Tyimo said:
Could you draw a sketch of both of your suggestions/questions? I have a feeling I'm giving answers to questions that I have not understood
Magura 🙂
Tyimo said:
This is effectively what we have been discussing the whole time
Yes it works, but you need a pre that's able to deliver som juice to drive it.
Magura 🙂
I'd think about replacing that 2SJ74 based current source with a bipolar based source along the lines of the diyaudio current sources found in the tube forum. (SY and Pink Mouse) You won't need all of those big electrolytics and they have much better performance overall than a single fet implementation. (All at the cost of a couple of small signal transistors, a led and a resistor or two.)
Tyimo said:
If you take a look at the schematic in the first post, and read on a few posts, you will find that your schematic is an exact match of what we have been discussing.
My advice to you is to go for the differential pair version. It suffers hardly any drawbacks, and is not much more trouble to build.
Magura 🙂
carpenter said:
You remind me of something 🙂
I tested our little adventure into buffered diff. pair inductor loaded.
The not X-ed version sounded at least as good as the X-ed version.
The buffered version is a patch for not having an adequate powerfull pre, with the right pre, it's pointless as far as I could tell.
Choky spent some time giving advice on the side, this drove me to make a new design, which is shortly to be tested.
Magura 🙂
Thanks Magura!
Basicaly I am so much happy with my own Choke Loaded Mosfet follower amp (driven with a ECC88 Mu follower voltage stage), that I would like to stay by this kind of amp design.
I am interested for this Jfet amp only, because I have a dozen of this Lovoltech Jfet and I would like to use them for something...🙂
What do you think about a pure Jfet amp? For example 2 power Jfet paralel with choke load, ca.15Vdc, 2A , would be enough for ca. 14-15W music. Drived with a 6H30 or E182CC preamp (36-50mA)
Greets:
Tyimo
Tyimo said:
I have had the same idea, I though dismissed it due to the fact that you need a lot more than 2 JFETS in parallel to get 15W music, and that I don't see no ill effects of the cascode solution, contrary to the need to drive hich capacitance in this topology if running a bunch of JFETs in parallel.
I think 20W per JFET is just about the max. dissipation, so you will need at least 4 in parallel. I also don't see how you will keep them within their liniar region in this topology?
Magura 🙂
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