F4 power amplifier

Nelson Pass · 09:29 AM

http://www.firstwatt.com/f4.html

Zen Mod · 5th March 2007, 09:17 PM

Quote:

Originally posted by Babowana
Thanks. I was waiting for this, without sleeping.
But, I could not open the web site -- problem on my side.
I will send e-mail to Lee for a copy.

if you have problem ,just say-I'll send it to ya

Zen Mod · 5th March 2007, 09:21 PM

Quote:

Originally posted by Babowana
Again, thanks for the help.
But, the server is blocked here for certain reason I don't know.

I will try to get it from Lee . . .

just sending to ya

Babowana · 5th March 2007, 09:26 PM

Quote:

Originally posted by Zen Mod

just say-I'll send it to ya

Hi Choky,
Yes, I need your help for one copy to my e-address. Best Regards

Zen Mod · 5th March 2007, 09:26 PM

Quote:

Originally posted by Babowana

Hi Choky,
Yes, I need your help for one copy to my e-address. Best Regards

shrinked and sent

jacco vermeulen · 5th March 2007, 09:36 PM

Oh dear, i'm having F4-X images on my retina.
Welcome back, Master.

Zen Mod · 5th March 2007, 10:41 PM

hehe
1 hour without single post.................
seems that someone practice reading.............mumbling "how many bloody IRFs I have in my drawer........oh....why 9240?............."

hifimaker · 6th March 2007, 12:08 AM

Will this amp be offered commercially? If so how much?

Pretty cool!

When does te group buy start for boards?

-David

apassgear · 6th March 2007, 12:28 AM

F4!!! a very attractive circuit. Mmmmm… first time I see Nelson using a TL431…interesting application for that 3 legged bug.

GRollins · 6th March 2007, 12:50 AM

In an attempt to short circuit the inevitable questions:
--Yes, you can increase the bias as long as you have sufficient heat sinking/power supply/etc.
--Yes, you can decrease the bias.
--Yes, you can substitute the usual MOSFETs for the IRF outputs.
--Yes, you can substitute the input JFETs, but the field of candidates is much more limited.
--I don't have the datasheets for the input JFETs with me at the moment, but I don't think you're going to want to increase the rail voltage much. The outputs can take it, but the inputs can't. If someone knows where to find 100V low noise, complementary JFETs with reasonable current capability, I'm all ears.
--Yes, you can decrease the number of output MOSFETs, but watch the heat dissipation per device.
--Yes, you can increase the number of output MOSFETs, but bandwidth and distortion will suffer as a result--though not fatally.
What'd I miss?

Grey

5th March 2007, 09:02 PM	#1
Nelson Pass The one and only Join Date: Mar 2001	F4 power amplifier http://www.firstwatt.com/f4.html Last edited by Variac; 31st March 2011 at 09:29 AM.

5th March 2007, 09:36 PM	#6
jacco vermeulen diyAudio Member Join Date: Oct 2004 Location: At the sea front, Rotterdam or Curaçao	Oh dear, i'm having F4-X images on my retina. Welcome back, Master. __________________ Not so much,.......if it says "ZM" in the corner.

5th March 2007, 10:41 PM	#7
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	hehe 1 hour without single post................. seems that someone practice reading.............mumbling "how many bloody IRFs I have in my drawer........oh....why 9240?............." __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

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6th March 2007, 12:08 AM	#8
hifimaker diyAudio Member Join Date: Oct 2003 Location: San Jose	Will this amp be offered commercially? If so how much? Pretty cool! When does te group buy start for boards? -David

6th March 2007, 12:28 AM	#9
apassgear diyAudio Member Join Date: Nov 2002 Location: Viña del Mar, Torreon	F4!!! a very attractive circuit. Mmmmm… first time I see Nelson using a TL431…interesting application for that 3 legged bug.

6th March 2007, 12:50 AM	#10
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	In an attempt to short circuit the inevitable questions: --Yes, you can increase the bias as long as you have sufficient heat sinking/power supply/etc. --Yes, you can decrease the bias. --Yes, you can substitute the usual MOSFETs for the IRF outputs. --Yes, you can substitute the input JFETs, but the field of candidates is much more limited. --I don't have the datasheets for the input JFETs with me at the moment, but I don't think you're going to want to increase the rail voltage much. The outputs can take it, but the inputs can't. If someone knows where to find 100V low noise, complementary JFETs with reasonable current capability, I'm all ears. --Yes, you can decrease the number of output MOSFETs, but watch the heat dissipation per device. --Yes, you can increase the number of output MOSFETs, but bandwidth and distortion will suffer as a result--though not fatally. What'd I miss? Grey

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