[Vaughn]

member nick n caught me skulking around the vintage receiver forum and asked me to post on a T50rp rebuild I had started a while ago.
 
My intent was to completely rebuild the housing in an attempt to angle the drivers. My hope was this would give me a little better soundstage. I had experimented with angled Stax pads in the past and the results were very favorable, if somewhat expensive.
 
I built the cups up from aluminum with the baffle fixed to a hemisphere. Due to the construction I had to use the original driver reversed, i.e. back facing out. Since the front and rear of the driver seemed to be identical this didn't appear to be a problem. I removed the filter paper front and back in order to make them more "symetrical" (this may have been my first mistake). I stuffed the enslosures with some long hair wool I had and wired them up. Well expectation bias and psychoacoustics came heavily into play at this point as I believed what I was hearing was a substantial improvement. Luckily I had purchased a second pair of T50rps as my control group (unmodified). When I switched back to the unmodified T50s they were better, and remained so.

 
I futzed with the damping and tried molding the face of the baffle up with museum putty in an attempt to improve the sound but all of my efforts were wasted. I just couldn't get them to sound good. I became so disgusted with the project I haven't touched it in months. I haven't given up totally yet though. I think I need to pull the long hair wool out and replace it with basic fiber glass and attempt to reinstall some type of filter over the front and back of the driver similar to the original.
 
 

 
 

 

[Armaegis]

They look neat (but must be huge on your head). Did you build the shells yourself? or are they from something else?
 
Are there any vents on the cup or is it completely closed? Any baffle holes either?

 

[DefectiveAudioComponent]

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What went wrong with the sound of those? They have a fine space-age look to them.
 
 
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TDS-15 seems best both of them in details retrieval, instrument separation, and sense of air, but lacking bass in stock form.

 
I am thinking the bass is quite good / deep in the TDS-15. But those flat stock pads are so extremely uncomfortable - they go inwards in the middle, like a flat tyre.

 

[Vaughn]

Quote:

They look neat (but must be huge on your head). Did you build the shells yourself? or are they from something else?
 
Are there any vents on the cup or is it completely closed? Any baffle holes either?

 
The shells are actually intended for baking. You can get them in a variety of sizes, in case you want to make a cake that looks like a snowman. There is a vent on the cup, about 5/16" of an inch. I might try sticking a grommet in it as a hole shrinker and see what effect that has on the sound. No holes on the baffle.

 

[Vaughn]

@ DAC,
 
Still trying to suss that out. This is the problem with approaching something like this with less than scientific rigor. I'm not really sure what point I should backtrack to and start again.
 
I think a large part of it is I should not have removed the filter screens attached to the front and back of the driver. Now I'm left with trying to fabricate a reasonable facsimile. Also, I'm sure I overstuffed the chambers. 

 

[ludoo]

Quote:

I am thinking the bass is quite good / deep in the TDS-15. But those flat stock pads are so extremely uncomfortable - they go inwards in the middle, like a flat tyre.

 
+1 my exact same impressions

 

[Armaegis]

Quote:

 
The shells are actually intended for baking. You can get them in a variety of sizes, in case you want to make a cake that looks like a snowman. There is a vent on the cup, about 5/16" of an inch. I might try sticking a grommet in it as a hole shrinker and see what effect that has on the sound. No holes on the baffle.

 
Hah, I was thinking it was from a lamp or something. Try adding a tiny pinhole to the baffle.
 
How does it currently sound? (or how does it compare to stock?) I've done my fair share of transplants so I'm curious. 

 

[Hutnicks]

Ha Ha (and I am laughing with you not at you for sure. I suspect the rub is in the hemispherical shells you have used. I had (am having if I ever get round to working on them again) a very similar experience with a pair of sawafuji drivers in skullcandy hesh (hey I paid 4 bucks for em and they aint worth that, so for parts....) which have a hemi enclosure. While it seemed a great idea at the time, I believe the hemisperical enclosure reflects way too much even when damped and is resulting in nodal lines removing some of the frequencies. I had thought of A) cutting the rear of the hemi off and putting a flat plate over the hole or B) using some kick ass ceramic putty to create a deep and irregular surface in the shell. After thinkng it over, it pretty much would be a more economical venture to haul out the router and dremel and just make a different enclosure out of wood. As for the hesh...well... 4 buck aint bad for a headband, is it?
 
My enligtened scientific conclusion. Hemi, good for internal combustion engine, bad for orthos
 

 

[Vaughn]

Quote:

 
Hah, I was thinking it was from a lamp or something. Try adding a tiny pinhole to the baffle.
 
How does it currently sound? (or how does it compare to stock?) I've done my fair share of transplants so I'm curious. 

 
I will try the pinhole for sure as it is easy to undo. See below for the sound
Quote:

Ha Ha (and I am laughing with you not at you for sure. I suspect the rub is in the hemispherical shells you have used. I had (am having if I ever get round to working on them again) a very similar experience with a pair of sawafuji drivers in skullcandy hesh (hey I paid 4 bucks for em and they aint worth that, so for parts....) which have a hemi enclosure. While it seemed a great idea at the time, I believe the hemisperical enclosure reflects way too much even when damped and is resulting in nodal lines removing some of the frequencies. I had thought of A) cutting the rear of the hemi off and putting a flat plate over the hole or B) using some kick ass ceramic putty to create a deep and irregular surface in the shell. After thinkng it over, it pretty much would be a more economical venture to haul out the router and dremel and just make a different enclosure out of wood. As for the hesh...well... 4 buck aint bad for a headband, is it?
 
My enligtened scientific conclusion. Hemi, good for internal combustion engine, bad for orthos
 

 
I think you are right about this. The entire midbass area seems to be MIA. There is plenty of deep bass but the sound is completely hollow. I think I'll make a cheap and cheerful diffusor to go in the back of the cup. Maybe something like the energy dome helmets Devo wore, except made out of closed cell Creatology foam from Michaels. 
 
 

 

[Hutnicks]

Quote:

 
I will try the pinhole for sure as it is easy to undo. See below for the sound
 
I think you are right about this. The entire midbass area seems to be MIA. There is plenty of deep bass but the sound is completely hollow. I think I'll make a cheap and cheerful diffusor to go in the back of the cup. Maybe something like the energy dome helmets Devo wore, except made out of closed cell Creatology foam from Michaels. 
 
 

I found that everything seemed flat it was like just about every other frequency was blocked until you got up into the high wavelengths. Rather sounded more  like very good split mono insted of stereo.
 You can probably pick up  those energy domes cheap now, That'll be the next trend after Dre's beats , 50 Cent and Ludacris.efforts to murder the sound perception of our youth. Have to admit, a Devo desinged ortho or electostat could potentially be awesome, you should pitch em on that one

 

[yhong26]

hi any idea to recable HP-3? any nice cable to suit it? 

 

[stacker45]

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hi any idea to recable HP-3? any nice cable to suit it? 

 
For a monent there, i tought you were referring to Grados HP-3, sorry, carry on

 

[kalbee]

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oh the YH-1000 dropped in price then

 
I wonder if there is corrosion on the driver traces in this one.
 
Kalbee i would be curious to see their attachment method for the aftermarket headband whenever you get around to it.

 

 
Punched through. How? I have no clue! which is why I was unsure on it being a DIY.
 
I would imagine the only easy way to do it would be to remove metallic part from the cup, insert it backwards into the headband, and fix it to the cup again. But when I took everything apart I couldn't see any easy or proper way to removing the ball joint without minor destruction.
The other side of the headband is broken on the side of the punched hole; you can imagine how little material there is there considering how thin the headband is at that point. It is currently being held by electric tape, and it's working but temporarily.
 
Seeing as it isn't adjustable in any way, and that they can rotate freely indefinitely (kind of like Grados but on a different axis), I'm lucky it fits just perfect on my head. Though the cups are then highly angled forward.

 

[Armaegis]

Quote:

 
I think you are right about this. The entire midbass area seems to be MIA. There is plenty of deep bass but the sound is completely hollow. I think I'll make a cheap and cheerful diffusor to go in the back of the cup. Maybe something like the energy dome helmets Devo wore, except made out of closed cell Creatology foam from Michaels. 
 
 
 

 
Probably the first thing I do for any ortho damping is put some acoustic foam behind the driver. Anything to break up the immediate reflection. Where is the cup vent located? Perhaps instead of one big one, it'd be better with several smaller ones. This would also make it easier to tune and experiment. I see a lot of closed headphones these days with four small holes hidden somewhere along the cup. 
 
When you say the midbass is missing, can you say roughly what frequency it falls at? I have a Nuforce HP-800 I reviewed recently which has a big hollow aluminum cup and it has some crazy bass, but drops quite strongly at 400Hz. 

 

[nick n]

Vaughn   Thanks for popping in

  There will be some sort of solution for those awesome looking items you built. Things seem to go haywire when they are missing for the most part it seems.
 
If you want send me a PM I have some similar white fabrics that may do the trick for replacing the stock backing paper/materials.  I can send some out, if you want ( no pressure no pressure ) at least you can see and if none of it seems close to you then throw it out
 
Quote:

 

 
Punched through. How? I have no clue! which is why I was unsure on it being a DIY.
 
I would imagine the only easy way to do it would be to remove metallic part from the cup, insert it backwards into the headband, and fix it to the cup again. But when I took everything apart I couldn't see any easy or proper way to removing the ball joint without minor destruction.
The other side of the headband is broken on the side of the punched hole; you can imagine how little material there is there considering how thin the headband is at that point. It is currently being held by electric tape, and it's working but temporarily.
 
Seeing as it isn't adjustable in any way, and that they can rotate freely indefinitely (kind of like Grados but on a different axis), I'm lucky it fits just perfect on my head. Though the cups are then highly angled forward.

Yeah i had to quote that picture again
Too cool not to.
 
The only way i can see they did that is countersinking where top the pin top seats in for swivelling, then right through the middle of the headband end there, then next putting the pin through and in place with a bit of glue on the very tip,  and pushing that back into the cup mounting hole.
 
Make sense?  Pretty good considering really.
 
YHONG26 :
 
For the recable on the HP-3, I did up an HP-50 ( same thing basically ) with I think some Koss cable because i needed to make it into stereo mode, but you might want to find something that allows you to use the stock strain relief(s) from each cup entry point.( I forget if the HP-3 is single or dual entry ) They will slide off the stock cable  and onto the new cable... This will allow you to control that area so it doesn't turn into some sort of venting and make the one side slightly different sounding. I also found it goofy without something holding the cable properly at that point since these are press-fit baffles and no screws to secure things down except the built in tabs. Just my two cents.
 
It sure makes it easy to do it that way rather than fighting the entry point into the cups with something else.
If you do reuse the strain relief it will mean that you can't go with a huge jumbo cable that is any bigger than the stock diameter cable.
 
 
 
What is it you want to recable for?  Stock one is probably fine. Were you wanting to go nuts on a silver cable or something like that to change up the impedance/capacitance and sound?  You could always sheath it in some techflex or similar covering tightly with some shrinkwrap if you don't enjoy the appearance as is...
 
it'll give you a nice chance to open them up and experiment with some damping though. Just make sure to post pics of that if you do