50 vs 120 ohm HD-595
Feb 23, 2005 at 8:17 PM Thread Starter Post #1 of 12

dsrjohn

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Hi All

Does anyone know what the differences are between the 50 and 120 ohm versions of the HD-595? Is one better than the other? Is one easier to drive vs the other? I didn't think Sennheiser's audiophile line of cans came in anything lower than 120 ohms. I can't find any info on the web on the 50 ohm versions and only noticed recently that they came in a 50 ohm vesion.

Please let me know.

thank you

john
 
Feb 23, 2005 at 8:35 PM Post #2 of 12

rligeti

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50 ohm should be easier to drive and I'm guessing that's why senn created them, to be used with sources that dont have alot of juice, like portables, ipods, etc. If i can get a hold of some, my primary device will be my laptop....
 
Feb 23, 2005 at 8:58 PM Post #3 of 12

fr4c

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the 50 ohm version are just easier to drive than the old ones. this way you can use the HD595 efficiently without a dedicated amp in some cases. try to get the 50 ohm version if you can.
 
Feb 23, 2005 at 9:06 PM Post #5 of 12

rligeti

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harkens back to the grado vs senn debate.I guess this is how they might get some grado converts....
 
Feb 23, 2005 at 10:06 PM Post #6 of 12

quackattack

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Is there a disadvantage to the 50 ohm? Seems like they had to give up something to make them easier to drive...
 
Feb 24, 2005 at 9:03 AM Post #7 of 12

Andrea

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Quote:

Originally Posted by quackattack
Is there a disadvantage to the 50 ohm? Seems like they had to give up something to make them easier to drive...


Absolutely not, as far as I'm concerned.

Technically, (mine is a simplistic interpretation but after all realistic, I believe) lowering the impedance will 'automatically' highten the sensitivity. And a lower impedance driver coil isn't by itself neither better nor worse performing than a higher impedance one.
Or will it be lighter, so likely to make the driver 'faster' ?? I think it's possible, but it's an aspect completely under the designer's control.

So if the folks of Sennheiser haven't messed up things, the two versions are just about the same at sound quality (within some inevitable 'tolerances').

I, for myself, can tell that the HD595 with 50 ohm imp. is neither aggressive nor more forward than expected (not really
smily_headphones1.gif
), nor lacking smoothness in any way. I just love it 'as is', but then I haven't made direct comparisons like Sysiphos did.

Then again, in his case it's likely to have been the simple result of different burn-in amounts (& -- two Senn. cans with both little playing time on them -- neither had its sound really 'settled down' yet
smily_headphones1.gif
).
 
Feb 24, 2005 at 11:36 AM Post #8 of 12

breez

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Might be able to do a comparison of HD555 120ohm vs. 50ohm if my friend decides to buy the phone and gets a 50ohm model. If he gets the 120ohm model I'll do a blind test of my burned-in pair (~1500-2000 hrs) vs. the brand new.
 
Feb 24, 2005 at 5:58 PM Post #9 of 12

Nak Man

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This time the 'easier to drive' part are more clear than previous 590 vs 650 unamped issue. Using the same headphone calculator =) ... 120 ohms actually have quite low sensitivity = 94.8dB/mW, while the newer 50 ohms version sport a whopping 99dB/mW to achieve 114dB/1V.

And to get 90dB:
- 120 require 1.67mA at 200mV (=0.33mW), while
- 50 require 1.58mA at much lower signal 79.1mV (=0.13mW) !
eek.gif


I'm also curious whether there's some kind of tradeoff that came with this higher sensitivity. Anyway I wonder why the 120 ohms seem to be easier to drive than 650 (needs less 'volume'
biggrin.gif
).
Quote:

In order to produce 90dB with different impedances:
- 590 require 1.27mA at 153mV (=0.20mW)
- 650 require 0.74mA at 223mV (=0.17mW)


Now that's weird.

confused.gif
 
Feb 24, 2005 at 6:36 PM Post #10 of 12

Andrea

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Nak Man, on the box of my 595 the stated sensitivity is 112 dB (not 114).

Anyhow, in my case (with my amp) it's the 650 to be virtually more sensitive (needs lesser volume level).
eek.gif
 
Feb 24, 2005 at 7:20 PM Post #11 of 12

Helter Skelter

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Wanna see something really weird, Nak Man?

Plug in the numbers for the Grado SR60 and the Sennheiser HD595 (120 Ohm version) and compare the results.

Here's the specs for each, pulled from their respective boxes.

HD595:
120 Ohm
104 SPL

SR60:
32 Ohm
98 SPL

And just for fun, the AKG K271 Studio:
55 Ohm
91 SPL

The HD595 and the SR60 are actually quite close together in terms of power needed to get to a similar volume. 72mV for 90dB with the SR60, and 65mv for the HD595 to reach the same level. This seems to suggest to me that the HD595s are actually slightly EASIER to drive than the much-vaunted Grados, though it's a very close race. In contrast to all this, the K271 needs a whopping 210mV to reach 90dB. This all seems to line up with the findings of my own ears, but of course numbers don't mean everything.

EDIT: Wait a sec, my numbers are off, give me a moment. Or maybe I just don't understand quite how to work that calculator. Ah, bugger it.
 
Feb 24, 2005 at 7:42 PM Post #12 of 12

Nak Man

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Quote:

Originally Posted by Helter Skelter
HD595:
120 Ohm
104 SPL

EDIT: Wait a sec



Sorry, gotta go catch some sleep here ...
wink.gif


Btw 595's 104SPL is for 1V (not mW) so we gotta work the dB/mW unit using 1000mV as signal and do trials on dB/mW sensitivity box, right ? And what's on this Grado box, dB/mV ?? Oh well ...

Andrea, 114dB/1V taken from senn's site. I know, not accurate. =)
 

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