[DieForSurviving]

I KNOW this is possible to do, but I have not seen it done, be it that I'm just missing it, or some other reasons.

I wanna see An AMP that has a knob to adjust the output impedance.

REASONING:

     We all know how some headphones (I'm looking at you HD800 in particular) Are picky about the Amps? I'm not absolutely sure, but I'm well convinced that the Output impedance is the culprit. And if there was an AMP that had a Adjustable Output Impedance, it would make the Amp insanely useful, as you no longer have to search for that one amp that sounds perfect for your headphones.

IF there is not already, let us all start spamming the inbox of companies like FiiO, Schiit, Woo Audio, or just any other Producer of Amps.

(Notice: I'm not particulary good with circuits or electrical, I know a good bit, but mostly in the realm of Electric Motors and stuffs like that. So If anyone who knows the more advanced things about this thinks what i am saying is utter stupidity, please let me know.)

 

[PurpleAngel]

  I KNOW this is possible to do, but I have not seen it done, be it that I'm just missing it, or some other reasons.

I wanna see An AMP that has a knob to adjust the output impedance.

REASONING:

     We all know how some headphones (I'm looking at you HD800 in particular) Are picky about the Amps? I'm not absolutely sure, but I'm well convinced that the Output impedance is the culprit. And if there was an AMP that had a Adjustable Output Impedance, it would make the Amp insanely useful, as you no longer have to search for that one amp that sounds perfect for your headphones.

IF there is not already, let us all start spamming the inbox of companies like FiiO, Schiit, Woo Audio, or just any other Producer of Amps.

(Notice: I'm not particularly good with circuits or electrical, I know a good bit, but mostly in the realm of Electric Motors and stuffs like that. So If anyone who knows the more advanced things about this thinks what i am saying is utter stupidity, please let me know.)

 
Why have an adjustable output impedance?
My O2 (Objective 2) headphone amplifier has an output impedance of less then 1-Ohm, but can drive headphones from 12-Ohms to 600-Ohms.

 

[DieForSurviving]

Did you even read the "Reasoning" section of my post?

Even if Output impedance is not the reason for certain headphones being picky about amps, it still changes the signal. And at one point someone recommended to me add resistors to the internals of my headphones to help relieve crosstalk. (I didnt cause i am aware resistance can slow the sound down. EX: Phillips Fidelio X1's cable with oddly high impedance makes the bass slow.)

SO even if the intended cause is not happening, you could adjust the output impedance carefully and try get a sweet spot to help with cross talk without slowing the bass too much.

 

[PurpleAngel]

  Did you even read the "Reasoning" section of my post?

 
I did read the reasoning section, still do not understand why there would be a need to have an adjustable output impedance?

 

[bobby12]

hes saying its pointless since it can already drive those headphones

some people are just bitchy when it comes to amps, and when you get to expensive gear you get a ton of exaggerations

 

[TrollDragon]

  Did you even read the "Reasoning" section of my post?

Even if Output impedance is not the reason for certain headphones being picky about amps, it still changes the signal. And at one point someone recommended to me add resistors to the internals of my headphones to help relieve crosstalk. (I didnt cause i am aware resistance can slow the sound down. EX: Phillips Fidelio X1's cable with oddly high impedance makes the bass slow.)

SO even if the intended cause is not happening, you could adjust the output impedance carefully and try get a sweet spot to help with cross talk without slowing the bass too much.

Wow...

 
You need to ask this question in the Sound Science Asylum...

 

[DieForSurviving]

I know it can drive it, but that does not change that the HD800's are picky and sound better on some amps and not so good on others.

I know the HD800 are not REALLY a picky headphone and it's a myth, but as stv014 said on another thread,

 

" There is a grain of truth behind the myth, as the HD800, like other mid to high end Sennheiser dynamic headphones, has significantly varying impedance over the audio frequency range. Therefore, an amplifier with an output impedance of >100 ohms adds some slight bass boost and "warmness" (although probably also increased distortion) that many prefer."

As some people LIKE that change, they could use the adjustable impedance to find a balance that they like.

 

[DieForSurviving]

@TrollDragon

as i said, im not particulary good with electrical when it comes to audio, I'm more in the field with electrical motors and the such, which btw is much simpler in my opinion.

so if this thread is appallingly Stupid of a question/search, i would not be surprised.

 

[ProtegeManiac]

  I know it can drive it, but that does not change that the HD800's are picky and sound better on some amps and not so good on others.

I know the HD800 are not REALLY a picky headphone and it's a myth, but as stv014 said on another thread,

 
As some people LIKE that change, they could use the adjustable impedance to find a balance that they like.

 
So why not just get a headphone other than the HD800? Or why introduce what technically would be amount to a less than ideal situation (however general the 8x "rule" is) in order to EQ the sound, instead of using software EQ  straight up?

 

[DieForSurviving]

@ProtegeManiac

As I said in a previous Post, I was recommended to add impedance to my headphones to help deal with crosstalk. (he said because my headphones are single ended, the crosstalk is happening over the Ground, and adding resistors would fix the issue.)

Now Output impedance does have its issues so even if the original intention is not good, a small adjustment range to find some sort of sweet spot to help with crosstalk without encountering too many issues that come with high output impedance. (please note: I'm assuming headphone impedance and output impedance would have similar effect)

and you have a point with "why not use EQ straight up"

Should've thought of that considering I'm using Equalizer APO, with Profiles for all my headphones, and just use the Config to select which Profile to use.

 

[ProtegeManiac]

  @ProtegeManiac

As I said in a previous Post, I was recommended to add impedance to my headphones to help deal with crosstalk. (he said because my headphones are single ended, the crosstalk is happening over the Ground, and adding resistors would fix the issue.)

Now Output impedance does have its issues so even if the original intention is not good, a small adjustment range to find some sort of sweet spot to help with crosstalk without encountering too many issues that come with high output impedance. (please note: I'm assuming headphone impedance and output impedance would have similar effect)

 
As best as I understand it, Crosstalk isn't a function of impedance, but of proper amp design. If the amp wasn't a good design or shoddily built, then that can cause crosstalk. Properly designed and built SE amps (whether pure 2ch, or a 3ch with active ground design, which mimics the benefits of balanced without the hassles of recabling) with good potentiometers wouldn't have audible crosstalk.
 
IF higher impedance affects crosstalk, as best as I understand it, it will do so indirectly. Crosstalk is sometimes rated at "less than (-)xxdB" or "(audible) above xxxdB." As I understand that probably means that at very loud volumes you get more crosstalk.
 
So the thing is you need a clean, powerful amplifier that has a higher tolerance before you get audible crosstalk. Any good quality, even reasonably priced amplifier - no need to go into megabuck amps the size of speaker amps - should be able to provide that.

 

[DieForSurviving]

@ProtegeManic

Well I have the Genuine FiiO E12, and I only get crazy crosstalk on my Pro700MK2, On the HD681 EVO(and a few others), I still get crosstalk, but nowhere near as much, like i have to listen for it to hear it. on the Pro700MK2 I can completely cancel out a channel with the balance control built into windows, and get incredibly audible crosstalk. So it's a case on the headphones, not the AMP.

Funny thing is the crosstalk is not as bad if it is plugged in, charging. Internal Grounding issue?

 

[ProtegeManiac]

  @ProtegeManic

Well I have the Genuine FiiO E12, and I only get crazy crosstalk on my Pro700MK2, On the HD681 EVO(and a few others), I still get crosstalk, but nowhere near as much, like i have to listen for it to hear it. on the Pro700MK2 I can completely cancel out a channel with the balance control built into windows, and get incredibly audible crosstalk. So it's a case on the headphones, not the AMP.

Funny thing is the crosstalk is not as bad if it is plugged in, charging. Internal Grounding issue?

 
Could be. Also note that crosstalk is measured in dBs so it is possible that f there was that much crosstalk in one amplifier then a more efficient headphone would have louder crosstalk.

 

[DieForSurviving]

@ProtegeManic

Yeah the Pro700Mk2s are a higher sensitivity then my other headphones...

Any Amps you'd recommend with that active grounding? I REALLY wanna get rid of this crosstalk.

 

[jodgey4]

There's only one amp that does active grounding that I can remember, and I don't remember the name. Just rewire for balanced operation. What is your E12 plugged into? The problem is probably occurring before then.
 
As to the original question, I think it would be a cool prototype. Output impedance can change the sound by adding color as it gets higher. Some amps have 'gain' switches that just set the output impedance higher.