Looks for Headphone Tube Amp

Not using a DAC, should I use both a DAC and an amp?

RN using Apple Music, but will be getting tidal once I get my headphonees

You have opportunities to get substantial improvements from upgrading the amp, DAC, and streamer (source). 

About fifteen years ago I bought a decent set of headphones for my iPod… then did incremental upgrades (each a step up) to my system….  7 different amps, 5 DACs, and 5 different streamers. You can see my current system by clicking on my user name. Each of the many upgrades was substantial and wonderfully rewarding. The more effort and money you invest can be very enjoyable. I think amp, DAC, and streamer in that order is the way to go until they have similar quality (think very roughly cost). Then do it again. When your system is getting really good, do not neglect the streamer… it is easy to think the streamer just forwards bits… how could that impact the sound… it does. I learned by delaying too long.

i got an aune t1 tube headphone amp on ebay for around a hundo and really like it

should I use both a DAC and an amp?

Absolutely — your headphones are plenty good enough to reward you significantly by feeding it a better signal, and the DACs in iPhones and iMacs suck and will greatly limit your sound quality. At your budget I’d avoid tubes and go with a combo amp/DAC like an AudioQuest Dragonfly Red or something from Topping, etc. And get Qobuz instead of Tidal if you can — it’s cheaper and better with none of the intrusive MQA crap to deal with. BTW, you’ll also need an Apple Lightening to USB 3 cable (about $30) to be able to bypass the device’s internal DAC.  You won’t hear much difference with crap MP3 tracks, but CD resolution and up will sound much better.  Hope this helps, and best of luck.