[Yazi]

sorry for my poor english
 
I just wonder if you see this post?
 
http://www.anythingbutipod.com/forum/showthread.php?t=30962
 
It seem adding a impedence adapter (as u mention before, UE's impedence adapter) will fix the bass roll-off issues with the D2.
 
As you mention that impedance mismatching will result less bass response than the original design, or high frequency noise.
 
D2 have higher output impedance and get bass roll-off.
 
However, in their case, add a impedence adapter will end up with less bass rolled-off, and the background hiss disappears.
 
Moreover, in this post http://www.head-fi.org/t/544478/ultimate-ears-ue-x-pro-custom-appreciation-review-discussion-thread/45 (post #54 )
 
UE try to fix the impedance mismatching with a impedance adapter.
(They had claimed that UERM's attenuator is different from TF's.)
 
 
May you give me a detail review, thanks.
 
 
Best,
 
Yazi 

 

[WiR3D]

Quote:

sorry for my poor english
 
I just wonder if you see this post?
 
http://www.anythingbutipod.com/forum/showthread.php?t=30962
 
It seem adding a impedence adapter (as u mention before, UE's impedence adapter) will fix the bass roll-off issues with the D2.
 
As you mention that impedance msimatching will result less bass response than the original design, or high frequency noise.
 
D2 have higher output impedance and get bass roll-off.
 
However, in their case, add a impedence adapter will fix the usual issues.
 
May you give me a detail review, thanks.
 
 
Best,
 
Yazi 

You are half right, you want to DECREASE the output impedance, so that adapter wont work, I had to build my own.
 
You want the "Faux impedance decreasing adapter" as explained on page one. I have yet to see where I can buy one.

 

[Yazi]

Thank for your reply
 
I just don't know why their solution (for impedance mismatching) is adding an impedance adapter (add more output impedance) to player.
 
In your post, you all say adding an impedance adapter to player will end up with higher output impedance. (that seems right, at least for me.)
 
 
Does that mean damping factor is more lower? (getting more bass roll-off or ?)
 
However, their solution seem to fix this issues. Why?
 
There must be an explanation, right?
 
Therefore, I ask your help  
 
 
again, thank for you reply.
 
 
Best,
 
Yazi

 

[WiR3D]

aaaa, the problem is I don't know how dampening factor correlates to bass roll off.
 
Quote:

Thank for your reply
 
I just don't know why their solution (for impedance mismatching) is adding an impedance adapter (add more output impedance) to player.
 
In your post, you all say adding an impedance adapter to player will end up with higher output impedance. (that seems right, at least for me.)
 
 
Does that mean damping factor is more lower? (getting more bass roll-off or ?)
 
However, their solution seem to fix this issues. Why?
 
There must be an explanation, right?
 
Therefore, I ask your help  
 
 
again, thank for you reply.
 
 
Best,
 
Yazi

aaa, you will haveto wait for Chris J or stv014 to reply with specifics.
 
TBH I kind of ignored the bass roll off comment, and now it seems there is more to it then I thought.
 
When you decrease the output impedance, you get less colouration, cleaner bass, and more micro details and a HIGHER dampening factor.
 
When you increase output impedance its pretty much the opposite, but you also raise the noise floor.
 
 
But like I said, I don't know how dampening factor correlates to bass roll off, 

 

[Chris J]

Quote:

Thank for your reply
 
I just don't know why their solution (for impedance mismatching) is adding an impedance adapter (add more output impedance) to player.
 
In your post, you all say adding an impedance adapter to player will end up with higher output impedance. (that seems right, at least for me.)
 
 
Does that mean damping factor is more lower? (getting more bass roll-off or ?)
 
However, their solution seem to fix this issues. Why?
 
There must be an explanation, right?
 
Therefore, I ask your help  
 
 
again, thank for you reply.
 
 
Best,
 
Yazi

 
Hmmmm, I guess you must have an output coupling capacitor in your headphone amplifier?
If you do have a headphone amp with an output coupling capacitor then you may be getting some audible bass frequecy roll-off:  the output capacitor is acting as a high pass filter.
For example, That is one of the reasons why I CAN use my 600 headphones with my capacitor coupled OTL tube amp but CAN'T use my 62 ohm 'phones with my capacitor coupled OTL tube amp.
 
Can you be more specific?
What kind of headphones are you using?   I'm not too bright, I don't know what a D2 is!

And what kind of headphone amplifier are you using?
And which one of those resistor adaptors are you using?
 
thx,
Chris

 

[Yazi]

Quote:

 
Hmmmm, I guess you must have an output coupling capacitor in your headphone amplifier?
If you do have a headphone amp with an output coupling capacitor then you may be getting some audible bass frequecy roll-off:  the output capacitor is acting as a high pass filter.
For example, That is one of the reasons why I CAN use my 600 headphones with my capacitor coupled OTL tube amp but CAN'T use my 62 ohm 'phones with my capacitor coupled OTL tube amp.
 
Can you be more specific?
What kind of headphones are you using?   I'm not too bright, I don't know what a D2 is!

And what kind of headphone amplifier are you using?
And which one of those resistor adaptors are you using?
 
thx,
Chris

 
Hi Chris,
 
I don't have Cowon D2. I just see their post.
 
Here : http://www.anythingbutipod.com/forum/showthread.php?t=30962
 
In their post, add a impedence adapter end up with less bass rolled-off, and the background hiss disappears.
 
Moreover, UE try to fix the impedance mismatching with a impedance adapter.
 
See here: http://www.head-fi.org/t/544478/ultimate-ears-ue-x-pro-custom-appreciation-review-discussion-thread/45(post #54 )
 
I wonder what is happen, so I ask for ur help
 
 
Best,
 
Yazi

 

[Chris J]

Quote:

 
Hi Chris,
 
I don't have Cowon D2. I just see their post.
 
Here : http://www.anythingbutipod.com/forum/showthread.php?t=30962
 
In their post, add a impedence adapter end up with less bass rolled-off, and the background hiss disappears.
 
Moreover, UE try to fix the impedance mismatching with a impedance adapter.
 
See here: http://www.head-fi.org/t/544478/ultimate-ears-ue-x-pro-custom-appreciation-review-discussion-thread/45(post #54 )
 
I wonder what is happen, so I ask for ur help
 
 
Best,
 
Yazi

 
I will try to explain.
 
It would seem that:
The UE has a low impedance,  and the D2 probably has an output coupling capacitor
 
if the impedance of the UE is too low and the coupling capacitor in the D2 is too low (too small) then it is possible that the interaction will cause the low bass to roll off.
 
if you add the "impedance adaptor" then the load impedance increases so you get less bass roll off.
 
also if you add the impedance adaptor the sound level coming out of the D2 drops so the level of the hiss also drops.
The UE are very efficient so any hiss created by the D2 is easily heard thur the UEs
 
It all makes sense.
 
Not too sure if armature earphones like UEs really need to be driven by a low output impedance to sound their best.

 

[WiR3D]

nice writeup chris  
 
I should post that i put 2 4.7ohm resistors in parallel in the parallel section, was an even better end result. I dont think it will get much better now, but 4ohm output was definately not enough, 2.1ohm is much better.
was tricky as hell fitting 8 resistors into the neutrik female jack.

 

[Chris J]

nice writeup chris  

I should post that i put 2 4.7ohm resistors in parallel in the parallel section, was an even better end result. I dont think it will get much better now, but 4ohm output was definately not enough, 2.1ohm is much better.
was tricky as hell fitting 8 resistors into the neutrik female jack.

Thanks Mr. Wire!

BTW I'm glad the franken circuit is working out for you!

 

[WiR3D]

Quote:

Thanks Mr. Wire!
BTW I'm glad the franken circuit is working out for you!

the franken circuit was confined to the toolbox, for later experiments. its now in its final form.
I'm gonna upload pictures eventually lol.
 
this is gonna be funny, but it makes a bigger difference then changing opamps, and its the opposite with my AKGs.

 

[Yazi]

 
Hi Chris, 
 
 
Thank for your reply
 
I'm not sure I fellow through this thread completely.
 
You mean if I add the "impedance adaptor" then the load impedance increases?
 
According your previous posts, when I add a impedance adaptor then the output impedance increases, am I right?
 
The higher the output impedance, the larger variations in the frequency response, especially balanced armature.
 
I just want to know what will happen when I add a impedance adaptor to a playback device?
 
Will it increase load or output impedance?

 
 
In addition,
 
when I add the "impedance adaptor" form my UERM pack, I get a more tight bass.
 
However, when I add the "attenuator" form TF10s, I get a bit uncontrolled and more rumble bass.
 
 
 
Best,
 
Yazi

 

[WiR3D]

its because of the coupling capacitor
 
it changes things

 

[Yazi]

Thank for your reply
 
Could you explain more about the role of coupling capacitor in this circumstance?
 
I am just curious about how the coupling capacitor effect output impedance.
 
Many thanks
 
 
Best,
 
Yazi
 

 

[WiR3D]

reread Chris J's post I only just get it.

 

[Steve Eddy]

Quote:

Thank for your reply
 
Could you explain more about the role of coupling capacitor in this circumstance?
 
I am just curious about how the coupling capacitor effect output impedance.
 

 
Capacitive reactance.
 
Capacitive reactance, which is measured in ohms just as resistance is, is 1/(2piFC) where F is frequency in Hz and C is capacitance in Farads. As frequency goes down, reactance goes up. Reactance also goes up as capacitance gets smaller. Which is why, when you're driving relatively low impedance loads, you want a larger capacitance than if you were driving a higher impedance load as the output impedance forms a voltage divider with the load.
 
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