KOSS ESP6 REFURBISHED VINTAGE ELECTROSTATICS
Nov 2, 2007 at 12:03 AM Post #46 of 94

ericj

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Well i got the right-side earcup reassembled and no dice. I should have checked for contunity to the stators while it was open.

refurbing the left earcup now. The front stator wire was corroded near the solder joint badly enough that it broke off when i removed the screw on that hole. I almost miss the riveted tabs in the esp/9.

Soldered in a new filament of wire for the front stator. This wasn't hard to do, but does require removing the front stator portion of the driver from the back portion and peeling up a corner of the membrane. You don't have to peel it so far as would mess with the tension, so it's all good.

Right now the left driver's hardware is soaking in a 5% solution of acetic acid to try and remove the bulk of the corrosion. Will hit it with a contact cleaner and coat with silicone before reassembly.

I guess i could open up the right-side driver and check the stator wires now . . . .
 
Nov 2, 2007 at 8:13 AM Post #47 of 94

spritzer

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You hear nothing right as you would hear something if they were sunning SE.

My set was in horrible shape and all the wires were snapped so I drilled new holes for the back stator connection and ripped the driver apart for the other two. Mines started to act up again so I have to fix them again.
plainface.gif


I would also check to see if all the connectors are mounted securely to the PCB's as some were loose on mine. Koss sure loved those damned things...
 
Dec 31, 2007 at 9:55 AM Post #48 of 94

facelvega

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REVIVAL: wow, now that I've nabbed Spritzer's old ESP6, I turned back to this old thread to notice that I was the first respondent. Here's what I wrote:

Quote:

Originally Posted by facelvega /img/forum/go_quote.gif
a fine contribution to the forum, not just for today but one of those nuggets that the search function will turn up again and again when we need it. Many thanks!


Odd that I'd completely forgotten this now as I was doing exactly what I mentioned back in April. Though I'm sure it was having once read this thread that made me want to grab the ESP6 in the first place.
 
Mar 8, 2009 at 7:25 PM Post #50 of 94

mudihan

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Does anyone have the schematic for ESP.6A? I got a working one recently and am enjoying the sound. However, I am planning to do a full upgrade with better parts. Thanks!
 
Mar 8, 2009 at 9:15 PM Post #51 of 94

mudihan

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Also, as far as capacitor upgrade goes, would changing the ceramic caps to Polypropylene film caps help with the sound? Thanks!
 
Aug 9, 2009 at 8:10 PM Post #52 of 94

edstrelow

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Quote:

Originally Posted by mudihan /img/forum/go_quote.gif
Does anyone have the schematic for ESP.6A? I got a working one recently and am enjoying the sound. However, I am planning to do a full upgrade with better parts. Thanks!


I posted the schematic on the first post.

I must say I continue to enjoy mine, even by comparison with the Stax 007A and Sigma/404, My favorites. Partly this is because I listen to them more when I need isolation, either to cover the sound of an AC unit or not to disturb the wife. After I replaced my old Pioneer amp with a Sherwood RX-4109, (about $99.00) from the Rat Shack, the sound took a real jump in quality. Some cheap silver IC's and a coating of Silclear and Progold on contacts and these things are really coming to life. Still some issues about volume fluctuations, mainly with classical music which has wide dynamics, but overall the set seems to get better the more it is used.

I generally prefer it to my Koss ESP 9, because the 6 has a better midrange. The Koss sounds like the mids are somewhat sucked out, sometimes giving a muffled, distant sound. The 9 has a somewhat more refined sound with deeper bass, and the 6 occassinally distorts the midrange at high volumes, but it still sounds better on about 80% of what I have listened to with it.

While the 9 has a mains-powered bias, which gives more stable volume levels, this does not translate to better dynamics and I generally prefer even the 9 in its self-energized mode.
 
Sep 2, 2009 at 4:16 PM Post #53 of 94

ourfpshero

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one of these on the way!
could a stax clone electret box be used to run these somehow? (with wiring work of course) i doubt my ldmk3 will drive these koss well
 
Sep 2, 2009 at 8:57 PM Post #54 of 94

wualta

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You mean, could you bypass the internal stepup transformers in the 6 and in effect turn it into a 7, as Spritzer did? Don't forget, either way you're going to need a speaker amp, and the 'phone will need about 200vdc of bias.

Which "Stax clone electret" have you got?

.
 
Sep 2, 2009 at 10:18 PM Post #55 of 94

ourfpshero

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i have a teledyne. the headphone has a burned driver. the box is identical to the old stax srd4 and such. i have a speaker amp that i use with my signet electrets.
i guess it would be much easier to wire the headphone cable into leads that plug directly into my speaker amp. even easier to make a female 1/4" plug with leads to the speaker amp.
what i dont understand is the bias. what is it and where does it come from, get adjusted, etc
 
Sep 3, 2009 at 2:35 PM Post #56 of 94

spritzer

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The bias on an electret comes from a special treatment of the polyester film, making it permanently polarized. It won't loose this charge over time but a parasitic charge can form on the diaphragm with no way of getting rid of it.

The bias for true electrostatics comes from a bias supply of some sorts which can be powered by pretty much anything since it draws so little power.

The bias is always a fixed value given the diaphragm/stator spacing of the driver (plus the drive voltages) and can't be adjusted.
 
Sep 10, 2009 at 7:42 PM Post #57 of 94

ourfpshero

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got them today, wonderful condition, the headband appears to have been replaced, barely goes large enough to fit my skull
 
Sep 11, 2009 at 4:10 AM Post #59 of 94

ourfpshero

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Quote:

Originally Posted by spritzer /img/forum/go_quote.gif
The small headband is the stock item. The ESP9 unit is very similar but has more extension.


aw. my head is only medium sized too! and this barely fits.
on the plus side- my xenos 3ha amp drives these to normal levels
 

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