[Mahay]

  What aftermarket pads are you using?  Thanks for the post very great idea.

Nothing special, just from Koss. But I am thinking about replacing them with ESP950's pads, only $5 from koss. I think it is worth to try.

 

[HiFiGuy528]

There's a NOS with box on the web.  Not sure if I should get it.  I'll most likely run it with Woo Audio GES amp.

 

[DaveK1977]

Does anyone here know the pinout for the Koss E-9 that drives ESP-9 cans?  I'm working on DIY electrostatics, and I can use the E-9 for testing until I get them working well enough to go for something nicer.  Though it's a plug identical to Stax, it's not pin compatible, and people talk about rewiring them to use a Stax amp, but never tell what the original pinout was.  I've even found schematics online, but I've not found the plug pinout.

 

[steklo]

Hello,

I was offered a unit of the Koss ESP-9 with energizer E-9 from first owner, probably bought in 1970 or 1971 (so an early unit). How would you value this headphone sonically today? Can it still keep up? Or is it better to go for a more recent headphone like Sennheiser HD600/650/660S, Beyerdynamic DT1990Pro or some Grado?

Best regards
Stefan

P.S. The Koss would have to be connected to an Audio Note P1SE valve amp outputting 10W/channel max.

 

[timb5881]

Hello,

I was offered a unit of the Koss ESP-9 with energizer E-9 from first owner, probably bought in 1970 or 1971 (so an early unit). How would you value this headphone sonically today? Can it still keep up? Or is it better to go for a more recent headphone like Sennheiser HD600/650/660S, Beyerdynamic DT1990Pro or some Grado?

Best regards
Stefan

P.S. The Koss would have to be connected to an Audio Note P1SE valve amp outputting 10W/channel max.

Sonically, the ESP9 are a very good headphones, but remember then are closed back. With that in mind, I think they are still competitive with mid to lower priced audiophile headphones. I just put on my ESP9B headphones to give you a current perspective. Your amp should be enough, as I am told 5 watts can be loud. Currently mine are hooked up to a 200w/channel. I paid about $120 for mine, but it is the 9b not a 9. Remember the pads suck, and plan on getting a new set. The headphones are a bit heavy, but nothing compared to Koss’s first electrostatic, the ESP6. Those had the transformers in the earcups and also had a vice like grip.
And, the bonus is that they are sealed, and other than the Stax and Shure iem’s, no full size estats are.

 

[steklo]

Thank you timb5881!

You mean my 10Watts amp might turn out to be somewhat weak to drive the Koss? Why would you say it's a bonus they are sealed? I've often heard people saying that open phones sound "more open"?

For my mobile I have an iGrado which I find surprisingly good. I haven't dealt much with headphones until now, though. Would you say the Koss would be an upgrade over the iGrado? Your signature displays amongst others different Stax as well as Sennheiser HD6xx – how would the Koss compare to those (in terms of soundquality)?

Best regards
Stefan

 

[timb5881]

With electrostatic headphones, sealed ones are rare. Sealed headphones do collapse the soundstage, but they tend to have deeper bass. Also sealed headphones reduce external noises and others can’t hear what you are listening to.
The Koss is faster and more detailed than my HD6xx, but the HD6xx is a more forgiving to bad recordings. You hear more of the mistakes or poor choices used in a recording.
Upgrade, maybe, but that boils down to what you like. I consider the Koss a decent headphones with a non fatiguing presentation. Nice bass and very detailed high frequencies. If you can get them in working condition for $100 then they are a great deal.

 

[steklo]

Hi and thanks again – obviously the earpads would have to be changed after so many years. I asked Koss but they do not offer replacement pads anymore. Do you have a suggestion where to get repalcement earpads for the Koss?

I do and I probably will keep on doing my main listening through my speaker-system. Introducing the Koss with its Energizer would mean I would have to put the latter between my power amp andd my speakers – any experience in how far this has negative impact on the performace of the speakers? Usually anyone tries to lkeep the number of cable joints as low as possible in the signal path in order to avoid adding contact resistance and other effects, but with the Koss in play I would actually add some cable joints (and some more joints within the Energizer) to the signal path. Would that be a no-go for someone who listens with headphones only as second option?

Best regards
Stefan

 

[timb5881]

I believe the Koss Pro 3aaa and the Pro4aa pads fit properly. If you can wait a week or two I have some aftermarket leather pads ordered and I can tell you about them.
You are correct that you want as few connections as possible.

 

[timb5881]

How can I tell if my amp has a common ground?
I may be using them with an old optonica sm-4545 stereo receiver (mid-late 70s).

Common ground causes issues with class D switching amps. Some solid state amps may have issues as well. I have not heard of any tube amps having any issues.

 

[steklo]

Hi again,

Sealed headphones do collapse the soundstage

Soundstage is something important to me – would an open headphone give me a bigger and more detailed soundstage (more similar to my speaker system)?

The unit I could get is a very early 1970/71 device – I read somewhere there were issues with humming of the Energizer which were only solved with the latest versions (not sure if it's meant the Energizer is mechanically humming or adds humming to the signal fed into the phones). Do you have any knowledge about that and if this could be improved somehow?

Unfortunately my amp does not have a second pair of speaker terminals. The fact, that the Energizer then needs to be placed into the signal path to my speakers worries me a bit, as speaker-listening will remain my preferred way of listening. Thus I would not really like to have this potential degradation as a permanent installation. Only in rare cases I might pick up the phones, late night alone or so... The other possibility, un-wire the speakers and connect the Energizer every time I want to listen to the Koss is not a really attractive alternative. Any other idea?

Maybe I would be better off with more modern headphone (or simply stay with my iGrado) connected to my iPhone (maybe complemented with a mobile headphone DAC/amp) and stream via iPeng app from my LogitechMediaServer and leave the main audio system switched off in these rare cases; additional benefit would be I could take it outside as well...

Best regards
Stefan

 

[timb5881]

Here is the owners manual:

 

[timb5881]

I got the sheepskin ear pads today. Way more comfortable than the old rubber ones from Koss. They do make the fit more comfortable and the seal is much better. I also notice an increase in bass.

 

[timb5881]

Rocking with Depeche Mode with the 9b headphones. The new pad’s definitely improve the bass and treble.