diyAudio - Power supply craziness
Go Back   Home > Forums > Blogs > abraxalito

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
Power supply craziness Lowest possible low-frequency impedances
Old

Ziggurat passive shunt for chipamp

Posted 5th May 2014 at 04:34 AM by abraxalito
Updated 23rd May 2014 at 12:34 AM by abraxalito

Two tiers in order to achieve the lowest ESR - top is using 4700uF and bottom, 15,000uF. Total around 0.8F, 25V.

I plan to try this out first with my TDA8566 but that's limited to 18V so if that sounds promising I'll look for a new chip which can handle the full 25V supply capability.

Update1 : Wired the top tier only underneath my new TPA3116 class D amp board from Taobao. Seems here the dynamics aren't limited by the capacitance on the output stage supply, rather on the analog supply (pin17 of the TPA3116) which goes to an internal LDO regulator. No amount of capacitance on this pin (I went up to 100,000uF) gives the chip the LF dynamics of my class AB amp so I've been off in search of a class D chip which doesn't have an internal reg so might be amenable to a hexacap on its supply...

Update2 - NXP's TDA8932 is on order now - this is a chip which can be DIYed because its in a manageably small SO32 package, so no need to order up an eval board. Over...
Attached Thumbnails
Click image for larger version

Name:	P1010100.JPG
Views:	191
Size:	707.5 KB
ID:	1285   Click image for larger version

Name:	P1010104.JPG
Views:	57
Size:	710.7 KB
ID:	1291  
abraxalito's Avatar
diyAudio Member
Views 223 Comments 0 abraxalito is online now
Old

One Farad capacitor array

Posted 3rd April 2014 at 03:08 AM by abraxalito
Updated 4th May 2014 at 04:53 AM by abraxalito

This array of 127 10,000uF caps measures -j2.9mohms at 50Hz which I reckon makes it comfortably over 1F in capacitance. ESR is 1mohm @ 50Hz.

The individual caps were measuring on average 8,500uF. Although they're marked 10V (the brand is ChengX a slightly shady Chinese one) they're not good for anywhere near this voltage. I reckon they're in reality 6.3V and they seem to have decently low leakage at this working voltage. I shall be using them at 5V or below.

Update1 - seems I wasn't using enough copper in the wiring. I've now built a second one with 2.5mm2 wiring around the loops and 1.5mm diameter cross links and ESR is down to 0.5mohm @ 50Hz now, decreasing at higher freqs. I have enough caps left for a third one...

Update2 - now the first array has a basement level giving 2.1F total with ESR below 0.4mohms @ 50Hz. There are six paralleled TDA1387s atop the combined hexagons giving unprecedented LF dynamics. Amp long, long overdue for an upgrade.......
Attached Thumbnails
Click image for larger version

Name:	P1010094.JPG
Views:	237
Size:	693.3 KB
ID:	1264   Click image for larger version

Name:	P1010095.JPG
Views:	191
Size:	708.6 KB
ID:	1269  
abraxalito's Avatar
diyAudio Member
Views 480 Comments 10 abraxalito is online now
Hide this!Advertise here!

New To Site? Need Help?

All times are GMT. The time now is 11:35 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2