F4 power amplifier

[flocchini]

buzzforb and ZM - comments always appreciated

 

[buzzforb]

I would erase my name, if it were me!

 

[Tyimo]

Hi!
Is it possible to use 2sk1529/SJ200 instead of IRFP mosfets?

Greets:
Tyimo

 

[Zen Mod]

yes

 

[Tyimo]

Thanks!
Without any mods?

 

[Zen Mod]

usual care with biasing

check pinout - I'm lazy to remember trivia like that

funny - ask me while I'm sleeping , and I'll give you pinout for 2N3055 and 12AT7

 

[Tyimo]

O.K. Thanks!

 

[6L6]

What's the quick 'n dirty to increase the bias? I've got the pot cranked and can't get it past .1v across the source resistors, with zero DC offset...

I'm using Fairchild 16N25/12P20 outputs. K170/J74 8.5 Idss

FWIW, it does sound really nice...

 

[flocchini]

6L6

From memory I believe you lower R9

Zen Mod can you confirm?

Best

Bob

 

[Zen Mod]

yup

set P1 to max resistance

decrease R9 to 5K6

fiddle P1

 

[6L6]

That's easy. I will do when I'm back in town (about a week)

Thanks!

 

[flocchini]

I built my F4 headphone amp using attached circuit. I inserted Jensen transformers as described in post 3422 of this thread.

I was kindly gifted (thanks buzz) some 2sk2013s and 2sj313s that I would like to use in this circuit. The 9510/510s bias at 5V where as the 2013/313s bias at 3V.

Can somebody point me to what I need to do to change bias?

Thank you

Bob

 

[buzzforb]

Flocchini
Here is the datasheet. Page 28 shows the circuit and calculation needed to figure voltage. for the part. Ill send over my excel calculator if I can find it.

http://www.ti.com/lit/ds/symlink/tl431.pdf

 

[Zen Mod]

R6 R7 increase to first next standard value
R8 decrease to first standard value

 

[flocchini]

thanks buzz and ZM

 

[Navyblue]

Would this heatsink be good enough per output MOSFET?

Heat Sink for 1W 3W 10W LED | eBay

Or how about this one?

1pcs Aluminium Heatsink for 10W High Power LED Panel Free Shipping mAh | eBay

Am I right to assume that dissipation is about 10W per MOSFET? Or is it closer to 15W?

 

[Zen Mod]

first one never

second one only with fan

 

[Navyblue]

So what would be a safe heat sink size for use without fan? 100x100x20mm?

 

[Zen Mod]

this is post #3559 in thread

plenty of pics on previous pages ......

 

[Navyblue]

I searched "heat sink" in this thread, I got 2 pages. None has explicit heat sink requirement. And unfortunately the forum has yet to implement image recognition search.

Am I right to say that dissipation is about 10W per device? Which would translate to at least about 2 C/W heatsink rating?