[rhythmdevils]

Quote:

Where do they exit on the back of the driver?

Here's a picture taken from the T50rp thread, I've circled the holes in red.  Only one of them goes all the way through (the one at the top of the driver), but it is completely open into the pad enclosure -you can see through it.  Bluemonkeyflyer just reported that he stuck a paperclip through the other 3 holes and hit plastic at the end. 
 

 
Also, nice work Nickn!  I love the 70's headband, I have one just like that.  I love all those metal headbands with real screws.  It's funny how many phones at that time used the same design.  But it works, and looks good. 
 
 

 

[wualta]

Oh! the pressure relief thingie so your ears don't pop and the diaphragm doesn't get biased by the trapped air. Yep, it's a known thing. Sorry, should've said something earlier. I thought you guys had discovered some hidden acoustic short circuit Fostex had slipped in either by stealth or by accident.
 
Eurobass-- base-- is pronounced bah-ZAY. It's got an accent mark and a moustache and everything.

 

[gurubhai]

Quote:

From all the posts I read these PMB500 are supposed to have the full square pads aren't they? This one has the "L" shaped on the same model#.
A later or earlier version? A retrofit/repair job?
 

My PMB500 came without pads, so can't help with that.
But its probably a retrofit, using the L shaped jecklyn float pads.
 
Unfortunately, they are lying unused since the my PMB adapter has only one channel working.I was planning to repair it but just haven't got the time.Anyone know of an electrostat amp that would work with these ?
 

 

[wualta]

The PMB 100 had the Jecklinesque L-shaped pads, but you're right, the 500's pads were classic circumaural. See krmathis' post (and photo) here.

 

[rhythmdevils]

Quote:

Oh! the pressure relief thingie so your ears don't pop and the diaphragm doesn't get biased by the trapped air. Yep, it's a known thing. Sorry, should've said something earlier. I thought you guys had discovered some hidden acoustic short circuit Fostex had slipped in either by stealth or by accident.
 
Eurobass-- base-- is pronounced bah-ZAY. It's got an accent mark and a moustache and everything.

You sir have an amazing ability to pull up relevant posts in this thread.  I think around page 20 was when I got woozy looking at how many pages were left in the thread and I started skipping around. 
 
So you don't think it was an attempt to get more soundstage effects by mixing in some backwave like the electrodynamicals do?

 

[Armaegis]

Well some type of sound coming through the vent is inevitable. The question is whether it is simply a reflected backwave, or if the hole acts as a bass port to give us a one-cycle delayed signal.

 

[wualta]

 
Quote:

 
So you don't think it was an attempt to get more soundstage effects by mixing in some backwave like the electrodynamicals do?

 
Nah. It's a pro audio headphone. Soundstage is an audiophile concept to them, only suitable for wussphones.
 

Quote:

Well some type of sound coming through the vent is inevitable. The question is whether it is simply a reflected backwave, or if the hole acts as a bass port to give us a one-cycle delayed signal.

 
My gut feeling: Sounds that could get though this hole without being delayed are low frequencies well below the bottom-end cutoff of the 'phone. But we can check it-- plug it up as shown in my photo linked to above (well, plug it from inside the earcup), and listen for differences.
 

 

[nick n]

Here's those scans from the PWB Electrostats I just got in the box. This is the same headphone as the one pictured below, which I also have( that pic is from the first set auction ). This model appears to be the E.S.2. line, which from reading the included paperwork seems to be a line of Electrets. The same headphone throughout but with slightly differing transformer box setups. This setup I just got is the baseline model,  but I am not complaining at all.  Just least classy looking. (  just took that pic of the adapter ) Listed as the Budget Version. Type P.1. No speaker outs on this model. Just on the higher 2.
 
I'd really like to get a working pair of E.S.1. 's with a transformer box ( anyone have any they want to part with? even more variations of this is cool hit me up with a PM ) that have the same exposed pins as Stax, and I assume to be a full fledged Stat. ( bias needed ) There's a picture of those up on the Wikiphonia site.
 
I want to start a PWB ( or is that P.W.B. ) collection over time.
 
Thought you'd be interested in the scans of the paperwork, the pricelist is especially droolworthy and chock full of goodness. To me anyhow. I'm posting the scans directly because all to often when seeing old posts and hitting the links=== *blah* ===link dead. Of course those prices are for British Pounds in '78, not Dollars.
 
I'd try to open them up for a peek at the insides but last attempt it seemed they were sealed up good no method of opening nor seams to be found that were open-worthy. (EDIT: OOPS There are typical screws to get into these. )
 
Box itself is simply a white cardboard thing with a black sticker/white lettering that says : PWB Natural Sound Professional Electrostatic Ear Speakers. That's it
 
 

 

[wualta]

Extra cool! Have you seen the other bits of Beltiana? like so:
 

 
From left to right, it's the electret being tested (and not being shabby about it), then an ad for it, then maybe the ES1, then finally the rare and goofy Dyna-X. Now we know it competed in the same price range as the Wharfedale Iso. Problem is, of course, and you saw this coming, it's so stinking rare that only one Ortho Roundupper, JadeEast, has one. Farz I know.

 

[nick n]

Wow thanks for that. Interested in any stuff that comes my way I would like to grab it even if people think it is lame. Just for the sake of preserving what's out there still.( Did you hear that internet ) Kicking myself for not attempting that thing I linked you in the PM way back. It'll come around sooner or later.
The Dyna-X is what I assume you are talking about re: rarity.
 
Only other stuff I have is the free Rainbow Foil and Creme Electret samples they sent me. They are still selling tweaks... Where'd you scoop those images from? I looked all over but not good enough it seems. The few forum posts are rife with controversy and name-calling   But didn't Sony even find different colored wires better in their ECR's?
 
I JUST noticed that there are MOVING COIL headphones on that pricelist too, so some DYNAMICS!!!!!!!!!!!?????

 

[wualta]

Yes. We are pretty sure that Belt was an actual Stax distributor in the early early days (the SR-3 was the only product) but modified the transformer box for what he said were safety reasons, and eventually (apparently) made his own headphone chassis for Stax (?) drivers. Where/when the Dyna-X came in, we don't know.  This info was on a very nice webpage the Belts maintained which has now disappeared. The photos I posted are from that site. Wikiphonia has a couple more, including one of a naked ortho diaphragm of Belt's own design... which as far as we know never was used. The Dyna -X used a modified SFI driver, and yes, it's rarer than the 'stats, based on online auction action over the past 6 years.

 

[ardgedee]

Does archive.org have a copy of the deleted site?

 

[yvfed1]

Well, I don't think they sourced antyhing from China in 80s, or got anything from Yamaha....Copying, yes, most likely.

 

[wualta]

 
Quote:

Does archive.org have a copy of the deleted site?

It was a .pdf on <http://theadvancedaudiophile.110mb.com>, and if you can find it in the Wayback Machine, we'll be grateful. I can't find it myself.


Quote:

Well, I don't think they sourced antyhing from China in 80s, or got anything from Yamaha....Copying, yes, most likely.

yvfed1! you're back! ...This is the man who showed me what Электроника could do.
 
 

 

[Currawong]

 
I'm back. Posted about these here. Apart from the lack of a treble peak, I actually enjoy the sound out of them from my iPhone + (wrong amp for these) Pico Slim. Very relaxing.