[please help] sound card and AKG K240DF

2003-04-19 09:37:45

At first I decided to buy a DT831 for my soundcard, which is a m-audio revolution (may upgrade later).
However, considering the physical and sound comfortness, I finally changed for a K240DF after some audition, since DT831 is too excited a headphone for a whole day's wear during work. (Generally I spend 10 hours in front of my computer per day). On the other hand, I think high impedance & low sensitivity headphones may performs better than high sensitivity ones on computer, if they are drived well.

Don't know if there are any sound cards around $200 that can drive the 240DF to an acceptable level. The analog output of my revolution is 1.2 Vrms (no more details), which may be not enough. I have a headphone amp which has enough power, but I really don't want to use it in the office. It's not very suitable:)

Sincerely thanks
Voxel

[please help] sound card and AKG K240DF

Reply #1 – 2003-04-20 14:42:06

I assume K240DF has a similar spec to K240. It is a good headphone but the impedence is 55ohm which is quite a heavy load for a PC snd card.

I think one easy way to drive it is to use the headphone jack of a multimedia speakers because those speakers usually involve amplification for headphone.

Would u like to try this method? 

[please help] sound card and AKG K240DF

Reply #2 – 2003-04-20 16:09:23

Thanks WavOx, but I don't think I will try in this way. Good headphones and multimedia speakers are totally different things 

Till now I have received very little answers for my question. Seems I should use my amp in the office  BTW, the 55Ohm K240 is 240s, while 240DF is 600Ohm and 88dB

[please help] sound card and AKG K240DF

Reply #3 – 2003-04-21 08:04:10

The only problem you could have driving high impedance headphones such as AKG 240DF with the Revo headphone output, is not getting loud enough sound level. So, if you have the alternative of the headphone amp, you could get the headphones and try without headphone amp, and if the level is too low, then use the headphone amp.

[please help] sound card and AKG K240DF

Reply #4 – 2003-04-21 08:25:52

Doing some approximate numbers:

sensitivity of the 240DF is 88 dB and impedance is of 600 Ohm. Sensitivity in headphones is SPL for 1 mW; Max. output of The Revo is 1.2 Vrms.

So, power for max. output or Revo would be approximately P = V^2 / R = 1.2^2 / 600 = 2.4 mW.

And the SPL for max.output then would be SPL = Pref + 10 log V/Vref = 88 + 10 log 2.4/1 = 88 + 3.8 = 91.8 dB

So the max. output level RMS would be around 91.8 dB, which I think could be enough, but maybe not if you like listening to high levels.

[please help] sound card and AKG K240DF

Reply #5 – 2003-04-21 10:51:04

Thanks KiKeG.

I've done this computation before (the max output of Revo is 1.26 Vrms), and I agree that 240DF is easier to drive than some low impedance headphones, since its impedance is insensitive to frequency. However, I think 92dB is not enough for normal listening, especially for classical music.

And I heard from some people that 240DF needs more power than specifications since it has a circuit in it or for some other reasons

Regards,
Voxel

[please help] sound card and AKG K240DF

Reply #6 – 2003-04-21 11:16:35

If the output impedance of Revo's headphone output is not very high, lower impedance headphones would be more easy to drive at acceptable levels.