MOSFET power follower project

Ilianh · 26th February 2003, 05:20 PM

Hi,
Anyone ever did this project?

Any feedback would be highly appreciated.

I can't seem to find those irf350 anywhere, anyone knows any replacements?

Could be good for a triamp system

halojoy · 26th February 2003, 06:12 PM

Quote:

Originally posted by Ilianh
Hi,Anyone ever did this project?

Any feedback would be highly appreciated.
I can't seem to find those irf350 anywhere, anyone knows any replacements?
Could be good for a triamp system

And what MOSFET power follower project
do you mean?
Any special, yours or from some website?

/halo - is not a mind reader

- but suspect it has something
to do with a website

Ilianh · 26th February 2003, 07:56 PM

...

http://sound.westhost.com/project83.htm

bah...

Ilianh · 27th February 2003, 01:34 AM

anyone knows if one of those would work? they are all hexfet
(and I have many of them at home)
IRF540
IRF640
IRF740
IRF840

they have similar caracteristics as the irfp350 that I need

(I think the irf740 would be the closest one)

Circlotron · 27th February 2003, 02:14 AM

The lower the current rating of the fet, for the same current the further up the transfer curve you work it where it is more linear, away from the bottom where it is a big curve. The curvy part means distortion. Monster size fets runnning at low current make more distortion.

/Circlotron - doesn't practice what he preaches.

Ilianh · 27th February 2003, 02:32 AM

Thx Circlotron for the info.

Well originaly the design is with a IRFP350, wich is
Vdss 400v
Rds 0.3 ohm
Ids 16 amps

the IRF740 is
Vdss 400v
Rds 0.55 ohm
Ids 10 amps

Andypairo · 27th February 2003, 09:11 AM

Since Vdss is not an issue I'd rather go with 640 or even 540, which have higher current ratings.
Other choiches can be IRFP150, 240, 250, etc, commonly used in similar projects (the former is used in Ciuffoli's Power Follower).

Cheers

Andrea

Ilianh · 28th February 2003, 01:30 AM

Anyone has any ideas how much power can Ciuffoli's Power Follower output on 8 ohm?
and ayone knows how good are power followers of this kind when the output impedance is 4 or 6 ohm?

argo · 28th February 2003, 08:52 AM

Quote:

Originally posted by Ilianh
Anyone has any ideas how much power can Ciuffoli's Power Follower output on 8 ohm?
and ayone knows how good are power followers of this kind when the output impedance is 4 or 6 ohm?

It will depend from rail voltage and bias current.
It will work well into 4 or 6 ohm but you need to feed more current accordingly.

Here is an approximate calculation for different loads

Jay · 28th February 2003, 06:26 PM

Power follower type has a low distortion figure. Anyhow, many high-end builders do not appreciate this type of amplifier. The reason is that the overall sound is “dull”. An argumentation to defend this design might be (from my opinion) that this amplifier doesn’t color the sound. It just “passes” the signal from the source. So, you must be very careful in choosing your pre-amp. I guest a bipolar design like Bride Of DOZ will do a great job.

26th February 2003, 05:20 PM	#1
Ilianh diyAudio Member Join Date: Oct 2002 Location: Montreal, Canada	MOSFET power follower project Hi, Anyone ever did this project? Any feedback would be highly appreciated. I can't seem to find those irf350 anywhere, anyone knows any replacements? Could be good for a triamp system __________________ Time is the best teacher; unfortunately, it kills all its students

26th February 2003, 07:56 PM	#3
Ilianh diyAudio Member Join Date: Oct 2002 Location: Montreal, Canada	... http://sound.westhost.com/project83.htm bah... __________________ Time is the best teacher; unfortunately, it kills all its students

27th February 2003, 01:34 AM	#4
Ilianh diyAudio Member Join Date: Oct 2002 Location: Montreal, Canada	anyone knows if one of those would work? they are all hexfet (and I have many of them at home) IRF540 IRF640 IRF740 IRF840 they have similar caracteristics as the irfp350 that I need (I think the irf740 would be the closest one) __________________ Time is the best teacher; unfortunately, it kills all its students

27th February 2003, 02:32 AM	#6
Ilianh diyAudio Member Join Date: Oct 2002 Location: Montreal, Canada	Thx Circlotron for the info. Well originaly the design is with a IRFP350, wich is Vdss 400v Rds 0.3 ohm Ids 16 amps the IRF740 is Vdss 400v Rds 0.55 ohm Ids 10 amps __________________ Time is the best teacher; unfortunately, it kills all its students

28th February 2003, 01:30 AM	#8
Ilianh diyAudio Member Join Date: Oct 2002 Location: Montreal, Canada	Anyone has any ideas how much power can Ciuffoli's Power Follower output on 8 ohm? and ayone knows how good are power followers of this kind when the output impedance is 4 or 6 ohm? __________________ Time is the best teacher; unfortunately, it kills all its students


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

27th February 2003, 02:14 AM	#5
Circlotron diyAudio Member Join Date: Jun 2002 Location: Melbourne, Australia	The lower the current rating of the fet, for the same current the further up the transfer curve you work it where it is more linear, away from the bottom where it is a big curve. The curvy part means distortion. Monster size fets runnning at low current make more distortion. /Circlotron - doesn't practice what he preaches.

27th February 2003, 09:11 AM	#7
Andypairo diyAudio Member Join Date: Sep 2002 Location: near Milano , Italy	Since Vdss is not an issue I'd rather go with 640 or even 540, which have higher current ratings. Other choiches can be IRFP150, 240, 250, etc, commonly used in similar projects (the former is used in Ciuffoli's Power Follower). Cheers Andrea

28th February 2003, 06:26 PM	#10
Jay diyAudio Member Join Date: Feb 2003 Location: Jakarta	Power follower type has a low distortion figure. Anyhow, many high-end builders do not appreciate this type of amplifier. The reason is that the overall sound is “dull”. An argumentation to defend this design might be (from my opinion) that this amplifier doesn’t color the sound. It just “passes” the signal from the source. So, you must be very careful in choosing your pre-amp. I guest a bipolar design like Bride Of DOZ will do a great job.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Pavel Macura's MOSFET Power Follower	soundNERD	Solid State	25	24th February 2011 03:23 PM
Macura dispre with mosfet power follower?	sopapo	Solid State	10	8th May 2006 09:08 AM
Does anyone has mosfet PP power follower schematic?	bogdan_borko	Solid State	0	11th December 2005 09:37 PM
Driving a MOSFET power follower	RichardJones	Pass Labs	19	22nd July 2002 03:02 PM
MOSFET Power Follower help	RichardJones	Solid State	0	28th January 2002 07:01 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read