Simplistic NJFET RIAA

[SGregory]

That makes sense AndrewT. I ran the calculation on 20r and came up with 2.00e-5W (20uW) with the 1mA current source. So I went for it.

I was about wimp out until I verified that the current was about right using my other DVM and 1000R resistor

 

[Salas]

Now I am curious to the sound of it with it properly loaded. I may have to pull the Pheonix out and try it.

 

[SGregory]

I'll try it tomorrow morning. I am bread boarding the new 12b4 preamp. It is cold walking to the woodshop in 45cm of snow.

 

[Salas]

Good luck with the new 12B4A.

 

[merlin el mago]

Merlin attention. Denon 103R spec is not only misleading for compliance which we have found with FFT and test record is really 16, but also for output impedance which is also wrong and really is 19 Ohm. I measured it. Now I use 220 Ohm load and goes very fine with 1.2R fleshed out mid bass. As it happened it was nicely a bit rounded over with 150R for 1.2 and its ''faster'' tone, but 1.2R proves more musically correct as it put me in some suspicion. I will even weigh the cart If I will take it out for some other thing.

Thanks for the input, I have something to correct: in my unbalanced Riaa cap I have 15.73nF instead 15nF so I will change & tell you, I am lucky I have on hand a couple of Caddock MK132 221R so I will try & if goes Ok I will order a couple of Vishay Tx2575 nude to Michael Percy Audio.

 

[merlin el mago]

Now I am curious to the sound of it with it properly loaded. I may have to pull the Pheonix out and try it.

+1

 

[Salas]

First change the load and then play with the HF Riaa cap. Also 180R load is possible.

 

[nicoch58]

misure the cartride don't magnetize the core ??

 

[merlin el mago]

First change the load and then play with the HF Riaa cap. Also 180R load is possible.

I haven't 180R, I have 200R Dale PTF65. Ok first I will change the load & after the HF Riaa cap.

 

[SGregory]

Isn't the core a magnet anyways?

 

[Salas]

Audiophile hype. Don't use a DMM not to see our coils are not the same per channel it boils down to be. They will fuse, it will magnetize my a**! My cart plays the same. All the others don't do such following our practice, I don't know your DMMs nor I suggest any practices. Ask your dealer, he will know all analogue secrets, and tell the truth.

 

[SGregory]

It is probably prudent to mention that if you do try, read the manual on the meter and make sure current is less than 1mA. Otherwise do as AndrewT suggested. The older meters probably pass more current to get an accurate measurement.

 

[merlin el mago]

That God catches us confessed if we have to trust in the dealers.

 

[Salas]

Scott now I remembered, when you will weigh the cart, can you please weigh it alone one time, plus the bolts and nuts it comes with, another time? I want to check again the exact give its suspension has. I know my arm's moving mass is cross checked plus I have the FFT.

 

[SGregory]

Good point Merlin, I personally learned that the hard way recently

 

[Salas]

That God catches us confessed if we have to trust in the dealers.

Why? They are all trained in the factory seminars of all brands they deal and have immaculate integrated servicing facilities.

Bottom line: What? You measured you coils? Be glad it still works! Take this $3K demag gadget now, didn't you listen to your soundstage collapsing after the crime you committed?

 

[SGregory]

Salas I won't be heading to the plant until tomorrow, will that be soon enough?

 

[Salas]

Its only for the record so to know better about matching arms. No haste. I have a good resonance already.

 

[RCruz]

In a MC, the core is not a magnet.

The magnet surrounds the windings.

 

[SGregory]

Not to start a flame war, you are correct that the core is not a magnet. But if I understand correctly, the core does focus the magnetic flux from the magnets to keep the coils in a more "ideal" magnetic field. In other words, what few uTeslas that were generated from the DVM is nothing compared to the strength of the magnets.