- Dec 16, 2021
Only 25 mW in 300 ohm. Let's say you have a HD650. The specs: Sennheiser states the sensitivity is 103db/1mv which is wrong. Its's 103db/1v which is not the same. This is probably a marketing decision. 103 Db is a highter number so let's got with that. Marketing destroys everything.This headphone amp measure 26 mW in 300 ohms. Not a lot of power. I don’t know of this one but even today not many audio interfaces use USB 3. In this particular case, the type A connector seams to suggest it could be USB 3, but regardless if the BUS power is the limiting factor or not, The vast majority, starting with those tested here of low cost USB audio interface have weak HP amps. Most will also want backward compatibility, and also the USB audio standard, the streaming part is specced for USB 2 connections.
Thr actual sensitivy is 98db/1 mw (1) Let's say you want to play music with them EXTREMELY loud (110 Db. I wouldn't recommended listening to these levels for too long. I suggest not more than a minute or two. But if you want to destroy your ears go for it. Personally i don't think it's very enjoyable listening at those levels but this is subjective. It's louder than in a club which mostly pump out 100 Db (average)
To get this earsplitting SPL levels on your HD650 you need 16 milliwatts (power) / Voltage 2,19V and a current of 7,3ma. Most audio engineers mix at a more reasonable level of 85 Db. The requirements drop significantly. You only need 1 mw / voltage 0,5 V / 1,8 ma
Most audio interfaces can manage that. But the most important thing to remember is that you use a headphone amplifier with an output impedance of < 2 Ohm so you will not get in trouble with low impedance headphones.
@solderdude. You're the GOAT (Greatest Of All Time). Or in Dutch: Jij bent de (electronics) bom!