always is system dependent.

R.

Thank you for the nice words, Raul.

As far as the usefulness of an understanding of LOMC capacitive loading is concerned, for one thing it has provided guidance to the OP as to which of the two settings of the capacitive loading switch on his phono stage is likely to provide best results. And that in turn perhaps saves him the trouble of having to evaluate a number of different resistive loading settings twice, once for each of the two capacitance settings.

And the experience reported by Catcher10 certainly serves to illustrate that knowledge of this issue can be helpful to other audiophiles as well.

Finally, while I certainly agree with your concluding statement that...

... I always try to make things in the best way and in an easy way because at the end what I and we want is to enjoy the MUSIC and always is system dependent.

... in a hobby where a lot of audiophiles concern themselves with dubious and unexplainable minutiae such as which way a fuse is oriented an explainable and potentially significant phenomenon such as this seems to me to be a reasonable thing for audiophiles to be aware of.

In any event, thanks again for the nice words.

Regards,
-- Al