It's a tad noisier...but I think that's because I am using a 2N3819 instead of a K30A. Maybe I should put in the K170 instead...doesnt it have better noise specs than the 2N3819?
I wonder if anyone here has had any experience with these:
As I said, I tested many brands of 2SK30A in the Fame Studio C010 microphone, which shares the same topology with many other microphones: jFET+Bipolar Transistor+Transformer (low ratio). The Chinese jFETs (taken from other cheap mics) performed very well according to the catalog specs. (including low noise).
20 Euros!!!!! What a deal! Ill see if there are any used locally. So during my testing, I swapped boards with a known good 420 with my bad 420, and the transformer board on the bad one is the culprit of the all the noise and low signal. So now, I gotta figure out what component on the transformer board is is bad...transformer measures the same on both, 129:59 give or take....
And I will order from another source:
Khron is right. They are not original Toshiba, we rarely find NOS, but the Chinese have made great technological advances, in fact they are able to produce almost anything with very good specifications. The only problem is rogue traders.Why would they be original? The 2SK30A has been discontinued for a 'few' years now and even reputable distributors (Mouser, Digikey etc) no longer stock them, so... "you do the math"
Like I said, I'll give it a try. I ordered 2SK30A from aliex..
Are you sure they are connected in parallel, i.e. forming a 940pF capacitor?
They are both connected to pin 1 and 3 on the pattern switch. I took them out and put in a 1000pf polystyrene i had lying around. No difference. But it looks cleaner, and no more solder blobs all over the fet board. I actually desoldered everything and cleaned it up, so many blobs! So far, ALOT less noisier, and the output seems to be what I know of the AKG Perception to be like.
Or you can make a small PCB, pin adapter, so as not to overheat the jFET or break its very small, fragile terminals
