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Old 4th December 2016, 11:47 PM   #1
2 picoDumbs is offline 2 picoDumbs  Australia
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Default F4 Beast Builders

Based on tips from Papa, and using IXYS Hockey Pucks let's see your F4 Beast builds (might come up with a better name later). It's up to you to decide what to use for the 2 gain stage front end circuit.
The aim here is to have fun building (not necessarily cloning down to the last detail).

Suggested hockey pucks so far, are as follows (probably add a couple more later):

P Channel
IXTN40P50P (Out of 5 measured for transconductance, averaging around 6.8S at 2A and 52C measured at the interface of the heatsink and edge of hockey puck)
IXTN90P20P
IXTN32P60P

N Channel
IXFN48N60P (Out of 5 measured for transconductance, averaging around 6.4S (same conditions as above))
IXFN44N80P Patrick's suggestion
IXFN40N90P needtubes suggestion

I don't think there is a right answer to what is best, it depends what you want to achieve.
They are all in the ball park. No bbq stopper here.

I have measured up 48N60P and 40P50P and they appear to be a nice match.

Papa's Tips (for the greedy boys)
Quote:
Originally Posted by Nelson Pass View Post
I will tell you this so that you can reverse engineer it:

Three stages, DF is about 700, high current, high slew, .00x% distortion,
40 uV output noise, big Class A envelope, 25 watts into 8, 100 watts into 2.

And it sounds great.
Quote:
Originally Posted by Nelson Pass View Post
As to biasing, you can do it the regular way, or you can just use a big sink
and adjust the value until it settles into where you want it - just takes a
little longer warm-up time.
Quote:
Originally Posted by Nelson Pass View Post
In any case, the drift of Ids against temperature is quantifiable and can be
easily handled without degeneration if you have adequate sinking and are
willing to do lengthy adjustment and put up with longer warm-up times.

Just things that DIYers are good at and commercial manufacturers are not.

Here is the front end for my beast, I'm not giving resistor values, use ya brain my dear fellow dumb bastards.

R14/R8 and R16/R9 are biasing trimpots, as seen around here in other circuits, just calculate the appropriate value required.

Click the image to open in full size.



Assembling Output Stage

Click the image to open in full size.
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Last edited by 2 picoDumbs; 15th January 2017 at 11:49 PM.
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Old 4th December 2016, 11:51 PM   #2
needtubes is offline needtubes  United States
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How about the IXFN40N90P as a match for the IXTN40P50P? Problem is, it seems to be hard to find here in the US. No one has it in stock.
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Old 5th December 2016, 01:09 AM   #3
2 picoDumbs is offline 2 picoDumbs  Australia
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Quote:
Originally Posted by needtubes View Post
How about the IXFN40N90P as a match for the IXTN40P50P? Problem is, it seems to be hard to find here in the US. No one has it in stock.
Added to list
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Old 5th December 2016, 06:58 PM   #4
generg is offline generg  Germany
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F4 Beast Builders
Default Hockey Puck puzzle

All thanks to Nelson for unique box of bricks,

so here comes my Hockey Puck Puzzle.....

combined from

F4 and Sony II bias system, NTC added

and Sony II frontend

and F4 like output stage without source resistors....

Have fun!

Tell me if you see errors, I use to make them....

so I got an error specialist....

and thanks to 2picodumbs hosting me.
Attached Images
File Type: jpg Hockey Puck front end.jpg (109.2 KB, 2473 views)
File Type: jpg Hockey Puck bias and output.jpg (93.8 KB, 2424 views)
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Old 5th December 2016, 07:06 PM   #5
Tea-Bag is offline Tea-Bag  United States
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Old 5th December 2016, 07:14 PM   #6
2 picoDumbs is offline 2 picoDumbs  Australia
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Quote:
Originally Posted by generg View Post
All thanks to Nelson for unique box of bricks,

so here comes my Hockey Puck Puzzle.....

.
That is essentially what I have.
The only difference between your front end circuit and mine is slightly different resistance values in the feedback loop (but that may change again), zero source degeneration through out entire circuit, but I may change that to zero degeneration on jfets, then 5 to 10 Ohms on 2sk2013/2sj313.

Edit: I was also considering using Laterals (just to be a little different) with zero source degeneration instead of 2sk2013 and 2sj313, but I'll wait and see to decide.
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Last edited by 2 picoDumbs; 5th December 2016 at 07:26 PM.
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Old 5th December 2016, 07:14 PM   #7
Zen Mod is online now Zen Mod  Serbia
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Dodossesss .........

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clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
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Old 5th December 2016, 07:26 PM   #8
generg is offline generg  Germany
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Quote:
Originally Posted by Zen Mod View Post
Dodossesss .........

is that a kind of dinosaur?

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Old 5th December 2016, 07:29 PM   #9
generg is offline generg  Germany
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@2picodumbs

yes you can run J-Fets with 6-7mA Idss without source resistors, I just see I put in 22R in my frontend. This high value is due to the Spice model of my J-Fets having around 12mA Idss.

So if someone has 8-10mA Idss the normal 10R for source resistors is the better choice...!
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Old 5th December 2016, 07:39 PM   #10
generg is offline generg  Germany
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and keep in mind that I use the "old" Sony frontend, there is newer version in the Sony II thread with slightly changed resistors and possibly better sound as Nelson was told when he got some feedback from people.
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