[Chris J]

Quote:

 
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

 
Hello Yazi,
 
Short version:
 
I can't tell exactly what value resistors are actually in the impedance adaptors, but at the risk of starting World War III (LOL!), I can tell you that without a doubt you are increasing the output impedance of the amp.
Or to put it another way, you are increasing the load impedance.
In really simple terms, it works out to the same thing, as far as you are concerned.
Easiest way to verify this is to try the 'phones with and without an impedance adaptor.
If adding an impedance adaptor decreases the volume then you are undoubtledly increasing the Output Impedance by adding the impedance adaptor from the 'phones point of view.
But the amp also sees it as an increase in Load Impedance.
 
Sounds like the impedance adaptor form the UERM pack is the same or very similar to Wired's "Franken Circuit".  Sounds like this is the one to go with. Like Franken Circuit, the UERM adaptor has stuff in it to counter-effect the effects of high output impedance.  I assume this adaptor also reduces hiss and volume?
 
The impedance adaptor from TF10s is probably just a resistor in series with the 'phones. I assume this reduces hiss and decreases volume?
 
Confused yet?

 
BTW, I am an Electrical Engineer with approx. 25 years experience with Power Distribution, Power Conditioning, Power Conversion and Analog Signal Processsing.
For a reality check, I asked a few of the Electrical Power Distribution guys whom I work with if the adaptor increases the output impedance of the amp, they all said yes.
 
CJ
 
.

 

[manveru]

Quote:

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.

 
Any updates? Pics? 

 

[WiR3D]

Quote:

Any updates? Pics? 

Been using it exclusively. its amazing. A MUST HAVE with the Denons especially my newish D7000. Sorts out the bass, and reveals micro details. Pairs nicely with 2x TH4032 Opamps in the I/V section of the card. They could be oscillating but I don't give a damn. An this adapter eats so much power any DC offset is null and void.
 
Pictures will be boring ill post now now. Had to fit 8 resistors in, because I didn't want to wat for 2.21~ohm resistors. so i put two 4.7ohm resistors in parallel in the parallel section. was crazy. For future reference the MALE neutrik 1/4" jack has more space then the female 1/4"inch.

 

[WiR3D]

 

[manveru]

Quote:

 
Looks neat. Something like this would really come in handy for me, but the only way is to make one yourself right? I don't have any DIY knowledge/skills. -__-

 

[WiR3D]

Quote:

 
Looks neat. Something like this would really come in handy for me, but the only way is to make one yourself right? I don't have any DIY knowledge/skills. -__-

Don't worry DIY cables and adapters are much easier then you think. My father tought me how to solder.
This was only my third thing I made, and you never know, you may like it. 
 
The downside you need a fairly good multimeter, a solder, and all the bits.

 

[manveru]

Quote:

Don't worry DIY cables and adapters are much easier then you think. My father tought me how to solder.
This was only my third thing I made, and you never know, you may like it. 
 
The downside you need a fairly good multimeter, a solder, and all the bits.

 
I probably would like it. I won't have any money for tools/supplies for a while though. I should get into it eventually as I'm sure it would come in handy a lot.

 

[WiR3D]

Quote:

I probably would like it. I won't have any money for tools/supplies for a while though. I should get into it eventually as I'm sure it would come in handy a lot.

I think it is worth it, it really is fun, and nice to get your hands busy and actually build something physical.

 

[paaj]

Thanks for the list, I've been searching for these adapters to get the Q701 in line (designed for 120 ohm output I believe) and they are hard to find pre-made.

 

[Impulse]

Really interesting stuff, I'm surprised the thread hasn't garnered more posts... I have an STX too and I'm curious to try my hand at a similar adapter in order to improve it's performance with some of my other headphones. I bought the STX to use primarily with DT 880's 250 ohm but I'm getting the curious about some of the portable closed cans out there (most are pretty low impedance) and I'd like to be able to power them at home off the STX without bass getting out of control.

 

[WiR3D]

Quote:

Really interesting stuff, I'm surprised the thread hasn't garnered more posts... I have an STX too and I'm curious to try my hand at a similar adapter in order to improve it's performance with some of my other headphones. I bought the STX to use primarily with DT 880's 250 ohm but I'm getting the curious about some of the portable closed cans out there (most are pretty low impedance) and I'd like to be able to power them at home off the STX without bass getting out of control.

its a fair amount of effort getting the parts and putting it together.
 
reminds me I should update the first page, do some calculations first and notify others that if they want a bigger they must modify the serial resisters, not the parallel ones - or something like that.
 
You just want to minimize the power going down the negative rail. - at 100% on max gain and too much power on the negative rail it could fry your card. combined with other factors thats what I did.

 

[ertai]

Sometimes I run a particular setup like this: USB DAC lineout >> amp (with bass boost) >> headphone (32Ohm). I am satisfied with the sound I get but the lowest volume is still very loud and not really good for long term listening.
 
I did some research and figured an impedance adapter would help me.
 
My question is: will adding an impedance adapter change the sound signature?

 

[WiR3D]

Quote:

Sometimes I run a particular setup like this: USB DAC lineout >> amp (with bass boost) >> headphone (32Ohm). I am satisfied with the sound I get but the lowest volume is still very loud and not really good for long term listening.
 
I did some research and figured an impedance adapter would help me.
 
My question is: will adding an impedance adapter change the sound signature?

Depends on the headphone. 
 
With Denons yes, and for the worse. With Grado not really, it may change the sound but not for the worse. 
 
Its a trial and error. But it will drop the volume.
 
or you can build a faux impedance decreasing adapter, that will chow a lot of power, so that will also work without the side effects, its just more work.
 
EDIT: spelling

 

[ertai]

Thanks for the suggestion

 
For the purpose of solely reducing volume, do you think this item would be suitable?
http://www.ebay.com.my/itm/281009593372?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
 
I am using a different headphone than an Etymotic though

 

[paaj]

Sound may change, no way to tell other than trying (at $11 what's to lose?), but it'll definitely lower volume. Read the previous answer again, it still applies to your question. Except that you probably need to exchange fax with faux. It's mentioned in the topic start
 
I got one like those (well, the other one in the start post as I thought it looked nicer) at 120Ω and the volume really is significantly lower.