After the messages about headphones and iems used with the SR25, please let me give you my opinion. I believe that this player works extremelly well with easy to drive headphones and iems. I have tried everything I and my family have. I will give you my opinion as to performance.
- Sennheiser HD 599 impedance 50 Ohms, slp 106 db (1 vrms) max volume 100 out of 150. The SR 25 drives this effortlessly and my favorite sound by far with a balanced cable
- Denon Ah-D900 32 Ohms, 106 db, old vintage headphones, also easy to drive and sound wonderful with the SR25, but uncomfortable.
- Sony WH-1000xm3 47 Ohms 104,5 db, Max volume 110. Again driven effortlessly with the cable connection
- Final audio E4000. 15 Ohms 97 db, balanced cable. Sounds amazing with the Sr25.
- Sennheiser cx 5.00i 18 Ohms 118 db, very nice sound. Also similar Sennheiser cx300s. In this case amazing how well it sounds with such cheap iems.
I have also tried the Jabra elite 65T and Apple airpods pro, both with Bluetooth with good results.
In all headphones and iems with cable I had more than enough power and excellent sound. Better balanced. This is of course only my opinion. All are easy to drive devices. I am sure it is completely different to drive 300 Ohms headphones but I do not have any of those.
Also I have been playing with the EQ. All experts please excuse me, but I hope this will help other beginners like myself. I found out about the
jaakkopasanen/AutoEq a collection of EQ settings for thousands of headphones and iems to achieve a certain result, the so called Harman target. I decided to try.
Also, To fiddle with the EQ of the SR25 I found this very helpful.
Also note that the curves can be manipulated manually and the gain increased in the advanced mode, expanding manually the curves.
My conclusion after trying the Autoeq: I like very much the result with the Sony Wh-1000xm3, so much better than the overcooked bass that comes from Sony. For the Sennheiser HD599, I do not dislike the result of EQ, but since I do also like the setting without EQ, I use them without EQ. Finally, I do not like the result with the Final E4000. So, I would say it is worth a try, maybe you will like the result, specially if you have too much of something, bass in my case.. I hope this helps and please excuse the long message.