NAD RP18 and Yahama YH-1 / YH-3 Orthodynamic

Discussion in 'Headphones' started by purr1n, Apr 21, 2020.

  1. purr1n

    purr1n Finding his inner redneck

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    A blast from the past and history lesson. Decades before the ortho craze reignited with the HiFiMan, Audeze, and Dan Clark Audio a bit later, there were orthodynamic headphones from the 70s. These two headphones in particular were modded by @rhythmdevils, who has recently arisen.* One thing to keep in mind is that they do not sound good in stock form.

    b1195b2a_c66e39a1_DSC_0192.jpg

    Take a look at the driver diaphragm. Sure it's not "nano" meter scale material (and that's probably a good thing when it comes to durability); however, take a look at how fine the traces are! That's Japanese manufacturing at its best. (Fostex was the OEM).
    3300580459_fa03f78cee_o.jpg

    * We think he might be the star-child who can only wake on occasions when humans reduce their levels of conspicuous consumption, which is the current situation right now because of CV-19.
     
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  2. purr1n

    purr1n Finding his inner redneck

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    Back then, I wish I knew then what I knew about headphone measurements now. But for some idea on how they may sound, these are the frequency response plots. These were taken on the V1 rig, an open cell foam coupler that simulated free-air as much as possible. As such, these measurements cannot really be compared to any other measurement here.

    The limitations with the V1 coupler are as follows:
    1. The measurements may show less bass because it's "free-air "and there is no seal. Different headphones will react differently to this. Some headphones require a strong seal to get bass, others less so.
    2. The lack of an air cavity results in less effective damping. With ortho type headphones in particular, we may see higher level ridges in CSDs than if the measurement were taken on a coupler with a seal.
    The benefits may be that the treble might be more "accurate" in the sense that there wouldn't be high-frequency waves bouncing around all over the place inside a cavity.

    NAD RP18 (Kapton) RD-modded frequency response
    Changstar V1 "Open" Coupler
    RP18BH-FR.txt5015.jpg

    NAD RP18 (Kapton) RD-modded CSD
    Changstar V1 "Open" Coupler
    RP18BH-L.txt21a2.jpg
    RP18BH-R.txt2bb7.jpg

    NAD RP18 (Kapton) RD-modded CSD
    Changstar V1 "Open" Coupler
    Harmonic distortions
    rp18bhl88ac.gif
    rp18bhr6b5d.gif

    I don't know how good the HD measurements are, considering the V1 coupler is used, and I had developed a consistent methodology to do these. However under 1% throughout, even in the bass!
     
    Last edited: Apr 21, 2020
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  3. purr1n

    purr1n Finding his inner redneck

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    Excerpt from @rhythmdevils:

    So for those who don't know, the NAD RP18 is an OEM of Fostex's original large driver ortho made in 1975, the T50v1. Yes, this headphone was made in 1975!!! It has a large driver of similar size to the LCD-2, is open back. There are 2 versions that were made for NAD, one with a mylar diaphragm and one with a kapton diaphragm. This is the kapton version, which in stock form puts out more bass than the mylar version, but which is controlled through damping. Both versions can be very neutral from bass to midrange with the right damping.

    http://wiki.faust3d.com/wiki/index.php?title=NAD_RP18

    Guru has some good links too which have some good info posted by Wualta.

    I've been wanting to see measurements of these for a long time (as have many ortho-heads), and I hope this is a testament to how far we haven't come with ortho technology. This is what Fostex was able to do nearly 40 years ago when they tried to make the best ortho they could, targeted at the audiophile market. Goes to show what should be possible with today's advancements in materials and manufacturing. Think about where electrodynamics were in 1975, and how much improvement we've seen over the last 40 years. Compare an HD800 to the 70's electrodynamics. Fostex never updated this design, it was (AFAIK) their first attempt, and their only attempt at an audiophile ortho. Ever since then they have focused on cheaper models, which were all products for a target price and target market with limited, specific design goals. Today's T50rp is not an "all out" design either, it's made specifically for the prosumer market and isn't intended to sound good. Let's compare to Sennheiser's products- if this was Fostex's "HD800" type product (statment, all out design) in 1975, today's T50rp would be like Sennheiser's HD280 or something. The other neo orthos are good, but they could be much better. I would love to see what Fostex could do today if they tried to make something that sounded good. I honestly think they could rival the best electrostats and electrodynamics (the "super" LCD-3's probably give us a taste of what is possible). Though I'm sure I couldn't afford it with today's pricing and the way Fostex prices their TH series. ​
     
  4. purr1n

    purr1n Finding his inner redneck

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    These are my succinct impressions (which was my understated style back then):
    • Clear and articulate
    • Good bass extension with slightest roll-off. Don't expect Audeze impact though.
    • Little rough in the lower treble
    • Lots of air
    • Holy crap. These ancient NAD RP18s / open T50s are amazing.
    FWIW, the only modern ortho that gives me the vibe of these is the Verum. Not Audeze, not HFM. This is why I love the Verum so much. Also, we can read in the prior post @rhythmdevils sadness when it comes to current pricing, and this was 2013!

    A Changstar trait was for us to be constantly angry at the high prices. After all, wasn't Head-Fi Jude's point to be able to build a headphone system that rivaled two-channel fidelity for a fraction of the cost? Hahaha, it would seem to be that the opposite is true now! We pay a premium for headphone systems because they are more compact and require less space in the house.

    Anyway, SBAF has sort of accepted today's pricing. We do need to take inflation into account. But perhaps we should be cheapskates again.
     
    Last edited: Apr 21, 2020
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  5. purr1n

    purr1n Finding his inner redneck

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    The Yamaha YH-1 were these little supraaural buggers. No pix. Measurements here for reference.

    Yamaha YH-1 RD-modded Frequency Response
    Changstar V1 "Open" Coupler
    YH1  fR.txtf848.jpg

    Yamaha YH-1 RD-modded CSD Waterfall Plot Measurements
    Changstar V1 "Open" Coupler
    (again, the open coupler will show more ringy behavior)
    YH1 L.txt146e.jpg
    YH1 R.txtb6f9.jpg

    Yamaha YH-1 RD-modded Distortion
    Changstar V1 "Open" Coupler
    yh1l0979.gif
    yh1r367c.gif
     
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  6. purr1n

    purr1n Finding his inner redneck

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    Don't be surprised if the site gets renamed Changstar for a month. I miss that rebel, but with a clue, attitude.
     
  7. YMO

    YMO it's not drinking alone if you're on Zoom

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    Do it.
     
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  8. Magnetostatic_Tubephile

    Magnetostatic_Tubephile Friend

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    Yes please!
     
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  9. zerodeefex

    zerodeefex Grumpiest admin

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    To be clear, I've been an advocate of cheapassa thought process since day 1.

    I'd take a $500 setup that sounds pretty good and $9500 in my pocket for vacation with the fam over a $10k rig any day of the week
     
  10. fraggler

    fraggler A Happy & Busy Life

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    Especially for how far $500 can take you now. Not sure why I keep trying to baby step out of that bracket.
     
  11. gixxerwimp

    gixxerwimp Professional tricycle rider

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    I see this:
    Then this when I click on the link.
     
  12. purr1n

    purr1n Finding his inner redneck

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    It's dead link. Stuff from 10000 years ago. History.
     
  13. gixxerwimp

    gixxerwimp Professional tricycle rider

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  14. purr1n

    purr1n Finding his inner redneck

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    Before Audeze and HFM, there was a "cult of ortho". To this day, the current Fostex T50RP, properly modified, remains an excellent headphone if one desires accuracy and isolation. Dan Clark and ZMF started with mods of the T50RP and went on to better things. It wasn't unusual for folks to own several pairs of T50RPs for modding.

    FWIW, my son is using these modded per this: https://www.superbestaudiofriends.org/index.php?threads/fostex-t-x0-ii-headphones.7972/. I think that drop failed expectations. Oh well.
    [​IMG]

    I still use the Fostex for electric bass practice when in the middle of the night.
     
    Last edited: Apr 21, 2020
  15. Cynric

    Cynric Rando

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    The RP18 are really amazing phones. Of course considering their age, but also especially how individually you can tune them with some experimentation in damping. I've had mine for 8 years now (Kapton, minimal damping with very little medical tape on the back of the magnets, BD 990 Pads with taped-off holes, sound signature smooth with a light DT990 Pro-like V-shape) and I've always liked them a lot. Incredibly comfy with the velours BD earpads and a HD650 head cushion.
    The possible sound signatures are sheer endless, with some tape, felt and a bunch of pads you can really go nuts. Only issue is the from a bass-light mylar phone you are never gonna get the punchy deep bass of the kaptons. My buddies and me got a total of 3 of these legends, and each is tuned differently to the taste of the owner - although 2 of them were made to sound very similar even though one was kapton, one mylar - the main difference was the bass impact of the kapton can.

    They are not picky about the source impedance, but what they do need is power. And lots of it. The phones are incredibly insensitive, when switching between the HE4xx and the NADs the volume about 10dB lower on the latter - although they use double-sided magnets..
    As said, I got mine 8 years ago and these cans marked the first long break on my headphone journey. If I hadn't bought the HE4xx last year, they would still be my main phones. But the HE4xx just seem a little more precise and refined in bass and treble and much more spacious. I guess there has to be some progress in 40 years..
     
  16. CEE TEE

    CEE TEE Free Agent

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  17. dBel84

    dBel84 Friend

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    Aaah, so many memories. It is a real pity the ortho wiki is down, so much aggregated data that is now lost.

    Still love the vintage orthos and still fun to modify.
     
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  18. dBel84

    dBel84 Friend

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    Thanks @purr1n for rekindling these memories. I know the orthothread is a beast to dig through and thought I would rehash a little of the ortho history here as people may find it relevant and interesting. With todays testing abilities, it would be very interesting to revisit a bunch of these old orthos to see why they behaved so differently.

    This is not my picture but one that presents many of the old classics

    [​IMG]

    The first planarmagnetic that we know to exist was made by wharfedale - merely called the isodynamic but the inner circle referred to it as ID1 ( because wharfedale later released the ID2 )

    It was your quintessential 70's glam

    [​IMG]

    It's driver was high tech pleated kapton and suspended much like a ribbon between two "fridge magnets"

    [​IMG]
    [​IMG]

    Most owners used their power amps through a transformer to drive these back in the day. I have a picture of the setup somewhere but it took me long enough to find all these images on my backup drive.

    The Fostex T50 - iirc there were 3 versions of this, @gurubhai and others could correct me

    [​IMG]

    There were a number of OEMs with similar serpentine large drivers - the NAD, the Akai, the Sansui ( not quite an OEM, more of a rare beast unto itself )

    [​IMG]

    The later wharfedale ID2 also attempted more of a serpentine pattern

    [​IMG]

    yep - that is how "clean" it left the factory

    [​IMG]

    and LEAK made an OEM of it that was ever so slightly different

    [​IMG]


    I am getting carried away with pictures here - I had only planned to highlight a few of the crucial differences

    Center pinned - behaves more like a "ring radiator"

    [​IMG]
    [​IMG]

    [​IMG]

    Dual sided tracing vs Single sided traces

    Bar Magnets vs round magnets ( chamfered square holes vs round )

    [​IMG]

    pleated diagphragms vs fine pin holes vs embossed

    [​IMG]


    and I couldn't really post this without a nod to Walt who kept the ortho dream alive and whose thread inspired HFM to make their first ortho and the orthounderground members who got Audeze to take their planar microphone concept and turn it into a headphone . and of course the great Smeggy who brought us thunderpants and truly blazed a trail for small fostex modifiers like Dan and ZMF

    [​IMG]

    [​IMG]

    Hope this many pictures don't strain the system
    ..dB

    EDIT - it must have been late for me - so very good to see our dear friend @rhythmdevils tapping on the keys again
     
    Last edited: Apr 23, 2020
  19. gurubhai

    gurubhai Friend

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    A blast from the past indeed! Great to see this thread and even better to note that @rhythmdevils is back from his exile.
    Years back, I received RD's modded Fostex T50rp which remains the best T50rp mod that I have ever heard.
    That said, my own heart has always belonged to vintage Yamaha orthos and they have been my daily driver for more than a decade now. The Yamaha HP-1 (aniso) being my particular favorite along with the Yamaha HP-50.

    Not many of these vintage orthos sound great stock ( with a few exceptions) and need to be modified significantly to perform on par with modern headphones. Regardless even though I have tried a few modern headphones like hd800, Abyss, utopia etc; on my setup and for my tastes, nothing else seems to be able to replace the magic and charms of these vintage orthos!

    still possible to access some of the wiki through archive.org :
    https://web.archive.org/web/20150723060023/http://wiki.faust3d.com/wiki/index.php?title=Main_Page

    Edit : Adding Yamaha Brochure since I can't resist :
    Yamaha1_doc.jpg
    Yamaha_2_doc.jpg Yamaha_3_doc.jpg Yamaha_4_doc.jpg
     
    Last edited: Apr 23, 2020
  20. Ishcabible

    Ishcabible Friend

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    You can still find a lot of Wikiphonia through the Wayback Machine! Trying to restore it as best I can has been a project I’ve wanted to start on for a couple years now. I always had much more fun experimenting with older orthos than trying new stuff, and with more eyes now than ever, we might be able to uncover more stuff we didn’t know about.
     
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