SIT-Preamp

Some descriptions of Russian transistors seem to be erroneous. The kp903 of any grade are the same power stud mount jfets, only Idss differ. kp601 contain the same chip as kp903, but have different case, similar to those of Siliconix transistors.

Thanks, so this implies if I understand that the suffix is the Idss family, with you preferring the /A; like the postfix of 2SK30-A/B etc.
Then the B I bought will be higher Idss and need a larger source R-degen in your last schema.
A little 'less' current than 160 mA would not harm :zombie: the concept I expect.

(I once had an OTL from Krohn Hite, 200 watts from the socket for 5 watts output/8 ohm. Since then, I like less is more)​
 
Thanks, so this implies if I understand that the suffix is the Idss family, with you preferring the /A; like the postfix of 2SK30-A/B etc.
Then the B I bought will be higher Idss and need a larger source R-degen in your last schema.
A little 'less' current than 160 mA would not harm :zombie: the concept I expect.

Simply I have some quantity of A-grade. A-grade corresponds to highest Idss, B - to medium, V - to smallest. Spread is rather big inside of any grade, so source resistors must be adjusted in any case.