I am trying to construct this https://diyaudioprojects.com/Solid/...ozhound-Labs-JFET-MC-Pre-Preamp-Schematic.png MC cartridge pre amplifier using J201 instead of 2SK170. Thought it would be a good substitute, for some reason. But when I tested the amp with 1 kHz sine wave, I measured a voltage gain of only approx 14-15 dB. Should be around 30 dB. What am I missing here, and how to increase the gain of this circuit. Increase the drain resistor value?
J201:
1. IDSS is much lower than for 2SK170
2. Transconductanse yfs is much lower than for 2SK170
3. Noise is much higher than for 2SK170
An advice:
Use 2SK170 and forget J201
1. IDSS is much lower than for 2SK170
2. Transconductanse yfs is much lower than for 2SK170
3. Noise is much higher than for 2SK170
An advice:
Use 2SK170 and forget J201
Best substitute for 2SK170BL is 2x 2SK209GR (matched Idss) in parallel.
https://www.diyaudio.com/community/threads/njfets-for-source-follower-applications.329131/
Patrick
https://www.diyaudio.com/community/threads/njfets-for-source-follower-applications.329131/
Patrick
Thanks, very useful.
Ok, don't know why I did realized this. Probably because a had J201 and wanted to make it work them, I'll probably try to get the 2SK170.
Anyway, for experimental purpose I'll try to get it working with J201.
You can buy matched quads of the Linear Systems LSK170 at the diyAudio Store. The Linear Systems LSK series JFETs are clones of the original Toshiba 2SK series.
https://diyaudiostore.com/collections/frontpage/products/matched-jfets?variant=39335246889033
https://diyaudiostore.com/collections/frontpage/products/matched-jfets?variant=39335246889033
Or there's the brand new JFE150 which is close to the 2SK170 in performance (higher transconductance), although you'd need a breakout adaptor board for it (SMT package).
