F5 power amplifier

[tinitus]

I suppose your right
I will try
But I also intend to not be too hysteral about it
Meaning I wont let it lead to other compromises

Im still in doubt about the rail voltage
But I will probably stick to 25V with raised bias

Regarding Jfets
Are you sure that an effective heatsink on each Jfet wont be just as effective
And with each leg connected to solid wire
It should be able to deal with the worst temperature variations
I suppose the constant temperature variations is the problem
If temperature is more stable, DC variations should be less, even if both Jfet are not thermally connected
Just speculation

Anyway, it will be hardwired all through, and "layout" is just an overwiev, and things may change a bit once I start soldering

[udailey]

Tinitus,
Thats a cool looking program for your schematic. Which program is it?
Uriah

[tinitus]

Hi Uriah
Its the simple "paint", nothing special
But yeah, I like it
I think it followed with windows
At first it seems useless
But there are some useful tricks here and there

Let me know if you want to use it
I will tell you the tricks, wont take long

Also useful fore making speaker cutting plans
Just bought a used lazer printer cheap
Black and white, but ok fore simple schematics etc

[tinitus]

If of any interest, I have made a small change to supply
I was tempted to put in a couple resistors at the last supply cap, fore the Jfet/bias curcuit

But soon realised I better not do that, again
Instead I have "seperated" the last caps with a "thinner" wire
May not matter at all, or may be one of those little things that might make a small difference

btw, supply caps are planned to be BC 22.000uf/40V

[bobodioulasso]

I suppose the constant temperature variations is the problem

Differences in Jfets temperature variations can lead to a no very stable offset.

[massimo]

Why not also put a trimmer between Jfet sources and ground as recently suggested by NP?

[enochRoot]

Originally Posted by bobodioulasso

Differences in Jfets temperature variations can lead to a no very stable offset.

Does Nelson physically clamp the Jfets together as I've seen some people do around here? Is that absolutely necessary? If they are physically close, but not touching/clamped will they still be stable?

[Zen Mod]

Papa don't loose much sleep on that jfet kissing affair ;

at least looking on pictures of his Fugly! amps .

maybe explanation is that they're usually warm inside ....... Jacco will probably say - Papamps are cozy inside ........

[enochRoot]

That's what I thought at first, but after looking at the pictures again the transistors I could spot (which are not located next to each other) are the CCS transistors. I assume the Jfets are hiding back in the picture toward the rca jacks.

At any rate, if it's good enough for him, it's good enough for me. I have the Cviller boards so they are physically close together, but still separated by 1-2mm.

[bobodioulasso]

I do not know what Nelson does. This cannot be seen on Six moons review.
Both ways are working. In doubt, it cannot be wrong to make them touch when trying to do the best possible.