Followup:

       My headphones: beyerdynamic dt 770  pro 250 Ohm 

DAC: Fiio ka3

I feel like im pushing the edge of the amp.. on loud recordings 90% vol is fine and enough but on those old recordings (or Steven Wilson's remixes) I need to turn it up to 97%..

I have all the right apps, (FiiO control, UAPP) and my dac is configurated..

The headphones are connected to the regular headphone jack bc they don't have a balanced cable ):

Should I buy a new dac?

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That's one of the old audiophile claims that I am not sure if it is scientific or not.

The idea of headroom, and how when an amp gets closer to the minimum and maximum power, the output becomes unstable and starts to introduce unhealthy amount of distortions to the gear.

I am not sure if you 'd find it convincing or not, but here are the sources:

https://www.youtube.com/watch?v=Rtx2pYOS-dg

Headroom is simply having more power than you will need. Powering a 25 watt rms speaker with a 100 watt rms amp leaves 75 watts of headroom. If that amp is putting that 100 watts rms out with .005% THD. Imagine what the THD is if the amp is only putting out 15 watts. Probably not measurable at all. Definitely is not audible. So there is plenty of headroom for distortion also. Which is the important one really.

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It depends what a person means when they say headroom. There is a big difference between having enough power for your average db vs having enough power for transients. There is no need to have “headroom” more than you need for transients but in the OPs case it clearly does not do that.

If OP listens at 80 db average at 90-97% volume then the peaks in the music will be cut off. Depending on the type of music you listen to you could have anywhere for say 15-30 db transients. The rub is that the power needed is not linear with the increase in db but instead exponentially. So where you may only need 50mW of power at 80db you will need 150mW at 85 db (I made up those numbers but a headphone power calculator can tell you exactly what they are depending on your headphone).

My suggestion would be to use a headphone power calculator and input your resistance (ohms) and sensitivity (db/mW) and then see how much power it needs at 115db. I typically listen at around 80-85 so this covers me for an additional 30-35 db of “headroom” for transients. That way even if you typically only listen at 70 you know you are covered if you want to really go crazy for a bit (but be sure to limit your time doing this if you do).

It is also worth noting that if you plan to EQ (and you should if you can because why not) that you will need to take into account your negative preamp into the equation. So it you listen at 80 but have a negative preamp of -5db you will need to include that in your power calculation by adding another 5db to your listening level.

So if people mean they want headroom so that they can listen at 95db with full transients for 1 song well then maybe? But otherwise there is no headroom needed past what your headphone requires to fully show transients. Just another warning that while listening at this kind of level for a short time is “ok” but definitely don’t do it for long periods of time and you can always see what OSHA says as far as exposure at certain levels that is a good reference.

Got the same KA3 and is it set to high impedance and gain? Because sometimes I forget to switch those up when I go from IEMs to the big bois

I'm not sure what the output power actually is on the KA3 single ended socket but, I would expect your dt770 to be a stretch for it depending on your preferred volume. I used a Fiio BTR5 for a while with an IEM that has unusually low sensitivity, for an IEM, it was loud enough for me at 50% volume from the SE socket. This IEM's impedance was only 14 ohm, your headphone will be quite a bit more demanding. You could get an amp and feed it from the KA3, this is likely to be cheaper than buying a new DAC/amp.

Have you paired the 250 ohm DTT70 with the btr5? I'd imagine it won't be enough so I might as well get the 80 ohm one

I don't have the dt770, they should be a lot more demanding than the IEM I compared them to judging by the sensitivity and impedance.

The 770 pro are high impedance, so the voltage(2v on SE) gets saturated and the amp is clipping. You would be better off using balanced on the KA3 with those HPs, though modding of the headphones is required to achieve that. Or get something with more power(higher max voltage, imo 4V at least) to pair with your HPs.

It’s entirely dependent on what the amp is driving and how it was designed

It's scientific that you can push an amp into clipping if it doesn't have the current, although it more typically happens with lower impedance headphones than higher ones.

Volume controls voltage and with low impedance headphones you usually can turn the volume up higher than the amp's capability to supply current, if you do this you do get clipping and a huge spike in distortion.

You can see this in the 16Ω measurements for the KA3 unbalanced, and the 32Ω as well with the balanced. It's not apparent in the 68Ω or 300Ω though, that goes to max voltage without clipping, although distortion does start to rise again above 20mW (not to the level it would likely be audible).

https://www.l7audiolab.com/f/fiio-ka3/

DT 770 250Ω are quite hard to drive, substantially harder than something like the Sennheiser HD600, and I would think you probably should be using something more powerful than the single ended out of a KA3, yes.

You could mod them to balanced, or get a more powerful desktop amp. The Douk U3 at $30 might be a good option, it does 1.3W and you can use the KA3 as a DAC into it.

Thank you everyone for your advices! The existance of helpul ppl in this community make me belive in humanity!

Now that iv'e understood that the KA3 isn't enough, and modding the headphones is out of the table, is there any portable amp-dac combo/ amp that could drive the DT770??

you might be at the limit for the amp. mine is always below 70%(blessing 2 dusk, s22ultra)