[gurubhai]

yep
 

 

[maverickronin]

Quote:

The NADs are slightly more difficult  to drive than LCD-2 which is odd since the published sensitivity specs would suggest the reverse.
 
Is it possible that the old magnets have been loosing some of their 'oomph' over time ?

What do the magnets look like?  AFIK only alnico magnets lose their strength over time but I think those are actually a different color from the normal ferrites.
 
What shape are the rest of the 'phones in?  Any kind of magnet can lose its strength if subjected to repeated and severe shocks, but I'd imagine anything strong enough to do that would wreck the rest of the headphone.
 
Its also possible that someone may have managed to partially degauss it at some point.  Do you happen to store them on top of a CRT monitor?  Or maybe the last guy who owned them did.
 
Basically there are a lot of things that could have happened to something that old and its hard to say what, if anything, actually did.

 

[gurubhai]

The magnets are samarium-cobalt .
The headphone itself is in excellent condition & the other pair I have seen also had similar sensitivity.
 
May be the published specs themselves are not accurate.
 

 

[nickchen]

Quote:

I need bigger diaphragms

That shows that you are a severe geek, normally guys in your ago age would long for bigger balls or bigger cars.

 
But BTT, I don't think biggger is necessarily better with diaphragms. Similar to a big oldfashioned V8 roaring big block vs some modern lightweight efficient turbo engines, I think those big systems also do have built in drawbacks, most of all their sheer weight and size. I doubt that I will ever get serious PRaT out of these big boys, the tiny AT/Sansui systems and all my dynamical cans run circles around them.
 
But they all don't offer that special roaring...

 
BTW, how big are the LCD2 systems, and do they "roar" as well?
 
 

 

[BoilermakerFan]

 
Quote:

What do the magnets look like?  AFIK only alnico magnets lose their strength over time but I think those are actually a different color from the normal ferrites.
 
What shape are the rest of the 'phones in?  Any kind of magnet can lose its strength if subjected to repeated and severe shocks, but I'd imagine anything strong enough to do that would wreck the rest of the headphone.
 
Its also possible that someone may have managed to partially degauss it at some point.  Do you happen to store them on top of a CRT monitor?  Or maybe the last guy who owned them did.
 
Basically there are a lot of things that could have happened to something that old and its hard to say what, if anything, actually did.

Nah, nothing like that.  They only sound less efficient because they are so bass heavy and with a 30 year old stock cable, corrosion is setting in so the cable has more resistance than when it was new. The specs are from when the headphones were new.  Replace the cable and they be more efficient, but then after damping them to cure the errors of their ways they are back to less efficient... but I think they are a little more current hungry than LCD-2s too. 
 

 

[wualta]

Yes, big diaphragms are fun, but when you make a diaphragm big you also create other problems. You've already mentioned the sheer mass of the magnet structure. In addition, the cups and baffle have to be strengthened to maintain alignment while the magnets try to fling one another across the room. That's a lot of force to hold safely in place. Analysis of the forces on the cup can lead to a design that contains the forces but doesn't weigh so much. The magnets have to be big enough to fling a magnetic field over the diaphragm that's powerful enough to give the headphone sufficient sensitivity. But you can trim diaphragm mass and reduce magnet mass proportionately.
 
Then there's the problem of standing waves once the diaphragm is big enough to support a wavelength in the audible region. Any clamped diaphragm has this problem-- energy travels across the tensioned film and reflects off the boundary, in this case the clamped outer edge. One solution is to make the diaphragm shape irregular, as Sony did with the ECR-500 and Rick W. proposes to do with his PM-1. Or you can use a circular or rectangular diaphragm and clamp it between two identical but irregular pieces of felt.
 
RE efficiency: there are so many different ways to measure it that unless you know the exact methodology the factory used plus the factory tolerance limits, you only have ballpark figures. If they're close, it's good enough.


 

 

[maverickronin]

Quote:

Nah, nothing like that.  They only sound less efficient because they are so bass heavy and with a 30 year old stock cable, corrosion is setting in so the cable has more resistance than when it was new. The specs are from when the headphones were new.  Replace the cable and they be more efficient, but then after damping them to cure the errors of their ways they are back to less efficient... but I think they are a little more current hungry than LCD-2s too. 
 

And just when I though I had enumerated all the possibilities...

 

[nickchen]

I thought more of the sheer diaphragm mass which makes it moving slower. I guess those PRaT disadvantages and the propably complicated production and QC routines were the main reasons they've ceased building such monsters.
 
Maybe that effect gets a bit compensated with better pads, but right now, with T20 pads, that NAD is one of the slowest cans I ever experienced. But as we all know, that presentation has a beauty of its own...

 

[gurubhai]

Quote:

 

Nah, nothing like that.  They only sound less efficient because they are so bass heavy and with a 30 year old stock cable, corrosion is setting in so the cable has more resistance than when it was new. The specs are from when the headphones were new.  Replace the cable and they be more efficient, but then after damping them to cure the errors of their ways they are back to less efficient... but I think they are a little more current hungry than LCD-2s too. 
 

Mine are recabled & damped. They have the same efficiency as my friends stock pair. They both are slightly more power hungry than LCD-2 though.
 


Quote:

I thought more of the sheer diaphragm mass which makes it moving slower. I guess those PRaT disadvantages and the propably complicated production and QC routines were the main reasons they've ceased building such monsters.
 
Maybe that effect gets a bit compensated with better pads, but right now, with T20 pads, that NAD is one of the slowest cans I ever experienced. But as we all know, that presentation has a beauty of its own...

I don't understand what the fostex was upto. The mylar version has no lack of PRaT & is nigh-perfectly damped from the factory.
Did they just forget to place the diaphragm under tension on the Kapton ones.?

 

 

[nickchen]

Maybe the big bass also misleads my PRaT judging...

 

[iQEM]

Quote:

Thank you!!
 
One reason why I want mine to be the bassy one is that I can eventually equip it with super comfortable W11 pads then, I have enough supraaural orthos meanwhile. My buddy NoXter once had those pads on his W1000, great comfort I must say. Actualy it was the only thing I liked about the W1000 at all besides its looks...

 
mine only test with Sony DR11 pads wich is small circum rounds, the inner hole diametre are match with the grill on the baffle...
sound more open&airy but not much with stock damping...that's why i roll the damping scheme's alot until i found "the right one", even it's still sound great with the stock pads...
i'll share some picts of my mod later...i haven't transfer the picts from my camdig yet...

 
Quote:

Quote:

I have the mylar version, slightly modded to enhance the bass.
A friend of mine recently got a pair of NAD too, but his pair is also mylar driver/balance sounding. His stock pair currently sounds a bit light in bass compared to my modded pair.
 
 

Yup the mylars vary a bit from one to another in bass heavyness. But they are all more balanced sounding stock.
Obviously it means it requires less damping, its one or the other.

yes, that's why i never touch the inside of the mylar NAD that i purchase from you...
it's already sound good for my ears, but i still end up selling those after found the kapton NAD from .de ...
more balance maybe not, but i love the first time i heard em...i feel this one have bigger potential than the simple mod mylar NAD, atleast for me it's very challenging to tweak something from stock...

 
Quote:

The eagle has landed. Your systematic was obviously correct, they have the round Y-splitter and have considerable bass, hello kaplon RP18!
 
First impression (besides the slightly muffy vintage smell) is that I don't miss that much SQ-wize. I am sold to that bone dry bass and its rich mids, and I am confident that some presence can be digged out quite easely. Technically, one can hear that this is really a different leage than all the other orthos I've tried until now, I expect it to end up somewhere close to my beloved MS Pro Ulti when everything is tuned in properly.
 

 
Reacts quite well on pad rolling and has enough ooomph for all sorts I tried, but I haven't found ideal pads in my inventory. Sounds okay with J$ pads and with those cheap Superlux ones, but I guess it deserves something "better".
 
Got a slight buzz from one side when it plays hefty deep bass, nothing serious, propably dirt...

 
clean the dirt then...open the driver capsule from baffles, replace the factory sealer with blutak or silicon sealer like i do...

 
Quote:

 
Owing to suboptimal pad circumstances, I switched the EQ on to dig more presence out of the RP18. The preset turned out not to be as brutal as I had expected (by far), and so I sat down and just shuffled through my collection, Squarepusher, Bach, Monolake, Keith Jarrett, Monteverdi, Mogwai, Yello, David Sylvian, Amon Tobin....
 
I must say, the most enjoyable session I've had for years

. I wouldn't say this thing can compete technically with all those 1K $ cans that get raved so much nowadays, but that manic sound weight and musicality is just outstanding. In respect of the latter, it even beats the DT531, which has been my (sadly dull) all time favorite in that respect. What is really special about it is its laidback and mellow character, even the most annoying stuff becomes much more listenable than with any other of my HPs, no fatigue at all. Musical bandwidth is okay, but not worldclass, it definetely suits better to fat and rhythmic stuff than to single violin partitas or kitten music IMO. And returning to the technical view, the gap between that NAD and my other orthos is really frightening, I'd locate it at least 2 classes above every other ortho I've tried or owned until now...

agreed...


Quote:

I thought more of the sheer diaphragm mass which makes it moving slower. I guess those PRaT disadvantages and the propably complicated production and QC routines were the main reasons they've ceased building such monsters.
 
Maybe that effect gets a bit compensated with better pads, but right now, with T20 pads, that NAD is one of the slowest cans I ever experienced. But as we all know, that presentation has a beauty of its own...

the stock pads are better, i suppose...

 
Quote:

Mine are recabled & damped. They have the same efficiency as my friends stock pair. They both are slightly more power hungry than LCD-2 though.
 



I don't understand what the fostex was upto. The mylar version has no lack of PRaT & is nigh-perfectly damped from the factory.
Did they just forget to place the diaphragm under tension on the Kapton ones.?

 

i believe nickchen use T20 pads when posting about PRaT...

 

[nickchen]

I've introduced the RP18 to my buddy NoXter and I've never experienced him that impressed before. He just grinned and stated, damn, I have a problem now. We also found an "intermediate" pad combination to bridge the time until the W11 pads arrive, taped TD770 pads actually sound nice, and the look and wear feel is also very positive. Still no PRaT monster, but the overwhelming slowness feeling has almost completely gone. Must have been partly a brain thing due to that overwhelming deep bass with the T20 pads.
 
Having NoXter's extra pair of hands available, I opened one system to try to get rid of the deep bass buzz, and it worked well. Now the bad news: The other side (which also has some ksssss issues) has been glued together by one former owner. No I've got to decide if I tolerate that buzz or if I rather try some more "robust" and dangerous methods to open that system.

 

[rhythmdevils]

They are not slow though right, I mean technically speaking, an ortho driver is fast.  A warm and bassy signature can definitely sound slower than a bright signature though. 

 

[Kabeer]

Quote:

Having NoXter's extra pair of hands available, I opened one system to try to get rid of the deep bass buzz, and it worked well. Now the bad news: The other side (which also has some ksssss issues) has been glued together by one former owner. No I've got to decide if I tolerate that buzz or if I rather try some more "robust" and dangerous methods to open that system.

Hm so they must have heard the buzz and thought glue was the solution. Can you show a clear photo of the glued portion thats causing the problem? Depending how it was implemented it might not be too hard to deal with.

 

[nickchen]

I'm afraid a pic wouldn't help here, because there's nothing to be seen from outside. It's just that the driver components stick togeter like hell on 80% of their outer sealing area, and if you try to widen the small gap on the unglued part, things don't give in at all. I think they would rather break, must be superglue or epoxy that had been used. I think the reason the driver halfs got glued was that one of the 4 screws had lost most of its winding. Not an entirely competent solution...
 
I think the only possibility to get through to the diaphragm would be using the mini dremel circular saw, but umhhh...I'm rather of the self confident sort with such things, but in this case I rather tend to keep it untouched actually, as no spare parts are available when I destroy something. The diaphragm's copper side areas are frightening close to the region where "housing violence" was to be applied in the repair case.
 
Dependent from the dirt's actual position, the buzz only occurs seldom, only songs with deep humming bass lines w/o percussion, but that one is quite unlistenable then. The buzz can be triggered to go away or become stronger by means of strong acceleration (drum heavy songs, or knocking against the driver). Blowing in the system also triggers change, but is complicated as so much is to be ribbed apart at the front side.