Nostoi
Headphoneus Supremus
What headphones/IEMs are you using? Personally I wouldn't worry. I was using various Lotoo DAPs with the immensely powerful Thrax Resolute poweramp, which also has no volume control, so controlling the output solely from the variable LO on the DAP side and the results were very good - complete control even with IE900.I'm mostly asking because the headroom of the pre-amp section is also very important. If the power-amp is asking too much from the source it may have an impact on especially the "ease" the music is reproduced and dynamics. But perhaps the DAPs were designed with this in mind so it could definitely work.
drftr
In that case, the Thrax was asking a great deal from the DAP but the variable LO on Lotoo is very well implemented. The Sound Tiger amps are very modest in comparison - 920w output, so it doesn't really present an issue.
The main thing is to use variable LO rather than headphone out.