Voltage divider values for AMZ buffer

[manson]

I'd like to make a buffer / signal splitter. It's much like the AMZ jfet splitter and this one:



What are good value resistors to make a voltage divider to supply 4.5v to the 1meg gate resistor? I've seen 10k's, 47k's, 100k's in various schematics. AMZ is using 2x 10k in the basic buffers article.

[bbmonster]

Check out this thread at http://www.diystompboxes.com/smfforum/index.php?topic=70581.0 which leads to http://www.geofex.com/circuits/biasnet.htm

I'm still a newb at all this and that thread and page helped me out tremendously. In short, the answer to your question is depends on what is using the voltage divider.

[manson]

Ok, there are two J201's in there, with a total gate current of 100mA. That would make a total of 9k ohm /2, or let's say two 3k9 resistors. Is that right?

[petemoore]

What are good value resistors to make a voltage divider to supply 4.5v to the 1meg gate resistor? I've seen 10k's, 47k's, 100k's in various schematics. AMZ is using 2x 10k in the basic buffers article.
  First I'd asses if there's an existing divider I could use...
  Then use an LM386 if I have one, hook it up to the power supply and the output is 1/2v, spot on.
  Or use two = value resistors, say >22k's to divide, they're easier to match than smaller values [does it matter...?], then a 'big' [>220k] impedance setting resistor tied to that divider for the gate bias [the 1meg shown in schematic], higher values raise the input impedance, I would stick with  ~1meg.