Number 268, April 25, 2004

Boycott Verizon!

Listening Session
The Agony of Disappointment, the Joy of Success

by Ken Holder

Exclusive to TLE

When my best friend David moved back to Abilene, Texas 7 or 8 years ago, he stopped by our house in California, and gave me his old pair of Koss ESP-9 electrostatic headphones. I'd been an admirer of them ever since he got 'em back in about 1975 or whenever it was (I don't remember for sure). They were the first headphones that worked like an electrostatic speaker, and for some years they were the best headphones you could buy.

Electrostats use high-voltage DC to polarize two screens, with a conductive thin diaphragm between them that has the audio signal applied to it as a high voltage — as the audio signal varies in magnitude and polarity the diaphragm is alternately attracted by one screen and repelled by the other screen, causing it to move back and forth, generating an acoustical signal. Since the electric charge is distributed uniformly, the motion of the diaphragm is also very uniform, and thus low in distortion. The diaphragm is also very light- weight and can follow the changes of the audio signal very quickly. All this results in very clean and clear sound reproduction. The ESP-9 first came on the market in 1972, although electrostats go back a long ways as speakers. The most famous being the Quad from England, and the KLH Model 9 from the US.

The Koss ESP-9s are the sealed-enclosure type, which gives some isolation from outside noises. They must be operated from the speaker outlets of a power amplifier instead of a headphone jack, since they do need the higher voltage a power amplifier provides. They come with an interface box that has a speaker/headphone switch, as well as an AC-line/self-enegerized switch. This switch allows them to get their polarizing voltage from the AC power line, or to derive it from the signal itself using step-up transformers and rectifiers. The self- powered feature, in my experience, doesn't work very well; even through the charging circuits have a long time-constant, with very soft music the voltage slowly drops, and with it the sound volume. This is particularly annoying with wide dynamic-range recordings, and then when a loud passage comes along, it is distorted for a second or so until the polarizing charge builds back up. Annoying.

So, the line-powered setting is only one to use. Alas, David gave the things to me without the line cord. I've tried several times over the years to find a replacement, but it was some odd proprietary detachable socket that apparently nobody else made, and Koss no longer has the parts in stock for the ESP-9. Rats. So, I never used the things until recently when I decided I must be able to hear what was going on in my Current Personal Project of transferring some of my old LPs to CD. I have 3 different headphones in house, none of them having accurate sound. I've got some cheap-assed Radio Shack Realistic Minimus-7 speakers as computer speakers, and while they do sound better than those even cheaper-assed "computer" speakers you see everywhere, they're not really pro recording monitors either, and don't let me accurately hear what I'm recording. And my pro recording monitors are in the other room being used for playing back the TV and DVD sound — and although they're "mini-monitors", they're not something you'd want to tote back and forth, along with the receiver being used to power them.

Well, there were those Koss ESP-9s, still in the boxes they were in when my oldest buddy gave 'em to me. Out they came. I opened up the control box, cleaned and lubricated the various switch contacts, attached the right kind of end-connectors to the wires going to the amplifier's speaker connections (RCA phono plugs in this case), hooked them up, and gave a listen. Triumph! Despair! They worked, but only in the left channel! CRAP! After much agonizing, grumbling, and so on, I decided that maybe the self-charger circuit for the right channel might be defective, so I started looking to get the AC line powered connecting going. It's similar to the standard 3-blade socket you find on the back of your computer ... hum ... except it's 3 large pins. Well, now those pins are the same spacing as the regular 3-slot plug ... but the opening for the plug is smaller. Okay, I took a wood rasp and ground some of the plastic off of a computer power cord, until it fit the opening. Yep, it makes contact. Plug it back in to the amp ... damnit, only sound in the left channel still. RATS!

Hum ... then I found that if I jiggle the toggle switch for the speaker/headphone option, lifting it up a bit from "Headphone" and whaddyaknow, I got sound in both channels! I'd never done that for a long enough time in self-enegerized mode for it to charge up the right 'phone so it could make sound. So I tried it, and I get sound in both channels on the self-enegerized setting, also, when I diddle that switch and wait a while. So I, once again, opened up the control box and tried bending the switch contacts so they'd maintain contact in the right position ... didn't quite get it right the first time, though. Several tries and I got a solid, reliable connection at both switch settings.

The round pins don't really want to stay in the blade-type sockets of the power plug, they slowly push it out, eventually far enough to loose contact, at which point the charge on the screens begins to fade, along with the sound. Drat. So, I decided I'm just going to cut one end off a 3-way extension cord, and solder the wires in place — it's also hard to loose the power cord that way, for sure.

And so, I did. Actually, I took the power cord out of a power strip with surge-suppressors in it. When we had that lightening strike a couple years ago, it fried the surge-suppressors, but the power cord was still okay. Of course, it's a big, thick, 16-amp power cord, and the ESP-9 Energizing box only draws 1-watt. Overkill, but what the heck, eh? The only 3-wire/3-plug spare cord I had, anyway. So I got it installed. I got the speaker/headphone switch adjusted until it works correctly. I got it all put back together. And it works. The whole thing works. Triumph! (About time!)

So, how do these 30-years-old-plus antique Koss ESP-9 headphones sound, anyway? Well, they sound damned fine! Although, as David remarked right after he first got them, _hearing_ the deepest bass in your ears, without also _feeling_ it in your body like you normally would, is kind of a strange sensation. When the ol' pipe organ hits low-low-LOW C at the end of each 8-measure repeat of the bass-line in Bach's Passacaglia and Fugue in C-minor, for example, in an actual church or auditorium, you feel that 32-Hz sound in your guts. You don't get that with headphones — as David put it, it's more like butterflies tickling your ears. But you shore by ghodd get everything else, oh yeah. Heh, I suppose yer could listen to them with yer subwoofers turned on and getting their signal ... if yer had some subwoofers, of course. I don't. Alas.

And yes, I remembered these headphones as the clearest, cleanest, most distortion-free sound reproduction I'd ever heard. Guess what, they still are. Dang. In fact, the quality of sound they make can only be called astonishing. At another time I'll make y'all an annotated list of some of my best-sounding recordings after I've had a while to just wallow in their sound over these fabulous gizmos.

Now, where can I get some speakers that sound this good, eh? Eh? Eh? Heh!

Er ... well, yes. There are electrostatic speakers on the market. In fact, the famous Quad ESL is still made. The latest and best version is called the ESL-989. It cost $8,000/pair. It has certain picky needs are far as amplifiers due to its complex reactive load. Oh, and many people regard it as the best speaker you can buy, all things considered. There's a review at US importer's Website at

Electrostats are also made by:

and there are some others.

And there are the various planar and ribbon designs that operate in a fashion similar to the electrostatic, except using electromagnetic force instead of electrostatic force. The Magnepan "Magneplaner" designs being the most famous — some people consider the Magnepan MG-20 the best speaker around. I once heard a set of Magnepan Mark IV speakers, driven by enormous Mark Levenson power amplifiers, and that is the most awe-inspiring loudspeaker sound reproduction I've ever heard. There are also speakers using large almost-full-range ribbons like the VMPS RM-40 and RMX, and the Sound Line speakers (make in Riverside, CA, of all places!), all which marry a line-source electromagnetic planar midrange/tweeter with a conventional cone bass driver.

I'm listening to the ESP-9s right now. I do wonder how much better they'd be with something other than this antique cheap 1.8-watt per channel Radio Shack Realistic SA-102 integrated amplifier I use with my computer, but what the heck, eh? I'm listening to the Scottish National Orchestra play Sir Malcolm Arnold's "Tam O'Shanter" followed by Hamish MacCunn's "The Land of the Mountain and the Flood". Recorded by Chandos, released on CD in 1981. How's it sound? Stunning, is how. Stunning. And while they're big and heavy, Koss managed to design them so they're comfortable over long listening sessions. Don't sneeze without clapping your hand to them, though!

You can't buy Koss ESP-9s anymore unless you find a used set in working condition somewhere. Hum ... I just found out Koss still makes a later version called the ESP-950, MSRP is $1,000! Yikes! But has 'em for $550. If you've got a spare $550 to spend, check out this buy-me link at

And, you can also buy that album I'm listening to from as well (it's one of my favorites):

Scottish Overtures
Sir Alexander Gibson conducting the Scottish National Orchestra
    Mendelssohn: The Hebrides Overture (Fingal's Cave)
    Berlioz: Waverly Overture
    Arnold: Tam O'Shanter
    Verdi: MacBeth Act 3 Ballet Music
    MacCunn: The Land of the Mountain and the Flood, Concert Overture
    Chandos CHAN 8379

Ken Holder intended to spend his retirement listening to records but instead he's spending it scrambling to earn enough money to stay alive and (in the winter) un-frozen. He edits TLE in his spare time ... come to think of it ALL of his time is spare time. "Buddy, can you spare a time?"


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