They have actually connected two JFETs directly in parallel, which i find mildly surprising, since most other such units make use of two JFETs in cascode arrangement. Cascode attenuates loading effects and makes the gain closer to constant, while with a single JFET, you will get a varying amount of gain. And of course the gain stage is present twice, once for the + pin of XLR and the other for the - pin. The unlabelled light grey boys should be inductors, not sure of their exact purpose in the arrangement, odds are together with the capacitors they form the phantom power passthrough filter, but i can't quite figure out how it works right off the bat like that. The very early FETHead had just one K170 JFET per XLR pin, but they switched to K209 here, which they for sure had to, since K170 was discontinued a long time ago; there is now a new K170 manufacturer but this new stuff is quite expensive, like $7 per piece as opposed to like a fraction of a dollar, and they weren't really available for a while except for shady junk. So the thing is though modern low-cost JFETs aren't quite so low noise and aren't exactly well matched, so odds are, by pairing them up like that they're alleviating both of these issues. The video that you link also has the same parallel arrangement of the same JFETs, it's obvious that the gates are connected together for each pair.
I'm using mid range bluetooth buds (JBL Live 300) and the Fethead without plugon is the best to my ears. The plug in does an impressive job otherwise but sounds like it improves your workflow so there ya go. 😎
Hi Cameron. Your videos are wonderful and useful
They have actually connected two JFETs directly in parallel, which i find mildly surprising, since most other such units make use of two JFETs in cascode arrangement. Cascode attenuates loading effects and makes the gain closer to constant, while with a single JFET, you will get a varying amount of gain. And of course the gain stage is present twice, once for the + pin of XLR and the other for the - pin. The unlabelled light grey boys should be inductors, not sure of their exact purpose in the arrangement, odds are together with the capacitors they form the phantom power passthrough filter, but i can't quite figure out how it works right off the bat like that.
The very early FETHead had just one K170 JFET per XLR pin, but they switched to K209 here, which they for sure had to, since K170 was discontinued a long time ago; there is now a new K170 manufacturer but this new stuff is quite expensive, like $7 per piece as opposed to like a fraction of a dollar, and they weren't really available for a while except for shady junk. So the thing is though modern low-cost JFETs aren't quite so low noise and aren't exactly well matched, so odds are, by pairing them up like that they're alleviating both of these issues.
The video that you link also has the same parallel arrangement of the same JFETs, it's obvious that the gates are connected together for each pair.
I'm using mid range bluetooth buds (JBL Live 300) and the Fethead without plugon is the best to my ears. The plug in does an impressive job otherwise but sounds like it improves your workflow so there ya go. 😎
try Bertom VST Noise reduction , it changes the tone slightly , but can make a huge difference. it is donation ware
just saying when you out it back together you need to twist the wires again as you took it out because twisting the wires also cancels noise.
Hi Carmeron. Not sure the best way to contact. I've dropped you an email on the Cameron.me address. Is that still used? Cheers Justin
Please spoke slower!