...Going into a small box in the Kitchen to hang on the wall. Ideally, I want one power cord entering the box rather than relying on a trailing socket, laptop PSU, USB power supply and wirey mess.
I need two DC voltages, 15-16V for a TPA3116 and 5V for the CC-Audio.
Assuming I'm buying PSUs off eBay etc, what's the better way?
a) One 15V SMPS for the TPA3116 and add a DC-DC buck to provide 5V for the CC-A.
or
b) One 15V SMPS for the TPA and another SMPS giving 5V for the CC-A?
Space in the box is not an issue. It should form a centre panel in between two wall hanging speakers. Only real restriction is the height of 2" or 50mm.
Cheers,
J.
I need two DC voltages, 15-16V for a TPA3116 and 5V for the CC-Audio.
Assuming I'm buying PSUs off eBay etc, what's the better way?
a) One 15V SMPS for the TPA3116 and add a DC-DC buck to provide 5V for the CC-A.
or
b) One 15V SMPS for the TPA and another SMPS giving 5V for the CC-A?
Space in the box is not an issue. It should form a centre panel in between two wall hanging speakers. Only real restriction is the height of 2" or 50mm.
Cheers,
J.
The TPA3116 datasheet says that the source voltage can be as low as 4.4V. Couldnt you use 5V power then for that as well as with CC ?
Option A
12-24V supply and a V7805-1000 for 5V 1A @ 88-93 % efficiency.
V7805-1000 CUI Inc. | Power Supplies - Board Mount | DigiKey
🙂
12-24V supply and a V7805-1000 for 5V 1A @ 88-93 % efficiency.
V7805-1000 CUI Inc. | Power Supplies - Board Mount | DigiKey
🙂
It wouldn't make the required power. I make it under 2 watts into 8 ohms at 5V.
So a common 5V supply seems to be out...
J.
I have finally got around to trying out my setup with the buck powering the Chromecast Audio. I'm getting noise though. Seems related to Chromecast and phone comms. Any suggestions?.... Other than bin the buck and run the Chromecast Audio mains adapter alongside the SMPS?
An externally hosted image should be here but it was not working when we last tested it.
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Try with different powering options the aim is to identify if a particular supply is the problem. It could even be the class D.
It's definitely related to the buck... Read that as the buck plus the feed and rather hacked USB lead. On the supplied Chromedcast audio adapter, the config is essentially silent.
I've tried grounding the shielding of the USB to different points but that made no difference.
A couple of suggestions I've had so far are to twist the supply leads and to ground not just the USB shielding but the cropped data wires that are currently floating.
J.
Now eliminated grounding the unused USB data wires along with the shielding. Still getting the same noises. Almost certain most of it is WIFI from/to the Chromecast.
Choices....
- Ditch the buck and run the CCA PSU off mains.
- Ditch the buck and run a 7805
- Blitz many +/- pairs with ceramic caps.
- Shield the buck itself in grounded foil.
J.
Choices....
- Ditch the buck and run the CCA PSU off mains.
- Ditch the buck and run a 7805
- Blitz many +/- pairs with ceramic caps.
- Shield the buck itself in grounded foil.
J.
Tried something else today that worked...but is impractical.
Connected a separate 16V thinkpad PSU to the buck to power the CCA. It worked perfectly, though I could reproduce the problem by connecting the grounds.
J.
Connected a separate 16V thinkpad PSU to the buck to power the CCA. It worked perfectly, though I could reproduce the problem by connecting the grounds.
J.
Yesterday, I connected the newly arrived ground loop isolator in the line-in to the TPA3116. It seems all of the interference has been removed.
J.
J.
Hi Jerms,
I've been having exactly the same issue when trying to power my CCA from the same 12V power supply as my TA2024 Class D amp.
I've tried powering the CCA using both with a 5V Buck converter and a 7805 (which got v hot even with a heatsink). Either way I get noise.
What ground loop isolator are you using?
I've been having exactly the same issue when trying to power my CCA from the same 12V power supply as my TA2024 Class D amp.
I've tried powering the CCA using both with a 5V Buck converter and a 7805 (which got v hot even with a heatsink). Either way I get noise.
What ground loop isolator are you using?
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I'm going to try a slightly different tactic. Rather than using a ground loop isolator between the CCA output and amp input I'm going to try out the advice of a friend who suggested that an isolated power supply might also do the trick.
So for my 12V to 5V DC conversion I'm going to try one of these:
MEV3S1205SC | Murata Power Solutions 3W Isolated DC-DC Converter, Vin 10.8 → 13.2 V dc, Vout 5V dc, I/O isolation 3kV dc | Murata Power Solutions
I haven't tried it yet but this thing is pretty small (20mm x 8mm x 10mm). Just waiting for some suitable accompanying capacitors to arrive.
More expensive than the buck converter I was going to use, but about the same as a buck converter and the ground loop isolator, plus potentially no signal loss.
I'll keep you posted.
So for my 12V to 5V DC conversion I'm going to try one of these:
MEV3S1205SC | Murata Power Solutions 3W Isolated DC-DC Converter, Vin 10.8 → 13.2 V dc, Vout 5V dc, I/O isolation 3kV dc | Murata Power Solutions
I haven't tried it yet but this thing is pretty small (20mm x 8mm x 10mm). Just waiting for some suitable accompanying capacitors to arrive.
More expensive than the buck converter I was going to use, but about the same as a buck converter and the ground loop isolator, plus potentially no signal loss.
I'll keep you posted.
I'm, happy to report that the Murata DC converters work perfectly and eliminate the ground loop noise that I was experiencing.
Additional point to ponder maybe....
Whilst looking for isolating DC DC converter boards, I found loads of isolating AC-DC converters and they are cheap. I've not tried them but possibly an option for eliminating ground loops... At the expense of having to "play" with mains voltages in your DIY project.
Isolating DC-DC converter boards appear "rare". Though I have bought and received this one.
https://www.amazon.co.uk/gp/product/B015E4835U/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
I haven't had an opportunity to use it yet though.
Whilst looking for isolating DC DC converter boards, I found loads of isolating AC-DC converters and they are cheap. I've not tried them but possibly an option for eliminating ground loops... At the expense of having to "play" with mains voltages in your DIY project.
Isolating DC-DC converter boards appear "rare". Though I have bought and received this one.
https://www.amazon.co.uk/gp/product/B015E4835U/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
I haven't had an opportunity to use it yet though.
How did you wire it? And where did you put those capacitators (which ones) for what reason?
Have you tried this yet?
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