a more innovative way of adding impedance without loss in SQ?

Small transformer. For the win.

Little baby inductors on the outputs of the amp are mostly to stop RF from coming into the amp through the outputs and should have very little effect if any in the audio band. Its actually a pretty nice idea/addition. There are some very convincing arguments that say by keeping RF out of the amp this way the amp in general works out better which gets you better sound. 

Resistors are a 50/50 choice. Sometimes they work out well, other times they just screw things up. I think the RE-zero are single drivers (I could be wrong) so its probably worth a try. There are a bunch of headphones I PREFER with resistors, even full sized ones.

Stay away from caps unless they are essential in your circuit.

Quote:

Originally Posted by nikongod 

Small transformer. For the win.

 

Little baby inductors on the outputs of the amp are mostly to stop RF from coming into the amp through the outputs and should have very little effect if any in the audio band. Its actually a pretty nice idea/addition. There are some very convincing arguments that say by keeping RF out of the amp this way the amp in general works out better which gets you better sound. 

Ding ding ding.

Just remember to check spec sheets for frequency response, as some transformers will roll off high frequencies.

right, transformers are inductors.  Frequency response will definitely be affected.  nikongod keep pushing this rediculous idea thinking it would replace an amp!!!(whatt a nut), need to see some FR graphs nik.
 

Quote:

Originally Posted by samsquanch 

Ding ding ding.

 

Just remember to check spec sheets for frequency response, as some transformers will roll off high frequencies.

 

Quote:

Originally Posted by High_Q 

right, transformers are inductors.  Frequency response will definitely be affected.  nikongod keep pushing this rediculous idea thinking it would replace an amp!!!(whatt a nut), need to see some FR graphs nik.

 

I posted my bandwidth measurements weeks ago. 

http://www.head-fi.org/forum/thread/553094/continued-sidetrack-discussion-from-tiniest-portable-amp-i-can-build-nikongod-microtransformer-based-impedance-step-down-box

Post 5 

I suck with computer based test gear so you will probably never see a pretty RMAA graph out of me. Just trust me it was very flat between those ends. Id happily admit a resonant peak or dip in there like I called out the obvious saturation at 1V & 20hz but there is nothing to report. 

can you find an impedance VS frequency graph for your headphones? 

The resistors change frequency response in a way that roughly follows the impedance of the headphones. In a kind of funny way, most of the effect of resistors GENERALLY happens in the lower frequency but I also hear it in the highs. See if there is anything that makes sense there.

Yup, I experience that with ER4P, it def changed the frequency response to my ears.  I also want to know how adding impedance removes hiss.  I cannot put all the relationships to understand it fully. Every time I run into an explaination, it contradicts another.

We had a discussion about that here, and Anaxilus thinks it add to the SQ?

Quote:

Originally Posted by psgarcha92 

I tried two resistors of 45ohms on each channel, making a total impedance or resistance around 60ohms, and it killed the hissing totally. But, the highs and clarity of my RE-ZEROs have been affected in a bad way. What would be the reason of killed highs here?and what can be a solution?

Quote:

Originally Posted by High_Q 

Yup, I experience that with ER4P, it def changed the frequency response to my ears.  I also want to know how adding impedance removes hiss.  I cannot put all the relationships to understand it fully. Every time I run into an explaination, it contradicts another.

 

Adding impedance inline effectively reduces the VOLTAGE sensitivity of the headphone. 

This reduces apparent hiss in many systems because random noise voltage is constant without any significant dependence on volume/voltage output. If you have a noisy source, ahead of a quiet amp, which causes random noise to increase and decrease with the output signal level that sucks as much as your source.

Anyways, use Kirchoffs voltage law on a 100ohm resistor in series with a 100ohm headphone VS just the 100ohm headphone. Lets say that the headphones need 1vrms to play at the desired level, and that the random noise is constant at 1mvrms. Although the noise and signal become inseparable once they are combined consider them as separate components for this problem. Label your schematic for noise and signal voltage separately and it should be very easy to see.

The thing to look out for as you, psgarcha92, and I pointed out is that series resistance changes frequency response. Sometimes it changes for the worse, others for the better. Not a bad experiment to spend $1.50 on as the results can be very nice with some headphones.

Sensitivity is power dependent.  Condtradiction is:

one would say, it's high current and resistor reduces the current.  Then you hear about having the output impedance to 0, and adding resistor is adding a real impedance to the output to get rid of hiss.  

Resistor does not equate to impedance.  its a real device, that decipates energy, not reactive device(which changes the phase, but yes there are some dicipation of energy).  But still don't know, how that factors in.
 

Quote:

Originally Posted by nikongod 

 

Adding impedance inline effectively reduces the VOLTAGE sensitivity of the headphone. 

 

This reduces apparent hiss in many systems because random noise voltage is constant without any significant dependence on volume/voltage output. If you have a noisy source, ahead of a quiet amp, which causes random noise to increase and decrease with the output signal level that sucks as much as your source.

 

Anyways, use Kirchoffs voltage law on a 100ohm resistor in series with a 100ohm headphone VS just the 100ohm headphone. Lets say that the headphones need 1vrms to play at the desired level, and that the random noise is constant at 1mvrms. Although the noise and signal become inseparable once they are combined consider them as separate components for this problem. Label your schematic for noise and signal voltage separately and it should be very easy to see.

 

The thing to look out for as you, psgarcha92, and I pointed out is that series resistance changes frequency response. Sometimes it changes for the worse, others for the better. Not a bad experiment to spend $1.50 on as the results can be very nice with some headphones.

Quote:

Originally Posted by High_Q 

Sensitivity is power dependent.  Condtradiction is:

 

one would say, it's high current and resistor reduces the current.  Then you hear about having the output impedance to 0, and adding resistor is adding a real impedance to the output to get rid of hiss.  

 

Resistor does not equate to impedance.  its a real device, that decipates energy, not reactive device(which changes the phase, but yes there are some dicipation of energy).  But still don't know, how that factors in.

 

Depending which MFR's specs you read headphone (and speaker) sensitivity will be given in db/power OR db/volts. There are advantages&disadvantages to both standards, but you can read up on that on your own time. 

P=V^2/R. Have you ever direclty measured power? Using a power meter (which measures voltage and current and calculates power) does not count. I chose to use units that are easy to measure and work with.

On that note, would you agree that the POWER in the headphones themselves is the same in both examples I suggested (ignoring the noise) The headphone has 1vrms across them in both cases....

I would not say this problem is due to high current, or low current, or that it has anything to do with current. Noise is generally a voltage problem, which makes sense since the majority of people use voltage output amps. You brought up current because you like to be contrary. 

For resistors Z=R u shud no that. AC Electronics, sometimes included in freshman level electronics classes....

DP

Quote:

Originally Posted by nikongod 

 

Depending which MFR's specs you read headphone (and speaker) sensitivity will be given in db/power OR db/volts. There are advantages&disadvantages to both standards, but you can read up on that on your own time. 

 

I don't think you understand what voltage is, and the relationship to loudness  IF you did, then you would know  it's is power that matters. not call sensitivity based on voltage.

 

P=V^2/R. Have you ever direclty measured power? Using a power meter (which measures voltage and current and calculates power) does not count. I chose to use units that are easy to measure and work with.

I don't know how this is related to my post above.  But I can see where you errors are.  No, understanding of fundamentals.  Freshman level stuff as you would call it.  P=IV.  P=V^2/R only if it is purely resistive system.  Like DC signal for example.  V is the drop over the R or purely dissipative component.

On that note, would you agree that the POWER in the headphones themselves is the same in both examples I suggested (ignoring the noise) The headphone has 1vrms across them in both cases....

I would not say this problem is due to high current, or low current, or that it has anything to do with current. Noise is generally a voltage problem, which makes sense since the majority of people use voltage output amps. You brought up current because you like to be contrary. 

Once again, no understanding of fundamental relationships.  Also, I didn't bring up the current thing, someone else did.

For resistors Z=R u shud no that. AC Electronics, sometimes included in freshman level electronics classes....

Read my post above again, I have corrected you.  You seem to have it backwards.  You keep calling reistor impedance.  Z=R+jX.  R is resistance.  It's very elementary and you seem to have no understanding of what impedance really means.  I guess you can say if there is no reactance, x=0, so therefore Z=R. But at that point it is R, not Z.  Z is complex. 
 

AC electronics?  LOL  you are talkign about R right?  There is no so called AC electronics classes in my school.... Possibly in trade school.  you probably wouldn't know..  Also, for so called AC electronics, Z doesn't not equate to R.  Frequency dependant??