aviel said:will a DMM that measure hfe be enough for selecting the fets?
i have ~6x 2N5457 and ~20x J201, hopefully i can use J201 instead. do you select the 5457s according to hfe? or Voltage?
No, DMM with HFE measurement function do not help here. The whole topic is well explained in the internet, check google.
An easy way to select the right Fet for your application is to build up one gain stage of the Hamptone preamp and check in circuit(with a socket). Than you can select easily for the right drain voltage.