So I've done a drawing of how it was setup.
Because i had the mic mounted on a headset in replace of a much worse mic I didnt really need the high levels of amplification. Just adjusting the volume slider on the computer was enough given it's close proximity to my voice. My voice sounded rich and full through it.
Bare in mind this was a capsule I pulled out of a device that's probably over 10 years old so it won't be as tidy as the modern day ones.
I believe the little retangular component was the jfet. No markings on it. I suspect it was a fet with built in bias (resistor) which is why it worked seperate from the pre amp. Could be wrong as I am a noobie.
It's tough understanding all of the technical jargon
It doesnt have to be an exact replacement. If someone could explain what i have to do if i just bought a standard jfet or better yet, a better one.
I've seen an ebay listing of this 2SK170 BL which apparently is real low noise. Whether it's genuine or not is another thing.
I looked at the JFE150 but the daft postage cost makes it all dumb. I'm sure there's a reason for it.
I know i could just by a new headset but that's boring
Plus I already have some nice headphones that doesn't have a mic.