Maybe, maybe not. The capacitance is different at different operating regions,
so you don't want to rely heavily on the figure given. Take a look at
Gate charge vs Vgs as well as capacitance vs Vds.
Still, at $6, you should buy a pair and see.
I found this, take a look:
https://www.tme.eu/pl/Document/4f53e9d79c55d7a235aac54309458ddc/UJN1208K.pdf
https://www.tme.eu/pl/Document/4f53e9d79c55d7a235aac54309458ddc/UJN1208K.pdf
Hi couguarek. I bought a while ago 4 pieces of UJN1208K which is a depletion N-channel JFet. I used one to experiment in a DEF amp instead of SJDP120R085 as prescribed by Mr. Pass. Works.
Here's a couple curves I ran on it a few years ago, Common Source without
feedback into 8 ohms. One thing that recommends it is a load-line character
that gets a 2nd harmonic null to .1% at 1w. Bandwidth is 100 KHz with a
600 ohm source, which is also pretty good.
feedback into 8 ohms. One thing that recommends it is a load-line character
that gets a 2nd harmonic null to .1% at 1w. Bandwidth is 100 KHz with a
600 ohm source, which is also pretty good.
Attachments
Yes, but you'd have to redesign the bias circuit as the ujn is a depletion device that needs a negative voltage at gate from source where as the r100 wants a positive one.
So it is similar to the r085, there is a f2 thread about that or you can look at the arch nemesis article where Nelson shows a negative bias supply if you wish to tinker yourself.
Alternatively you could add large source resistors but that will lower gain and waste watts.
If you feed the speaker output back to the Source of the Fet instead of ground,
then you get all your gain back, or you can split the Source-to-Ground resistor
into two resistors and attach to the center point for an in between character.
Keep in mind that the circuit is inverting, so the "ground" output is positive
speaker polarity.
then you get all your gain back, or you can split the Source-to-Ground resistor
into two resistors and attach to the center point for an in between character.
Keep in mind that the circuit is inverting, so the "ground" output is positive
speaker polarity.
Uncalibrated and room temperature. Useless for absolute measurement but fun for comparison. 3 Kinds of Semisouth R125, R100 and R100A and 6 kinds of Cree. Semisouth are all bunched up on the left with the farthest right being a single IRFP150N.
Enjoy!
Hi SoundHappy! Happy New Year!!! 
I couldn't get the trace to work on that one but it measures DUT fine. I ended up getting a new one from Locky_Z on eBay actually and even there I struggled a bit (thanks to Dennis for rescuing me!) to get the latest software working.
It's a great toy for sure! I just wish I could find a way to use these Cree parts ...
I have some IXTH6N50D2 as well. I'll measure those next.
I couldn't get the trace to work on that one but it measures DUT fine. I ended up getting a new one from Locky_Z on eBay actually and even there I struggled a bit (thanks to Dennis for rescuing me!) to get the latest software working.
It's a great toy for sure! I just wish I could find a way to use these Cree parts ...
I have some IXTH6N50D2 as well. I'll measure those next.
Continuing the exploration from my F2J experiments and thought maybe this thread is more appropriate because I have an F6 Cree as well as F2J Cree running and a 3rd FW derived amp with Cree device instead of SS so it's not just F2J that can use these SS alternatives.
I have a couple of favorites from Cree but some of those are hard to get now so here are the next 3 challengers. 1 from Cree, 1 from United and 1 from ST.
This will be fun!
I have a couple of favorites from Cree but some of those are hard to get now so here are the next 3 challengers. 1 from Cree, 1 from United and 1 from ST.
This will be fun!
Not a fan of that Cree 650. They sounded metallic having poorly focused bass compared to IRFP in SE arrangement, 19v+/-, 1.6A with aleph ccs. But I'd love to hear that someone got them to work, perhaps they want/need a particular operating point and input. I eventually put SS R125 in there and never looked back... warm, articulate. Enterprising minds might do better though.
Hi Twitchie -
As a novice, I am just learning a bit about how to digest data sheets and barely getting into understanding what factors "matter" and how to set a load line with a curve trace. I found some similar parts while wandering sites that suggested "substitutions" for some of the SS / Tokin parts. I wasn't brave enough to pick any up.
Thanks for sharing what you've already found and are trying out. Looking forward to your observations.
As a novice, I am just learning a bit about how to digest data sheets and barely getting into understanding what factors "matter" and how to set a load line with a curve trace. I found some similar parts while wandering sites that suggested "substitutions" for some of the SS / Tokin parts. I wasn't brave enough to pick any up.
Thanks for sharing what you've already found and are trying out. Looking forward to your observations.