Orthodynamic Roundup

[leeperry]

  But speaking of AKG, do you recall that AKG patented some really interesting orthos that never got produced? 

 
They made very clear in the K1000 brochure currently available on wiki that ortho designs with neo magnets were bound to fail in their opinion due to excessive weight. It's equally clear to me that they were entirely right when I see +500g neo-orthos(and up to 650g lol) without a double headband which would be a major no-go to me, it's only now that they are finally using proper HP1'esque headbands with the HE400i/HE560 duh. OTOH, Oppo prefered to build a highly effective dual-sided diaphragm and the weight of the PM3 is in the 350g region IIRC.

 

[nick n]

Yup 327g if I recall correctly for the PM-3.  Which is now on sale a lot cheaper now ( all models )= like-new refurbs with all accessories and warranty even which should drive second hand prices lower, unless second had has a warranty which I doubt. Second hand is more like a hand wave warranty...
 
over a LB of weight is a bit much.
 
FWIW PM-2 refurb is $200 off
 
++++ OWW how did I miss the last few posts.
 Master Nomax is at it again, been wondering what he has been on about lately. Will see I guess soon.
 
16 ohms, also why would anyone put that on a shell. Photoshop joke maybe. The headband assembly looks rather primitive for an AKG production.

 

[ericj]

   
They made very clear in the K1000 brochure currently available on wiki that ortho designs with neo magnets were bound to fail in their opinion due to excessive weight. It's equally clear to me that they were entirely right when I see +500g neo-orthos(and up to 650g lol) without a double headband which would be a major no-go to me, it's only now that they are finally using proper HP1'esque headbands with the HE400i/HE560 duh. OTOH, Oppo prefered to build a highly effective dual-sided diaphragm and the weight of the PM3 is in the 350g region IIRC.

 
Nonsense. The T50RP only weighs 330g. 
 
There are plenty of dynamic headphones heavier than that, including the TH900 at 400g. 

 

[leeperry]

^ Your document was released in 1979, remember? Anyway, check the K100 brochure and see why they decided to give up on orthos. I am not impressed by the T50RP to the least and it's pretty obvious that the larger the diameter of an ortho driver the "thicker" and more life-like it will sound IME. There's a good reason why the latest russian orthos are 80mm IMO.

 

[ericj]

  ^ Your document was released in 1979, remember? Anyway, check the K100 brochure and see why they decided to give up on orthos. I am not impressed by the T50RP to the least and it's pretty obvious that the larger the diameter of an ortho driver the "thicker" and more life-like it will sound IME. There's a good reason why the latest russian orthos are 80mm IMO.

 
Document? 
 
I never spent much time with the T50RP myself. 
 
And i don't really care why AKG gave up on orthos. Different engineering organizations go different ways for different reasons that aren't necessarily solid. 

 

[zeroduke]

I have just found (and obviously bought) a Peerless PMB 80, NOS (sealed box). I am surprised by the clear sound (though weak bass) of this headphone.  Just one thing:  it seems that time has aged the bonding of the pad edges (white velour). I understand there is no original pads for the PMB 80 now.  Does anyone here know which pads could fit in? Thanks.

 

[MuZo2]

Open them and check if foam has deteriorated, it gets pretty bad and go inside the drivers.

 

[zeroduke]

Foam seems to be ok.

 

[JamesBr]

 

Open them and check if foam has deteriorated, it gets pretty bad and go inside the drivers.

 
What would you suggest to replace them?

 

[MuZo2]

If you like current sound just replace it with any open cell foam. You can also try felt or cotton or combination.

 

[zeroduke]

I've found that these ear pads fit perfectly well on Peerless PMB 80:
http://www.german-maestro-shop.de/epages/61902279.sf/en_GB/?ObjectPath=/Shops/61902279/Categories/Zubeh%C3%B6r/Ohrpolster
Even they've got the little hole at the back, as the original ear pads.
I own the Charteroak SP1, which in fact is the German Maestro GMP450. 

 

[musiclife]

 

I've found that these ear pads fit perfectly well on Peerless PMB 80:
http://www.german-maestro-shop.de/epages/61902279.sf/en_GB/?ObjectPath=/Shops/61902279/Categories/Zubeh%C3%B6r/Ohrpolster
Even they've got the little hole at the back, as the original ear pads.
I own the Charteroak SP1, which in fact is the German Maestro GMP450. 

Interesting, thanks for the tip.

 

[zeroduke]

It seems that German Maestro (or the staff) was related to MB Quart in the past.  And MB was previously owned by Peerless, when they made the orthodynamics (it  was MB Peerless).  That could be the reason the ear pads are so similar if not the same.  Anyway, it's good to have new replacement pads for the PMB 80.

 

[ericj]

  It seems that German Maestro (or the staff) was related to MB Quart in the past.  And MB was previously owned by Peerless, when they made the orthodynamics (it  was MB Peerless).  That could be the reason the ear pads are so similar if not the same.  Anyway, it's good to have new replacement pads for the PMB 80.

 
Once upon a time there were two companies, named Peerless and Mikrofonbau. 
 
history here: http://wiki.faust3d.com/wiki/index.php?title=PMB_/_MB_Quart

 

[DefectiveAudioComponent]

I have just found (and obviously bought) a Peerless PMB 80, NOS (sealed box). I am surprised by the clear sound (though weak bass) of this headphone.  Just one thing:  it seems that time has aged the bonding of the pad edges (white velour). I understand there is no original pads for the PMB 80 now.  Does anyone here know which pads could fit in? Thanks.

Those PMB drivers do usually produce deep (quite) strong bass - if you take the drivers out and put them to your ears, how do they sound then?

(Instead of sealing the cups and damping the drivers, I prefer to minimize bass backwave cancellation on PMB drivers by placing the drivers extremely close to the ears, I have done that with my RT-10, with very good results.)