500W PA amplifier with Limiter - Page 98

sekhar · 28th November 2010, 09:59 PM

i am falling asleep ..................................

:s leep:

here is a sneak peek of the updated pcb still a lot of work to do will update tomorrow ....................and pcb size finalized 300mm X 68 mm..... max can be a bit less......

regards
sekhar

engel dela pena · 28th November 2010, 11:12 PM

Quote:

Originally Posted by sekhar

i am falling asleep ..................................

:s leep:

here is a sneak peek of the updated pcb still a lot of work to do will update tomorrow ....................and pcb size finalized 300mm X 68 mm..... max can be a bit less......

regards
sekhar

sekhar
wake up buddy
time to work

andrewlebon · 28th November 2010, 11:28 PM

hi apexaudio
greetings should R23 BE 680 OHMS or is 330 OHMS correct will
MJE340 MJE NEED heatsinks
thanking you
andrew lebon

apexaudio · 28th November 2010, 11:59 PM

Quote:

Originally Posted by sekhar

i am falling asleep ..................................

:s leep:

here is a sneak peek of the updated pcb still a lot of work to do will update tomorrow ....................and pcb size finalized 300mm X 68 mm..... max can be a bit less......

regards
sekhar

Track mising

apexaudio · 29th November 2010, 12:10 AM

Quote:

Originally Posted by andrewlebon

hi apexaudio
greetings should R23 BE 680 OHMS or is 330 OHMS correct will
MJE340 MJE NEED heatsinks
thanking you
andrew lebon

For BIAS setup R22 should be 1k2 instead 680R for triple darlington output stage, and R23 is correct 330 ohms.
Q5 (MJE340) must be on main heatsink with outputs.
Predrivers MJE340/350 can use smal heatsinks, but no need.
Regards

thunderjets · 29th November 2010, 03:00 AM

Hi Mr. Mile

i have built B500 in bridge mode, i use 1800va transformer ,rail voltage 63+/- vdc(45ct45) . caps 6 x 10.000/100vdc. are those caps enaugh for this ?

sekhar · 29th November 2010, 04:23 AM

ok frnds so i am up good morning every one ...............................

regards
sekhar

sekhar · 29th November 2010, 04:37 AM

miles can i use the same junction marked in red for protect and reference (needed with step driver)................

regards
sekhar

Workhorse · 29th November 2010, 05:04 AM

Stringent SOA needs in Class-AB are met with relaxed ones in Class-H.

For example, 1kW @ 2Ohms in Class-AB using 5200/1943 requires atleast 9-10Pairs with rails around +/-90V whereas only 5Pairs will do the job in Class-H if rails are split in say +/-55 & +/-95.

In a Class- AB reactive loading we have high dissipation because output device has considerable VCE + Ic across it hence heating very much, Whereas in Class-H, this VCE is quite less across the device for same output load, hence less heat and more headroom.

sekhar · 29th November 2010, 05:18 AM

so workhorse how much power do u think 12pairs of 2sc5200/1943 with rail voltage of +-140 and a 2 step driver will produce safetly

regards
sekhar

29th November 2010, 05:04 AM	#979
Workhorse diyAudio Member Join Date: Dec 2004	Stringent SOA needs in Class-AB are met with relaxed ones in Class-H. For example, 1kW @ 2Ohms in Class-AB using 5200/1943 requires atleast 9-10Pairs with rails around +/-90V whereas only 5Pairs will do the job in Class-H if rails are split in say +/-55 & +/-95. In a Class- AB reactive loading we have high dissipation because output device has considerable VCE + Ic across it hence heating very much, Whereas in Class-H, this VCE is quite less across the device for same output load, hence less heat and more headroom. __________________ It's a fruitless endeavor to try and educate a fool that rejoices in ignorance

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28th November 2010, 11:28 PM	#973
andrewlebon diyAudio Member Join Date: Feb 2008	hi apexaudio greetings should R23 BE 680 OHMS or is 330 OHMS correct will MJE340 MJE NEED heatsinks thanking you andrew lebon

29th November 2010, 04:23 AM	#977
sekhar diyAudio Member Join Date: Jul 2009 Location: West bengal/siliguri	ok frnds so i am up good morning every one ............................... regards sekhar

29th November 2010, 05:18 AM	#980
sekhar diyAudio Member Join Date: Jul 2009 Location: West bengal/siliguri	so workhorse how much power do u think 12pairs of 2sc5200/1943 with rail voltage of +-140 and a 2 step driver will produce safetly regards sekhar