Head-Fi.org › Forums › Help and Getting Started › Introductions, Help and Recommendations › Noob Ohm questions, re. BD Dt880 pro.
New Posts  All Forums:Forum Nav:

Noob Ohm questions, re. BD Dt880 pro.

post #1 of 5
Thread Starter 

I need to sort out, how to "translate" different ohm impedances in any kind of amplifier, for use with my BeyerDynamic DT880 pro 250 ohm.

When I look at one kind of dedicated headphone amplifier it says:

Output Power
1.1W into 32Ω
Output impedance less than 1Ω

 

Consumption 25 watts

 

So how do I translate that info for my DT880 pro?

Is it possible to get any kind of amplification that has 250 ohm in output power?

And can you get amps that have say 600 ohms for the 600ohm DT headphones?

post #2 of 5
No, no - you are misunderstanding the specs. You do NOT match the output impedance of the amp, or the output power rating with the headphone impedance - those are related, but completely different things.

The power rating of the amp changes with the load it is driving. They pick a particular load and then say how many watts the amp can output into that load. The load they pick is somewhat arbitrary - in this case they used 32 ohms, but they could have used any impedance and then measured the maximum output. The output wattage will decrease as the load impedance increases. That's why higher impedance headphones are considered "harder" to drive.

The impedance at the output of the amp is without anything plugged into it. Typically, you want that number to be much lower than the impedance of the load you attach to the amp. This will provide good damping for the amp so that it does not become unstable. An output impedance of 1 ohm is perfectly fine.

The impedance of the headphones is the load those headphones will put on the amp. Impedance actually varies with frequency, so the number will not always be 250 ohms. There are actually two specs that together will indicate how difficult a headphone is to drive: 1) Impedance, and 2) Sensitivity. The sensitivity of headphones is usually measured in dB SPL/milliwatt @ 1 KHz. The headphone sensitivity says how loud a headphone will play for a given wattage, and as we already discussed, the headphone impedance indicates how many watts the amp can output into a load. High sensitivity and low impedance means the headphone will play loud even from a weak amp like your phone, and low sensitivity and high impedance means you need a powerful amp to reach high volume levels. There are other nuances associated with current and voltage, but this is the basic idea.

Now - for your real question: Can your amp drive your headphones? I don't know - probably - what amp are you talking about?
Edited by billybob_jcv - 1/11/14 at 9:09pm
post #3 of 5
Thread Starter 

I was thinking about the wattage just after I posted my question. And now I can see you confirm it, that the impedance gets lower the more wattage/power you put into the phones. Thats why the big impedance amps always are much bigger than the smaller ohm amps.

 

I bought two amps a couple of days ago, one surroundsound-receiver which has 6ohms to 150 watt.

And also a Audiolab Q-Dac/headphone amp with 40 wpc into 8 Ohms, 60 wpc into 4 Ohms

 

The surround-amp has way more power and punch, feeded with my Dune HD mediaplayer, than the Pc-Dac-Headphone combo or the Pc-Dac-Surroundreceiver combo.

The surroundreceiver is just a cheap 350£ on sale for 250£ Pioneer Vsx-923, that I can use for an entrylevel surround-solution, and also as a relative good stereo-amp until I upgrade for better equipment.

 

Can you tell me what kind of how many ohms into watt I need to look for then? I know almost absolutely nothing about electricity and currents, so for a noob whats the rule of thumb when looking at the ohms and watt specs?

I understand there is a difference in ohms out and ohms in. What it is I will try to learn :)

post #4 of 5
Quote:
I was thinking about the wattage just after I posted my question. And now I can see you confirm it, that the impedance gets lower the more wattage/power you put into the phones. Thats why the big impedance amps always are much bigger than the smaller ohm amps.

NO. There's aren't "big impedance amps" - there are big wattage amps. The impedance does not get lower the more wattage you put in the phones. The way to say it is that the maximum watt output of the amp decreases as the impedance of the headphones increases.
Quote:
I bought two amps a couple of days ago, one surroundsound-receiver which has 6ohms to 150 watt.
And also a Audiolab Q-Dac/headphone amp with 40 wpc into 8 Ohms, 60 wpc into 4 Ohms

The surround-amp has way more power and punch, feeded with my Dune HD mediaplayer, than the Pc-Dac-Headphone combo or the Pc-Dac-Surroundreceiver combo.
The surroundreceiver is just a cheap 350£ on sale for 250£ Pioneer Vsx-923, that I can use for an entrylevel surround-solution, and also as a relative good stereo-amp until I upgrade for better equipment.

Now you are changing the story a bit - speaker amps aren't the same as headphone amps. The specs are different. The power ratings for a speaker amp or receiver are based on driving speakers, not headphones. You also need to know the frequency response and the distortion level for the stated power rating.

I think you are trying to get too much information from the specs. The mfrs will twist the specs and leave out important details to make the specs seem better or more important than they are. In general, you don't buy headphones and headphone amps based on the published specs.

My advice is to read the reviews and focus on what people are saying about how the gear sounds and works - not on the published mfr specs.
post #5 of 5
Thread Starter 
Quote:
Originally Posted by billybob_jcv View Post


NO. There's aren't "big impedance amps" - there are big wattage amps. The impedance does not get lower the more wattage you put in the phones. The way to say it is that the maximum watt output of the amp decreases as the impedance of the headphones increases.
Now you are changing the story a bit - speaker amps aren't the same as headphone amps. The specs are different. The power ratings for a speaker amp or receiver are based on driving speakers, not headphones. You also need to know the frequency response and the distortion level for the stated power rating.

I think you are trying to get too much information from the specs. The mfrs will twist the specs and leave out important details to make the specs seem better or more important than they are. In general, you don't buy headphones and headphone amps based on the published specs.

My advice is to read the reviews and focus on what people are saying about how the gear sounds and works - not on the published mfr specs.

 

I try to read and look at reviews a lot. Thanx for the answers.

Still a bit hard to understand but I´ll try to.

New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Help and Getting Started › Introductions, Help and Recommendations › Noob Ohm questions, re. BD Dt880 pro.