Review: Refurbished Micro Seiki MX-1 Electrostatic Headphones (MS-2 headphones & MP-1 amplifier)
Jun 19, 2010 at 1:42 AM Thread Starter Post #1 of 11

peli_kan

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First off, thanks to hembergler for generously mailing me free 6-micron mylar, spritzer for his expert advice, and Joerg Baar for being a living, breathing repair manual.  They helped make refurbishing these headphones possible.  
 
The Micro Seiki MX-1 is composed of the MS-2 headphones and MP-1 amplifier, supposedly produced by Stax in exchange for Seiki's UA-7 and UA-9 tonearms.  For a general overview, visit this link: http://www.thevintageknob.org/THEVAULT2/MS2MP1/MS2MP1.html 
 
Originally, the diaphragms were made of polyurethane, which had long disintegrated before they arrived at my workbench.  My refurbishment job consisted of disassembly, removing old polyurethane particles from the chambers and stators, recreating the diaphragm with mylar, coating the diaphragm, and reassembly.  
 
Disassembly was simple.  The earpads unlock with a slight turn, and the rest is intuitive.  The hardest part was stretching, mounting, cutting, and coating the mylar.  My final iteration used 1.4-micron mylar from turnertoys.com, available in a 12.5" x 10' sheet for $11.50.  As a coating, I used 80 mL water + 20 mL PVA glue + 5 drops of carbon pigmented ink, a formula roughly based off the one popularized by this DIYaudio thread:  http://www.diyaudio.com/forums/headphones/132573-has-anybody-made-els-headphone.html  Since the mylar tears easily, even when cut with the sharpest of "I can push-cut paper" blades, I used a red-hot needle to shave off excess mylar after mounting the film.  
 
APPEARANCES, BUILD, COMFORT:  picture borrowed from TAC

These are sharp looking headphones, both sturdy and lightweight.  Padding is minimal, but the headband swivels open to distribute weight.  The earpads are soft vinyl, and provide a seal without clamping.  I used the Chesky Ultimate Demonstration Disc, ran through a modest NAD integrated amp out to the MS-2 / MP-1.
 
SOUND QUALITY:
I'm no expert, and I'm speaking from limited headphone experience.  I'll do my best to compare them to both what I've heard from other headphones as well as what I've heard as a percussionist in concert bands.  
 
My reference headphone for frequency response is the Etymotic ER-4B with Shure olive tips.  The Seiki's have a sharp roll-off around 50-hz or so, but thankfully lacks the mid-bass hump that usually tries to compensate for this deficiency.  Since these are electrostatic headphones, the roll-off was hardly surprising.  The mids are an itty-bit recessed, not noticeable unless compared with the Etys.  Highs are strong, but with no noticeable spikes.  
 
The excellent speed of these headphones is obvious even at the first listen.  Drums of all sorts are incredibly realistic, with a gritty "thwap" that I've never heard in any other headphone.  Brass has bite, with squeals, flutters, and overblown notes all viscerally rendered.  I hope that's what "speed" means at least, the faithful representation of steep wavefronts.  Whatever it is, the Seiki's are textured to the point that you feel the music in a way that seems to extend beyond the ears.  The 1.4-micron mylar diaphragm matches that of the Stax Lambda in thickness, but since I've never heard those headphones I can't make a meaningful comparison.  
 
As far as imaging goes, I don't have much to compare them to.  I own and have listened at length to the Alessandro MS-1000 with wooden cups and large bowl pads, but even with those I haven't had a coherent "out of head" experience.  The Seikis do benefit from transparency, so that sound always seems to inhabit a realm well beyond the headphone pads, but I could never close my eyes and "see the band."  Again, I can't make a sophisticated analysis of this aspect.   
 
CONCLUSION
 
The textured sound, transparency, and relatively flat frequency response of these headphones let me thoroughly enjoy them with music of all genres.  Although bass extension is lacking, only electric bass seems to fade to nothingness; acoustic jazz bass, concert bass, and concert bass drum all possess the higher overtones needed to still stand present.  With its addictive sound, the Micro Seiki MX-1 electrostatic headphone and amp is a great listen.
 
Feb 22, 2011 at 3:32 AM Post #2 of 11
 
MICRO SEIKI HEADPHONE MS-2  MP-1
Hello
I replaced the membranes of a headphone MS-2. The sound is not very powerful and background noise bursts the left membrane.
It is possible to have the shéma of repair, an idea on the breakdown and where there are spare parts.
Thank you very much.
Paulin 1313
FRANCE
mc29@live.fr
 
May 14, 2017 at 5:08 PM Post #4 of 11
I also succesfully replaced the diaphrams of a MicroSeiki/MicroScript headphone with 6 micrometer mylar. I glued the diaphrams to the metal ring with cyanoacrylate instant super glue. I stretched and taped the mylar on a glass mirror. Then as a coating I rubbed-in some graphite powder (used to lubricate locks etc). After that I removed the excess powder with alcohol (methylated spirit). Now my electrostatic headphone has been working OK for already 2 or more years.
I love the addictive sound.

For people who try to repair these phones: There is a kind of needle which connects to the metal ring with the mylar diaphram. This needle is insulated with a very tiny plastic tube. Make sure to not lose this tiny tube because it is crucial to maintain the high voltage of this phone.
Cheers, Nico
 
Dec 21, 2019 at 9:51 AM Post #5 of 11
I am struggling to understand how the 4 Pin DIN on the MS2 plug manages to create an HT lead in the ear cups. It appears both stators have two 1.5 M resistors in the cups which I think may in some way be involved and go back to the centre 2 way bit of plastic (I think this could be disassembled) that each individual cup leads links to. In the MP-1 box there is what appears to be a simple multivibrator that links to a step up transformer and connects to the 4 Pin DIN. Does anyone have a schematic? Whilst there are links to one on this board the links are dead.

I am pleased with the sound from the MS2 following replacing the very perished membranes with 2u Mylar and one coat of anti-static spray. Do wonder whether they would sound better if rewired to 5 DIN plug as it seems the MX5 has.

Best Wishes

Tim
 
Jan 16, 2021 at 1:42 PM Post #6 of 11
First off, thanks to hembergler for generously mailing me free 6-micron mylar, spritzer for his expert advice, and Joerg Baar for being a living, breathing repair manual. They helped make refurbishing these headphones possible.

The Micro Seiki MX-1 is composed of the MS-2 headphones and MP-1 amplifier, supposedly produced by Stax in exchange for Seiki's UA-7 and UA-9 tonearms. For a general overview, visit this link: http://www.thevintageknob.org/THEVAULT2/MS2MP1/MS2MP1.html

Originally, the diaphragms were made of polyurethane, which had long disintegrated before they arrived at my workbench. My refurbishment job consisted of disassembly, removing old polyurethane particles from the chambers and stators, recreating the diaphragm with mylar, coating the diaphragm, and reassembly.

Disassembly was simple. The earpads unlock with a slight turn, and the rest is intuitive. The hardest part was stretching, mounting, cutting, and coating the mylar. My final iteration used 1.4-micron mylar from turnertoys.com, available in a 12.5" x 10' sheet for $11.50. As a coating, I used 80 mL water + 20 mL PVA glue + 5 drops of carbon pigmented ink, a formula roughly based off the one popularized by this DIYaudio thread: http://www.diyaudio.com/forums/headphones/132573-has-anybody-made-els-headphone.html Since the mylar tears easily, even when cut with the sharpest of "I can push-cut paper" blades, I used a red-hot needle to shave off excess mylar after mounting the film.

APPEARANCES, BUILD, COMFORT: picture borrowed from TAC

These are sharp looking headphones, both sturdy and lightweight. Padding is minimal, but the headband swivels open to distribute weight. The earpads are soft vinyl, and provide a seal without clamping. I used the Chesky Ultimate Demonstration Disc, ran through a modest NAD integrated amp out to the MS-2 / MP-1.

SOUND QUALITY:
I'm no expert, and I'm speaking from limited headphone experience. I'll do my best to compare them to both what I've heard from other headphones as well as what I've heard as a percussionist in concert bands.

My reference headphone for frequency response is the Etymotic ER-4B with Shure olive tips. The Seiki's have a sharp roll-off around 50-hz or so, but thankfully lacks the mid-bass hump that usually tries to compensate for this deficiency. Since these are electrostatic headphones, the roll-off was hardly surprising. The mids are an itty-bit recessed, not noticeable unless compared with the Etys. Highs are strong, but with no noticeable spikes.

The excellent speed of these headphones is obvious even at the first listen. Drums of all sorts are incredibly realistic, with a gritty "thwap" that I've never heard in any other headphone. Brass has bite, with squeals, flutters, and overblown notes all viscerally rendered. I hope that's what "speed" means at least, the faithful representation of steep wavefronts. Whatever it is, the Seiki's are textured to the point that you feel the music in a way that seems to extend beyond the ears. The 1.4-micron mylar diaphragm matches that of the Stax Lambda in thickness, but since I've never heard those headphones I can't make a meaningful comparison.

As far as imaging goes, I don't have much to compare them to. I own and have listened at length to the Alessandro MS-1000 with wooden cups and large bowl pads, but even with those I haven't had a coherent "out of head" experience. The Seikis do benefit from transparency, so that sound always seems to inhabit a realm well beyond the headphone pads, but I could never close my eyes and "see the band." Again, I can't make a sophisticated analysis of this aspect.

CONCLUSION

The textured sound, transparency, and relatively flat frequency response of these headphones let me thoroughly enjoy them with music of all genres. Although bass extension is lacking, only electric bass seems to fade to nothingness; acoustic jazz bass, concert bass, and concert bass drum all possess the higher overtones needed to still stand present. With its addictive sound, the Micro Seiki MX-1 electrostatic headphone and amp is a great listen.
Hi - this is a (very) old post, nonetheless relevant: I recovered an old MS-2 headphone that lost all ability. After opening, I found the crumbles of the offwhite membrane that I need to replace. I could not identify any source of micro-thin membranes (unless industrial quantities in France). I guess the important properties are a very small weight (=thin) and conductibility (what would be a good resistance?). One thought I had was actually to use gold foil, which costs next to nothing, has a thickness under 1micron and is extremely conductive, while the use of graphite can never achieve that low a resistance.
I would be very grateful for any advice how to reconstitute the broken membranes.
Cheers
 
Jan 16, 2021 at 4:44 PM Post #7 of 11
Hi ThBader,
Good idea to repair the MS2 headphone. It is relatively simple but maybe you will have to give it a few tries:rolling_eyes:
You will need a type of mylar which can be shrinked by means of hot air. Shops with model plane gliders usually do sell this kind of mylar to cover the wings of the plane! I just learned from another member who repaired 2 MS2 headphones this month(1 with 2 u mylar and 1 with 6u mylar) that sound quality of the phone with 2 u mylar is a lot better...As far as I know the membrane must have a high resistance to prevent arcing between the membrane and the stators. And I do not know whether gold foil can be shrinked by means of hot air. Most simple solution is probably to use 2 u mylar and to make it high resistance conductive with antistatic spray. The member mentioned above used this procedure with good result. I repaired my MS2 ca 5 years ago and it is still going strong. I used 6 u mylar and graphite powder. Using anti static spray will be a lot easier I guess.
Most important warning: carefully note the location of the very tiny insulation tube that is used over one of the contact pins. If you forget to mount this tiny tube you will create a short circuit and maybe your amplifier does not like this😜
 
Last edited:
Jan 16, 2021 at 5:08 PM Post #8 of 11
Hi ThBader, here is a link of a shop in UK: freeflightsupplies.co.uk
This shop sells 2 u mylar sheet. But I guess there are also model plane shops in France.
Cheers, Nicolas
 
Jan 17, 2021 at 8:17 AM Post #9 of 11
Hi ThBader,
Good idea to repair the MS2 headphone. It is relatively simple but maybe you will have to give it a few tries:rolling_eyes:
You will need a type of mylar which can be shrinked by means of hot air. Shops with model plane gliders usually do sell this kind of mylar to cover the wings of the plane! I just learned from another member who repaired 2 MS2 headphones this month(1 with 2 u mylar and 1 with 6u mylar) that sound quality of the phone with 2 u mylar is a lot better...As far as I know the membrane must have a high resistance to prevent arcing between the membrane and the stators. And I do not know whether gold foil can be shrinked by means of hot air. Most simple solution is probably to use 2 u mylar and to make it high resistance conductive with antistatic spray. The member mentioned above used this procedure with good result. I repaired my MS2 ca 5 years ago and it is still going strong. I used 6 u mylar and graphite powder. Using anti static spray will be a lot easier I guess.
Most important warning: carefully note the location of the very tiny insulation tube that is used over one of the contact pins. If you forget to mount this tiny tube you will create a short circuit and maybe your amplifier does not like this😜
Great, thank you very much for your reply. And yes, I noticed the insulation and its purpose. The arcing argument sounds very reasonable!
Cheers!
 

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