Power Supply Resevoir Size
 User Name Stay logged in? Password
 Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read Search

 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
 24th March 2013, 02:14 PM #1841 DF96   diyAudio Member   Join Date: May 2007 Energy in joules = 0.5 x C x V^2
ginetto61
diyAudio Member

Join Date: Sep 2009
Location: Stavanger (NORWAY)
Quote:
 Originally Posted by DF96 Energy in joules = 0.5 x C x V^2
Thanks a lot !
no ... I was wrong. I checked roughly and more or less there is the same stored energy (higher V but also much less uF in the tube amps)
Thanks again
Regards,
gino

gootee
diyAudio Member

Join Date: Nov 2006
Location: Indiana
Just for fun, I fixed the method used to calculate the reservoir capacitance required for a sine output from a class AB power amplifier, at the clipping threshold, for the case when the signal frequency is greater than or equal to the AC mains frequency. I will post a corrected spreadsheet, sometime soon.

Still need to also re-work the case for signal frequeny less than the mains frequency, which currently is wrong and gives capacitances that are too low (probably by 10%-25%). I think I know how, but haven't had the time, yet.
Attached Files
 Reservoir Capacitance Requirements_gootee_v5_26MAR2013_docx.zip (62.8 KB, 153 views)

Last edited by gootee; 26th March 2013 at 11:42 PM.

 26th March 2013, 11:47 PM #1844 fas42   Banned   Join Date: Jun 2012 Location: NSW, Australia You amaze me, Tom, with the energy you're putting into this! Thanks for doing it, I hope to be inspired to do something likewise ... Cheers, Frank
 27th March 2013, 03:00 AM #1845 gootee   diyAudio Member   Join Date: Nov 2006 Location: Indiana Hi Frank. Well, the sine-only part isn't really important (since the DC@peak vs rated power stuff solves the original problem very well). But it's one of those things I just want to do. It's like a certain type of puzzle that I like to try to solve, just for the love of trying. For me, it's similar to going out in the woods and hunting for Morel mushrooms, or working "Killer Sudoku" puzzles (see krazydad.com). Also, even though the math isn't even close to what I used to be able to do, back in, say, 1980, it still kind-of makes me feel young again, to relearn some small parts of it.
 27th March 2013, 03:33 AM #1846 gootee   diyAudio Member   Join Date: Nov 2006 Location: Indiana Well, I posted that document too soon. Wish I had more time for this stuff. It turns out that the sine-only calculations that I said were good for f_signal >= f_mains are really only good up to 2*f_mains, i.e. 2*f_mains >= f_signal >= f_mains. Back to the drawing board... Sorry about that.
 27th March 2013, 10:09 PM #1847 fas42   Banned   Join Date: Jun 2012 Location: NSW, Australia Not really something to worry about, but as a demonstration of what's possible if you absolutely must have the lowest power supply impedance at very high frequencies, the ultimate decoupling strategy so to speak, there's this: http://www.sanmina.com/pdf/solutions...nical_0106.pdf. The strategy, and precision required, is very different from that of audio circuits, but it gets results for supply impedance: 10 milliohms at 100Meg, 100 milliohms at 1GHz. Frank
simon7000
diyAudio Member

Join Date: Nov 2008
Location: Oakmont PA
Quote:
 Originally Posted by AndrewT This seems unusually high. The pics I have seen all support a MUCH shorter conduction period. Even the saw tooth ripple on the smoothing caps shows a MUCH shorter conduction period.
Are you looking at both peaks? 60/360 = 16.66..%

 27th March 2013, 10:36 PM #1849 Kindhornman   diyAudio Member     Join Date: Aug 2012 Location: Los Angeles, California Does a snubber designed bridge rectifier increase the conduction angle, or is there no effect from the snubbers around the diodes? I am talking about a capacitor resistor snubber design.
 28th March 2013, 02:25 AM #1850 gootee   diyAudio Member   Join Date: Nov 2006 Location: Indiana No. Snubbers do not usually appreciably change the conduction angle. They might typically shorten it by just a hair.

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is Off Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home Site     Site Announcements     Forum Problems Amplifiers     Solid State     Pass Labs     Tubes / Valves     Chip Amps     Class D     Power Supplies     Headphone Systems Source & Line     Analogue Source     Analog Line Level     Digital Source     Digital Line Level     PC Based Loudspeakers     Multi-Way     Full Range     Subwoofers     Planars & Exotics Live Sound     PA Systems     Instruments and Amps Design & Build     Parts     Equipment & Tools     Construction Tips     Software Tools General Interest     Car Audio     diyAudio.com Articles     Music     Everything Else Member Areas     Introductions     The Lounge     Clubs & Events     In Memoriam The Moving Image Commercial Sector     Swap Meet     Group Buys     The diyAudio Store     Vendor Forums         Vendor's Bazaar         Sonic Craft         Apex Jr         Audio Sector         Acoustic Fun         Chipamp         DIY HiFi Supply         Elekit         Elektor         Mains Cables R Us         Parts Connexion         Planet 10 hifi         Quanghao Audio Design         Siliconray Online Electronics Store         Tubelab     Manufacturers         AKSA         Audio Poutine         Musicaltech         Aussie Amplifiers         CSS         exaDevices         Feastrex         GedLee         Head 'n' HiFi - Walter         Heatsink USA         miniDSP         SITO Audio         Twin Audio         Twisted Pear         Wild Burro Audio

 Similar Threads Thread Thread Starter Forum Replies Last Post Burnedfingers Power Supplies 28 19th July 2017 08:03 AM SanderW Power Supplies 25 4th January 2013 04:12 PM BigE Power Supplies 11 5th July 2011 02:59 PM diymixer Power Supplies 1 10th October 2010 05:47 AM spooney Car Audio 3 6th December 2007 11:50 PM

 New To Site? Need Help?

All times are GMT. The time now is 07:40 AM.