Cartridge Loading for a phono pre amp

I don’t care of you about, useless and futile. My last posts to imhifi..  makes no reference to you .

 

Bye, bye ! !

 

R.

atmasphere

One of the side issues associated with this topic is that of ticks and pops. If the phono section has good RFI immunity and if it also has good high frequency overload margins, that peak at 1 or 2MHz won't overload the input of the phono and you'll get less ticks and pops.

That is absolutely true. In fact, with a clean LP (the only kind I play), ticks and pops are virtually non-existent. I've played LPs brought by visitors, after cleaning them ultrasonically, and they've been astounded by the silence.

I use an ARC Ref Phono 2SE balanced into a Ref 5SE. With an MC cartridge, the difference between 47K and 100 ohm loading is virtually undetectable and may even be zero. (You can use the Ref Phono remote to change loading from your listening chair.)

For all the ad hominem attacks, handwaving and double-talk that has plagued this thread, I've yet to find any fault with what @atmasphere has explained.

Dear @cleeds :   " I've yet to find any fault..." , good because all statements are only " anecdotes " or imagination that proves nothing.

 

Take a look:

" The industry spec is 47K for all cartridges.  " where is the " official " announcement about, say by the AES that coul confirm it? where?

 

"  less able to trace high frequencies. " again: where are the white papers that can confirm it.

 

 

holmz asked:

" Wouldn’t loading it down to 250 ohms from say 47k make it softer as the back EMF os gone that “would have been” stalling the motor? "

his answer was:  " EMF?. No...." the same answer on other 2 subject treads different forums where was proved that it's EMF:

"Yes, it really is back EMF- it's calculated using Lentz's law and is a consequence of Faraday's Law of Induction and it occurs as a result of the change in current through the coil- that's where the frequency dependent term comes from (the derivative). The term is subtracted from the voltage generated by the cartridge and in that way it acts to reduce the output voltage and hence the current, so there's a degree of negative feedback.  "

and in this thread you can find out the equations used. In this and the other threads your " man " "just " dead silence "  against that EMF analysis the engeenering did it, not a single comment.

This is the 4 time he posted this " tale " or in the best sense a non proved anectdote:

"  He ( J,Carr ) and I met and spoke about this topic at a Munich audio show 6 years ago; "  so WHAT??????

 

"  I have maintained is that the additional stiffness may decrease the ability of the cartridge to trace high frequencies, "" again, where are the white papers that shows and proves that that is happening? where?

Then he posted other tale: " the Grado Gold MI bad tracker anecdote "  that proves nothing.

 

" 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.  "  again: where are white papers that shows exactly that and not mere " imagination "?

 

" Your target for mechanical resonance is between 7-12Hz. The mechanical resonance is a product of the mass of the cartridge in the arm vs the compliance of the cantilever of the cartridge. Changing the load from 47K to 100 Ohms can easily get you outside of this target window- and that can cause tracking problems.. "

That is ridiculous and with no facts or diagrams/equations that shows exactly that. I That " can easily get you outside of this target window ( ideal resonance frequency range. ) " is not proved here or in any other subject threads. Again: only IMAGINATION.

 

Another " anecdote "/tale that rpoves nothinG:

" won't overload the input of the phono and you'll get less ticks and pops. I had this graphically demonstrated to me when an employee complained of a noisy LP he had bought. His LP played fine on the shop system so he brought in his preamp and there were the ticks and pops, sounding for all the world as if they were on the LP surface. "

 

So, "  I've yet to find any fault.." ? wow ! ! I had the impresion that you was or have higher audio knowledge levels. Well all we learn something every day.

 

At " least " J.Carr shows his white papers diagrams that are self explained. 

R.

 

 

 

I use an ARC Ref Phono 2SE balanced into a Ref 5SE. With an MC cartridge, the difference between 47K and 100 ohm loading is virtually undetectable and may even be zero. (You can use the Ref Phono remote to change loading from your listening chair.)

Why ARC featured such function in their reference phono stage that serve no purpose? So they can charge more?🤔

holmz asked:

" Wouldn’t loading it down to 250 ohms from say 47k make it softer as the back EMF os gone that “would have been” stalling the motor? "

his answer was: " EMF?. No...." the same answer on other 2 subject treads different forums where was proved that it’s EMF:

"Yes, it really is back EMF- it’s calculated using Lentz’s law and is a consequence of Faraday’s Law of Induction and it occurs as a result of the change in current through the coil- that’s where the frequency dependent term comes from (the derivative). The term is subtracted from the voltage generated by the cartridge and in that way it acts to reduce the output voltage and hence the current, so there’s a degree of negative feedback. "

and in this thread you can find out the equations used. In this and the other threads your " man " "just " dead silence " against that EMF analysis the engeenering did it, not a single comment.

Thanks @rauliruegas

Are these the equations you are referencing?

 

 

My Sonic Lab Ultra Eminent BC: 0.6Ω output 0.29mV

 

Voltage Input: At 0.29 mV, the Wizard determined the optimal gain level at +70 dB of gain. This setting has audible hiss coming from the speakers at 30% volume without any record playing. On careful listening, the gain level was sufficient. Optimal loading was determined to be 180Ω by the Wizard.

 

Current Input: At 0.6 Ω, the Wizard determined the optimal gain level to be I/V + 20 dB, but based on listening test I preferred a much lower setting of I/V + 5 dB.

 

According to Ohm’s Law where I = V/R, Current = 0.29 / 0.6 = 483 Micro Amps, a very sufficient level of gain based on the low impedance of the cartridge.

 

Clearaudio Goldfinger Statement (GFS): 50Ω output 0.9mV

 

Voltage Input: At 0.9mV, the Wizard determined the optimal gain level to be 70dB of gain on the Voltage input. On listening test, I preferred +60 dB of gain, a much lower setting. Optimal loading was determined to be 330Ω by the Wizard.

 

Current Input: At 50Ω, the cartridge required IV+ 20 dB of gain.

 

According to Ohm’s Law where I = V/R, Current = 0.9/50 = 18 micro amps, the GFS’s high input impedance resulted in a very low level of gain regardless of the Goldfinger’s output of 0.9mV, which is relatively high for an MC cartridge.

If that is the case I still appear to need feeding to compute the back EMF.
Luckily you stated:

I think that all forum participants has a responsability and is not spread false information with no real evidence. That responsability comes by the fact that Agoners forums have different knowledge levels gentlemans and everyday comes rookies looking for advise looking for help so the higher knowledge level participants in the forums have all a higher responsability about that’s exactly that: give help and good proved advises.

 

Well… I am the rookie that needs some help.

Ralph stated that the cantilever gets stiffer as the impedance goes down,

you stated this most recently:

"Yes, it really is back EMF- it’s calculated using Lentz’s law and is a consequence of Faraday’s Law of Induction and it occurs as a result of the change in current through the coil- that’s where the frequency dependent term comes from (the derivative). The term is subtracted from the voltage generated by the cartridge and in that way it acts to reduce the output voltage and hence the current, so there’s a degree of negative feedback. "

and earlier this:
 

@holmz : " He never posted that loading to hard a cartridge will cause stiffness to the cartridge cantilever enough to mistracking. "

I was who posted that only to clarify that J.Carr never support those false statements by atmasphere. Tha’s all.

 

" to which answered " with false statements. Good for you if that is what you was looking for.

 

I paste all those information coming for true experts for we audiophiles can learn and don’t believe in what " some one " is spreading every where with out facts.

I would have assumed that the higher impedance was making it more difficult to push the current, and that the low impedance would allow it to flow easier and result in a lower voltage at the phono stage.

But Ralph says it is the other way, and another gentleman as well.
(Hence the statement I made about needing a real physicist.)

I would like to understand how the loading affects the voltage at the phone stage as well as the stiffness change at the cantilever/stylus.