[shamu144]

Just fit the E vinyl pads to the A model and you are done. The A almost makes the E version sound blurred...
 
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The DT48-A is the audiometric version with the red and blue cups and rubber pads.  I haven't tried one, but I've seen reports of them being uncomfortable.  The DT48-E is the set designed for monitoring and has nice stuffed vinyl pads.  I think you'd be a lot happier with the E version, though those red and blue cups are awfully cool.

 

 

[kool bubba ice]

Nice.. But I hear the HE6 is a beast to drive, so my comparisons might not reflect the true nature of the headphone..
 
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Looking forward to reading your impressions... In a few days, I will also be able to compare my DT48A to an HD800 in my system. Should be very instructive.
 

 

 

[EYEdROP]

Can you fit A version pads on the E model? How does it sound? 
 
Quote:

Just fit the E vinyl pads to the A model and you are done. The A almost makes the E version sound blurred...
 


 

 

[shamu144]

Never had the curiosity to try it out. But why the hell would you do that ? Based on my experience with the A version, soundstage was much smaller and upfront (in your face). I didn't really noticed a shift in tonal balance but again, didn't spend lot's of time with those awfull rubber pads

 
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Can you fit A version pads on the E model? How does it sound? 
 

 

 

[FourierMakesFunk]

There has been a fair amount of talk about impedance and adaptors lately, so just so people who don't know don't get confused (mind you this isn't all there is, and it's simplified, but it should give you a working model):
 
Impedance is equivalent to resistance, only for AC rather than DC (as in, for things like headphones). Unlike resistance, impedance actually varies depending on the frequency of the oscillations of current. This means a 50hz sine wave can have a different impedance (resistance) to the current being pushed though it than a 10,000hz sine wave. Even though companies quote the impedance of their headphones, this is just for one frequency. If you graph the impedance over the frequency you can see some headphones (like Grados) have very little deviation, while others will vary greatly between 20hz and 20,000hz (these graphs can be seen at Headroom).
 
Things get more interesting because amps also have an impedance. With many modern solid state amps there will be next to no impedance, while others have a lot. It all depends on the design used and whether or not resistors are put into the signal chain, blah blah blah.
 
The impedance of your headphones and the amp interact, so the amp can alter those frequencies where the impedance of your headphones vary (changing the frequency response curve). However, since different amps have different impedances, some amps will bring out some frequencies while other amps won't, thus one of the many reasons why some headphones will sound good with an amp, while others won't, but sound amazing with another amp. These are all things amp designers and headphone designers factor in.
 
 
Adding a pair of resistors in an adaptor doesn't change the impedance the amp sees, just what the headphones see. So, if the amp wasn't designed for low or high impedance headphones, adding a resistor adaptor doesn't fix that, it only changes the impedance of the amp. 
 
BUT, for some more complicated reasons many modern amps have 20ohms or less of impedance across many frequencies. However, 120ohms has been declared by those who make standards as the standard source (amp) impedance that headphones should be designed for. Many designers ignore this, arguing that that was declared the standard since it's the halfway point between the average impedance of older and newer amps, but Beyerdynamic claim that their professional headphones are designed for this source impedance (including the DT48's, but this has been debated). Few amps offer 120ohm impedance, so, though what you hear may be great, it probably isn't at the impedance they have designed their 'phones for.
 
Adding resistors will add to the source impedance, so it will fix this!
 
This is why many people report their DT48's sound better after adding 120ohm or 100ohm impedance adaptors. This interacts with the impedance-frequency curve to change the frequency response (adds bass (what often happens with headphones), etc). Maybe you don't like the way that this changes the sound, maybe the intended design doesn't jive well with your headphones, but for some this can add that bit of extra sauce to get everything grooving together.
 
 
 
So hopefully this answers some people's questions and we can all bask in the glory of science! This also helps to explain some of the differences between the different impedance versions of headphones (which is another complicated issue for another day). If your are curious about your amp, look at the spec sheet or ask the designers of it. They should provide you with both the internal (source) impedance, and what impedance they are designed to drive. Then check out your headphones. DT48's claim to be designed for 120ohm source impedance, but other cans vary greatly.
 
Also, if you really want to know, resistors aren't optimal in theory to change impedance, you actually want to use transformers, but let's save that can of worms for another day. Resistors are fine for quick, dirty and cheap adaptors to up the impedance of your source and it's arguable that the differences are small.
 
 
As always, remember, this is just part of the picture. Science and engineering is good to figure out how to get a good sound in a design, but if it sounds good, it sounds good. Trust your ears! (Even for that "mother of tone" or "magic audio pebbles" stuff, but if you are a science guy like me, that stuff won't convince you. To each their own. I still wait for faith based audiophiles.)
 
 
P.S.    Sorry for the length!

 

[lejaz]

I should have my transformer based impedance adapter tomorrow. I'll report on the results...hopefully some better low end. The LD mkV was designed to work with headphones between 32ohms and 600ohms, I think, but that doesn't mean it will be 'ideal' for that whole range of impedances. My dt48 is outside of that range anyhow at 25ohms. The new Schiit Asgard amp was designed for low impedance headphones FWIR... would like to hear that one with the dt48.

 

[kool bubba ice]

I use a 120ohm adaptor with my 8ohm DT48 & it really sounds like I'm listening to the DT48 through a tube amp with my Yamaha reciever.. Without the adapter, total opposite of what tubes do to the sound of a headphone.. Sounded sterile, cold, a little thin in comparison...BUT, clarity & ambient detail improved.. Along with better & more distint instrument separation.
 
& Shamu.. You will be the first to compare the DT48A to the HD800.. Others used the e versions.. Curious to see how you feel the DT48a compares to the HD800 in tonal balance..Distortion.. Clarity..Detail.. Mid range.. & let me know if the HD800 speed feels artificial compared to the DT48. I heard that from two DT48 owners..

 

[FourierMakesFunk]

Sounds like the usual shift one can achieve with a better source impedance, in this case better lows and a more appropriate balance. If only people could stick to some kind of standard so there wouldn't be all this malarkey.
 
Quote:

I use a 120ohm adaptor with my 8ohm DT48 & it really sounds like I'm listening to the DT48 through a tube amp with my Yamaha reciever.. Without the adapter, total opposite of what tubes do to the sound of a headphone.. Sounded sterile, cold, a little thin in comparison...BUT, clarity & ambient detail improved.. Along with better & more distint instrument separation.

 
Do you know what transformers they put into the adapter? Brand and core material? Transformers can have a sizable effect the sound of a system (though not so much with impedance altering devices), to the point where some recording/master gear lets you switch between nickel, iron and steel core transformers.
 
Quote:

I should have my transformer based impedance adapter tomorrow. I'll report on the results...hopefully some better low end. The LD mkV was designed to work with headphones between 32ohms and 600ohms, I think, but that doesn't mean it will be 'ideal' for that whole range of impedances. My dt48 is outside of that range anyhow at 25ohms. The new Schiit Asgard amp was designed for low impedance headphones FWIR... would like to hear that one with the dt48.

 

[shamu144]

Thank for this extremely informative post. It starts to all make sense to me now. It would also explain why the LD mkIII had a sharply rolled off bass response with my DT48E / 25ohms, despite the use of the 100 ohms adapter. The impedance adapter didn't change what the amp was seeing, and the LD mkIII is simply not able to drive 25 ohms impedance cans, at least when it comes to bass response..
 
It could be interesting to list the available comercial amps that are trully 120 ohms and would work well with the DT48E. The Beyerdynamic A1 and DNA Sonett comes to mind, but unfortunately are rather expensive. BTW, the A version is not designed to work at 120 ohms, but anywhere between 4 and 1000 ohms.
 
Quote:

Adding a pair of resistors in an adaptor doesn't change the impedance the amp sees, just what the headphones see. So, if the amp wasn't designed for low or high impedance headphones, adding a resistor adaptor doesn't fix that, it only changes the impedance of the amp. 
 
BUT, for some more complicated reasons many modern amps have 20ohms or less of impedance across many frequencies. However, 120ohms has been declared by those who make standards as the standard source (amp) impedance that headphones should be designed for. Many designers ignore this, arguing that that was declared the standard since it's the halfway point between the average impedance of older and newer amps, but Beyerdynamic claim that their professional headphones are designed for this source impedance (including the DT48's, but this has been debated). Few amps offer 120ohm impedance, so, though what you hear may be great, it probably isn't at the impedance they have designed their 'phones for.
 
Adding resistors will add to the source impedance, so it will fix this!
 
This is why many people report their DT48's sound better after adding 120ohm or 100ohm impedance adaptors. This interacts with the impedance-frequency curve to change the frequency response (adds bass (what often happens with headphones), etc). Maybe you don't like the way that this changes the sound, maybe the intended design doesn't jive well with your headphones, but for some this can add that bit of extra sauce to get everything grooving together.

 

[lejaz]

X2
Apparently most SS amps have very low impedance outputs these days...maybe hybrids too. If many of the amps designed to work with low impedance headphones have a low impedance output, maybe they're not ideal for the dt48's. It seems to be a very complicated issue, unfortunately. The transformer based impedance adapter that my friend built will change the impedance the headphones see...plus the impedance the amp looks at according to him. Hope to have it tonight.

Quote:

Thank for this extremely informative post. It starts to all make sense to me now. It would also explain why the LD mkIII had a sharply rolled off bass response with my DT48E / 25ohms, despite the use of the 100 ohms adapter. The impedance adapter didn't change what the amp was seeing, and the LD mkIII is simply not able to drive 25 ohms impedance cans, at least when it comes to bass response..
 
It could be interesting to list the available comercial amps that are trully 120 ohms and would work well with the DT48E. The Beyerdynamic A1 and DNA Sonett comes to mind, but unfortunately are rather expensive. BTW, the A version is not designed to work at 120 ohms, but anywhere between 4 and 1000 ohms.
 

 

[FourierMakesFunk]

 
Transformers change the ratio between the impedance of the source and input, so they will each see things differently. Think of it this way: since transformers actually convert voltage into current or visa versa, you can up the current your amp is kicking out (low impedance headphones need more current) while the power remains the same (minus some loss due to flux leakage, blah blah blah) since power is voltage multiplied by current.
 
Quote:

X2
Apparently most SS amps have very low impedance outputs these days...maybe hybrids too. If many of the amps designed to work with low impedance headphones have a low impedance output, maybe they're not ideal for the dt48's. It seems to be a very complicated issue, unfortunately. The transformer based impedance adapter that my friend built will change the impedance the headphones see...plus the impedance the amp looks at according to him. Hope to have it tonight.

Quote:

 
Your very welcome, just trying to give out all the information I've been picking up.

That could explain it in part, but things get complicated since even when things are matched up to the technically best specs (getting the proper source impedance, input impedance, etc), this could do bad things to the sound. An amp sound be designed to sound good with headphones that aren't designed for it's source impedance. Many times amp designers listen with actual headphones and tweak things accordingly. For example: the sonic characteristics of an amp could be bad for your phone's sonic characteristics. If an amp is designed to make headphones that tend towards too much or too little bass sound more accurate, a pair of headphones that's already accurate will be thrown off. Or if the amp adds some harmonic distortion to a certain bandwidth, but your headphones do the same, things could get ugly.
 
Also due to variations in the impedance curves of headphones, some headphones won't respond well to impedance adapting. Grados for example have a very flat impedance to frequency curve, so they won't change much, but still need lots of current to be driven properly. HD800's have a huge bump in the bass impedance, so they will be effected a lot by the source impedance.
 

 
If your really interested in all this, read up on the "dampening factor".
 
Quote:

Thank for this extremely informative post. It starts to all make sense to me now. It would also explain why the LD mkIII had a sharply rolled off bass response with my DT48E / 25ohms, despite the use of the 100 ohms adapter. The impedance adapter didn't change what the amp was seeing, and the LD mkIII is simply not able to drive 25 ohms impedance cans, at least when it comes to bass response..
 
It could be interesting to list the available comercial amps that are trully 120 ohms and would work well with the DT48E. The Beyerdynamic A1 and DNA Sonett comes to mind, but unfortunately are rather expensive. BTW, the A version is not designed to work at 120 ohms, but anywhere between 4 and 1000 ohms.
 

 

[kool bubba ice]

Should get the HE6 today.. So you will get to comparison of high end headphones VS the lowly DT48.... DT48S NAGRA Vs the HE6 & the DT48A VS the HD800 (Shamu) Anyone placing bets

 

[EYEdROP]

I still belive the HD800 and HE6 will not match match the DT48 in terms of a truly unaltered sound, faithfulness, consistency. I can almost garuntee the HD800 and HE6 will have more bass impact, extention, musicality, soundstage, Mabey more detail, due to hyped up highs from the hd800. etc... The DT48 has a simple, no frills sound. Thats why they are so special.  
 
EDIT: I have never heard the hd800 or he6. 

 

[kool bubba ice]

You are probably right.. But who knows.. I just wish I have a power amp to really drive the HE6.

 

[joelpearce]

Okay, my new DT100 pads for the DT480 just arrived, and it's like wearing completely different headphones.  I think the gaps in the old pads were letting much of the air escape, and suddenly the bass is pretty flat down to 50hz.  This warms up the sound to neutral, and makes everything so much more musical.  In fact, I'm really liking what I'm hearing now.
 
I might have to pop them open yet again to unmod them a bit, to see what they are naturally capable of.  KBI, did the ones you listen to have old, flat, dried out pads?