Quick simulation question

east electronics · 19th November 2019, 10:19 AM

i think most of us familiar with L10 amplifier see also schematic on picture

I have one application that I have primary rails of regulated supply to feed the first stages lets say up to the drivers and a lower rail very beefy to feed the output

Can one quick simulate for what is the maximum voltage to feed the input stage ?

sgrossklass · 19th November 2019, 01:24 PM

Ironically, this one cannot be determined by simulation (which rarely represents breakdown voltage accurately) but requires old-fashioned studying of datasheets instead. I think the 2SD667/2SB647 are the bottleneck, being Vceo = 80 V parts and having to swing almost rail to rail. So roughly +/- 40 V max, or +/-50 for 667A/647A. In the latter case a fault condition with the output pulled to V+ may still destroy Q6 (a 65 V part) and/or C4.

Ian Finch · 11:34 PM

Vceo max. may vary between manufacturers. Some examples of 2SD667A/B647A appear to use the same die as 2SD669A/2SB649A (as for example, do BD139/BC639). http://www.secosgmbh.com/datasheet/p...OD/2SD667A.pdf

There are even standard T092 versions of 2SD669/B649 to add to the confusion. Even with datasheets, I would test the breakdown voltage before fitting.

19th November 2019, 11:30 PM	#3
Ian Finch diyAudio Member Join Date: Apr 2010 Location: Coffs Harbour, NSW	Vceo max. may vary between manufacturers. Some examples of 2SD667A/B647A appear to use the same die as 2SD669A/2SB649A (as for example, do BD139/BC639). http://www.secosgmbh.com/datasheet/p...OD/2SD667A.pdf There are even standard T092 versions of 2SD669/B649 to add to the confusion. Even with datasheets, I would test the breakdown voltage before fitting. __________________ If only I had listened.... Last edited by Ian Finch; 19th November 2019 at 11:34 PM.

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
Quick 'n dirty sub simulation?	head_unit	Subwoofers	2	30th January 2012 12:34 AM
IV Simulation Question	PigletsDad	Digital Source	1	7th April 2008 01:41 PM
Quick quick question !	guitvinny	Pass Labs	6	7th February 2007 05:20 PM
simulation question	schiller	Multi-Way	13	6th September 2006 10:22 AM

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


	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

19th November 2019, 01:24 PM	#2
sgrossklass diyAudio Member Join Date: Nov 2004 Location: Germany	Ironically, this one cannot be determined by simulation (which rarely represents breakdown voltage accurately) but requires old-fashioned studying of datasheets instead. I think the 2SD667/2SB647 are the bottleneck, being Vceo = 80 V parts and having to swing almost rail to rail. So roughly +/- 40 V max, or +/-50 for 667A/647A. In the latter case a fault condition with the output pulled to V+ may still destroy Q6 (a 65 V part) and/or C4.