[cotdt]

Saw a thread about it on diyaudio.com. Worth doing?

diyAudio Forums - The next best thing to 2SK389 / 2SJ109 ? - Page 1

 

[digger945]

Interesting. It looks like EUVL may be in the beginning stages of a group buy.
Guess these guys are tired of waiting for Linear Devices to produce a 109 replacement.
He(EUVL) has certainly done his homework. According to him, it has promise, and the potential to surpass matching on the 389/109's.

This could also be used for 2240's>3381's and 970's>1349's.

 

[Ferrari]

I would say yes… matched pair input JFETs (or quad, depending on applications) and thermal coupled to improve thermal stability. These CNC heatsinks look very good.

In some of my amps I built in the past, I have thermal coupled the matched pair input devices by putting them back-to-back and wrap a small piece of copper sheet (1mm thickness) around the pair devices to keep them together, while the copper serves as heatsink.