[sdiy] Substitute for IMF-3958 ARP 4015 S/H SubModule

[Csaba Zvekan]

Hi everybody,

I am looking for the IMF-3958 or 2N3958 N-Channel J-FET for a ARP 4015  
S/H Submodule (ARP2600). Is there a good substitute ?
Also looking at the schematics from ARP-TECH's site. I don't  
understand what the "GUARD" means coming from the Source of the 2N4392  
to the two Gates of the 2N3958.


Thanks

Csaba