dalethorn

No idea how they do it, but supposedly all impedances have to meet the DIN standard and I assume that means they have to sound the same. I have a feeling the drivers do all sound the same at least from 1974 on, but I think people way underestimate the influence of the earpads. The new oval earpads reduce the efficiency of the DT48 by many decibels compared to the original oval pads. You can hear the enormous difference by trying the round pads first then switch to the oval pads. The volume drops a lot!

FiiO E17, Headstreamer, Audioengine D1, Dragonfly.

Very good question. The magnets and voice coils would be the same.

I had this model headphone, bought new at the same time as two other DT-48's, so I had 3 total, one silver 8 ohms, one black 25 ohms, one black 200 ohms. All sounded the same when the same earpads were used. But it's also possible that long before 1974 when I got mine (and the 1974's are the same as today's, 38 years later), back in the 1960's, that some of the DT-48's were not tuned for audiometry. Back then they may actually have made different drivers for different purposes. From 1974 onward they have not.

If NwAvGuy designs a DAC plus headphone amp in the box like the O2 amp I have, then it is desktop-only, not really portable. If it sounds better than the Headstreamer or Audioengine D1 or Dragonfly then that could be a good selling point. If it's not obviously better, then those other DACs plus headphone amps would be much more convenient to carry around or even to use at home, and maybe cheaper too unless you build the O2 plus ODAC yourself.

It has analog out which has 2 modes: Fixed volume for amps and variable volume for headphones. Edit: The sudden appearance of several low-cost DAC and headphone amps tells me someone produced a new set of chips.

It's just the difference in the pads. He probably changed something, but even then they change anyway.

The Youtube video also has a summary of the 4 other DAC options I've reviewed: http://youtu.be/NSVu-ZeBH-A When I connected the AudioQuest DragonFly to my computers I was pleasantly surprised that it interfaced perfectly with no configuration effort. Since the DragonFly is exactly like a typical USB thumb drive, excepting the 3.5 mm jack on the end where headphones and other output devices are connected, the only cable issues occur when you connect something other than a headphone such as powered speakers or a power amp to drive non-powered speakers. In such a case I would recommend a very high quality cable to maintain the full benefit of the DragonFly's sound processing properties. There is no physical volume control on the DragonFly, no doubt because it's just a small USB device the same size as a typical USB thumb drive. Since you'll need the computer's volume controls with the DragonFly, how they work on the different computers can be a minor challenge. On PC's using Foobar2000, I keep the Foobar volume slider all the way up and open the computer's volume window after Foobar is loaded. I suppose you could set the computer volume to maximum and then use the Foobar slider, but in my case the Foobar volume slider is so small I use the computer slider instead and that works fine. There may be cases where one method is better than the other sonically, but I didn't find that to be significant in my case. On the Apple Mac I use iTunes only with WAV-format files, and there I set the computer volume to maximum and used iTunes' volume slider instead. One thing I really like about the DragonFly besides the convenience of having a DAC and headphone amp in one little plug-in device is the fact that it doesn't get very warm in use. My air conditioner died about 36 hours ago and I've been running a laptop PC with the DragonFly in an indoor temperature ranging from 86 to 89 degrees F. While the DragonFly feels slightly warm after playing music for a couple of hours, it's surprisingly cool given the ambient temperature plus the fact that all of those electronics and the LED status light are contained in such a small package. The body is 1.75 inches long less the metal USB connector, the width is nearly 0.75 inches, and the height approximately 0.5 inches including the small hump on top which accomodates the 3.5 mm headphone jack. Fortunately the DragonFly includes a good secure cap for the USB connector, but I don't see a way to attach a lanyard to it. For those people who have been using the headphone jack on their desktop or laptop computers, and assuming that those computers have USB ports, they should expect better sound using the DragonFly instead of the computer's headphone jack. The actual improvement with my computers is a cleaner sound with a greater sense of "space" and "air" around the instruments. The fact that the DragonFly includes both a DAC and headphone amp in such a tiny package suggests to most audiophiles that the DragonFly's sound would be of much less quality than the typical separate DAC's and headphone amps selling for twice as much or more. I don't own the more expensive separates myself, but I have other DAC-plus-headphone-amp devices such as the HRT Headstreamer and Audioengine D1, and I have the HRT iStreamer DAC-only for Apple i-devices that I use with the Objective2 headphone amp. I don't hear anything to suggest that the DragonFly is less than a good upgrade to the computer's headphone output in spite of the very small size. Doing lengthy comparisons yesterday and today with the DragonFly and my other DAC-plus-headphone-amps, playing a variety of 96 khz music tracks downloaded from the HDTracks and DownloadsNow sites, I don't hear a significant difference between them. I did expect to hear some differences in the ultra-high-frequency harmonics and so on, but in spite of the amazing detail in these tracks and the resolution of the USB DAC/amp devices, there's so little difference that I could easily guess wrong about which is better than the other. I could tell rather easily that these 3 DAC/amps were better than the iStreamer plus Objective2 headphone amp (and I think the limiting factor there is the iStreamer) and better also than the FiiO E17 DAC/amp which has additional features. I'm going to take a guess here that since the DragonFly costs about $80 USD more than the Audioengine D1 and $110 more than the Headstreamer, and given the very small differences in sound (for the intended users at least), I expect people will buy the DragonFly because of the small size and convenience of not having to use a USB cable, or possibly other reasons. If such a small USB DAC were used with audio systems driving speakers, then one extra little cable would probably not make any difference, especially since the cable carries only digital data and the signal processing and jitter reduction occur after the cable in the DAC. But used with headphones, plugging the DragonFly directly into the USB port without a cable is a great convenience, especially when a laptop computer is being used away from the home desk/workstation. An important issue to consider when purchasing audio components to improve sound quality is detail, i.e. how much additional detail will be revealed in the music tracks by the new components. It's possible that a new audio component could reveal existing distortions in the recording in a way that makes them less pleasant to listen to, and some buyers may experience that dreaded feeling of "Uh-oh, I need to buy more stuff", or "Crap - this isn't working out the way I expected". I didn't have that issue with the DragonFly though - the sound was more revealing but less harsh, which is interesting since I would normally expect more harshness and sibilance with the greater detail. I suppose it's the natural result of having better components to process the data in those digital music tracks. Questions have come up in several places as to whether a typical computer's USB port can supply enough power to run the DragonFly's DAC and headphone amp, to provide good volume especially in the bass where the greatest power demands occur, and to have enough headroom to avoid clipping or otherwise distorting the loudest most dynamic music passages. The answer seems to be yes, since I have many FLAC format music tracks with a 96 khz data rate that have extreme dynamics which distort noticeably when sufficient power is not available. Some of those tracks that I've made 320k MP3 copies of for playing on the iPhone will not play on the iPhone at the full volume I prefer because of the extreme dynamics, however those same MP3's will play without clipping on the computer using the DragonFly DAC and headphone amp. Headphones tested with include the Shure 1840, Philips L1, ATH M50, and B&W P3/P5.

As a DAC plus headphone amp from the computer compared to headphone amp only from a ipod/iphone LOD, there's little or no difference I can detect. The DAC should be better, but it's already very good so the only way I think you could do better is a very pricy DAC and amp. The Audioengine D1 or Headstreamer or Dragonfly or the rPAC might be better, but those last two are $250 USD and I haven't tried them, so I don't know yet, until tomorrow anyway. I think the first two are slightly better, but I would need more testing to be sure. Still, the E17 offers better features and portability and sound quality than anything else so comparing the E17 to desktop DACs, even low priced desktop DACs, might not be appropriate. If I could only have one it would be the E17 - easy decision.

I don't hear the harshness with the E17 that I get with the Audioengine D1 or the Headstreamer. And yet the E17 does not lack detail. It just sounds a little better, although the bigger soundstage of the other two may just be artifacts of boosted highs.

I'm thinking the FiiO E17 would be a great match for the DT48, A or E.

Not clear at all. In the first link they mention 1937 and also the DIN standard, but do not say when that standard was applied to the DT48. I'm certain that the 1937 model is very different from the 1974 model. Then in the second link, the 45620 standard is applied to the DT48E, not the DT48A.

So apparently we have some driver differences. Then it's my guess the biggest driver differences were before 1974, probably in the 1960's? I don't know about changes since 1974 to now, but I'm going to guess there was very little change, or none. It's good to remember these were not designed as audiometric headphones originally, so maybe someone could find out when the DIN standard was applied the first time to the DT48, to make them (or the one version) official as audiometric.

You didn't clarify about earpads like I did, also didn't mention using the same earpads and integrated amps etc. to minimize impedance differences. Mine all sounded identical, and I bought them new directly from Beyer corp in New York.

In 1974 I bought a DT48 25 ohm, then a DT48s 8 ohm, then a DT48 200 ohm. When I put some oval pads on the DT48s (silver, 8 ohms) they all sounded the same. Actually they sounded the same from a receiver and integrated amp, but from a preamp only (similar to headphone amp) the DT48s sounded different because of the low impedance.

http://www.audioquest.com/usb_digital_anal...r/dragonfly-dac

I might get a combo ODAC plus O2 someday, but in the meantime I now have iStreamer, Headstreamer, Audioengine D1, FiiO E17, and Dragonfly. So all of these are good for improved detail and less distortion. I think the E17 would probably do good with the DT48.

Last listen was with O2 amp connected by LOD from iphone. I didn't have the DACs yet so that would be interesting to hear.

I hear a kind of perfection with the DT48 that has similarity in speakers in the very expensive horn types and possibly planars and electrostatics. The distortions under normal listening conditions are an order of magnitude less than conventional dynamics. The fully-machined driver system with the specially encased magnet assembly is unique, giving great control over the membrane that is approached only by the Tesla drivers in the dynamic designs.

The original 650 was very similar to the 600, just a little less veiled. Then they apparently re-tuned the 650, so I wouldn't expect it to be as good as the 600. Of course there's no comparison to the DT48, where you have the ultimate driver right next to your ear with no filtering.

The cable Beyer put on my DT48a is cheap - really cheap. A good cable would be better, but you have to be extremely careful with those drivers - they really are special.

The pics show up good on iphone.

I don't hear anything negative in the E17 - it sounds smooth as can be. Very nice sound. I imagine the really good tubes sound like that.

Don't let all that propaganda about audiometry fool you - the DT48 was designed for spy work. The audiometry thing was a ruse at the end of the war to keep the allies from seizing them.

I did a long compare last night to the O2 and E17, both running from iphone connected through the LOD. The O2 is slightly better, so no worries. Just the E17 is more portable. (Plus it's very cute)