So I’m looking to get a network streamer and Roon is very new to me - I don’t use it.
Looking over the product docs on the nucleus its not clear to me how you control what is playing. Do I you need a pc/mac with the roon app to control the nucleus? Can I use my phone to tell the nucleus to play from my qobuz / tidal subscription?
My goal is a simple app to control the streamer but not require a dedicated computer to talk to the streamer - that seems rather pointless to me.
You need either a PC/Mac, a tablet (Android, iPad), and/or a phone. The PC/Mac and tablet apps have all the features for editing and DSP setup. (There are only small differences between PC/Mac and tablet, but if you intend to do a lot of database editing you will want the PC/Mac). The phone app is more limited and used predominantly for playback control and light tasks of choosing what to play. You can’t edit metadata or configure DSP at all on the phone.
This is possible on the phone, though, despite its limitations.
A tablet seems the best of both worlds. It just looks nicer when browsing the library and is more convenient for many things you may want to do in Roon. You could even add a physical keyboard if you desire later. You will want an 8" or larger display (this is the size limit for Roon to display the tablet interface and not the phone interface).
With pretty pictures:
The Nucleus isn’t really a streamer per se it’s a dedicated computer that runs Roons server software and can house your files. It doesn’t have any traditional audio connectors. It can however be used to play music to other Roon compatible devices over the network by its own proprietary transport or via others such as Airplay or Chromecast and a few more. Or it can be connected direct via a USB connection usually to a DAC or via HDMI to an AVR ( it doesn’t support HDMI ARC). Its main purpose is to serve your own files or those via streaming services to other devices that connect to your Hifi.
This may help:
Others have provided quality responses. I’ll add that iPad’s are my choice and provide a superb solution for control.
But my iPhone 14 Pro Max also works well in a pinch (especially with guests over).
In simple layman terms, you need a computer device to act as the Roon server. It can be a PC, laptop, Roon Nucleus, or some other computer device.
To control Roon, you need a device to run the Roon app. That can be a phone, tablet, or computer. It can also be the same computer (PC or laptop) that is acting as your server.
Finally, you need an endpoint device to receive the sound signal via ethernet or WIFI. This device is connected to your DAC, usually by USB or HDMI, etc.
You could also connect your music system directly to your Roon server via USB or HDMI if you want. Most people, separate their Roon server from their music system for perceived sound quality and convenience.
For best results, your Roon server needs an ethernet connection to your router or ethernet connected switch.
thanks for the responses all.
At least for my intended use case / needs I don’t see how Roon really fits. I just want something to play audio to a dac or pre-amp and control that from my phone. The audio is either tidal/qobuz or maybe off of my NAS where I have mp3/flac files. It seems the roon setup is a good deal more involved than I really want. My goal is not to have yet another computer to manage 
You don’t necessarily need another computer, but you do need a computer. It doesn’t have to be totally dedicated to Roon. That said, many Roon customers decide they prefer a headless, always on, dedicated computer to run as a Roon server.
Also, I think most decide a tablet is much preferrable to a phone to use as a Roon control device. I actually prefer my laptop for that. I also use my iPhone and iPads.
Unfortunately computer audio is just that, it needs a computer to act as the server, the good news is that the Nucleus is just that but it masquerades as a piece of hi fi kit, once set up it is self maintaining . Roon’s software is auto update and the Nucleus will look after itself . Think of it as Firmware Update of other hi fi components. It needs a power line and an ethernet cable to your router and you’re done
In terms of control , any mobile device will do it , Apple, Android etc but from my experience the bigger the screen area the better the experience. Personally I use an iPad Pro 12.9 its wonderful.
If you just want “something to play to”, then a WiiM Pro Plus or similar streamer with AirPlay 2, Chromecast, and TIDAL Connect as well as the Tidal and Qobuz apps may be all you need.
You answered it yourself, so just get a streamer of your choice with its own phone control app and don‘t look back - Roon is not for you, it‘s that simple!
I can’t help but feel that some of the responses above are over complicating your original question.
With a Roon Nucleus you can absolutely control playback via your phone, without the need for a dedicated desktop computer.
Two steps
1. Nucleus One → USB cable → your DAC [1]
2. Install the Roon control app on your phone & connect it to the Nucleus to control music playback
You’re now up and running & playing music and controlling it from your phone.
[*] For this to work your DAC does need a USB audio input, the Nucleus doesn’t have any of the ‘normal’ analog or digital audio outputs like S/PDIF or RCA connectors that you’d normally see on a piece of audio equipment, which is what several of the replies above are flagging up. Just to clarify, do you already have an DAC?
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However, as has already been pointed out above, depending on your needs it might be cheaper / simpler to get a basic hardware streamer like a WiiM Pro and ‘cast’ directly to it from the native Qobuz app. Obviously by going that route you don’t get Roon’s nice interface and features, on the other hand you can continue to use the native Qobuz app on your phone, which might be all you want.
Ah so the nucleus CAN play through usb to a dac that opens things up a bit.
I’ll play with the server on my laptop for a little bit to see if I need / like it. I want something that I don’t have to jump through a lot of hoops for.
So I’ve fiddled around more. I have the roon server running on my synology nas and casting to an eversolo a6
the eversolo is … interesting. It has support for qobuz, tidal and a bunch of other stuff. The roon server happily sends music to it and it works nicely.
Now to figure out if I need roon or just stick with the apps on the eversolo.
Roon is … growing on me. Thanks for the responses all - appreciate it. While not always relevant to what I was asking the combination of everything was very helpful
I have an Aurender streamer that has it’s own app as well and that can “integrate” Qobuz and Tidal also.
According to reviews and posts on fora it’s a great app but the experience is nowhere near Roon.
And with the price of a Nucleus One I recommend that: simple and no maintenance.