Simplistic NJFET RIAA

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#13,642
Dear Sir,

Thank you very much, your link seems be a good opportunity.
Now "I have l'embarras du choix", what should I buy please... BF245A, BF245B or BF245C, please....?
How could I check their correct functionality, please (schematic and values)?
It's necessary to use similar (close enough...how close) transistors on my PCBs?

Warm regards,
Ion Bebe
 
#13,643
pellesmil said:
Sweet

have you settled for 1 ohm?

roughly you would have about 100mv ripple in that setup

Going to about 15 ohms decreases the ripple to aprox. 16mv

Per
Click to expand...

and

skouliki said:
No i havent really settled to specific values, just using what i already had in hand. Salas if i increase the value of R to 15ohm , how would that affect the reg down the line?
Click to expand...

Sorry for bringing an oldie back online. What tools do you prefer to use for calculate this?

What input values is needed - current, voltage - more? What wattage is needed for the R part of the CRC?

Regards
 
#13,645
Salas said:
I prefer seeing such stuff live on the scope but Duncan's PSUD2 isn't a bad software tool for that either.
Click to expand...

Ok thanks salas, the scope will be used - what wattage is needed for the center R? The PSUD2 seems to be from a tube perpective - easy to miss things or overly concentrate on things not needed for SS. But the scope will be used of course and what wattage are we talking about for 1000uF - R - 4700uf? This so the fuse holds and the R doesn't burn 🙂

I've both seen and used an excel spreadsheet maybe (wouldn't call it a program) where one atleast could see the ideal graphs. Maybe it was in the SS or chipamp sections...

Regards
 
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#13,647
Salas said:
Resistor nominal power equal or greater than 3*(VRdrop*current)
Click to expand...

Well, the facts on the table so far is that in a CRC setup the VRdrop goes from zero to maximum and the current from maximum to zero in an ideal circuit unloaded and without losses (RC not taken in consideration as the circuit is unloaded as I don't have the load constant in my head). I will find the tool i need eventually and work backwards to find plausible loads and other values given the facts I found in this thread.

Regards
 
#13,657
Yes, mm as I have a few good ones I thought of giving them the best amplification 😀. Sonus Blue Gold, Stanton 881S mk2 and AKG P8ES Supernova... And some others as the usual Shures and a Pickering.
I use the switch to select different capacitances for loading to manufacturers specs.

In business...
An externally hosted image should be here but it was not working when we last tested it.
 
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