First of all I have to mention that this thread started following Mark’s idea found in this thread https://www.diyaudio.com/community/...apacitors-smd-assembly-max-3a-max-48v.405099/
I needed clean power for a vfet follower amplifier that was getting its juice from a 90w laptop brick followed by a sk80h buck boost converter. Because there was also low frequency noise beside the high frequency one I decided to add the cap multiplier inspired too by an earlier design from same Mark.
So practically the only thing I did was to play around a bit in my pcb design software to put together the pcbs.
It all started here https://www.diyaudio.com/community/...d-assembly-max-3a-max-48v.405099/post-7505998
And then after that this part followed..
A few users asked by private messaging about the single rail pcb but also about a dual rail or bipolar pcb. At the time I had only the single rail pcb so I drew the bipolar version. I call it bipolar because how it`s designed but it can be use as a dual too.
For the bipolar version I created 2 pcbs. One that has a single ground plane for both rails and another that has the two ground planes separated. Initially I done the single ground pcb and then asking Mark for a suggestion I got the dual ground pcb.
On the dual gnd pcb you have the possibility to connect the gnds at the input or at the output of the filter.
For each pcb I will attach the schematic, bom, a few photos of how it looks and the gerbers.
I was planning to release these gerbers in a week or two after testing my single rail unit(I don`t intend to build and test the dual/bipolar pcbs) but then realized that it will be a bit late for those who want to have something to solder in the holidays period.
The dual pcb can be used as both positive, positive and negative or both negative filters.
The lower half of the pcb is designed for a negative filter but if you reverse the electrolytic caps and instead of the pnp bjts you place the npn ones as on the positive rail you can make the bottom part a positive filter so you will have 2 positive filters on same pcb.
If you need two negative filters on same pcb you will need to reverse all electrolytic caps on the upper half and instead of the npn bjts place pnp ones. Simple as that.
Edit1: all the boms miss the heatsink that is needed on the bd139/bd140 devices. After I build the single version I will edit all the boms with the needed part.
Edit2: after testing the single rail pcb I found that there is no need for a heatsink for the bd139/140 devices so nothing to add to the boms. Same thing is valid for the bipolar version too.
I needed clean power for a vfet follower amplifier that was getting its juice from a 90w laptop brick followed by a sk80h buck boost converter. Because there was also low frequency noise beside the high frequency one I decided to add the cap multiplier inspired too by an earlier design from same Mark.
So practically the only thing I did was to play around a bit in my pcb design software to put together the pcbs.
It all started here https://www.diyaudio.com/community/...d-assembly-max-3a-max-48v.405099/post-7505998
And then after that this part followed..
A few users asked by private messaging about the single rail pcb but also about a dual rail or bipolar pcb. At the time I had only the single rail pcb so I drew the bipolar version. I call it bipolar because how it`s designed but it can be use as a dual too.
For the bipolar version I created 2 pcbs. One that has a single ground plane for both rails and another that has the two ground planes separated. Initially I done the single ground pcb and then asking Mark for a suggestion I got the dual ground pcb.
On the dual gnd pcb you have the possibility to connect the gnds at the input or at the output of the filter.
For each pcb I will attach the schematic, bom, a few photos of how it looks and the gerbers.
I was planning to release these gerbers in a week or two after testing my single rail unit(I don`t intend to build and test the dual/bipolar pcbs) but then realized that it will be a bit late for those who want to have something to solder in the holidays period.
The dual pcb can be used as both positive, positive and negative or both negative filters.
The lower half of the pcb is designed for a negative filter but if you reverse the electrolytic caps and instead of the pnp bjts you place the npn ones as on the positive rail you can make the bottom part a positive filter so you will have 2 positive filters on same pcb.
If you need two negative filters on same pcb you will need to reverse all electrolytic caps on the upper half and instead of the npn bjts place pnp ones. Simple as that.
Edit1: all the boms miss the heatsink that is needed on the bd139/bd140 devices. After I build the single version I will edit all the boms with the needed part.
Edit2: after testing the single rail pcb I found that there is no need for a heatsink for the bd139/140 devices so nothing to add to the boms. Same thing is valid for the bipolar version too.
Attachments
-
single w 3d.jpg -
Project Outputs for A2CMx bipolar single gnd.rar
-
A²CMx bipolar single gnd bom.pdf
-
A²CMx bipolar single gnd schematic.pdf
-
dual sg back.jpg -
dual sg w dim.jpg -
dual sg w 3d.jpg -
Project Outputs for A2CMx bipolar dual gnd.rar
-
A²CMx bipolar dual gnd bom.pdf
-
A²CMx bipolar dual gnd schematic.pdf
-
dual back.jpg -
dual w dim.jpg -
dual w 3d.jpg -
Project Outputs for A2CMx.rar
-
A²CMx bom.pdf
-
A²CMx schematic.pdf
-
single back.jpg -
single w dim.jpg
Last edited:
Beautiful work, @schultzsch ! Congratulations.
I will ask the Forum moderators to create a brand new thread here in the Power Supplies Forum, with A2CMX in the thread title, so that members can find it very easily and so that builders of your board design(s) can offer suggestions, advise, and technical support to one another.
I will ask the Forum moderators to create a brand new thread here in the Power Supplies Forum, with A2CMX in the thread title, so that members can find it very easily and so that builders of your board design(s) can offer suggestions, advise, and technical support to one another.
This is a great idea, looking forwards to seeing it develop !
🙂
🙂
I attached a small heatsink to Q2 though it gets barely warm.
I settled for the minimum Vdrop which was ~2.4v and connected a 30v smsps to the input of the filter.
The Vdrop was set with the load connected.
The load was a vfet amp biased at 1.8a
The first two attachments show the oscilloscope connected to the input of the filter.
The third attachment shows the oscilloscope connected to the output of the filter.
The fourth attachment shows filter as it was used for the test.
I settled for the minimum Vdrop which was ~2.4v and connected a 30v smsps to the input of the filter.
The Vdrop was set with the load connected.
The load was a vfet amp biased at 1.8a
The first two attachments show the oscilloscope connected to the input of the filter.
The third attachment shows the oscilloscope connected to the output of the filter.
The fourth attachment shows filter as it was used for the test.
Attachments
Thanks ABSNimes but this wouldn’t have been possible without Mark’s work so a big thanks to him!
I noticed that with the filter in the middle my amp got rid of the turn on and turn off thumps.
I noticed that with the filter in the middle my amp got rid of the turn on and turn off thumps.
1st screenshot shows how the output of the ps looks
2nd screenshot shows the output of A2CMx when powering the amp
3rd screenshot shows the output of the amp when the amp was powered directly from the smps
4th screenshot shows the output of the amp when powered by same smps but with A2CMx in the middle
2nd screenshot shows the output of A2CMx when powering the amp
3rd screenshot shows the output of the amp when the amp was powered directly from the smps
4th screenshot shows the output of the amp when powered by same smps but with A2CMx in the middle
Attachments
When you have also mains noise(50hz or 60hz and harmonics) present at the output of your dc power supply.
A2CMx is available as Dual or Single rail version.
"Dual" offers a second choice : common or separate Gnd.
There is also a CapMX at the output.
Pick what you prefer 😉
Merry Christmas to everyone
Hello schultzsch,
I've got a noob question about D2 polarity.
Do I need to reverse polarity vs D1 ?
From what I see on schematic the answer should be yes.
I use a Dual A2CMx (P + N).
Regards
Hello schultzsch,
I've got a noob question about D2 polarity.
Do I need to reverse polarity vs D1 ?
From what I see on schematic the answer should be yes.
I use a Dual A2CMx (P + N).
Regards
Last edited:
Merry Christmas ABSNimes
Yes, the diode on the negative power supply must be reversed compared to the positive power supply.
Yes, the diode on the negative power supply must be reversed compared to the positive power supply.
Hi, nice work and something I might need sometimes. I believe it should be possible to create PCB:s from your project file but I don't understand how to do. Please teach me🙂
You need to download the Project output archives depending on the pcb you want to build.
Then you go here and click the blue button +Add gerber file. Once the pop-up window opens you need upload the earlier downloaded . rar file.
You can select the number of pcbs, the color, the thickness of the copper traces and other stuff.
5 pcbs should cost you less than 5$ shipping included.
Then you go here and click the blue button +Add gerber file. Once the pop-up window opens you need upload the earlier downloaded . rar file.
You can select the number of pcbs, the color, the thickness of the copper traces and other stuff.
5 pcbs should cost you less than 5$ shipping included.