What was the final conclusion about the TH500 driver diaphragm, were the traces actually slightly different than T50Mk2 ?
Or was it simply the new addition of the rear damping removal on one grid section.
Have lost track I recall some conversation about that ages ago resulting from a Fostex product presentation.
What was the final conclusion about the TH500 driver diaphragm, were the traces actually slightly different than T50Mk2 ?
Or was it simply the new addition of the rear damping removal on one grid section.
Have lost track I recall some conversation about that ages ago resulting from a Fostex product presentation.
Surprising measured changes (less even treble) from moving from 85mm hybrid pads to 95mm hybrid pads with Fostex T30. The 95 is a bit oversized for the ~82.5mm baffle. This I think caused less seal around baffle edges. Front baffle was confirmed leaky when disassembled. The front baffle is meant to pivot to allow some angle adjustment, but this also means front baffle is not coupled to rest of enclosure...
Rearranging the pads to try and stuff the mounting edges in between tiny baffle/cup gap did have an affect on measured frequency response.
Though the pads increased by 10mm in diameter, the ear holes only increased by like 2mm so I dont think that is making much difference.
I will go back in and try to seal. I wont bother too much though because these are destined for transplant mod. Actually, may just go back to slightly smaller and slightly less comfy 85mm pads.
Bought a YH-100. Ive seen them on ebay much more commonly and cheaper than HP1a, so settling for now.
Reading the first few pages of most recent YH-100 related posts say the YH-100 enclosure is worse than HP1a. YH-100 ani driver is a smidge thicker than HP1a’s. Magnet thicker or there is an extra plate? Didnt catch much detail or pics. Im guessing YH-100 and HP-1a drivers very similar otherwise. Buying YH-100 and moving driver to a HP|YH-1 enclosure is the easiest way to get an HP-1a now?
I tried more damping using micropore tape on cup grills. Typical damp improvements except yielded a small 2kHz hump. So trying increased damp with 6# foam in cup instead of the micropore. I also put some foam on edge where front baffle rotates towards open towards face for extra security of seal.
Too much damping? Should I have cut thinner? Maybe I need to try HFM pads then damp. Not tried listening to this mod yet...
edit: Overdamped. Bass drop. Listening to overdamped is interesting at first because mids/highs go up another level in transients and imaging and layering/detail. Just sounds sweet. But bass loses impact and volume.
I will try cutting thickness of cup foam in half. But first I am curious to see how it measures.
You are approaching this the only way it can be done. Trial and error till you find your sweet spot. It always fascinates me how you can get so close and then tweak a little more and lose the thread altogether. Your mission to get this right has inspired me to revisit some older attempts that I had given up on.
Good fun indeed. Easy to play but difficult to master. If I understood more basic audio principles itd be easier, except then I wouldve been building headphones from new parts, and never wouldve known about these awesome vintage ortho drivers.
Ill be planting vintage ortho seeds in a few weeks so hopefully will see some other users with fresh enthusiasm and ideas. YH-2 or YH-100 to @rtaylor76 ; He already owns a vintage T20, a diyer, plus EARS equipped. YH-1 to @Merrick ; He brings more good gears and good ears. Both are active posters and good guys. Recommended!
Ill keep one Yam for myself but dont know which. YH-100 looks to be a cursed headphone. Anyone actually prefer it to the other Yamahas?
@BucketInABucket has shipped the RP18 kapton. A bit modded (no damp or ear-side grill). I had to order an xlr to 1/4” adapter. I should probably get a balanced amp with more power anyway though. Package is coming from overseas (china) so I dont know avg arrival times. You can be sure Ill update with impressions asap.
6# foam thickness sliced in half. Not perfectly cut, hopefully no imbalance. Pre-cut 1/4” foam sheets is the way to go for future orders.
As you can see also the driver front side damping felt removed. Why was this here to begin with? The stock original flat pads earholes were narrow, basically the diameter of the non-felted inner circle area. Was it there for the same reasons I tried doing that to T10? To unplug some of the driver front wave from the leather earpads? Well, T30’s aftermarket pads ear holes are wide enough not to cover the driver so then I dont need felt buffers. Or do I? Let’s see.
Hi guys gonna pop my head back in this thread again for a bit, been a while!
Just to recap, these are the mods I applied to the RP18 I sent Phil: pretty old-school clay stuff (I've completely forgotten the name at this point) to seal the back of the driver against the cup, a larger circle of arctic cotton/bamboo and the middle being the other one of the two (completely forgot which one was which again).
For my current project, I'm transplanting T50v1 drivers into this woody shell, using the original baffle the T50 came with, coupled with a pair of cheap hifiman velours that Tak recommended to me a while ago. Just waiting on a set of mini drill bits in order to drill some new holes into the cups for the screws.
Good to see you here! I misunderstood and thought they were undamped. I would like to try a closed mod too but with THX00 cups. That wood enclosure you shared looks good, do you have a link to order?
Ehehe I do have another pair...but unfortunately, I misplaced the screws that are used to screw in the baffle, so I sent you my modded pair instead cause I figured a complete can would be nice.
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arrived in great shape -- nicer than my v1 ;p havent listened to it yet... soon 
