[Charivari]

Greetings all, I've been a fan of vintage Infinity speakers for some time (owning a pair of Quantum 2s that I'm finishing up the refurbishment of and a pair of Reference Studio Monitors) and have wanted to try electrostatic headphones. Well, an opportunity came up on a pair of Infinity ES-1 e-stat headphones with the ME-10D energizer.

Yes, I realize these 'phones are near unto three decades old, but I tend to like vintage gear as it is and these fit my budget far better than a several hundred dollar pair of newer ones.

Does anybody know anything about these? All I can find is a brief mention on The Audio Circuit and some specs in the product archive of the current Infinity Systems site (Post-Harmon tragedy).

PRODUCT SPECIFICATIONS
Frequency Response: .. 20Hz - 25kHz, +/-2dB
Sensitivity: ............... 98dB spl at input of 2 volts at 1kHz
Output Level: ............ MAX - 118dB spl @ 1kHz
Input Level/Impedance: MAX - 50 watts at 100Hz
Impedance: ............... SOURCE - 4-16 ohms


I'd appreciate any information as I'm quite excited about these. The membranes/diaphragms may be broken, but if I'm the least bit fortunate the problem was due to the seller not leaving them plugged in to charge. Knowing my luck, though, I'll probably need to replace them. Anyone know of a source for replacements or a place in the US that can affect the repair?

Sorry about all the questions and thanks for any assistance.
- JP

Edit: Forgot the link to the TAC page on the ES-1s I was able to find.

 

[wualta]

Be sure to report on them when they arrive. As I recall, they were rare and rather expensive when new.

 

[Charivari]

Sheesh, wualta, you seem to be on every half-decent audio forum. Unfortunately, due to the headphones being late shipping out, I won't receive them until Monday at the earliest. I was hoping to get them in time for the weekend when I'd have a chance to really dig into them. Ah well.

In the meanwhile, my questions elsewhere have dredged up some more information. That is these 'phones were made sometime around the early side of the mid-70s and had a retail price somewhere between $500 - $700 at the time. That is the equivalent in today's dollars of somewhere around $2300 to $3100!!

(Using the Federal Reserve Bank of Minneapolis's Inflation Rate Calculator [most accurate and easy to use one I've found]).

Vintage may not always hold its own compared to new items, but the value can sure be awesome. Can't wait to get these, repair them, and enjoy them.

- JP

 

[wualta]

Yes, it's true, I skulk down the dark alleyways of every half-decent audio forum and shuffle along the wet cobblestones of chiaroscuro'd newsgroups. Why? Because I'm only half-decent myself. But enough of me, let's dig into the problem of these crumbling Infinities of a certain age.

I don't recall now how Infinity got away with pricing their electrostats so high, since I believe the box contains transformers rather than a nice class-A high-voltage amp, but the price certainly discouraged a lot of people. It will be very interesting indeed to see how they were constructed and what is in fact in the box.

Low output and bass buzzing sounds like insufficient bias voltage to me. It's not likely the diaphragms are blown [but see post #6, below], since the seller says they simply deteriorated in storage, so I'm hoping it's an aged capacitor or blown diode somewhere in the bias supply (should be something like 250VDC). Meanwhile, you can try jumpering the headset into a working Stax amp or xformer box to isolate the problem.

I'm also hoping another owner will heave into view and relate a bit of history for us.

 

[Charivari]

Hey now, still enjoying picking apart the semantics of my posts? I was just referring that you seem to be an active member of any forum that's at least halfway decent with a good knowledge base. Which is why I'm here, actually, surely the biggest and best headphones forum would know something about these aged e-stats. I am somewhat surprised that noone's come forward with personal experience around here, but I guess the cost of entry was too high for there to be too many around (and/or the value didn't make it worth it.)

I posed the same questions over at Audio Asylum and a former Infinity dealer relying on faint memory produced the possible price, so the range may not be too accurate. Supposedly these are a bit more peaky sounding than the better known Koss ESP9bs, though the latter is spec'd at a +/- 5 dB rating vs the +/- 2dB of these, which when combined with my experience with similar vintage Infinity loudspeakers -- and thus knowing that they are very accurate for their age -- leaves me a bit doubtful of this comparison.

I see you found the auction I won these off of. No worries with that, though I did pay more than I normally would've, more than I picked up my Tannoys for. I'm just trying to overcome my reluctance to part with cash where I should, ie I'm trying to fix being a cheap person. It's good to have two different people now telling me that the diaphragms are likely to be ok; I drew the original conclusion about them being shot from the TAC's other pages concerning the repair of such parts where it was stated several times that their deterioration is a given with age. If it's just some worn out electronic parts, then it shouldn't be too terrible a task to fix aside from the lack of a schematic and the added week of waiting for the new components to arrive.

Still, I hold out the faint glimmer of hope that these are alright as they are. My research into vintage electrostatic headphones suggests that if they are not allowed to fully charge up for several hours before use the symptoms are very low output and bad bass. Something that sounds remarkably similar to what the seller described, as you referenced. Even if that is just the case, I'd still replace the old parts with drifting value, but at least I'd get to listen to these sooner.

Anyways, does there happen to be anyone out there with personal experience with the ES-1s? I'll throw up a picture of the pair on their way to me just to share and in case it jogs any memories.

- JP

 

[wualta]

Quote:

Originally Posted by Charivari Hey now, still enjoying picking apart the semantics of my posts?

With great glee, why?

No, I'm just going for the cheap laugh, that's all. Sometimes I do feel like Quasimodo lurching through the aisles of shiny new stuff mumbling about how the old stuff sometimes had a lot more to recommend it. Case in point, these 'stats. In many ways (not all), I expect them to handily outperform many Flavors-of-the-Month for a fraction of the price. You paid significantly less than the going rate for a working (sort of) pair of xformer-box 'stats, and I'm very interested to see whether or not the collective wisdom of the forum can get them up to running speed.

 
Quote:

I am somewhat surprised that noone's come forward with personal experience around here, but I guess the cost of entry was too high for there to be too many around.

I am too, actually. Seems to me another pair of these sold not too long ago. They're not so rare or obscure that no one's heard of them.

 
Quote:

combined with my experience with similar vintage Infinity loudspeakers -- and thus knowing that they are very accurate for their age -- leaves me a bit doubtful of this comparison.

Remember that Infinity probably didn't make this headphone and probably didn't expend much R&D to have it built to their specifications. Headphones like this were a tiny part of a tiny market and engineering terra incognita for anyone but real headphone mavens. Different world with vastly different engineering goals and hardpoints. I think they heard them, probably in a very different form, possibly the Micro Seikis that someone suggested, and liked them and thought they'd go well with the Servo Statiks. It could even be that someone in Japan heard the Servo Statik and sent a sample of their work as an acknowledgement of a job well done and a business feeler, all in one.
 
Quote:

I see you found the auction I won these off of.

Just a lucky guess.
 
Quote:

I'm trying to fix being a cheap person.

Don't do that! --where'd all the fun be then?
 
Quote:

I drew the original conclusion about [the diaphragms] being shot from the TAC's other pages concerning the repair of such parts where it was stated several times that their deterioration is a given with age.

I don't understand why they'd say that. It's Mylar. The stuff's been on the moon for 36 years and hasn't changed. [EDIT: Once again I'm proven wrong! It's not Mylar at all! Turns out Micro-Seiki decided to use something with better self-damping but worse everything else!-- an unstable grade of ultrathin polyurethane! Yikes! Keep this in mind as you follow our stumbling yet noble progress in this thread and the one linked to toward the end.]

Anything tensioned tightly enough will "creep" over time, that's true, but even slackening tension wouldn't make the diaphragm fail. It's much more likely that the connection to the diaphragm would go bad. A 'stat's diaphragm has either a conductive or semi-conductive coating which could fail due to a faulty or weak electrical connection that allowed arcing, but generally this requires a manufacturing defect or outright abuse, and again, the seller strongly implies that abuse didn't occur.

Well, we won't know for sure until they arrive. Warm up the macro setting on your camera and be prepared to stop down for max depth of field.

Consider the Mylar diaphragms in 40 year old Neumann condenser microphones. They don't usually fail from age.
 
Quote:

..it shouldn't be too terrible a task to fix aside from the lack of a schematic...

I can't imagine that there's much different here from the things being produced by Stax and Koss back then. There's just a small-current high-voltage DC power supply and a couple of high-quality transformers (and maybe some voltage-limiting devices like MOVs). Expensive but dead simple. Like I said, I suspect the power supply.

 
Quote:

My research into vintage electrostatic headphones suggests that if they are not allowed to fully charge up for several hours before use the symptoms are very low output and bad bass.

That's not my experience, but my oldest external-bias 'stats are only 15 years old. My oldest 'stats are electrets, about 30 years old, but they don't count in this, since their bias is always applied, so to speak. My ca. '87 Stax Lambdas come up to spec within seconds of power being applied. They may indeed perform better after an hour or so, but they're perfectly listenable at any level right at turn-on.

 
Quote:

Anyways, does there happen to be anyone out there with personal experience with the ES-1s?

Yes, or possibly one of the various models Micro Seiki produced in the '70s?

EDIT: In re The Audio Circuit (http://www.audiocircuit.com/#), aka TAC, Joerg Baar in Germany seems convinced that the Infinity was made by Micro Seiki based on a similarity in the shape and size of the diaphragms. He also runs a repair service for those and many other makes of vintage 'stats and describes in detail how he goes about it. He says the Micro Seiki diaphragms he found or bought (1 pair?) actually broke (!) "due to age or massive signal".
.

 

[Trance-Addict]

Im interested on your review of these headphones, after all electrostatic speaker technology has been my favorite for years.

Martin Logan Prodigy *drool*

 

[Charivari]

Ah, wualta, there you go again posting a long, in depth post that I can't even begin to answer in detail.

Sometimes it isn't fun being the newbie in a new audio arena. I'm hoping your right about the problem being in the power supply area and nothing major at that so I can affect a repair, I hope. My confidence in that, though, has gone down a bit since a nearly disastrous recapping experience with a Fisher SA-16 amp. Let's hope that if the problem is a bad component or two, it'd be a cheap fix rather than one of those expensive transformers you mentioned.

When I mentioned the bit about taking a while to charge up, I was referencing a few posts I found over at Audio Asylum in the Vintage and Planar/Electrostatic Speaker Asylums where a general search on vintage e-stat phones brought up regular mention of what I repeated before. That supposedly, the older electrostatics be it speakers or headphones require a few hours to charge up particularly if they've not been used in a while lest they demonstrate similar deficiencies to what was mentioned in that auction. Of course, thanks to my experience with posting in other forums, I've learned that not all that's said is based on scientific, researched fact or anything of the like.

I believe I ran across the same information concerning diaphragm repairs that you tried to link to. This link should work. This guy does seem to have repaired at least one pair, so if need be and I'm too cautious to do it myself, I may have to make use of his services. Still, he's in Europe so it wouldn't be a particularly enjoyable experience to ship the stuff over (even if its just the diaphragms) for repair, hence why I was asking about possible US repairers. If you're right about that one pair going bad due to a massive signal, I just hope they weren't being worn at the time. To break a diaphragm for that reason must surely take out the tympanic membrane at the same time.

Maybe going this route for good headphones wasn't such a good idea, not only would I risk blowing out my ear drums, but even when working I've a few kilovolts of juice flowing through stators a paint thickness away from my ears.

Well, in a little over 48 hours I should have the 9 lbs package containing the ES-1s in my sweaty hands ready for inspection. 'Fraid I can't take good pictures of them, though, thanks to my having a digital camera that makes a camera phone's product seem like an Ansel Adams print. Hopefully when I hook them up to the Speaker B outputs on my computer system's Pioneer SX-727, I'll be rewarded with incredibly reproduced music pleasing to the ear.

Trance-addict, I'll try to do somewhat of a review, but I don't think it'd be all that great of one. I've been stuck with rather poor quality headphones, some cheap '80s Koss, Pioneer SE-50s (horribly peaky response and 3.5 lbs of headphone), and a pair of barely tolerable Optimus Nova 71s. With regards to good phones, I managed about 5 mins of listening to some Grado SR-125s (model correct?) and liked what I heard aside from the brightness, but not enough to draw an accurate comparison. Though, I suppose, I could use my experience with planar speakers, such as the Magnepan MG-I, to draw some comparisons.

Thanks for the responses.
- JP

 

[tyre]

Quote:

Originally Posted by wualta I can't imagine that there's much different here from the things being produced by Stax and Koss back then. There's just a small-current high-voltage DC power supply and a couple of high-quality transformers (and maybe some voltage-limiting devices like MOVs). Expensive but dead simple. Like I said, I suspect the power supply.

It will be interesting to see the inside of the Infinity energizer. I have an old Realistic energizer that I bought off of ebay for parts and it's bias supply is bad. I haven't repaired it yet, but it should only cost a few dollars to replace the parts on it.

Quote:

Originally Posted by wualta He says the Micro Seiki diaphragms he found or bought (1 pair?) actually broke (!) "due to age or massive signal". I'd bet heavily on the latter.

My Realistic energizer has thermistors inline with the transformers for overcurrent protection. I'm not sure how effective that is though.

Quote:

Originally Posted by Charivari When I mentioned the bit about taking a while to charge up, I was referencing a few posts I found over at Audio Asylum in the Vintage and Planar/Electrostatic Speaker Asylums where a general search on vintage e-stat phones brought up regular mention of what I repeated before. That supposedly, the older electrostatics be it speakers or headphones require a few hours to charge up particularly if they've not been used in a while lest they demonstrate similar deficiencies to what was mentioned in that auction.

Here's a post from a guy on headwize that was having problems with a pair of Koss ESP-9 electrotatics and solved them by disassembling the headphones and cleaning the internals.

http://headwize.com/ubb/showpost.php...=1381&pid=9848

Quote:

Originally Posted by Charivari Maybe going this route for good headphones wasn't such a good idea, not only would I risk blowing out my ear drums, but even when working I've a few kilovolts of juice flowing through stators a paint thickness away from my ears.

I wouldn't worry about it. I doubt that the voltages on electrostatic headphones ever reaches a kilovolt. Electrostatic speakers, however, are a different story.

 

[wualta]

Quote:

Originally Posted by tyre I doubt that the voltages on electrostatic headphones ever reaches a kilovolt. Electrostatic speakers, however, are a different story.

Thanks for your post, Tyre. You're right about the voltages on old 'stats. Add to that the all-voltage-no-current aspect of 'stat tech, and there's no safety issue at all.

But yes, the warning about ESLs is apt: Never lick an electrostatic loudspeaker, no matter how delicious it looks.

 

[Charivari]

You know, I was joking with that comment. If I was being serious, I would never have bought these in the first place.

- JP

 

[wualta]

We know. But remember, newbious eyes are reading this, and in the back of their newbie minds they're asking the same question, for real. We know because the question's come up before. So it doesn't hurt to underscore the point.

It's okay to lick a Magneplanar.

 

[Charivari]

Understandable, though I too am a newb in this arena. Yes, it is perfectly safe to lick a Magnepan, with or without grill cloth, but I don't recommend it. Old Miloxane, wire, and dust doesn't please the pallet as much as you'd think. Well, with regards to the older ones, at least, the new Maggies with ribbon tweeters, I'd advise against lest you damage the ribbon.

Well, Infinity ES-1/ME-10D serial #347 arrived today in as good of shape as they left the seller. Truly, the packaging was great with both the energizer and headphones bubble-wrapped and double-boxed individually before being bubble-wrapped again and boxed up a final time. Aside from a ding on one corner of the energizer and of course the deteriorating leatherette on the phones, these look new. (And are quite comfortable to wear, I might add, aside from the large, course fabric covered cord).

I hooked them up and my dreams of a simple fix were dashed. Inside the energizer, everything looks like it just came out of the factory and there are no electrolytics to have gone bad. The layout (with three transformers, one power, two signal/output) is very clean and somewhat simple with only a handful of ceramic type caps and a couple of boxy white components (I was in a hurry to hook these up so I didn't take notes). The fuse appears to be the original 0.3 amp and still has the Japanese print on it.

Anyways, the output volume is not just low, it's nearly non-existent. I had to crank the Pioneer SX-727 powering the phones up nearly to full to hear what was playing (only for testing and for a very short time). The midrange and treble sounded alright, though very quiet. The bass wasn't merely distorted, it was buzzing badly. The left channel was quieter than the right and managed to cause the receiver's protection circuits to kick in when I adjusted the balance to the left to isolate any problems. Drat.

Any ideas? If I had to say, I'd declare it a problem with the diaphragms, but that's probably just demonstrating my own ignorance. I've not yet figured out a way to pull the ear pieces apart. The pads are glued on, though falling off in places due to the glue being attached to the leatherette coating rather than the underlying cloth. What I can find is a a plastic screen mounted in a circular section in the middle, but no screws. This may be glued or snapped in. From the outside, there's no point of attack, just a metal screen (open-backed phones, not closed, but that's no surprise being that these are e-stats). So, I can't get at the diaphragm, yet, to see what condition it may be in or whether it is very dirty. 'Course I'm not discounting bad components in the energizer and I may order up replacement small parts for it tomorrow, such as polyprops to replace the ceramics, and the like.

For what it's worth and to answer the curiosity of others, on the back of the energizer is this bit:
Quote:

Mfg for [size=small]INFINITY[/size] .........SYSTEMS INC. by [size=small]MECHANO ...ELECTRONIC[/size] ...INCORPORATION - JAPAN

Well, that mystery's solved, somewhat at least.

- JP

 

[Charivari]

I've been doing some work on these to see if I can fix the problem. I changed out the 4 0.01 mfd ceramic caps in the energizer and jumpered across the breaker (for testing purposes) that was giving me some slightly erratic resistance readings. With this, the phones are still very, very quiet and there's still a lot of buzzing. The caps did nothing. The right side is still a touch louder than the left.

There's not much to this energizer, just the three transformers, 10 resisters, 3 diodes, and the four caps. The diodes test alright no resistors are greatly out of whack, so far as my preliminary measurements show.

Any ideas where I should look for my troubles? Some input from those in the know would be nice.
- JP

 

[wualta]

I assume you've peeked inside to see if the diaphragms are intact-- in Joerg Baar's pictures, one of the diaphragms was torn right up the middle, a frightening sight indeed.

The next step would be to measure how much bias voltage the diaphragm is seeing.

Got some photos of the energizer's insides? Better yet, do you have another energizer (stax, koss) available?