[captslow]

Before getting to my question, I will provide a little background. I am just venturing into the headphone world from the Two-Channel domain where I have been active for the past decade. As a result I have quite a bit of HiFi gear, however, my current situation allows for only a small office system and everything else has been packed away for the foreseeable future. I am hoping my musical savior will be the headphone world.
 
Currently my office system consists of the following:
 
Amp (integrated): TEAC AI-2000 (designed by esoteric, dual mono)
Source: Rega RP3 (exact cart)
Speakers: Dali Zensor 1
 
I have no DAC as I have been an analog only guy, but will be buying one shortly, so many options to research.
 
Now to my question... Sorry for the long winded introduction. 
 
I have been advised to try the Hifiman He-6s since I already have a somewhat decent speaker amplifier. My TEAC has a headphone out (no it is not an opamp powered unit, it uses the regular output through a series of resistors). 
 
Is there a difference in using this headphone out rather than the HE-Adaptor or other speaker jack to headphone adaptor? I took a picture of the headphone resistors for the electrical engineers among the community who may be able to provide more insight. 
 
Thanks guys!
 


 

 

[Steve Eddy]

No, you're fine. Just plug in to the headphone jack. It's running through a pair of 330 ohm resistors which are ok for planars like the HE-6. I've driven my LCD-2s through my TEAC A-H500 which uses 390 ohm resistors and it sounds wonderful.

se

 

[captslow]

Thanks for your response Steve!
 
That is what I thought, I know Hifiman uses a lower ohm resistor pairing, and that is what initially sparked my curiosity.
 
What does the value of the resistor do to the amplification qualities? Does it limit current flow below 330ohms? 

 

[Steve Eddy]

The resistor just provides across the board attenuation. That's because the HE-6's impedance is virtually purely resistive and flat across the frequency spectrum, so you don't get the frequency response aberrations you'd get with dynamic headphones which don't have the same sort of flat impedance.

But I just ran the numbers, and given the HE-6's relatively low sensitivity, you might possibly need to replace them with lower values.

Have you tried the HE-6's from the headphone out yet?

se

 

[captslow]

The resistor just provides across the board attenuation. That's because the HE-6's impedance is virtually purely resistive and flat across the frequency spectrum, so you don't get the frequency response aberrations you'd get with dynamic headphones which don't have the same sort of flat impedance.

But I just ran the numbers, and given the HE-6's relatively low sensitivity, you might possibly need to replace them with lower values.

Have you tried the HE-6's from the headphone out yet?

se

The HE-6 is on the way, ordered the headphones today. Again I appreciate the help. So if I understand correctly, the higher the resistance in the circuit, in my case 330ohms (not sure if these are wired in parallel or series), the more the power is reduced? If I reduced the value of the resistors the power output would increase?
 
So with this being the case, simply buying the speaker to headphone adaptor that hifiman sells with the following specs, I would be able to better drive the HE-6's or other headphones, than with my factory headphone jack?
 
Input: Speaker Connector
output: 4 pin XLR
Resistors in parallel: 10 Ohm
Resistors in series: 25 Ohm
 
Sorry for all of the questions, I have just recently become quite interested in electrical engineering.... Maybe I should quit my job and go back to school Apparently my liberal arts degree is not useful for amplifier design... 

 

[Steve Eddy]

That's correct.

With regard to the speaker adapter, that will work, though personally I think it's a rather messy solution in a case where you effectively have speaker outputs on the headphone jack. Do you know of anyone near you who could swap out those resistors?

As for going back to school, there's plenty online where you can learn for free. In this case, just check out "voltage divider" on Wikipedia. Just the simple resistive one will do. You can think of Z1 as the resistors on the amp's output and Z2 as the headphone impedance. The HiFiMAN adapter uses another resistor that's in parallel with the headphones (that's to lower the source impedance seen by the headphones) but it's not absolutely necessary.

se

 

[captslow]

Thanks again for your input. Time to jump down the rabbit hole and learn the ways of electrical design.
 
I should be able to replace the resistors myself, I have a fair bit of experience with a soldering iron and assembling electronics (I just fail to grasp how everything works, its like magic to me). 

 

[Steve Eddy]

Oh, if you're handy with an iron, that's perfect.

Good luck! Feel free to shoot me a PM if you have any questions or run into any trouble.

se