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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

    Messages:
    6,555
    Location:
    Australia
    Yamaha CR-xxx receivers, CT-xxx tuners and CA-xxx amplifiers have some of the poorest illumination of any gear I know of, especially as they get old and tired.

    Simply replacing the incandescents merely highlights the diffuser deterioration and discolouration and it ultimately can look worse. LEDs can look excellent, but most, if not all examples I have seen look dreadful.

    Yamaha went for subtlety and restraint and attempted to clean up the light (with filters) to give a nice look. I will show a few examples of how I do it with LEDs. You are welcome to comment or add suggestions.

    I’ll use a recent CR-820 and CA-810 as examples with pictures I took at the time.

    Here’s the meter assembly of the CR-820- it was very dim and had a nasty dirty green/brown tinge. The tape has turned brown up against the meters and makes the light dull.

    IMG_0395 (Small).JPG


    Under the darkened tape, this is what you see. Only three bulbs, and light blue filters to clean up the light. The housings are heavily yellowed and this makes the light worse.
    IMG_0403 (Small).JPG

    Each bulb reflector is heavily yellowed
    IMG_0400 (Small).JPG

    IMG_0402 (Small).JPG
     
    Last edited: Jun 8, 2018
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  2. restorer-john

    restorer-john Addicted Member

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    The dial pointer reflector is also yellowed and unfortunately, the clear dial pointer itself has taken on a yellow colour from UV exposure from sunlight. They all do this.

    IMG_0405 (Small).JPG

    IMG_0408 (Small).JPG

    IMG_0427 (Small).JPG

    IMG_0428 (Small).JPG

    We will need to slice the melted bit to remove the blue filters (they will go back in later)

    IMG_0409 (Small).JPG

    Paint over the yellow discoloured plastic with some white enamel to give a better reflector and colour.
    IMG_0419 (Small).JPG

    These three LEDs are run in series and current was adjusted on the bench to give a pleasing and uniform light level. The original Yamaha aqua blue filters are returned after the paint has dried, along with new fabric gaffer style tape and trimmed to seal in any light leakage.

    IMG_0422 (Small).JPG

    IMG_0424 (Small).JPG
     
    Last edited: Jun 8, 2018
  3. restorer-john

    restorer-john Addicted Member

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    6,555
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    Warm white, diffuse 5mm leds were used which fit neatly into the original soft grommets and are wired in series (modern LEDs exhibit uniform voltage drops). I use the original old bulb wire and keep the colours identical.

    IMG_0416 (Small).JPG

    IMG_0417 (Small).JPG

    The dial pointer gets the same 5mm LED, but with shorter pigtails and heatshrink so it can fit into the housing.
    IMG_0426 (Small).JPG
     
    Last edited: Jun 8, 2018
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  4. restorer-john

    restorer-john Addicted Member

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    6,555
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    The CA-810 has a different arrangement for running the bulbs which is rather inefficient. A significant amount of wasted power (in the form of heat from the dropper resistors) discolours the actual PCB. The reflectors suffer the same discolouration issues and the foam light blocker has turned to sticky goo.

    IMG_0330.JPG
    IMG_0331.JPG
    The damage to the PCB is minor, but with LEDs, we can eliminate the wasted power and heat.

    IMG_0342.JPG

    The old globes are mounted on a soft rubber grommet like arrangement that pushes onto the pins- we will use exactly the same system but with LEDs.
    IMG_0333.JPG

    IMG_0335.JPG

    These LEDs are flat top 5mm which give a wide light, mostly from the top, which is what we want as the CA-810 uses a full width prism-like aqau blue filter.
    IMG_0337.JPG

    These LED conversions are of course 100% reversible should anyone ever wish to go back- unlikely.
    IMG_0339.JPG
    Resistors are calculated (two of them) to give exactly the level of illumination, disipation sharing and they are spaced above the board.
    IMG_0341.JPG

    IMG_0340.JPG
     
    Last edited: Jun 8, 2018
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  5. restorer-john

    restorer-john Addicted Member

    Messages:
    6,555
    Location:
    Australia
    The PCB is hard up against other parts and no fun to get in or out, but patience is the key. Normally, I would simply take out the transformer bolts and slide it back to get more room, but as luck would have it- one screw was factory stripped and wouldn't shift.

    IMG_0344.JPG

    As you can see, the original aqua filters now give a beautiful cast when lit with warm white. As you can see from the posts above, the blue filters never really had the chance to look as good as they imagined, perhaps only for a few months or years before the 4mm stanley globes became dull and yellow.
    IMG_0493.JPG

    IMG_0492.JPG

    Restraint and care are needed with LEDs, but the results are well worth it. Dropper resistors and wiring will depend on the installation and there is NO one size fits all.

    Consider all types of LEDs and buy lots of different ones to experiment. Forget high intensity, blues etc- they ruin everything they touch.

    Measure the voltage drop of the LEDs you are using and adjust the current within the 3-20mA range to give the level you want. Measure the voltage applied and calculate accordingly taking the combined LED voltage drops away and using Ohm's law.

    If it's AC, rectify it, filter it and do the same as above. Remember full wave rectification gives 1.414 times the AC RMS value and choose your cap correctly.

    No rocket science involved. Cheers.
     
    Last edited: Jun 8, 2018
  6. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Good instructions and sensitively done - many of the instructions here are applicable to any LED upgrade. :thumbsup:
     
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  7. restorer-john

    restorer-john Addicted Member

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    Often, the original dial pointer bulb wire is an ultra flexible, an almost Litz-like cable, designed to last thousands of dial spins from one end to the other.

    Do yourselves a favour and re-use that specialised wire. Normal stranded, tinned copper on the bulb won't last.
     
  8. Mr. Yamaha

    Mr. Yamaha Not so much Yamaha lately...

    Messages:
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    Location:
    Amsterdam Area, The Netherlands
    Nice work John :thumbsup: I will try painting the yellowed housing, that's a very good idea. In my opinion, the light is a bit too blue. I like to keep the OEM look. I've been experimenting a lot with different LEDs and LED colors. The Yamaha B-2 was a hard job to get it right due to it's black light absorbing meter backgrounds. I achieved best results with LED light filters, which are used in the film / photo industry to make LED light look more like normal light (Zircon LED Lighting pack from LEE Filters: http://www.leefilters.com/lighting/zircon.html). I bought a bunch of different sheets to experiment with. The pink ones are used to compensate for greenness and the orange ones to make the light more warm. They come in different strengths.

    Recent results on a CA-2000 / CT-1000 combo. The light appears too green in the pictures, but IRL it's a nice soft tone of green, but much more light than the stock bulbs.

    IMG_2366.jpg

    IMG_2368.jpg

    IMG_2369.jpg

    IMG_2445.jpg

    IMG_2447.jpg

    IMG_4302.jpg

    IMG_4303.jpg
     
  9. mr_light

    mr_light AK Subscriber Subscriber

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    On CR-xx40 receivers the bulbs have green rubber covers that fit on 5mm LEDs. With warm white LEDs the color is pretty close to original.
     
  10. Steven Tate

    Steven Tate AK Subscriber Subscriber

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    Love it! Very tastefully done. :thumbsup:
     
  11. MannyE

    MannyE Exterminate! Subscriber

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    Gorgeous! Do you have part numbers for the LEDs you used? Are they available from Mouser or Digi-Key? Also, is there any cure for the yellowed dial pointer? Or does the addition of the new LED eliminate any tinge?
     

     

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  12. Blue Shadow

    Blue Shadow I gotta get me a new title

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    The installation of LEDs instead of incandescents is something that needs this level of attention to detail to get the correct look. That is something much easier today with the wider selection of LEDs. Glad to see a proper how to for these lamps, now we need them for the other brands. One brand that would benefit is Marantz with many of the LEDed units looking damn near radioactive when lit up. This may be a personal choice of the owner and that is fine but lighting close to original is better in my book most of the time. To each their own.

    Thanks for this, John.
     
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  13. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Great thread John! Thanks for posting it.

    Cheers,
    James
     
  14. jobrewer1983

    jobrewer1983 AK Subscriber Subscriber

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    Always look forward to your posts John, such great info, and I know I'm always in for a treat!

    Fantastic work^^ :)
     
  15. restorer-john

    restorer-john Addicted Member

    Messages:
    6,555
    Location:
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    We can't change the yellowing, and some pointers are worse than others, but with filters and the right LED choice, it can get pretty close to the rest of the unit.

    I think with Yamaha, there is no real agreement on what is correct or what exactly Yamaha was trying to achieve colour-wise. Across tuners, receivers and amplifiers they messed with blue/green and aqua filters, green boots and prisms, bright bulbs and dim bulbs. Some receivers/amps had a classic orange/cream meter lighting when new, others like some tuners were dim, dark and greenish/yellow even when new. Cassette decks were always under illuminated and didn't match the other gear very well.

    Pioneer for instance is easy to LED light- their meters and dial colours work really well with warm white, but they may also need white paint where the plastic diffusers are yellow/brown. Marantz also looks good, as long as reflectors/velum are treated/replaced and you don't use bright blue.

    I'm currently messing with 5mm RGB LEDs and a microcontroller where I could conceivably adjust the colour to suit any brand of gear...
     
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  16. reydelaplaya

    reydelaplaya AK Subscriber Subscriber

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    Oh wow! Those look fantastic! I knew to get under (and replace) the dark tape on the front, but never once considered that the housing being yellowed would decrease light output and affect the overall color.

    Definitely going to give this a try this weekend. And even though I’ve switched back to incandescent bulbs (new, btw), I’m game to try the LEDs I’ve got again if this might be the end result. I’ve tried so hard to get this CR-1020 looking factory fresh (replaced damaged faceplate, restored the wood cabinet, etc) but the lighting just never came through - now I understand why. I’ve been lucky enough to not have the dial/meters turn yellow, so I might just be able to pull off something close to what you’ve done. That would be awesome!

    44173381-2014-4C4C-B99A-31F2318FAC3E.jpeg

    Thank you for sharing this with us!
     

     

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  17. OMGCat!

    OMGCat! AK Subscriber Subscriber

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    That's absolutely beautiful work! I can safely say this is the first time that I like an LED conversion better than the tungsten bulbs.

    I like how you've stood the resistors off the board as well. I've also got a pair of those lead kinker pliers and have been doing the same for any hot parts. They make it so much nicer to do the job.
     
  18. restorer-john

    restorer-john Addicted Member

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    That's great! The receiver looks pretty good alright for all your effort. :)

    Take a picture before with the incandescents and afterwards with the LEDs when you are happy with the results (adjust the camera for white balance each time on a white card) and post the pics of your method here? I'd like to see how it turns out, and the next guy doing a CR-1020 can benefit.

    The key is diffused LEDs, series operation where you can, and trim the current down for no visual hot spots.

    Your CR-1020 feeds the dial pointer bulb only via a 180ohm resistor from the full wave rectifier D713. It is not filtered with a cap at that point. You may want to tie a smoothing cap to ground in case you get any 100/120Hz strobing on your LEDs.

    I would tap in before the 180ohm resistor and take the DC voltage (should be around 20v) to get your dial pointer LED matching the 4 others- you don't want it dull or too bright. The 4 meter lights are run from the same 20V (19.23V on schematic) supply.
     
    Last edited: Jun 9, 2018
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  19. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

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    Very true!

    Nice work restorer john on the LED fitment. Yours look very similar to the LED's l did on my CA-2010. Like you mentioned earlier Yamaha must have wanted a bluish hue if they used a blue filter.
     
  20. restorer-john

    restorer-john Addicted Member

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    I believe the light blue filter was essentially a 'tungsten to daylight' filter (similar to what is used in photography). I think they wanted natural (as in natural sound) sun-light colour for their meters/dials. Sadly, as they age, incandescents rapidly go very yellow/red and dull. It didn't work for Yamaha.

    We could of course remove the blue filters and use a 'daylight' colour temperature LED (5500-6500K I believe), but I refuse to remove parts that could only get lost and render the item 'unable to be returned to original spec'. Silly, I know, but there's something strange about removing those funny little filters and I can't do it. :)
     

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