Cartridge loading

@lewm

Is THIS what you have?https://audiocubes.com/products/47-laboratory-4712-phonocube

Yes, it doesn’t work without special power supply, so there must be a power humpty (first in the list) and i have it with my phonocube.

If you’re buyin’ a Phonocube without power supply it looks like a good deal, but it doesn’t work. The power supply is 3 times bigger than the cube itself and superheavy. For superb results some people use 2 power supplies for 1 Phonocube (dual mono).

More images of this set with power supply and cube are all HERE (not mine).

And you can study about parts and its unique but very simple circuit HERE.
Let me know what you think now when that guy cracked it and explained why the input impedance is almost ZERO. But that guy is not the designer of the Phonocube, he just made a clone.

P.S. I think i posted all these in another thread long time ago.
The PhonoCube originally designed for Miyabi 47 Lab cartridge. 

Which current injection phono stage do you use ?

Let me know what you think now when that guy cracked it and explained why the input impedance is almost ZERO

@chakster This statement isn't correct. The **virtual ground** is almost zero, not the actual input impedance. Its a bit tricky explaining what the difference is but put it this way, if you turn the unit off you'll find that the actual input impedance is quite high. Apparently it has a pretty good opamp, since that is required in order for the virtual ground to approach zero.

The idea is to replace the input resistor with the cartridge itself- so that the virtual ground (present in any opamp circuit) is the output of the cartridge itself. In this circuit the cartridge isn’t doing the sort of work as it would be if the cartridge were presented with an actual 0 ohms impedance!!

Very interesting @atmasphere  
I wish i could understand more, they don't make Phonocube any longer, probably because they do not make Miyabi 47 cartridge anymore.  

Any other phono stages with the same circuit ? 

Dear @atmasphere  : Your post is not an answer to what I asked to you:


"""   how did you measure that " limit trace " as a function of loading and which is the point/value where the loading figure starts to " limit trace " abilities in the cartridge?  """

that is what needs a more specific answers because you posted here and in several other ocasions:

  """ will limit the ability of the cartridge to trace higher frequencies .."""


 Lewm my answer to you is that other than " science " we have to use common sense and here what I posted before to you:

"" did you know how much " force " do you need to apply/need/ at the base of the cantilever to really impedes at the stylus tip position its free movements, a tiny movement? no? 
Btw, do you know the " power forces/inertia " generated at the stylus tip when ridding the grooves at 33/45 rpm and what " force " is need it to " limit the trace " of the stylus tip to track when appliyed that force/loading at the other end of the cantilever? ..."""

Which is the force need it to broke that very high inertia generated by the friction between the groove modulations and stylus tip when the cartridge is ridding/tracking those grooves that can " limit trace HF "" ?

I don't know that answer concerning the loading resistor value to broke that inertia. We have to think that load resistance takes its effect at the cantilever base and the stylus tip is ridding at the other end/extreme of the cantilever and this makes " things " extremely complicated to that " limit trace " issue.

That theorical electrical loading effect is converted in mechanical energy ( the " force ". atmasphere said: stiffer the cantilever. ) what makes it even more complex due that in the mechanical land we have to take in count several parameters as: compliance of the cartridge, cantilever length and overall dimension and characteristics, status of the stylus tip because if the cartridge has over 1.5 khours of use its own tracking abilities changed that when the stylus had only 300 hours and not only that but even its compliance through more playing hours could changes too, the stylus tip inertia is different depending its position in the overall LP grooves and other parameter to take in count is the different velocities recorded through the LP grooves surface, etc, etc.

So, till now exist no true evidence that that " limit trace..." can happens.

@atmasphere can you answer the original questions?

R.

Dear atmasphere : You already had all the time and opportunities to show the evidence I asked about on that specific: " limit trace....".

Today I'm totally convinced that you has no evidence about evidence that we can duplicate in a system or at least evidence.

So Palmer was rigth ( years ago. ) when he proved that your " limit trace..." statement is FALSE.

For my part end of the issue due that now I can confirm that  the ones that like me that think that " limit trace.."" does not exist  we all are rigth and that's  what we need to know  thank's to your " answer ".

So never mind about, subject solved.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.