Fornicus Sag Cutoff

[ThomasAvenue]

Checked other Fornicus troubleshooting threads but from what I read those issues presented a little differently. When the Sag switch is engaged and the threshold is barely adjusted CW the entire signal gets swallowed up and cuts off. Totally unusable and not like demo videos.

Yellow LED is ~1.8V
FSW Red LED is ~1.5V
Momentary FSW Red LED is ~1.8V

 

[swelchy]

are the J201's legit?

 

[ThomasAvenue]

are the J201's legit?

Maybe not, but I got them from Tayda many years ago…?

I would’ve thought not but the Obsidious Preamp I just built uses two J201s and it’s also having strange choked signal issues that I can’t find a glaring fault for.

 

[swelchy]

Maybe not, but I got them from Tayda many years ago…?

I would’ve thought not but the Obsidious Preamp I just built uses two J201s and it’s also having strange choked signal issues that I can’t find a glaring fault for.

Ding Ding.... I'd suggest getting some smt ones on daughterboards... you'll generally have better luck with J201's that way....

 

[anevilspar7an]

For the Obsidious I would socket the JFETs as well, if I remember correctly they are in a mu configuration so they need to be arranged in a specific way. I would read up on JFET configurations to get some more context on this.

 

[owlexifry]

sounds like a marital issue

 

[ThomasAvenue]

Ordered some MMBFJ201 from Aion. I’d be thrilled if it was just some fake J201s plaguing a few builds. I do clean builds so I trust my work but I’m not initiated in vetting parts, so if something goes wrong that isn’t a mechanical or connective issue I get lost pretty quick on where to look.

 

[swelchy]

Ordered some MMBFJ201 from Aion. I’d be thrilled if it was just some fake J201s plaguing a few builds. I do clean builds so I trust my work but I’m not initiated in vetting parts, so if something goes wrong that isn’t a mechanical or connective issue I get lost pretty quick on where to look.

PM me if your in the states.... I can drop you 4or 5 legit through hole ones ones in the mail.... I have a small stash of through hole ones that are legit. Since you already have sip sockets soldered in you can swap through them and see if it acts right with some verified ones.