[Philimon]

I forgot to add my intiital impressions of these. (These were when stock covers were still on).:

Stock sounds mid-centric and peaky, sense magic but needs distance because fatiguing.
First pad swap: Geekria Grado style s-pad with hole. Sounds detailed and rich. Lifelike vocals, clear bass. Fast. Negative tilt frequency response and overall smoothness like KOSS 95X but the difference is that bass is satisfying with the ortho. I tried eq with KOSS 95X but it was still missing impact, however I would like to try again at some point instead with some mods and alternate pads. Overall tone and resolution they are not dissimilar, but 95X has big open transducers so you get those soundstage perks. Prefer YHD3 because better bass, smaller footprint (no energizer required), and cheaper.

I've been using high-gain for the first time with Vali2 because these phones are insensitive.

These are about similar in size to a Koss KPH30i (little bigger than Porta Pro). Comfy and light.

 

[Philimon]

Could not open cups. Tried pushing clips in, but dont know if it really worked. I heard a click sound, but dont know if that is from unclipping or breaking. Next tried prying apart front baffle from rear cup and could not get to budge. All that I got was stressing of plastic and bulging like about to break. I may not have understood @Kabeer directions.

 

[takato14]

@Philimon

The foam inside the cups has likely deteriorated and fallen apart. Be very careful with these as they are sensitive to kinetic shock and the driver seal may become compromised if they are dropped or smacked around.

Unlike the first and second generation orthodynamic designs with a center pin, the YHD series drivers are nearly impossible to service due to the chassis being pressed together and clamped at the edges with a sheet of aluminum.

It is definitely in your best interests to get some sort of damping behind that driver as the YHD headphones actually have nothing but a measly 1mm thick sheet of (now decayed) polyurethane foam lining the back of the mesh.

 

[Philimon]

@Philimon

The foam inside the cups has likely deteriorated and fallen apart. Be very careful with these as they are sensitive to kinetic shock and the driver seal may become compromised if they are dropped or smacked around.

Unlike the first and second generation orthodynamic designs with a center pin, the YHD series drivers are nearly impossible to service due to the chassis being pressed together and clamped at the edges with a sheet of aluminum.

It is definitely in your best interests to get some sort of damping behind that driver as the YHD headphones actually have nothing but a measly 1mm thick sheet of (now decayed) polyurethane foam lining the back of the mesh.

Thanks takato14.

Not sure I can open these myself. I think they will break. Anyone interested in trading for another Yamaha? Or buying? Comes with original packaging. Mostly interested in YHD1/2, HP1a. Would sell YHD1 for half what I paid to vintage ortho regular in USA, maybe Canada.

I did not know these were so fragile. The portable styling looks like it means it could handle some abuse. However, the insensitivity of the drivers means youre not going to be using these away from a desktop amp anyway.

I really like lightweight supra aural open foam headphones (Grado and Porta Pro). I would love to keep these forever if they were modded. Anyone want to mod for me? Ill pay (up to a point). Wouldnt hold you liable for damages.

 

[Philimon]

YHD3 needed dismantling because the decayed goopy foam is occluding holes everywhere. The driver “mesh” looks to be felt that’s held up well.

Certainly have broken all clips and heavily scatched up plastic of these recently NOS headphones. These are now keepers.

First cleaning then modding. Hopefully I didnt break with my oafish maintenance.

 

[Philimon]

More photos.

 

[Philimon]

First attempt:
Felt-ish disc behind driver. Damplifier (dynamat) laid around edge of driver and front baffle. Then a circle of felt on edge of cups.

 

[Philimon]

Had to rearrange green felt so cups could better clip together. Sealed up some front baffle holes. After I figure out pads then Ill play more with seal.

 

[Miiksu]

@Philimon I did something similar to my ECHO TDS-16. It may sound very good. Just don't overdo. You lose the sound pressure.

 

[Philimon]

Are the TDS-16 really equivalent of Yamaha drivers? I like the headband design and price. Id like to try listening with removed rear cups for less rear wave reflection.

 

[Miiksu]

Are the TDS-16 really equivalent of Yamaha drivers? I like the headband design and price. Id like to try listening with removed rear cups for less rear wave reflection.

It's good sounding headphone but it lacks sub bass because it's way too small and over ear. I like the sound signature it's a bit classic sounding and muffled sometimes but presents nicely whole spectrum when modded. I think it's because these two magnets have deep drilled holes. I don't personally know how Yamaha's driver sound.

 

[Philimon]

YHD3 mod caused bass to become more linear but lesser in amplitude compared to highs.

Id guess that disc felt is reflecting treble energy back, or is damping bass in combination with mass damplifer. Im going to remove disc felt and see what happens.

 

[master1s]

I have these Orthodynamic headphone

Akai ASE-40

Akai ASE-50

Aiwa HP500

Audiotronic AHP66

Dual DK720

Fostex T30

Fostex T50

Grundig GDHS 223

Heco HPI300

Hosiden DH-80

Kenwood/Trio KH-72

Kenwood/Trio KH-92

Kenwood/Trio KH-83

Kenwood/Trio KH-85

Kenwood/Trio KH-800

Lafayette RP-50

Leak 3000

Otto E-1000

Pacific Stereo Concept CE-H

Peerless PMB 80

Peerless PMB 100

Realistic Pro 30

Sansui SS-100

Technics EAH-830

Technics EAH-820

Victor HP-D30

Victor HP-D35

Victor HP-D50

Victor HP-D70

Victor HP-D90

Wharfedale ID-1 Isodynamic

Wharfedale ID-2 Isodynamic

Yamaha YH-5M

Yamaha YH-1000

Yamaha HP-1000

Амфитон ТДС-15

Электроника ТДС-5М

Электроника ТДС-5

Boots H3750

Sound track 42-200

 

[Philimon]

YHD-3 to Koss KHP-30i transplant. Benefit is no front grill obstruction. Also, I was annoyed at how all the YHD cups tabs broke so required extra mods to keep closed. Unfortunately, broke a tab on Koss too. Might order another now that Ive figured it out, or another Koss like KTXpro1.

I plan to shore up interior edges of cup to reduce front/rear wave cancellation.

 

[Philimon]

Mehsurements:

I used butyl to fill in sides for mass and to block rear wave cancellation. Stock koss lite foam in back of cup behind driver. Geekria Grado style S-pads. Happy that I could still use foam pads, more open and comfortable. Koss enclosure easier to mount pads too.