Cartridge Loading for a phono pre amp

@noromance : " While mechanical impact does occur as a result of electrical load- there is some back emf necessarily generated by the signal current that affects the mechanical motion, but a quick back of the envelope calculation using Lenz’s law and the 10uH cartridge suggests a 2 orders of magnitude difference between the generated signal and the back EMF for a 100 ohm load at 20kHz- certainly not enough to cause tracking issue. "

With no tracking issues, that Wayne measured and JC wihte papers shows, bandwindth/frequency response is not affected.

The OP, you or any one else can load their cartridges witrh the impedance that in each one system " sounds " the best with out worried on that electrical/mechanical load issue that no knows system can " detect " and even direct measures can’t. So why distress about? makes no sense .

Btw, @whistleraudio  posted: " we need a real physicist here. " and is rigth: he need it.

R.

In this context, is there any relationship between cartridge bandwidth and cantilever stiffness?

The stiffness is a function of the load impedance. Obviously it will be more supple if loaded at 47KOhms as opposed to 100Ohms!

This says nothing about the bandwidth of the cartridge itself, which would be unaffected by the load. However, the stylus has mass and to trace high frequencies must be low enough that its mass is easily moved by the modulations in the groove. Adding stiffness to the stylus support isn't going to help- at some high frequency (which may well be outside the audio band) the stylus will no longer be able to keep up. This does not take much to sort out.

Any modern cutter has bandwidth well outside the audio band. We use a Westerex 3D cutterhead, which was designed in the 1960s and it has bandwidth to 42KHz, at which point its bandwidth is intentionally limited by the electronics.

We can cut a 30KHz tone on a lacquer and play it back on some pretty conventional LP equipment- for that we use a Grado Gold mounted to an older Technics SL1200, the idea being that any cut we make should be playable on that machine. Its got no worries playing a 30KHz tone, but if we start loading the cartridge we can see the output level drop (with some distortion/noise apparently added), whereas at lower frequencies its still perfectly flat (once equalized).

Empirically speaking its easy to deduce that the load is affecting the ability of the stylus to trace the groove, which is why we see distortion as essentially the stylus is mistracking. 

Even though there is no microphone that has bandwidth that high, it seems a good idea to keep the stylus as planted in the groove as it possibly can be. So IMO its important that the phono section be immune to the RFI generated by a LOMC cartridge so a 47KOhm load be used to allow the cartridge to track to the best of its ability.

BTW, if an SUT is employed, you can side step this issue a bit as most SUTs lack the bandwidth to pass a 1MHz or even 200KHz noise source which can be really helpful to many phono sections! IMO this might be why SUTs have a certain following.

Dear friends: Stupidity exist over the world and certainly in this thread too.

" We use a Grado Gold " :

That’s a high compliance MI cartridge with a high frequency limit at around 55khz. Here a professional review pasted highligths of the Grado Gold:

""

The Grado Gold sits at the top of the Grado ‘colour’ cartridges. In this sense, the Grado Gold cartridge epitomises the sound that Grado is renowned for: a warm, full sound that tends to match especially well with vocal, jazz, classical and other forms of music that have rich arrangements. The Grado Gold is a ‘pick of the bunch’ version of the Grado Silver – one that is judged to be made with excellent quality and care.

The Grado Gold cartrige has a very warm, dark sounding midrange that results in your vinyl sounding like vinyl .....................................................This cartridge can be a little susceptible to hum. The Grado Gold cartridge review suggests that this is due to the design of the cantilever. When playing music the hum is not audible, but it will detract from some of the frequencies and result in less detail throughout those frequencies. ........................................................................................................................................... The Grado Gold is not the most spectacular tracker. Especially sudden changes such as sudden loud chords or grand detailed crescendos might result in some tracking errors. ..................""""

The sample reviewed was loaded at 47k as usually with this kind of Grado designs.

So, that election of cartridge trying to prove the HF mistraking can be no more poor or stupid for that load changes purpose:

" Its got no worries playing a 30KHz tone, but if we start loading the cartridge we can see the output level drop (with some distortion/noise apparently added),..........

Empirically speaking its easy to deduce that the load is affecting the ability of the stylus to trace the groove, which is why we see distortion as essentially the stylus is mistracking. ""

Really? the whole statements posted are false because the Grado Gold, with out loading changes, shows mistraking ! ! ! Go figure ! ? ! ?

Laughing for say the least, you make my day. Go a head ! !, be my guest. Tremendous post for every one can learns but you.

R.

@noromance : " While mechanical impact does occur as a result of electrical load- there is some back emf necessarily generated by the signal current that affects the mechanical motion, but a quick back of the envelope calculation using Lenz’s law and the 10uH cartridge suggests a 2 orders of magnitude difference between the generated signal and the back EMF for a 100 ohm load at 20kHz- certainly not enough to cause tracking issue. "

Can you show the envelope and the equations?

Btw, @whistleraudio  posted: " we need a real physicist here. " and is rigth: he need it.

R

Who is whistler?