Simplistic NJFET RIAA

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RCruz

RCruz

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Joined 2006
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Salas said:
6V I would advise as minimum Vin-Vout. This large change in buzz residual, rather shows that rectification gremlins looped somewhere in your build, and now that you smoothed the charging angle they lost their edge, but they do loop if there. Didn't you lose something subjectively on the other hand by dropping Vin in half?
Click to expand...

You are wright...!

After some time listening, I detect a softening on the low mids (upper bass).

There is less noise so I hear more detail but the sound lost a bit of "muscle".

It seems the charging angle affects attack and decay.

I decided to separate both channels using two identical toroids so I can get rid of the gremlins and use only one 2r2 12w before the caps.

Ricardo
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
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If the CCS Mosfet Vgs will be 4V then the difference will be 1.6V and if you use 10R you should expect 160mA in this example. What you will do is that you will put 10 Ohm resistror for R1 and when powered you gonna measure Volt across it. I=V divided by R. That will be your real current for your actual build with its tolerances. If it measures less than for 200mA, make R1 a little smaller until your V across your R1, indicates target 200 to 220mA by Ohm's law. I have wrote that a zillion times, you seem like not reading the scripts?:)
 
merlin el mago

merlin el mago

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Joined 2009
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RCruz,
Thks for the info about R1, I would like to put the choke at the PS between the rectifiers & the filter capacitor like do Erno Borbely in his EB-108/291 High Current Choke PS that I bought him.

Salas:
About the choke for the Low Voltage Salas Shunt Regs. I don't know if it's necessary the same choke value like the Erno Borbely PS with choke?

The Erno's Choke PS is for two types of loads current 100mA & 200mA, for both the power Tx is 100VA, the choke is the same 4H/60ohms/220mA, the only that change is the voltage for the Tx, for 100mA is 39VAC & for 200mA is 45VAC.

Another interesting thing to know is the resistor value for testing, Erno's use 150 ohms/10W across the outpout terminals to test for 200mA load current. For 100mA load use 330 ohms/7W resistors for testing.
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
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Choke input and 60R series resistance of it is going to kill your voltage way down at such constant current we use here. You got to ask him what kind of transformer it gets so for the rectification and filter to retain 55VDC out at 220mA that the reg needs to get, in what configuration with that choke. LC, CLC?. I can not predict the main PSU values with things I haven't used. Test resistor is just Ohm's law.
 
merlin el mago

merlin el mago

Member
Joined 2009
Paid Member
Hi Salas.

I forgot to tell you that Erno's PS choke is for +-24V., is type LC.

I ask you if it's possible to the same in your PS for your shunt regs?

Is not necessary that chokes must be the same value like Erno's use, but I need to know:
-Choke value in H/ohms/mA
-Tx value power in VA & secundary Voltage
-Resistor value in ohms/W to do the test

If there is a formula to calculate will be better, so anybody can get the voltage & ampers necessaries depending the applications.

I have the same Erno's PS with choke and without choke feeding his I/V Dac that I bought him & there is a lot of difference (speaking subjectively) better the choke PS but I know it's difficult to calculate because one time I asekd to Erno & he said that to calculate need to know: current consumption, voltage needed. So we know that values but I don't know how calculate & I am really interested how to do it because I want implement such kind of PS for the rest of mine devices.

Thks for help
 
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