Dac hat questions

I have a dac hat that is the same size as a pi model 3B/4 board; but I’m wondering whether it works to put it on top of an r pi 3A, given that would be a smaller board on the bottom. Would this present a problem?

Also, the rca outputs are on the short end of the DAC hat (above the usb). Does anyone know of a case that might fit (for any model pi)? Most cases for dac/audio hats seem to be built for rcas on the long side, so the cutouts won’t fit.

Thanks

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Hi Loise,

Welcome to the forum!

To answer your first question, generally yes.

The pinout for all of the 40-pin (essentially all) of the Pi is identical, and for most DAC HAT (if you’ve got a link or the SKU for the particular version you’ve got that’d be great!). Also, if the HAT is specifically designed for a Pi, usually you’ll find that the datasheet or specs cover all of the suitable boards.

Above is the DAC+, pinout, and matching datasheet, assuming this or a similar board is what you’ve got. As you can see, it uses a variety of pins on the Pi although it should still be suitable for any version of the Pi 3 or 4 which has a complimentary pinout.

Unfortunately, there’s limited choice for cases which accommodate large HATs such as this, you may be able to get away with a HighPi if you’ve got a 3/4 B, although I’ve put it together myself before on both boards, and without a little modification/removal of the lid of the case it’s very easy to bend or otherwise damage your pins and ports.

Designing your own custom case and 3D printing or laser cutting it may be a better option, you can use Fusion360, Blender, or similar CAD and CAM programs to draw it up and would give you the most freedom regarding dimensions and material.

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Hi Bryce. Thanks for such a helpful answer.

I’m trying to upload a photo… Being a newbie, not sure if it will work :slight_smile:

I was wanting to run the DAC on cheapest possible (workable) pi, hence thinking of a 3a. I think the pins will fit, so i might go for that, and sort out a case later. If you can see the pic, you’ll see that it doesn’t look like the high pi will work for this one.

Thanks again.
Louise

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Hi Louise,

No worries, we’re here to help. Yes, the image came through, although I don’t recognize the HAT, do you know what the name of that board is? Did you buy it at Core Electronics (no worries if you didn’t, just trying to work out what this is)?

A 3A should do nicely for that application, although the increase in performance from a 3A to a 4 by comparison to the price difference is quite significant while also ensuring compatibility with other future boards, OS, and projects.

Also, if you’re not able to identify the DAC HAT, can you use a ruler or calipers to measure it up and determine the dimensions. There are not many cases that I’m aware of which can accomodate that kind of footprint but we’ll see what we can come up with.

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It’s an audiophonics board… es9028…

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Brilliant, from the spec sheet on it, that board is 57 x 90mm although I’m not sure about how high it sits off the Pi. Have you been able to measure how tall it stands off a flat surface when attached on top of a Pi?

https://www.audiophonics.fr/en/dac-and-interfaces-for-raspberry-pi/audiophonics-i-sabre-dac-es9028q2m-raspberry-pi-3-2-a-b-spdif-i2s-p-12105.html

Here’s the specs if anyone else reading this needs it :slightly_smiling_face:

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Thanks Bryce. Good question. No, haven’t been able to measure that yet… My other pi is not accessible so i need another before i can measure!

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Hi Louise,

No worries, how about from the bottom of the PCB to the highest point on the RCA connector at the back? Should be able to get an approximation from there based on the standoffs that you use with the Pi for it.

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It’s 3.5 cm

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Hey Louise,

That’s a fair margin, you may be able to get away with using one of the larger cases for the Pi (although not from the stock I was able to find that we currently supply).

Personally, I’d recommend either using one of the Pibow cases if you’re just looking to protect your Pi (assuming you’ve got enough space under the HAT to clear the acrylic) or to organize with a 3D printing/laser-cutting service to have a custom case manufactured to fit your board to ensure that you get a decent fit. If anyone else has ideas for a case that may do the trick that I couldn’t find/think of feel free to add a suggestion too.

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Thanks bryce. One last question: if i get the pi 4, will it be ok (for the purpose of audio streaming) with the micro usb power supply connected to the DAC hat? I understand that powers the pi too - just want to make sure that’s enough for the 4. (Nearly ready to hit ‘checkout’ now…) Thanks for bearing with all the questions!

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Hey Louise,

From the product page for the DAC, it seems as if it would be all good, just note that the Pi 4 can use a bit more power from time to time so make sure that power supply that can output at least 3A (Absolute minimum suggested from Pi foundation). I can’t see any details for how much the HAT uses by itself so would go for a higher rated one if you can!

Liam.

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Hey Louise,

I’m not sure, as you’ll want to check the specs on your particular board to ensure that it can kick out enough current for the Pi and DAC HAT and I couldn’t find it listed anywhere:

Given you’re not running any other peripherals on your board (or at least anything that would draw a significant amount of current) it ‘should’ be okay, as microUSB is often rated for about 1.8A at 5V

That being said, I’d suggest powering it via the USB C on the Pi to ensure that your power supply can kick out enough current for both. From what I can see on the specs the traces on your DAC HAT are tied to the 5V out from the Pi so it should still be suitable. Please let us know if you have any other questions.

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