JFET Matching "Tweedy Bird" Breadboard help

[Loztboy]

I have never used a breadboard, but now I have to
I'm building the Tweedy Bird that I got from Chi_Boy, http://home.comcast.net/~gprause/PCB/Tweedy_V2.0_Build_Doc.pdf

I tried to transfer this schematic to breadboard:

I have subbed C1 470 uF with 100 uF, is that a problem?

This is how my breadboard looks now.
Can someone please check it and tell me if it's correct?
I know there are some unnecessary jumpers...




I get about 1.5 V on the J201's I have tested. (supply voltage is 9.3V)
To get about 4.6 volts i have to use a 1K2 resistor in R2.

[midwayfair]

I can tell you your pinout is wrong unless your FET has the gate in the center.

Look up the datasheet for the FETs you're using; they give the pinout.

[Loztboy]

Thanks Jon.
I swapped R3 and R4 and turned the JFET 180 degrees.
Now I get more reasonable results

Does it matter that I subbed C1 470uF with 100uF?

[midwayfair]

Does it matter that I subbed C1 470uF with 100uF?

Nah, that's just power filtering. In any case, all you're doing is looking for two JFETs that measure the same. In reality, you don't even need to use the same resistors he did, as long as you use the same ones for each round of measuring and are willing to bias them in-circuit. Also: Chi_boy has you creating a matched set of six JFETs (you're basically making matched preamp tubes out of them), but you could also just make them each matched pairs and socket/adjust the drain resistors. Just in case you don't end up with a big enough pile of fully matched FETs.

[Loztboy]

OK, thanks.
I managed to match six JFETs for the Tweed and four for the black
Now I just have to build them!

[chordball]

Does it matter that I subbed C1 470uF with 100uF?

Nah, that's just power filtering. In any case, all you're doing is looking for two JFETs that measure the same. In reality, you don't even need to use the same resistors he did, as long as you use the same ones for each round of measuring and are willing to bias them in-circuit. Also: Chi_boy has you creating a matched set of six JFETs (you're basically making matched preamp tubes out of them), but you could also just make them each matched pairs and socket/adjust the drain resistors. Just in case you don't end up with a big enough pile of fully matched FETs.

Cool tip... Thanks for sharing. I'm starting my builds as soon as my J201's come in.