Substitute of FET in the circuit below

[rajaram04]

Hello sir
I ve got a link related stereo to mono convertor (active type) which is here as follows

https://ahd1at.blogspot.in/2012/08/stereo-to-mono-converter-based-on-fet.html



In the above circuit what can we implant in place of the FET (2N3819) at final output ?

Is it possible to place any other type or same is compulsory ?

if yes then what is the substitute for it ? please comment . . . . . . . thanks

 

[Audioguru]

The 2N3819 Jfet has an IDSS of from 2mA to 20mA.
A 2N5458 has an IDSS of from 2mA to 9mA and can be used,
a 2N5459 has an IDSS of from 4mA to 16mA and can be used,
a 2N5485 has an IDSS of from 4mA to 10mA and can be used,
and a 2N5486 has an IDSS of from 8mA to 20mA and can be used.

 

[andre_luis]

The website bellow, presents all parameters of 2N3819:
https://alltransistors.com/mosfet/transistor.php?transistor=18148

By clicking on Equivalent transistors for 2N3819 link, you can adjust some parameters to a wider range to extend compatibility options :
https://alltransistors.com/mosfet/c...5&ugs=8&id=0.05&tj=150&fr=&cd=&rds=&caps=TO92

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[FvM]

You can use a bipolar transistor with additional bias circuit (base voltage divider, coupling capacitor).

 

[andre_luis]

Probably this option would bring some "complexity", due to be not a simple replacement on PCB, but to require not predicted components.


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[FvM]

Probably this option would bring some "complexity", due to be not a simple replacement on PCB, but to require not predicted components.

Yes. The original post wasn't quite clear what should be placed instead of 2N3819.

2N3819 is a popular and well available JFET, so I don't see a reason to replace it with a different type. I would probably use BF245C (or BFR30 SMD type), but almost any NJFET can do. If a larger input voltage level should be processed without distortion, higher Vgs,off values are necessary. A BJT emitter follower gives better linearity but higher part count.