RPi Specs for Direct-to-DAC

I’ve read with interest that, if you have a USB DAC, you can plug it directly into an RPi4 without the need for a HAT.

If true, has anyone tested this idea on an RPi 3+?

3+ or 3b+?
There’s a lot of users on the forum using 3b+ and usb dacs, having a quick look.

You can attach USB DAC to any RPi model.
HATs are I2S DACs and could be attached via GPIOs.
There are two different things and are not related one to another.
You can, for example, have HAT DAC + USB DAC connected the same time to one RPi.

I’ve used a Pi 2 and Pi 4 with my Topping D50S. For straight Roon use - no upsampling etc - the 2 was absolutely fine.

For HQPlayer the 4 was required in my set up at least as the 4 splits the bid for the Ethernet and usb whereas on the 1, 2, & 3 it’s shared and this causes drop outs at high bit rates.

Assuming you run Ropieee as your bridge software you can hook up the 7” R Pi touchscreen and have a full display too. Works very well.

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I have two RPi4’s, both running RoPieeeXL. I use one for ethernet to RPi4 then USB to Meridian Prime and Headphone amplifier. I use the other for WIFI to RPi4 then USB to Dragonfly Cobalt for battery powered portable headphone use. They work great.

The cost to assemble one from Amazon is US$77 including a 2GB RPi4, power adapter, 16GB micro USB card, and FLIRC case.

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You can. Some things to consider…
RPi4 has separate buses for USB and ethernet. Previous boards effectively shared a bus so if ethernet and usb were both pushing data, the exact situation that happens with streaming music, it can cause issues. This is why the RPi4 is recommended. However, I use a 3B+ in my office with ethernet to USB and experience no issues.

The other thing to consider is that the RPi is a noisy little computer. You won’t get the best sound quality out of it depending on how good your USB DAC is. Some DACs are worse than others and benefit greatly from a very clean and low jitter USB source. This is why things like the Ultra Rendu and USBridge Signature exist. There is, to my knowledge, no “USB hat” for a Pi. So, if you want low jitter / low noise from a hat then S/PDIF is your choice.

Yes, 3B+ works fine for me but my purpose built devices (I have a couple Allo devices) sound better. But you really cannot go wrong for the price of the 3B+. If possible, get the 4 though just because of it not sharing ethernet / USB bandwidth.

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I use a 3A+ with an Audioquest Dragonfly attached to the usb for headphone listening (using ropieee). In the past I had it connected to a Marantz DAC in my main system.

My logic for buying the 3A+ was that, with no Ethernet and only one USB port, in my mind it had to be less noisy than the 3B+. I’ve never compared the two but I’m happy with the performance I got.

The WiFi speed is good enough for 192/24 and DSD 128 as long as the signal is strong enough.