[MDR30]

Received a pair of HOK80-2s from Germany with the usual worn/aged pads and a stubborn patina of grime and dust, probably from a smoker's home. That oily, brownish layer doesn't respond to soap or alcohol, but must be worn down by pure patience.
 
So after putting in a few hours work in a day or two, including changing plug from five pin DIN to 6,5 mm TRS, I sat down and listened. Big disappointment: no bass, piercing mid and treble, plasticky sound (here referring to old transistor radios of same material with small paper cone speakers). I thought this was a lost case but decided to open the headphone since there was an intermittancy contact problem. Followed the guide by ericj (post # 787 in this thread) and added nothing but a circular piece of foam at the back of the driver to press it against the baffle.
 
Most important mod: took out the plastic disc covering the openings in the back of the cups. Cut the cable and resoldered it to the drivers. No OFC her, the East German copper was green as a dollar bill. Never mind, scraped off the worst and made sure the solder attached.
 
An now the reason for this post: I tried HD25 pads which fit like a glove, really. Listened again and the difference was huge: nice full sound, warm yet detailed. No wonder Facel Vega (what ever happened to him?) was a fan.
 
This is about the best PMB-driver type headphone I've heard. Well, at least of the semi-open kind. Work on the DK830 continues.
 
Gone: DIN plug and disc.
 

 
Green copper:
 

 
Cleaned HOK80-2s with Sennheiser HD25 pads:
 

 

 
Can be found for less than 20 euro on ebay.de - well worth the investment. Oh, they are quite power hungry and need an amp that can deliver a good amount of current.
 
 

 

[ardgedee]

Quote:

I guess it depends on what is inside of the velour coating on the Hifiman pads.  They could pretty easily have an inner material that doesn't let air through, but plain velour and foam lets air easily pass through, so it's definitely not a seal like leather or pleather is.  They seem to make it work, but I think it's possible that the things I don't like as much about their sound (cold tone, thin sounding, bright) are caused by those velours.  Could also be the damping they use though. 
 

I wouldn't be surprised if the velour pads for both the HiFiMan and HD 25 series headphones are velour fabric over a nonporous surface. (If I remember to, I'll check tonight). The pads for the HE-6, in particular, are very stiff. The pads for the HD 25 are softer, but feel overstuffed. In both cases, I'd speculate it's because the respective phones have high clamping forces that would flatten cushier pads.
 
An interesting approach is presented by the aftermarket pads that GermanMaestro/MB Quart sell; Velour, a couple different shiny plastics, and a combo pad designed to present a porous surface towards the driver and a smooth surface towards the wearer.

 

[wualta]

Quote:

yup, in general, no seal=not much bass. Oddly the HiFimans aren't nearly as fussy.

Remember the Sennheiser Lesson: keep the ear very close to the diaphragm and especially if it's a big diaphragm (which shadows itself), you won't lose as much bass as you might expect.
 
Quote:

Way too much top end- eyes fluttering & rolling in the back of my head style highs- and little bass. I agree that the open foam pads are probably the major contributor to the pain.

Har! Great description of the dangers of ignoring the bass-destroying properties of backwave-on-the-loose.
 
Quote:

I think if anything, a good earpad seal is probably more important with an open design because you're just letting all the back wave out. 

Preeeezeckly. 


Quote:

Received a pair of HOK80-2s from Germany. I tried HD25 pads which fit like a glove, really. Listened again and the difference was huge: nice full sound, warm yet detailed. No wonder Facel Vega (what ever happened to him?) was a fan.
 
Can be found for less than 20 euro on ebay.de - well worth the investment. Oh, they are quite power hungry and need an amp that can deliver a good amount of current.

Glad to hear you found a way to get some bass out of them. I knew from testing in the MOSFET Room that they were putting it out but just weren't delivering it unmolested to the ears. Ol' Facel-V. liked 'em because they were silly-cheap (he'd find them in Berlin for a single Euro) and, except for the lack of bass, they had that controlled ortho magic that makes itself known even when everything else in the design is going wrong. Anyway, Erik (Dr. Erik Ghenoiu-- you can read his dissertation online) decided to devote his time to his job. He's a visiting professor of architectural history and theory at Pratt Institute in Brooklyn. Looks like he'll be in Australia for a seminar this summer (their winter), too. So he's a busy guy. 
 
Plus, the HOKs are the only East German headphones we know of. Odd that an identical-looking driver shows up in some of the smaller/lesser PMB designs for Goodmans and Dual.
 
 

 

[NoXter]

Hey Guys,
 
Did someone tested the newer Audio-Technica pads which come along with A2000x and W1000x on the RP18? Actually I'm using W100 pads and thats pretty close to the W11 pads (except of wearing comfort).

 

[DefectiveAudioComponent]

It's a Magnat RT 10 high speed ribbon headphone. Altough, it's as you see an orthodynamic headphone with the early kind of PMB-driver. The PMB-80 has the later driver version, with one extra ring of holes in it. It's basically the same design as the PMB-80, it's just even more open (the PMB-80 has broad bars in the grille, the RT-10 has a wire mesh).
It's got the same sound as the PMB-80 I think.
 
Quote:

Those drivers look exactly like my drivers from the Peerless PMB-80. And the headband is very similar too. What is the brand of these ortho?

 

 

[rhythmdevils]

Quote:

Quote:

I wouldn't be surprised if the velour pads for both the HiFiMan and HD 25 series headphones are velour fabric over a nonporous surface. (If I remember to, I'll check tonight). The pads for the HE-6, in particular, are very stiff. The pads for the HD 25 are softer, but feel overstuffed. In both cases, I'd speculate it's because the respective phones have high clamping forces that would flatten cushier pads.
 
An interesting approach is presented by the aftermarket pads that GermanMaestro/MB Quart sell; Velour, a couple different shiny plastics, and a combo pad designed to present a porous surface towards the driver and a smooth surface towards the wearer.

 
I wonder if you could make a pad with closed cell foam in order to get a seal instead of leather wrapped around open cell foam. 

 

[chrislangley4253]

I've decided to add vintage headphones to the list of things I look for at garage sales. What are some names I should keep an eye out for? I know the older Yamaha orthodynamics. 

 

[rhythmdevils]

http://wiki.faust3d.com/wiki/index.php?title=Orthodynamic_Headphones_Rating_Chart

 

[BotByte]

Hey guys
 
I'm interested in buying a pair of Fostex T50RP's to sit in the middle of my headphone collection.
 
I have Grados and Sony mdr-v6's and I'm thinking a headphone with some good mids would be much appreciated in my set. My grados are highs and bright, my v6's are low and warm, so I want mids and neutral to settle down.
 
If I'm right, then tell me that they would be a good set.
 
If I'm wrong, can you lead me to a good set? I'm interested in a ortho otherwise.
 
Also, I like mods, any good and easy mods for the T50RP's?

 

[Armaegis]

They're cheap as borscht. Get one and go to town with blutak, dynamat, and some felt/fabric.

 

[DefectiveAudioComponent]

Quote:

Received a pair of HOK80-2s from Germany with the usual worn/aged pads and a stubborn patina of grime and dust, probably from a smoker's home. That oily, brownish layer doesn't respond to soap or alcohol, but must be worn down by pure patience.
 
So after putting in a few hours work in a day or two, including changing plug from five pin DIN to 6,5 mm TRS, I sat down and listened. Big disappointment: no bass, piercing mid and treble, plasticky sound (here referring to old transistor radios of same material with small paper cone speakers). I thought this was a lost case but decided to open the headphone since there was an intermittancy contact problem. Followed the guide by ericj (post # 787 in this thread) and added nothing but a circular piece of foam at the back of the driver to press it against the baffle.
 
Most important mod: took out the plastic disc covering the openings in the back of the cups. Cut the cable and resoldered it to the drivers. No OFC her, the East German copper was green as a dollar bill. Never mind, scraped off the worst and made sure the solder attached.
 
An now the reason for this post: I tried HD25 pads which fit like a glove, really. Listened again and the difference was huge: nice full sound, warm yet detailed. No wonder Facel Vega (what ever happened to him?) was a fan.
 
This is about the best PMB-driver type headphone I've heard. Well, at least of the semi-open kind. Work on the DK830 continues.
 
 
Can be found for less than 20 euro on ebay.de - well worth the investment. Oh, they are quite power hungry and need an amp that can deliver a good amount of current.
 
 

Nice work with the HOK It's a nice can. How is the clamping force on your set?
What PMB orthos have you heard?
 

 

[MDR30]

Clamping force is about ideal for me. Stock damping plus an extra slice of foam exhibit some inherent cup resonance (i e air volume, not material) but I wouldn't want to increase or decrease damping. Maybe try to bring up the treble a notch or two.
 
Have not heard as many PMB orthos as you, but the centre clamped diaphragms seem to share some sonic characteristics: bright with a tight but rolled off bass. I've tried thorough driver and pad seal (on the DK830) with many layered back damping, but that resulted in a muddy sound and no increase of bass. Not that I'm looking for heavy bass, only to redress the frequency balance somewhat. Still, I get the feeling that the PMB drivers - unlike the Yamahas - sound best with little or no damping or sealing (like other in this thread I held the naked drivers to my ears and the sound was surprisingly good!). Will report more in detail on my experiments with the DK830 when time permits. I'll leave them as they are now for extended listening before I make any conclusions. I'm getting some Maestro pads, have already tried DT880 pleather and velour pads (closed and vented backs respectively) with some success. At the moment Sony pleather pads with oval centres seem to suit them best. Pads sure make a difference...
 

 

 
Oh, and I won a pair of Magnats on German ebay about a year ago, but the seller vanished mysteriously . Show us some pics and let us know how they sound.

 

[nickchen]

Quote:

Hey Guys,
 
Did someone tested the newer Audio-Technica pads which come along with A2000x and W1000x on the RP18? Actually I'm using W100 pads and thats pretty close to the W11 pads (except of wearing comfort).

Looks like you are the first (again)

 
To all others: Chances to get a RP18 have increased slightly again, now that NoXter is finally equipped. But I bet the next north hessian meet will lead to new greedy debutants...
 
 

 

[DefectiveAudioComponent]

Quote:

Clamping force is about ideal for me. Stock damping plus an extra slice of foam exhibit some inherent cup resonance (i e air volume, not material) but I wouldn't want to increase or decrease damping. Maybe try to bring up the treble a notch or two.
 
Have not heard as many PMB orthos as you, but the centre clamped diaphragms seem to share some sonic characteristics: bright with a tight but rolled off bass. I've tried thorough driver and pad seal (on the DK830) with many layered back damping, but that resulted in a muddy sound and no increase of bass. Not that I'm looking for heavy bass, only to redress the frequency balance somewhat. Still, I get the feeling that the PMB drivers - unlike the Yamahas - sound best with little or no damping or sealing (like other in this thread I held the naked drivers to my ears and the sound was surprisingly good!). Will report more in detail on my experiments with the DK830 when time permits. I'll leave them as they are now for extended listening before I make any conclusions. I'm getting some Maestro pads, have already tried DT880 pleather and velour pads (closed and vented backs respectively) with some success. At the moment Sony pleather pads with oval centres seem to suit them best. Pads sure make a difference...
 
 
Oh, and I won a pair of Magnats on German ebay about a year ago, but the seller vanished mysteriously . Show us some pics and let us know how they sound.

I'll post a few more pictures of the Magnat soon. It is strange that they went for the open-baffle design. The people at Magnat must have known that the deep bass of the dipole would get cancelled out. The sound is special though.
 
Most PMB orthos do seem to sound best very lightly damped, and most appear to have rolled-off bass. I regret a bit that I sold my bass-heavy PMB.
 

 

[DefectiveAudioComponent]

Some more pictures of the RT-10
 

 
I took off the clamps, but the driver stays closed. It appears to be glued as well as clamped. Unless the sticky goo acts as a glue
 
Apparently, this is yet another version of the PMB driver...