SuperCharge your RPI power rails - RPi filter/buffer HATs

I was contacted about the DFRobot RPI filter HAT the other day. It seems the link I posted some years ago goes dead nowadays.

Let's recap. On this blog you'll notice more than once that none of my serious RPi installations goes without a filter/buffer HAT. 

A buffer or filter like shown above smooths out the RPi power rail. You'll 1. see much less noise on the rail. And 2. a buffer like that provides very fast local power (better transients/rise times).  Something you can't achieve with an external power supply that typically comes with awful long cable (even 1ft is too much), connectors, RFI, etc.

There are of course several other options for powering the RPi in a very good way. E.g. the IanCanada ShieldPi Pro . I use that one on my main audio system. There are also other options such as battery supplies asf asf. IanCanada also offers several of these. 

However. After trying this or that over the years, the to me most convenient, least complex and still well performing approach turned out to be the Buffer-HAT approach. 

That's why pretty much all my other RPi based systems also have a DFRobot Buffer/Filter HAT attached. 

That type of gadget IMO makes a worthwhile difference. Such a solution comes with a great price/performance ratio. Meaning: Before you run and buy an audiophile power supply that runs a 3ft cable and costing you an arm and a leg, try such a HAT first. If you have that audiophile supply already in place, you should give such a HAT a try anyhow. It all accumulates.

Note: 

I use these HATs also for my RPI5 installations. Even on a RPI5 based desktop system! Many sites do not list the RPi 5 as being supported though! 

I mostly power these HAT modules through the USB-C port of the RPi. It's not recommended though. Why am I still doing it? It's simply more convenient. However. If you turn power on there'll be a power surge. In my use-cases the RPi can handle it. The situation would probably be similar if you have USB devices attached to the RPi. However. If you already run close to maximum loads, things might get tricky. Check your power situation before you go that path! You don't want to fry your installation.
Of course all the cap charging for the HAT also runs over the RPi power section. It works - in my case. Not the greatest approach, I know. Best solution would probably be to power that HAT directly from an external supply. That's what the manufacturers anticipated. I have to admit though that I haven't tested that scenario on a RPi5!!!

There's another disadvantage that comes with these HATs. If you turn the RPi off, the HAT discharges over the RPi. That leads to a slightly delayed (a couple of seconds) power-down of the RPi. IMO nothing critical. I just wanted to mention it.

Now. On a quick scan I found some sites still listing the HAT. ( I have no business with them!)

Below some examples who still seem to sell the DFRobot module:

• The Pi Hut
• Audiophonics
• Mouser
• simply search for "DFR0940" 

or if you're a cost-no-object fellow and want the IMO best filter HAT:

• Ian Canada Store
• AudioPhonics

Bottom line. As usual. You need to find out yourself, if such a solution works for you or not.

Enjoy.