[khbaur330162]

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All suggestions, or spare parts, welcome.

After taking a closer peek at my empty HP-1 shell I agree with wualta. I can't remove that little universal joint without ripping metal and melting plastic which means you'd have to do the same in order to swap your broken part for mine. Cool thing about wualta's idea is the L/R badges probably have a little bit of space underneath them to hide the screw head so the repair job will only be visible from the side. Not bad if you can find the right screw. 
 
Congo: Very cool transplant. Oddly enough, I'm currently working on a project that's reaallly similar to your Stax T-20. More to come on that later, but thanks for your post. I wanted to try open-back, but maybe now I'll devise some kind of removable bass-port-plug or something to check out both platforms.

 

[nick n]

ahhh very nice Congo
I have a minty SR-40 shell awaiting just such a thing. Did notice that they don't clamp all that tight though.
If you still have those mineral wool damping pads that were in there stock ...did you try those out also?
 
Wonder if the headband can be bent a bit to increase clamping I'll have to dig them out.  Maybe try out some thin densities of black felt right at the rear screens to see also? That way you don't see it.
 
I DO like how easy these things are to get into, it's ingenious.
Pull the headband wires out, remove the grommets they fit into which also secure the cups together, pop open the shell. Done in under 30 seconds and no screws to mess with.

 

[Congo5]

Quote:

I have a minty SR-40 shell awaiting just such a thing. I did notice that they don't clamp all that tight though. If you still have those mineral wool damping pads that were in there stock ...did you try those out also?
 
I wonder if the headband can be bent a bit to increase clamping I'll have to dig them out.  Maybe try out some thin densities of black felt right at the rear screens to see also?

Yes on the no tools Assembly....gotta love it.....thank you Stax.
 
clamping force is adjustable by carefully bending wires,
I believe it is good quality spring steel.
spritzer has posted about this somewhere.
I would wait to adjust because the weight of the driver makes a difference..
 
did not use mineral wool pads, I used Transpore taped black stiff craft felt ( thank you BMF)
read that rock wool works best with stats- stats have much higher resonant frequency.
yes on black felt for appearance..
 
felt on the screens is what Wualta suggested
so that should help with FR also.
 
What drivers are you going to try?

 

[nick n]

Quick update for the HP-50A I got recently.
 Tonight even though it was one of those nights where everything goes wrong, things fall off, drop, mess up, break etc. I tackled the recable to stereo
Removed the white front papery crap that was on the earside and remove the foam disc from inside, tossed the musty smelling cable and pads.
 
 I had to recable from mono so I used an old koss ur-20 ( good for something it seems ), slid the stock cable entry strain relief thing up the cable and reused that, also left the headband wiring intact.
 
Pads I had laying around from a Pioneer Loop. I ran black electrical tape around the baffle seam, then cut out the parts that extended too far onto the front of the earside. Pads are stuck to the baffle with Doubletack double-sided tape and the edges are simply wrapped around the edges to hide the tape and it looks better that way anyhow. Three notches for the cables. Tapes obviously seal up any leaks on the baffle area
 
In went a tiny blob of Newplast to fill the small hinge cover indent, a ring of Arctic bamboo ( felty fabricy stuff ) around that area then another full disc of Arctic Bamboo on top of that. This effectively damped all the perimeter holes. Nice dimensionality to these. Good bass. No fatiguing trebly spikes or anything. Nice detail.
 
 I had tried messing around with some foams but it wasn't working, this was one of the simpler mods to do, finally.
 
 Thinking I got one of the bassier pairs or at least the ones that didn't have the lower bass issue. If I recall there was some mention of the variations from pair to pair in the HP-50 model range.
 
Anyhow I have some new portables, until I damp the T-10's then they can fight it out.

 
 
 
Sr-40 shell: possibly SFI's, or was also thinking of the HOK80 drivers even.
 I was thinking of giving them as a gift but most people I know don't sit at home listening so an open back for portable use might not be any  good. Could always seal the backs up though and add a bass port. Now there's an idea.
I'll post up if I ever get to it.

 

[gurubhai]

Nice work, Nick.
 
If you managed to tame the bass with two layers of arctic bamboo stuff, then you probably have a 'bass light' version.

 

[nick n]

If that's the case the bass-heavy must be huge. Does the big bass one obscure any of the rest of the sound =is it that much bigger?
Is it sort of a "luck of the draw" as far as what version a person gets, or is it consistent within particular models?
 
One thing I just realized is the baffle has all those holes in it ( no kidding ) but someone must have tried cutting that away so it doesn't obscure the driver. What's that sound like?( AT-2 style mod)
 
It's not so much tame the bass I would say as give it a better body and the cans better spaciousness. Perhaps that is taming it It still rivals the hp-1 so far from initial impressions. That may change as I a/b more
 
I did nearly the exact same mod to the HP-1 just now.
 
----Lined backs with 1/8 inch thick Creatology brand adhesive foam= A ring around the rear recess and a disc on top of the hinge assembly pressed down into the dip of the silver retaining cap.
----Disc of the Arctic Bamboo with notched bits for screw posts, then another on top of that without notches pressed down. It rides up the sides to take care of damping the perimeter vents and a tight damp to the driver also as the raised foam on the cup hinge presses the felty stuff well.
 
Really nice I actually want to listen to these now whereas before they just sat there and I couldn't tell you the last time I bothered even picking them up. 6  months ago maybe or more?. Even stock they sort of just sat there.
 
I tell ya this thin Creatology adhesive foam is also excellent stuff, especially the price @ ~1.75 a sheet, great for tight areas and it does wonders far as I can tell.
 
 
 
OK UPDATE for iQem and the Philips ( his model400 also )
 
Philips 6326 ( no not 6325 single entry ) dual entry Electret - TRS jacked -  hence the crappy transformers in the cups. Think they are 1000 ohms.
Ready for a project transplant.
80 mm drivers!
 
The backplate  serves as the contact and pressurized retaining mechanism for the driver layers.
 Interestingly the EM6721 Philips electret i just recabled to Stax cabling ( run off Stax adapter ) simply has a wide open stator rear, none of this funky backplate/retaining plate junk.
iQem I  have no idea what style yours have.
 Good luck getting into them without ruining the things too.( you can't )=
 
  before anyone freaks out I got these so dirt cheap and in not-so-great cosmetic condition to do just this. Search and destroy.
For a possible transplant . Possible maybe not so much now. We'll see.
 
...(Lightbulb flickers on above head )==>Maybe add thicker spacers to increase BASS POTENTIAL , recable to stax adapter, and secure the driver without the rear plate? Hmmm. Now there's an idea!
 
 
 
Do you think it would reflect nearly everything and do you think this backplate would contribute to why these are very treble happy. I think so myself.
 What's wrong with a different method to secure and make the contact to the stator, would have been cheaper. Did the company even test these, maybe it was a sound of the time.
I dunno.
here's the goods for those "innerset" in these.
 
Impossible to even see the seam flex on the cups so i had to go the sidecutter route. They are ( were rather ) bonded/secured at 5 or 6 key points around the perimeter, very well secured.
 
Same useless tiny transformers. I now have 2 sets ( set from the EM6721 also ) wondering about doubling them up somehow, but then again each only outputs according to it's design right ..( right???)
notice the four tabs that make contact with the stator.

 
gorgeous 80mms of driver real estate. Untapped potential possible?,  just look at this thing.

 

[khbaur330162]

So. Cool.

 

[nick n]

Going to see about how the driver in the PhilipsEM6721 is secured, if it is press fit also then in go the extra spacers from this. It's already a cool shell and should be a perfect addition !
 Here's hoping.
 
Damn I forgot these are single ended ( big sigh ) = one stator only, the other power lead simply goes to a ring on the rear frontside(!?). Essentially they reduced the front stator to an outer ring, the equivalent of wisdom teeth, often there but useless
Not only that there's all sorts of dust on the backside due to not having and dust filter in the rear cup port.
 
I may have inadvertently broken the edge there also while deconstructing. Oh well.
 I had a close look and there is pitting where these things have hit up against the rear front indented cup port disc! and corresponding silver marks where it has left those spots from the membrane.
 
Waitaminnit that's the earside bass plug rear not the back cup port.So all the dust was coming in through there and the driver was bashing against the earside. ( which has no dustguard, moisture guard or stator on the earsides. )
Makes me wonder what it would have been like if that wasn't so recessed and kept higher up, together with the brass retaining plate gone also..certainly not helping. I wonder if the intermittent driver cutout was this thing bottoming out against that part it seemed to happen with suction from a good seal so i bet it was. If anything they should have applied the green spacer junk to that also.

 
Got to sit back and think about this. Strange design.
 
In this first pic you can't see it really but the spacer on the stator is the green directly applied part, and also between each hole over the entire surface there are tiny green dots of the same material. I guess because it is so close, that green spacer doesn't seem all that thick.
  Below  with the camera angle you can see where it has been hitting the stator unless that is all dust but I doubt it.

 
 
what's on the earside. You can see the cable lead wire attached to the ring  on the outer perimeter. That ring is about 1mm tall. See where it has been smashing the earside baffle bass plug also.

currently toying around with a cup that has no back front intact.  I think that brass thing needs some more holes.

 
You'll never guess how I fixed the small tear.
 
 
anyhow enough of that, it's a planar and an odd design. More later.
 
 
= I love the HP-50a's. Not the most sensitive cans for portables, I had it @volume 34/50 with a FiiO E5 maxxed out and it was loud yeah but that's really high power for me to use. Granted the bass enhanced crossfeed cable inline with that setup might be eating some juice even with the capacitors it's got in there.

 

[Kabeer]

Quote:

Going to see about how the driver in the PhilipsEM6721 is secured, if it is press fit also then in go the extra spacers from this. It's already a cool shell and should be a perfect addition !
 

 
 
what's on the earside. You can see the cable lead wire attached to the ring  on the outer perimeter. That ring is about 1mm tall. See where it has been smashing the earside baffle bass plug also.

currently toying around with a cup that has no back front intact.  I think that brass thing needs some more holes.

 
You'll never guess how I fixed the small tear.
 

Oddly enough I have a set of these drivers ina box somewhere, I removedthem from  a phillips tret a few years ago. Because they are SO large, I thought one day I could cut out that 'reflector' on theback to make them mostly open, (thereflector onthe back need to be there at least on the edges to give an electrical contact), and hoped it would be less treble heavy. Never did get round to doing it thouhg, maybe you could. (not even sure how i could cut it out)

 

[leeperry]

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it's from a coby headphone cv185
 

 
fits the yh1 perfectly, the hp2 with a smaller diameter also fits with no problems. the inner holes are also larger than the stock pads.I must say the quality of these pads is very good, better than the stock pads of hd25. i have no discomfort on long listening sessions. also made my orthos bass tighter and gave more airiness and soundstage.

 
Touché! These earpads provide stunning deep bass response(the bassline of "Nick Cave - Red Right Hand.flac" never sounded this loud

) and a very focused sound thanks to their thick pleather, together w/ an even wider SS on my YH1. Muchas gracias por el consejo 

 
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Aren't the TDS5-M similar yet noticably different in some manner?

 
Hard to say coz the cable is microphonic to death, the earpads seem to be of very poor quality and I can only imagine how sloppy the stock damping must be...I will move/recable its drivers into a more favorable set up using w/ those COBY earpads. I also want to try the YH100 drivers in a YH1 shell.

 

[nick n]

thanks I'll take a look around for cheapo Coby sets to at least try one for the pads. 
 
Kabeer:
 All I was going to do is spin the brass backplate out again and start drilling as many evenly spaced holes as possible in the areas where I think it won't affect the structural aspect of it when I press it back down and spin it back into place.
 
This thing burned me out I actually had dreams about it, so it's gonna sit for a while.

 

[leeperry]

well, those earpads sound good but their foam is pretty stiff....I've let them to sit under a huge pile of books for a while....and the TDS5m seems to improve with burn-in, I presume that it's a NOS pair that remained unused for decades.

 

[nick n]

Does sitting them under the weight of the books simply make them small profile or does it actually soften up the stiffer foam, or compress the foam and give the pleater less tightness? That's frustrating with foam like that. Especially when it would otherwise be a perfect pad.

 

[iQEM]

woooowwww, nick_n...that was pretty impressive picts i must say..
thanks a million for the posts again, nick_n...i really appreciate that...

yes, it's look the same driver as the Aristona EK400 but i only can peek from the housing side, not from the ear side..
and if i read your post correctly, maybe i'm change my mind and not gonna tears apart this EK400 since its not belong to me...
after several months have it with me, i have replace all the layer dampener with a single tapes...
yes, this tapes beat 3 sandwich layer of thin glasswool, 1 disc of fake chamouis and semi dense green felt...
all i do was, open the brand tab and cover the holes with tapes..
now it sound more solid&balance than when it in stock form..

 

[wualta]

Quote:

Originally Posted by nick n /img/forum/go_quote.gif
 
This thing burned me out I actually had dreams about it, so it's gonna sit for a while.

 
Wuh oh. When headphones invade your dreams, it's time to get interested in something else for awhile... [backs slowly away]  Put down that biaxially-oriented polyethylene terephthalate axe! No! No!