[Paul Graham]

I have been fortunate to bag a pair of original HD400's recently really cheap and they're in mint condition.
 
I'm a bit of a noob to the more technical side of things so I need to know how to find out the impedance of my 400's.
Ive googled it but not having much joy lol.
 
All I know is compared to my HD25's, HD215's and so on I find these really quiet. However if I drive them too far with say my CMoy they start to clip on bass hits etc.
 
does this mean they're high impedance? Or Low/High sensitivity???
 
I'm kinda struggling on this side of things so please help if you can.
 
These babies..
 

 

[Paul Graham]

Anyone???

 

[roBernd]

Get a multimeter and measure the resistance... or google a tad longer on the plug (ground and any side) 馬鹿
Bonus: they are probably 1000 or 2000 plus low efficiency

 

[Paul Graham]

Thanks for the reply.
 
Unfortunately they're pretty rare so Not having any joy with google.
 
Also, Google the plug???
 
And - 1000 or 2000 low efficiency? Now Im even more confused lol!

 

[roBernd]

Quote:

Thanks for the reply.
 
Unfortunately they're pretty rare so Not having any joy with google.
 
Also, Google the plug???
 
And - 1000 or 2000 low efficiency? Now Im even more confused lol!

sorry, bout that. let me rephrase what I typed from my phone.
 
They are probably 1000ohms or 2000ohms. what I said about efficiency is crap.
I tend to believe that they fall in line with the famous HD414 and are probably 2000ohms.
 
probably close to this (HD414)
Impedance: 2000 ohms
Sensitivity: 102dB/mW (1.41V)
http://wiki.faust3d.com/wiki/index.php?title=Sennheiser_HD414
 
OR the respective 600 ohms version (link)
 
EDIT:
look what I found on the German Sennheiser-Page
http://94.100.244.130/sennheiser/old_manual.nsf/resources/HD_400_oNr_ohneDatum_Sp3.pdf/$File/HD_400_oNr_ohneDatum_Sp3.pdf
 
rated 300ohms per side

 

[Paul Graham]

You sir, Are a legend! Many thanks.
 
So Im guessing these are 600 ohms???
 
My Headbox II only puts out 300.
 
Think I need to look at a headphone amplifier more suited to these cans. 
Thanks for the help fella!!

 

[viveksaikia22]

There is one in Craiglist, going real cheap for $20.
As per the ad, the specs are as follows:
 
Transducer principle: dynamic
Frequency response: 20 - 18000 Hz
Nominal Impedance: 600 Ω
Sensitivity at 1kHz: per driver 94 dB
Power handling capacity (max. continuous power): 0.1 W
Distortion: < 1.2 %
Coupling to the ears: supraaural (exchangeable foam ear pads, open, on the ears)
Headband pressure: 2.5 N
Weight: approx. 80 g (without cable)
Cable: 3 m long steel cable with 1/4" phone connector
 
OP, how does the sound signature compares with that of the modern day headphones?

 

[Paul Graham]

Quote:

There is one in Craiglist, going real cheap for $20.
As per the ad, the specs are as follows:
 
Transducer principle: dynamic
Frequency response: 20 - 18000 Hz
Nominal Impedance: 600 Ω
Sensitivity at 1kHz: per driver 94 dB
Power handling capacity (max. continuous power): 0.1 W
Distortion: < 1.2 %
Coupling to the ears: supraaural (exchangeable foam ear pads, open, on the ears)
Headband pressure: 2.5 N
Weight: approx. 80 g (without cable)
Cable: 3 m long steel cable with 1/4" phone connector
 
OP, how does the sound signature compares with that of the modern day headphones?

 
Sorry for the late reply to your query...
 
To my ears they are very neutral and transparent.
Bass is on the light side but still defined enough and crisp to the point that bass lines don't slip through 
the soundstage.
Highs are crisp and very detailed, Maybe a tad 'Flat' to me - Difficult for me to explain.
Mids are not invasive or overbearing, But a gentle & clean presence.
 
All in all I would say if driven correctly they can and will sound utterly beautiful to the right set of ears.
I use them with Classical, Jazz & Blue Grass and find them best suited to those genres. 
 
They dont like anything modern with too much bass, But then that could be their age showing?!
 
At present Im driving them with my Fiio E17 as the +12db gain allows me to drive them a lot better than any of my other amps ( portable & home )
Once I sort out an amp with the correct specs, I can imagine they will sound far better again
 
If I was to compare them to anything in my collection, I would have to say they were very close to the Grado SR60's but with less low end punch.
 
Hope that helps?!
 
Paul

 

[David Corzo]

Those headphones were not meant for the way contemporary music is recorded nowadays. So be smart and don't break them. If you don't like them Ill buy them from you. Enjoy

 

[Paul Graham]

I'm about to start refurbishing these very soon.
I have a few amps that will drive them with no issues.

I also have learnt a lot since I made this post so I will be extremely careful in how I drive them and what music I listen to with them.
Currently I'm on the look out for a replacement cable that is either exactly the same or as close as damn it.
The drivers look intact and undisturbed. ( Had them safely stored away )

Watch this space as they say