How do Koss ESP/9 electrostatics stack up?

tmblack · 7th December 2010, 03:54 PM

Looking at vintage electrostatics headphones like the Koss ESP/6 and 9 and Marantz.
They resemble electrostatic speakers in the use of step up audio transformers.
They are bulky and probably need servicing.

How do they sound compared to modern headphones?
Like AKG 240s, Sennheiser HD600, or whichever ..... headphones?

jcx · 7th December 2010, 05:02 PM

the ESP950 is current production and comes with a ss amp - the amp is despised on Head-Fi but that could be the cheap plastic box and tiny split knob volume pot - I wonder how "audiophiles" would rate it in a 20 lb Al box with a 2"+ knob?

quality step-up xfmr is surprisingly hard for headphones - the ridiculously low power requirement doesn't save much core material when you need huge Lm to support 500+ Vrms at 20 Hz

tmblack · 8th December 2010, 04:01 PM

The ESP/9 have fairly good xfmrs, the leakage inductance of the transformer might be a concern, many modern headphones roll off the low end below 100Hz but not these ones.
How do the ESP950 compare with previous models?

jcx · 06:10 PM

the 950 are the only es I've owned

you can get your fill (or more) of subjective opinion at Head-Fi.org - Headphone forums and reviews for audiophiles

I believe the ESP/950 headphone is considered competitive with Stax (higher end Lambdas?) when driven from a "better" amp

chinsettawong · 10th December 2010, 01:03 AM

I only have a chance to compare ESP/9 with my DIY electrostatic headphones. Even though ESP/9 sounds pretty nice, I feel that my DIY headphones with open back sound more natural. The bass response on ESP/9 isn't as good either.

However, if you can get them cheaply, they are not bad at all.

Wachara C.

imfree707 · 10th December 2010, 02:05 AM

Quote:

Originally Posted by tmblack

Looking at vintage electrostatics headphones like the Koss ESP/6 and 9 and Marantz.
They resemble electrostatic speakers in the use of step up audio transformers.
They are bulky and probably need servicing.

How do they sound compared to modern headphones?
Like AKG 240s, Sennheiser HD600, or whichever ..... headphones?

I only posted this to make a bad pun and it may/may not be true. They don't stack up to Stax. This pair, $2200

banjo4ever · 23rd December 2010, 03:16 PM

I have had a chance to recently audition Koss in Singapore. I would compare them to My AKG 702. I found the mid to a bit harsh, the soundstage and space was good. The bass was thin. Good for vocals.
The build quality was not good. Koss offers a life time warranty on the product. I was also not inspired by the looks.

tmblack · 29th December 2010, 05:48 PM

Is there a source for the 5 pin connector?
Looks the same as the STAX connector.

tmblack · 30th December 2010, 08:52 PM

I found the Koss ESP/9 to be smooth sounding, rolled off compared to modern dynamics.
There shouldn't be any harshness, perhaps the capacitors need to be changed from ceramics to polypropylene in the audio path.
I would like to try them with a tube headphone amp but that would require DIY or modification.

speaker dave · 7th January 2011, 10:31 AM

I had ESP/9 and found them neutral and wide range, probably better fidelity than my Stax SR3. But the weight and the pressure was way over the top.

I still have the SR3 but traded the ESP/9s away.

David S.

7th December 2010, 03:54 PM	#1
tmblack diyAudio Member Join Date: Jan 2005 Location: UK	How do Koss ESP/9 electrostatics stack up? Looking at vintage electrostatics headphones like the Koss ESP/6 and 9 and Marantz. They resemble electrostatic speakers in the use of step up audio transformers. They are bulky and probably need servicing. How do they sound compared to modern headphones? Like AKG 240s, Sennheiser HD600, or whichever ..... headphones?

8th December 2010, 05:56 PM	#4
jcx diyAudio Member Join Date: Feb 2003 Location: ..	the 950 are the only es I've owned you can get your fill (or more) of subjective opinion at Head-Fi.org - Headphone forums and reviews for audiophiles I believe the ESP/950 headphone is considered competitive with Stax (higher end Lambdas?) when driven from a "better" amp Last edited by jcx; 8th December 2010 at 06:10 PM.

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7th December 2010, 05:02 PM	#2
jcx diyAudio Member Join Date: Feb 2003 Location: ..	the ESP950 is current production and comes with a ss amp - the amp is despised on Head-Fi but that could be the cheap plastic box and tiny split knob volume pot - I wonder how "audiophiles" would rate it in a 20 lb Al box with a 2"+ knob? quality step-up xfmr is surprisingly hard for headphones - the ridiculously low power requirement doesn't save much core material when you need huge Lm to support 500+ Vrms at 20 Hz

8th December 2010, 04:01 PM	#3
tmblack diyAudio Member Join Date: Jan 2005 Location: UK	The ESP/9 have fairly good xfmrs, the leakage inductance of the transformer might be a concern, many modern headphones roll off the low end below 100Hz but not these ones. How do the ESP950 compare with previous models?

10th December 2010, 01:03 AM	#5
chinsettawong diyAudio Member Join Date: Jun 2006	I only have a chance to compare ESP/9 with my DIY electrostatic headphones. Even though ESP/9 sounds pretty nice, I feel that my DIY headphones with open back sound more natural. The bass response on ESP/9 isn't as good either. However, if you can get them cheaply, they are not bad at all. Wachara C.

23rd December 2010, 03:16 PM	#7
banjo4ever diyAudio Member Join Date: Jan 2010 Location: Mumbai, India	I have had a chance to recently audition Koss in Singapore. I would compare them to My AKG 702. I found the mid to a bit harsh, the soundstage and space was good. The bass was thin. Good for vocals. The build quality was not good. Koss offers a life time warranty on the product. I was also not inspired by the looks.

29th December 2010, 05:48 PM	#8
tmblack diyAudio Member Join Date: Jan 2005 Location: UK	Is there a source for the 5 pin connector? Looks the same as the STAX connector.

30th December 2010, 08:52 PM	#9
tmblack diyAudio Member Join Date: Jan 2005 Location: UK	I found the Koss ESP/9 to be smooth sounding, rolled off compared to modern dynamics. There shouldn't be any harshness, perhaps the capacitors need to be changed from ceramics to polypropylene in the audio path. I would like to try them with a tube headphone amp but that would require DIY or modification.

7th January 2011, 10:31 AM	#10
speaker dave diyAudio Member Join Date: Nov 2009 Location: Toronto	I had ESP/9 and found them neutral and wide range, probably better fidelity than my Stax SR3. But the weight and the pressure was way over the top. I still have the SR3 but traded the ESP/9s away. David S.