Simplistic NJFET RIAA

[Salas]

Yes, correct

 

[merlin el mago]

Of course I have to use the 47K load resistor.

 

[merlin el mago]

Murphy's law: I don't have 91R on hand

 

[Salas]

Maybe you have 82R?

 

[merlin el mago]

No.

 

[stajo]

Maybe two 180?

 

[RCruz]

If its DC coming from a reg chip like in the Mezmerize there will be no emitted field or other correlation to the contacts so to contaminate the signal lines.

Hi Salas

So I will place a relay before R14 and switch between input stages.

I would like to use raw DC from the psu to feed the chip reg but typical 7812 has too low max input voltage (that can easily reach 50v).

Can you suggest a simple solution ?

 

[stajo]

Two resistors, voltage divider.

 

[RCruz]

Two resistors, voltage divider.

Yes, of course... I already thought about that but am wondering on what values to use.

 

[RCruz]

Imagining a 12v relay that consumes 9mA in it's 1300ohm coil, if I feed it with a 7812, what should be the current that the 7812 is drawing from the psu ?

I would like to use the highest possible resistor values in the voltage divider in order to unload the psu BUT without starving the 7812.

 

[RCruz]

I believe I can use a 1000 ohm to 2000 ohm voltage divider.

 

[RCruz]

Now I need the best possible small pcb relay......

 

[stajo]

You could give 1k5 as upper and 2k5 as lower, 7812 parallell to lower a go.

 

[stajo]

I believe I can use a 1000 ohm to 2000 ohm voltage divider.

Yep, gives you some margin.

 

[RCruz]

Good ? G6K-2P-DC12 Omron Electronics | Mouser

 

[stajo]

Non-latching. If you look for a latching instead the coil will only operate when switching.

 

[RCruz]

I did not find any latching type with low enough contact resistance....

Latching type will need a complex psu wiring I guess....

 

[RCruz]

Ok... here we have a dual coil latching that seems ok: TQ2-L2-12V Panasonic Industrial Devices | Mouser

In this case I must use push buttons to switch between states. As after switching there is no more power on the coils, I will need to use the extra relay pins to light the led indicators.

 

[alexkosha]

I used a 805 or 604 smd cap across the gap from Hot to Cold on the back of the RCA
This achieves the next to lowest RF impedance.

The lowest impedance would be a group of smd distributed around the whole perimeter of that gap from Hot to Cold.
On that basis using two lower value smd caps would be better than using one smd cap.

Have a look at the newer XLR plugs with the integrated & distributed capacitance from Hot to shell to conduct RF to Chassis.

Hi Andrew,
I do see Neutrik uses that technique, but they connect shield to GND. Not Hot to shield or GND.

I hope I got your advice correctly. Please see second picture. Caps must be 0.01uF. Right?

 

[Joao@AltheaMusica]

Hi Andrew,
I do see Neutrik uses that technique, but they connect shield to GND. Not Hot to shield or GND.

I hope I got your advice correctly. Please see second picture. Caps must be 0.01uF. Right?

It's only conencted on one side of the cables... source or receiver...