Getting LEDs right on Yamaha receivers and amplifiers

Discussion in 'Yamaha' started by restorer-john, Jun 8, 2018.

  1. restorer-john

    restorer-john Addicted Member

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    I think the only way LEDs could give a perfect colour, in line with what Yamaha wanted, would be to drive an RGB LED to produce essentially a tungsten light output spectrum colour temperature and then run it through the aqua blue filters. That's what I'm currently playing with. Yes, I'm a bit nuts. ;)
     
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  2. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

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    Thanks for that information, l wasn't sure what they would have looked like originally.

    I am with you on this, l don't like making any mods that can't be returned to standard easily either.
     
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  3. restorer-john

    restorer-john Addicted Member

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    I remember seeing some Yamaha gear, new, when I was young in the 70s. It seemed just 'lit' but had no colour 'cast'.* All other brands looked yellow/golden at the time. Pioneer had blue tinted Stanley wedge type bulbs in their receivers/tuners to give a similar effect once they moved away from blue dial backgrounds in the late 70s.

    That said, Yamaha messed with filtering a lot, especially with tuners and their hideous green misadventures. All we can do is light them in a way that is respectful to their period and try to match them as best we can. :)

    *apparently I have a 'photographic' memory for certain things...
     
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  4. Oerets

    Oerets AK Subscriber Subscriber

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    I have done a few with LED's and like the results. Never thought the OEM lamps were bright enough to begin with. Especially the dial strip. I used bright white for replacements. Also the LED's could be adjusted quite easily to the voltages required and they will last longer.
    Still looking for pictures of the CR1020 I did back a few the new owner just loves the look of.

    I grind off the round tip and sand it opaque then cleanup the old green covers.
     
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  5. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    Hi John,

    I’ve got a quick question if you don’t mind. When I bought my bulbs (both LED and later incandescent), I bought 12V. I see you’re suggesting 20V, but I’m confused. I was basing my purchase on what I could find in the schematic diagram in the manual since I was wiring in with original leads out to bulbs:

    5A85AA97-62A7-497C-AC49-531A2CFA3D09.png

    It shows here 12V 60mA x5 in that super-fine print under Meter and Dial Lamps.

    Maybe I misunderstood what actual voltage was driving those deeper in the circuitry since I’m not that experienced in electronics.

    As you know from the other thread, I got sidetracked working on my chairs last weekend so I didn’t get around to opening this up to do it, but I’ve got it slated for tonight or tomorrow since I’m at a pause on those chairs.

    If I need to order different bulbs than what I have, (and I’m going to try to return to LEDs if possible), please let me know when you get a chance. I won’t be pulling this 40-some pound receiver out of the audio cabinet until I actually know I’ve got the correct stuff I need to start and finish. LOL

    Thank you!
     
  6. restorer-john

    restorer-john Addicted Member

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    The originals were 12v 60mA which is 0.72W each. Not very bright.

    Not only that, Yamaha ran them at around 10V (to prolong their life, particularly the dial pointer which is moving) so I would estimate they were running around 0.5W each or less. They were dim to start with, let's face it.

    4 of the lights are run in series as pairs, the dial light via a dropper resistor. As the dial/meters are switched via the selector, I'd run LEDs the the same way.

    PM me if you need any help.
     
    Last edited: Jun 17, 2018
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  7. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

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    Thanks for sharing your memories of their original look :thumbsup:.

    The Yamaha illumination engineers or the lights themselves :D. I think some of the Akai engineers may have been closely related?
     
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  8. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    Thank you John. I didn’t remember until now that I need that white paint to touch up the interior plastic, so I’ll be starting this tomorrow afternoon when i get back. Might go ahead and pull it out of the audio cabinet tonight though.

    So my lamps, regardless if I go with LED or use the incandescent that I have in there now, should be fine at that 12V then? I’ll sand down the finish some more on those LEDs to see if that helps with dispersion.

    I had already scuffed up the plastic before to get more of a glow and less of a beam, but I’ll also try grinding down the tip as @Oerets suggested here. I’ve got plenty of those LEDs so I can experiment a little.

    EDIT: These are the bulbs (both LED and incandescent) that i have. Currently the incandescent are installed, but we’ll be trying those LEDs again tomorrow.

    20157237-9DC0-4A92-9CF6-FE64D621EC29.jpeg

    Thank you. I’ll post pics when I’ve got it open.
     
    Last edited: Jun 15, 2018
  9. restorer-john

    restorer-john Addicted Member

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    I would consider flattening the LED top and perhaps putting a small countersunk hole in the centre to spread the light. You have plenty of material in a 5mm LED to play with.

    I used to sandblast (lightly) clear 5mm LEDs to make diffuse ones.
     
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  10. brutal

    brutal YamaHoarder

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    Nice write up.

    I use adhesive backed foil (metal) duct tape to line any reflective surface. Works wonders.
     
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  11. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    John!!! :D

    I can’t believe it! I mean I saw it on yours, but I didn’t really think I would actually get anywhere near the same results.

    Before (incandescent):
    ADC93DAC-5674-4D6D-9B49-EC173BC2BA48.jpeg

    After (LEDs w/ John’s special treatment):
    C7D73602-05CC-479E-BDE6-E184C2DEE08B.jpeg

    It looks absolutely amazing! The iPhone camera is picking up slight shadows, but in person, they’re much more subtle - the meters have a consistent light turquoise glow across all three faces. And the dial pointer matches perfectly.

    I was so skeptical that I was actually going to get results like yours I was somewhat reluctant to pull this thing out of the audio cabinet. But tonight I was like, stop thinking about it and let’s just try it and see.

    Just wow!

    Thank you so much for explaining the process in how to get these back to a factory fresh look using LEDs and white paint. Thank you!!
     
    Last edited: Jun 17, 2018

     

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  12. restorer-john

    restorer-john Addicted Member

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    Done really well, glad you re-visited the LEDs and thanks for adding the before and after pics.

    :)
     
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  13. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    Well thank you again, John for figuring out and sharing the process. It was very unflattering before, even with the full set of replacement incandescent bulbs. Seemed to me to be something I’d just have to live with.

    But now I’ve just thought of something that might help smooth out the remaining soft shadows.

    I’m tempted to pull this apart again and try it, but it’s all reconnected and back in the audio cabinet, so it may just have to wait til next time, but -

    The turquoise lenses are completely clear. So they’re allowing the light to enter completely as it’s reflected off the freshly painted plastic. But suppose it was diffused there too?

    A 2-ply white paper towel, cut to the square of the lens as to completely cover it on the top where the bulbs are, moistened with water so it’ll stick without adhesive, then allowed to dry on top of the lens, should create a translucent diffuser that may smooth out the light pattern even more without overly affecting the color or intensity of the light passing through it.

    Basically, a step closer to a frosted bulb beyond rough sanding the gloss off the LEDs.

    Just a thought, not sure it’s worth yanking everything back out at the moment. But one day if I get bored and feel like stirring up the dust in the back of the audio cabinet again, I’ll give it a try and post the results.
     
  14. restorer-john

    restorer-john Addicted Member

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    Go with diffused LEDs on your next receiver, and adjust the current down, very carefully to get a soft light with no 'hot-spots'. Warm whites really 'whiten up' near their 20mA rating. I run them around half that and they look really nice.

    Yamaha's 'reflectors' were pretty crap to be honest. One bulb to cover the sides of two meters means the middle ones only get half the light.

    :)
     
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  15. the_nines

    the_nines AK Subscriber Subscriber

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    Great thread and great work as usual RJ.

    :thumbsup:
     
  16. smurfer77

    smurfer77 AK Subscriber Subscriber

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    John, thanks for this thread.

    I have a habit of doing things myself even when I could just pay someone to do it. So when it came to attacking lamps on some receivers I thought I would do the unusual (for me) and just buy some kits to save time. Well, it turned out to be a complete waste of time. Of 3 kits I bought, all had wrong colours, wrong brightness/resistors, and one kit even had one too few bulbs. Diffusion/angle was all wrong. And, the best part was that I was assured they are ok on AC, but when i peeled back the heat shrink on the leaded wires there is no diode in sight.

    So I've ended up doing a lot of sanding to get broader angles and have ordered a large stock of colours and types of LEDs to fashion my own, case-by-case, much as you suggest in this thread. I wish I hadn't tried to take other peoples advice and 'save time' with kits!
     

     

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  17. fernarias

    fernarias Super Member

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    Yes, they are a filter for the yellow in the original bulbs. I think warm white LED bulbs come close to what Yamaha intended. I didn't remove the filters also and got a faint blue that didn't match the dial pointer (haven't found a way to remove the yellow from acrylic like I have with abs). I ended up using a turquoise sharpie and colored the led on the dial pointer to match the dials (both faint blue when on)
     

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