Re: 6DJ8 substitute idea - reverse engineering

Stefan Rodowicz


Inspired by your travels down the rabbit hole, I took a short trip myself.

Found "Teledyne_-_Junction_FETs_Theory_and_Applications" in Internet archives which includes a FETRON technical discussion along with data sheets for the common FETRONs. (see page 56 - p 87)

Good hunting,

Steve Rodowicz

On 6/23/2021 1:15 PM, Jeff Dutky wrote:
I went down a small rabbit hole on FETRONs a while back. Sadly, some of the primary resources linked to from Wikipedia are no longer available on line (at least, not as linked), but I did find this web site ( which has an article with some small technical details (at least it has a schematic):

From the article, the FETRON circuit appears to be quite simple, and could easily be replicated with current production dual JFETs (e.g. Toshiba's 2SK2145 or 2SK3320 or On Semi's NSVJ69004DSB5 or NSVJ59008DSG5) that appear to be readily available from Mouser at reasonable prices.
Now I'm interested again. It might be a deeper rabbit hole this time.

-- Jeff Dutky

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