• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

All Cee's PSU for Class AB Amp

Founder of XSA-Labs
Joined 2012
Paid Member
This PSU arose out of a need for compact, low-cost PSU for the FH9HVX.

The All Cee's PSU features up to 40,000uF of bulk capacitance at up to 63vwdc. You can install a 0.22R to make it a CRC vs a CC PSU if you desire even lower ripple. Tests show that 20,000uF per rail sounds best in the FH9HVX with no hint of audible hum and a huge reserve for bass impact. Other features include provision for a snubber on the trafo input, bleed resistors, film bypass caps, LED charge indicators, and an on-board NTC ground loop breaker for connection to the chassis/protective earth ground. You can use all Faston tabs or the alternative Wurth 0.250in tab arrays which make it easier to install and keep aligned. All of this is a compact 80mm x 100mm package that will be easy install inside your chassis. If you are running your FH9HVX below 50v rails, you have enough room to install 15,000uF caps for even better performance. The caps in the BOM have been selected for the high ripple current to enable continuous higher power operation if needed. For higher power operation, it is advised to mount the bridge underhung and bolted to a metal floor plate for heatsinking.

Errata Jan 8, 2021: note that maximum diameter of main bulk caps is 30mm, not 40mm as stated on the schematic. 30mm dia snap in caps fit there best.

850136d1591375406-fh9hvx-budget-conscious-100w-class-ab-lean-times-cees-psu-schematic-v001-jpg


850135d1591375406-fh9hvx-budget-conscious-100w-class-ab-lean-times-cees-psu-3d-render-v001-jpg


850137d1591375406-fh9hvx-budget-conscious-100w-class-ab-lean-times-cees-psu-stuffing-diag-v001-jpg


This PSU is available in my shop for $20.

866635d1596916646-cees-psu-class-ab-amp-cees-photo-jpg


BOM here:
https://www.diyaudio.com/forums/att...00w-class-ab-lean-times-cees-psu-bom-v001-zip

Shopping cart for BOM here:
FH9HVX - Budget Conscious 100w Class AB for Lean Times

Thank you to JPS64 for another super layout!
 

Attachments

  • All-Cees-photo.jpg
    All-Cees-photo.jpg
    298.5 KB · Views: 2,140
Last edited:
Founder of XSA-Labs
Joined 2012
Paid Member
You would need an inductor with pretty low DCR circa 0.22ohm and high current circa 15A or more. I don’t know if anything would fit there unless you did flying leads. I would go for at least 10uH and more is better. Depends on what you are trying to filter. If 50Hz it will be huge. But RF then reasonably sized.

For example, an LC filter with 50Hz cutoff for 10,000uF is 1mH.
 
Last edited:
Note: The BOM linked above uses LLS1J103MELC capacitors w/ a 35mm diam. Looks like the board designed for a 30mm capacitor. LLS1J103MELB or LKS1J103MESB seems like a good replacement. (general purpose vs audio caps, shouldn't provide give a difference for input smoothing)
 
Last edited:
Founder of XSA-Labs
Joined 2012
Paid Member
Small error on X116 pads

Hi folks,
We just discovered a small error on the board at X115, the location for the jumper to turn the board from a CRC into an “All Cee’s” board. The pads for X116 meant for a Faston tab are orphaned. That is, they lack the spiders to connect them to the surrounding copper pours. There is a simple fix, use the nearby pads for R116 or use a solder blob to bridge pads from R116 to X116.

attachment.php


Sorry about the mistake - and hope it’s not too big of a problem.

Thanks for your understanding.
 

Attachments

  • 38B286D6-5D05-4BA8-9B66-A41998F8718C.jpeg
    38B286D6-5D05-4BA8-9B66-A41998F8718C.jpeg
    584.3 KB · Views: 1,089
Last edited:
Member
Joined 2011
Paid Member
How on earth did that mistake circumvent KiCad's error reporting? Pads on footprints are connected to signal nets on the schematic, and the PCB layout editor continuously compares the schematic to the layout. If they're not identical, it screams.

There's also a Design Rule Check feature in the PCB layout editor, with a "List Unconnected Nets" pushbutton. How is it possible for this error to go unreported?
 
Was wrapping up a bunch of work and got back to this. Just wanted to confirm that the P/N RN60D2202FB14 22KOhm is correct for R121 & R122 and wasn't rolled over from the wrong BOM. Part looked too big and wanted to check it with you guys.
An externally hosted image should be here but it was not working when we last tested it.
(not soldered, just placed)
 

Attachments

  • Image from iOS.jpg
    Image from iOS.jpg
    855.6 KB · Views: 194
Last edited:
Member
Joined 2011
Paid Member
Wow, the schematic in post #1 sure looks like KiCad.

So how do other diyAudio members who design their own PCBs, learn from this mistake? What could they do in the future, to prevent this type of mistake from happening on their boards? I hope you don't say it's inevitable, this type of error is unavoidable and undetectable and unpreventable.
 
Member
Joined 2010
Paid Member
Hi X,

Ran into a snag building up the All C's. I have soldered all comp's except the 10Kuf caps. This includes R115 & R116. I purchased 35mm Nichicon snap ins, and they will not fit. The schematic tells me the max should be 40mm. I have tried to force the caps in, but gave that up.

I am not sure if I desoldered C101, C102, R115, R116 and soldered on the bottom of pcb, whether I would even have enough room. The 35mm caps butt up against R115, R116, and the green leds (bending leads), butt up against X122 & X125, and butt up against C101 & C102 .

If I get 2 of the caps in, there is no way to get the other 2 mounted. May have to resort to building up the old CRC's I have laying around, as I really do not want to order 8 more caps to fit the All C's.

Need some ideas if you guys have any.

Thanks,

Myles
 
Member
Joined 2010
Paid Member
Hi X,

On the schematic, it shows in vertical writing, see attached. I do not think I have enough room as I have tried to bend and force quite a bit already. I will look again.

I will be using a 36VAC transformer. If I can get away with 50V caps and if they are smaller, I may have some that I can use or If 50V caps are good for the Xmas amp, I could use it there also?

Myles

All-Cees-PSU-Schematic-v001.jpg
 
  • Like
Reactions: 1 user
Member
Joined 2010
Paid Member
Further update X,

Tried everything to get them to fit. No Luck. I tried a dry fit with the other All C's pcb I have and still no luck, bangs up against the header, no matter which way the header is inserted, and still would require leads to be bent and/or components to be lifted/leads bent to make it work.

I have 8 x 6800uf x 50V caps that would fit real nice. Do you think 27,200 uf per board would satisfy the requirements for the Xmas amp (based on 25VAC transformer). If so I can use this as a work around and order a couple of more All C's boards for the FH9HV. Will still have to order smaller caps for the FH9HV though.

Myles