The Beyerdynamic DT48 Arrives...
Dec 27, 2014 at 2:45 AM Post #3,931 of 4,303
So, anyone know why a Beyer DT48 S would have a massively disorientating channel imbalance out of some sources while having perfect balance out of others? I suspect a grounding issue... but at the same time jostling the cable produces no alterations to the sound. I'm stumped.
 
Dec 27, 2014 at 6:15 AM Post #3,932 of 4,303
That is one beautiful DT48A you got there, one of the earliest made it seems. You are very lucky to get that for free.
Please keep it in good condition! They are a collector's dream.
 
 
  So, anyone know why a Beyer DT48 S would have a massively disorientating channel imbalance out of some sources while having perfect balance out of others? I suspect a grounding issue... but at the same time jostling the cable produces no alterations to the sound. I'm stumped.

Does the imbalance remain if you turn up the volume more? Maybe the volume imbalance is due to some amps having more juice and forcing you to turn the volume way down? Lots of amps have volume imbalance when the volume pot is turned down a lot.
 
Dec 27, 2014 at 11:20 AM Post #3,933 of 4,303
  Nice Xmas gift! If you ever move to Europe you must bring those babies with you. Would love to have a listen. By the way... how do they sound?
 
Huge Karma points to KBI 
wink.gif

Absolutely, KBI is the man!

Sound of these babies is pretty fun, compared to the E-25Ω they have a substantial roll-off up top, there seems to be a lot of missing information up top. The bass was an eye opener, compared to the E-25Ω these have more impact, they extend better, much better. The bass on these is great. Mid-Bass gets some impact, I noticed one peculiar characteristic in relation with compression pressure of the pads, at a certain point the Mid-Bass gets quite crazy, gains tons of impact. This is not apparent on the E-25Ω from 1989. Perhaps the tensile strength of the membrane of these very early DT48s was less than the later one's, I can't say. The Lower Mid-Range lacks the body. Slightly thinner than the Es.

In terms of the "Esoteric" differences as Dale would say, the Mid-Range is more resolving than the Es. Maybe more detailed, I don't know. DT48s are pretty detailed as is, can you really get more?
The excursion, if we go by the date 1939..a DT48A with 75 years of Burn-In hits much faster than my '89 E. For instance I'm sure the '89 E will never quit at 30Hz until it reaches max SPL and dies. 

Due to the very early headband, same as the 2nd Berlin. It was designed for the rubber pads so there is limitation to get a perfect seal due to modern Earpad obstruction. I'm not getting the best seal.

I would not put the DT48A up against the HE-60s I heard, the E is the worthy contender for that overpriced E-Stat Sennheiser.

Technical Experience with 5Ω 

I remember Dale mentioning that the DT48 doesn't really care about Under-Damping, my OTL at LG-3.5Ω Ouput Impedance at HG-10Ω. There was a lot of clipping at medium SPL.
So I plugged it into my SS, 10Ω OI. Gone was the clipping. The abnormalities were coming from nasty tubes. SS is the way to go. I will be getting a Beyerdynamic A20 - 100Ω OI to match the suggested Source Impedance standard.
 
Dec 27, 2014 at 11:38 AM Post #3,935 of 4,303
 
So, anyone know why a Beyer DT48 S would have a massively disorientating channel imbalance out of some sources while having perfect balance out of others? I suspect a grounding issue... but at the same time jostling the cable produces no alterations to the sound. I'm stumped.

Does the imbalance remain if you turn up the volume more? Maybe the volume imbalance is due to some amps having more juice and forcing you to turn the volume way down? Lots of amps have volume imbalance when the volume pot is turned down a lot.

Nope, tried that. The imbalance persists at all volume levels. It is not present with any other headphones, either.


 
Dec 27, 2014 at 2:20 PM Post #3,936 of 4,303
Nope, tried that. The imbalance persists at all volume levels. It is not present with any other headphones, either.


Measure resistance on both channels (tip/sleeve, ring/sleeve), they should be similar. Otherwise it can only be defects of membrane or coil, or more likely an out of centre voice coil not moving freely in the magnetic gap. This has been discussed earlier in this thread (a very sensitive adjustment).
 
Jan 1, 2015 at 4:18 AM Post #3,937 of 4,303



Just got my DT480 -200Ω. These are in immaculate condition. I was expecting them to be bruised and molested but they aren't.
The Glossy cups have no scratches which is awesome.

There wasn't much to restore. Put the Headband and Earpads in the washing, the WK100 was coiled so I wanted to restore it. I added a NP3X but there was a lot of distortion, the signal wires sounded like crap. So I'm using my DT150-100 WK100.


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



They came with the original box (Similar to the DT48 at the time) and paperwork from 1971. The seller had scanned a Audio Magazine from 1971. Here are some cool pictures 





The DT48 in Japan right in the 70s was 44000 Japanese Yen, the DT480 was cheaper at 32000 Japanese Yen.
Sonically. I find the Mid-Range energy of the DT48 and DT480 to be identical. The DT480 has some strong energy at 150Hz. The excursion on it is better than the Snr.40 A, it hits excursion at 40Hz at, I'm gonna say 82db, take that with a grain of salt. My DT48E to me sounds like it will never quit and keep running till it hits max SPL.

I was never a fan of the DT1XX ergonomics but the DT480 is different, it fits me perfectly, great seal. Comfort is excellent, I removed the baffle foam because it was nasty but with the foam it was surprisingly comfortable. Without the foam not so comfortable but..it doesn't bother me.
The mere 85 Euros I paid was a steal.
 
Jan 2, 2015 at 10:04 AM Post #3,938 of 4,303
So, what can you say about the DT480 driver? It appears to have some similarities to the DT48 unit...
 
Jan 2, 2015 at 10:06 AM Post #3,939 of 4,303
BTW, am I the only one who finds the new Master & Dynamic logo to be disturbingly similar to the old Beyer one?
 
Jan 2, 2015 at 10:49 AM Post #3,940 of 4,303
So, what can you say about the DT480 driver? It appears to have some similarities to the DT48 unit...

Assembly wise, I can't say. I haven't opened up the DT480 and probably will not. I had re-cabled a friend's DT100 some months ago and managed to rupture the contacts on the 6 Pin Socket, there was a very short connecting wire from the Voice Coil contact to the Socket and I managed to break it.

Sonically I find the DT480 similar to the DT48A that KBI sent me, they have a very similar response. The DT480 gaining more colouration in the mid-range and both having a super rolled-off treble. According to a Head-Fi'er the DT480 uses smaller sized diaphragms otherwise the overall Aluminium is the same as the DT48, just smaller.
I think the Mid-Range colourations from the DT480 could be eliminated if its put in a DT48 frame. A good analogy would be Apple, The Apple IIe....Woz Machine on a Apple PCB for the Mac. The colourations it gains are due to the DT100 housing. It also gains a lot of Mid-Bass impact. The SNr.40 DT48A extends better than either, the DT480 and the DT48E. Basically, Beyerdynamic played around with different options and gave birth to the DT480 which was for the people who couldn't afford the DT48.
 
Jan 12, 2015 at 3:35 PM Post #3,941 of 4,303
imbalance could be caused by some dried up sweat on the diaphragm, I usually turn the ear cup faced up and drop water til it covers the little holes, while playing some music thru them, vibrations thru the water acts similarly to an ultrasonic cleaner, I do both cups always. try 5 minutes on each side.

The S is substantially better than the A. Try stuffing the cups with sponge, that brings the sound closer to the ear canal, it should sound closer to the round foams.
 
Jan 13, 2015 at 1:03 AM Post #3,942 of 4,303
 
Measure resistance on both channels (tip/sleeve, ring/sleeve), they should be similar. Otherwise it can only be defects of membrane or coil, or more likely an out of centre voice coil not moving freely in the magnetic gap. This has been discussed earlier in this thread (a very sensitive adjustment).

But then why does it happen with some things and not others? 
 
Jan 19, 2015 at 3:20 PM Post #3,943 of 4,303
What do you guys think about creating an acoustic horn shaped waveguide which could be placed on DT 48´s grill? This wave guide would project sound more directionally to ear canal. This should make sound clearer. There´s this HE-500 wave guide mod http://www.head-fi.org/t/692494/hifiman-fuzzor-mod-driver-backwave-felt-damping-modification
One way to do this is to use 3d modeling software and then 3d print it from plastic. Other option would be creating it for from wood.I have access to Autodesk Inventor 2013 student version and i can try to model it with my skills gained from energy engineer studies.Here´s info about different horn shapes and their pros/cons: http://en.wikipedia.org/wiki/Horn_loudspeaker#cite_note-34
It seems to work well with HE-500,but DT 48 is completely different kind of beast.What do you think about this?
 
Jan 20, 2015 at 11:18 AM Post #3,944 of 4,303
imbalance could be caused by some dried up sweat on the diaphragm, I usually turn the ear cup faced up and drop water til it covers the little holes, while playing some music thru them, vibrations thru the water acts similarly to an ultrasonic cleaner, I do both cups always. try 5 minutes on each side.

The S is substantially better than the A. Try stuffing the cups with sponge, that brings the sound closer to the ear canal, it should sound closer to the round foams.

That's a noteworthy tip, Jeff.
Can you explain with a visual aid?
 
 
Jan 21, 2015 at 2:20 PM Post #3,945 of 4,303
imbalance could be caused by some dried up sweat on the diaphragm, I usually turn the ear cup faced up and drop water til it covers the little holes, while playing some music thru them, vibrations thru the water acts similarly to an ultrasonic cleaner, I do both cups always. try 5 minutes on each side.

Beyerdynamic clearly states that one must be sure NOT to drop fluids into the driver, so I would highly advice against this. Especially since the diaphragm suspension seems to be permeable to water.
The "sweat" production which the DT48 is known for, is not actually sweat. It is water vapor that condenses from your warm skin onto the relatively cold aluminium housing and diaphragm, which means it leaves ZERO residue, since it's pure water. Deliberately dropping water onto the diaphragms is likely to leave salt residues (not to mention oxidizing the contacts and voice coil), especially if one uses ordinary tap water.
 

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