Cree 60W LED replacement bulb review and tear down

Cree has entered the LED replacement bulb market with its own name brand bulb. Cree is offering both a 40W and 60W version of the light; My review here covers just the 60W version.

Cree 60W and incandescent

Here are the specs:

  • Dimmable
  • 800 lumens
  • Light appearance: 2700K
  • Life expectancy: 22.8 years, based on 3 hrs/day
  • Warranty: 10 years
  • Power: 9.5W; 120Vac, 79mA
  • Power Factor (measured): .98
  • Sold at Home Depot
  • $12.97 ea; or six-pack for $74.82 ($12.47 ea.)
  • (The 40W-replacement version costs $9.97 and uses 6W.)

First, the cosmetics: It’s similar in looks to a 60W incandescent bulb. The incandescent weighs 28.3 grams (1 oz) and the Cree weighs 113.4g  (4 oz.), so it’s a little heavier, but still quite light.

It dims quite nicely, with absolutely no flicker at the bottom end. I hunted around at the low end of the dimming range, right where the light turns off, but couldn’t make it flicker or flash. I tried dimming with both a Lutron Maestro dimmer and a garden-variety cheap triac dimmer, but the light output was smooth at all times. Very nice.

Along with flicker, audible noise is a bugbear for many LED bulbs. How does the Cree stack up? I had to get my ear within 12 inches to hear any hum at all. Aha, I thought, there must be some serious potting compound inside the bulb to damp out the high-frequency inductor noise. (Spoiler: I was seriously wrong here.)

The color temperature of 2700K  — a standard color temperature for LED replacement bulbs –is warm and pleasant. Cree does offer the bulb in a much cooler 5000K temperature and prices it a bit higher, most likely because at the cooler temperatures the bulb is more efficient at producing light. The 5000K bulb requires only 9W to produce 800 lumens compared to the 9.5W of the 2700K tested. In addition, people tend to think of the cooler temperature light as being inherently brighter because of the stark contrast with shadows. However, to live with on a daily basis, stick with the 2700K version.

At this point, I’m through with a consumer review for the Cree bulb. The light is warm and pleasant, the dimming excellent, there is no annoying noise, and it costs less than $13. Go buy one – it’s a great value and supplants my previously favorite LED replacement bulb, the Best Buy Insignia.

But what lies beneath? What design decisions did Cree, one of the Big Three LED component manufacturers, make when it put on its hat as a consumer product manufacturer?

To do a tear down, the first challenge is to remove the silicone-covered glass bulb cover. I used my favorite method (told to me by Peter Di Maso of Texas Instruments) for removing LED bulb covers: Soak it in the oven at 200F for 20 minutes and then twist the cover off while wearing thick leather gloves.

Pull the cover off of a Cree 60W replacement bulb

Worked like a charm. Even better, it was still possible to operate the light and probe for some voltages. At full power, the voltage across the LEDs was 220Vdc;  When dimmed to where the light cut out it was 207 Vdc.  220V is a pretty high voltage for powering an LED light. What’s up with that? Let’s take a look at the LED array.

Cree internal LEDs in 60W bulb

As you can see, the LEDs are mounted on a column that sticks up through the center of the light. (These are white LEDs, that is, blue LEDs covered with a white-light-emitting phosphor.) There are a total of 20 LEDs mounted in ten groups of two on a metal core pc board that’s scored between each two LEDs and then bent into a ten-sided shaped that slips over the column.

You can also see that each yellow-colored LED has four bumps in it. These bumps are probably LED emitters, so each individual LED component is actually a tiny matrix of four LED emitters that share the same phosphor coating. So that makes for [CORRECTION] 80 LEDs in series. (For more information about the LED used and how careful selection can reduce the BOM costs, see: How Cree saved on BOM costs in its LED light bulbs.)

There was no isolation transformer, indicating that the design was non-isolated (which continues the trend we saw in the Insignia bulb.) Non-isolated LED drivers drop the parts count significantly and shrink the space needed for power management, dimming, and power factor correction (PFC). As you can see from the photo below of the front and back pc board photos, this bulb has amazingly few components. It also has excellent PFC: I measured .98 PF with a Kill-o-Watt meter.

Cree 60W LED replacement bulb pcb front

Cree LED bulb pcb back

Sure enough, the 8-pin IC is a STMicroelectronics L6561D transition mode power factor corrector, driving a three terminal 3N40K3 N-channel 400V, 2A power MOSFET, also by ST.  Apparently, the PFC pre-regulator operates as the power management for the entire drive circuit.

I was impressed that the circuit was not potted, which is very unusual, especially in such a quiet bulb.

In addition, rather than relying on kludge-y hand-soldered connections, the bulb uses a couple of clips to transfer the power from the center of the LED column to the LED array on the outside of the column. (See the photo of the LEDs on the column above; The clips are on the left and right side of the column.) The whole assembly almost snaps together, making it easily and reliably assembled.

Also of note: It’s made assembled in the USA.

UPDATE: For more info on Cree’s design decisions read: Q&A with Cree about 60W-replacement LED bulb.


  1. says

    Nice write up. I’ve been playing with the 60W 2700K and have been quite happy with it, as well as impressed with what Cree pulled off.

    Home Depot reviews are all positive so far as well ( though they are all within driving distance of the Cree HQ, so we can give those some more time to shake out.

  2. Margery Conner says

    Sal – I noticed the “NC” address on the Home Depot reviews as well. Were you able to buy one at HD? My store doesn’t have them in stock, and online they were out until the end of the next week. I have some design questions in to Cree about the circuit, so I hope they respond. It’s by far the most elegant circuit design and packaging I’ve seen. (Plus, I think it will still work after I reassemble it.)

  3. says

    I’m using units from Cree right now, but my local store Home Depot has them in stock, at least according to HD’s site. That said, my local (10010) tends to get most of the LED products on the early side, including the new Philips A19 LED.

    Re design: Cree’s team must be very proud of what they did. Fitting the driver in the “filament tower” and keeping the componentry so minimal seems like quite the engineering feat. None of that would matter if the lamp didn’t work well, but I’ve been impressed so far.

  4. Chris says

    Enjoyed the review. Is there any reliable way to measure the operating temperature of this and comparable LED bulbs? I’d like to be able to use a 60W+ bulb in an enclosed fixture, even if this is against their better judgement. Also, is the new norm 25,000 hours instead of 50k?

  5. Margery Conner says

    Chris, good question about use in enclosed fixtures – I’ll ask Cree. As for the 50K life, I think that’s always been an idealized number of hours for the LED alone. A bulb’s life has to include the the lifetime of all the other components, including solder joints, capacitors, etc, so 25k is probably more reasonable. But for a household appliance, 10+ years is pretty dang good.

  6. says

    I was told the Cree LED is designed to be used in all applications where incandescents are used — so enclosures are fine and the lamp works in any orientation. I’m not sure if they expect there to be any effective on the lifespan if you have it in an enclosure though.

  7. Mark says

    I believe the bulb says it is assmebled in the USA, not made in the USA. There is a difference

  8. Robert says

    Can you please explain what this means, “In addition, people tend to think of the cooler temperature light as being inherently brighter because of the stark contrast with shadows.”

    How does color temperature possibly impact the contrast of shadows?

  9. Margery Conner says

    Robert – Because of the way the eye perceives light and color. Rods are sensitive to light and do most of the heavy lifting in low-light conditions, but they don’t perceive color very well. The cone cells perceive color, with one type each for red, green and blue. However, there is not an equal distribution of these three types of cones, and each has a characteristic sensitivity, causing the eye’s response between light and dark to be different at different colors. For more on the photropic response of the eye Cary Eskow has several good papers, such as, where he addresses the eye’s response to various color temperatures.

  10. Tyler says

    Thanks for the Tear down, Margery!

    I originally purchased on of these online to be picked up at my local store. I was informed it was on backorder, and would be notified once it was available. I then went to my local store for another purchase, and there was a big display of all 3 new bulbs (40w, 60w, 60w-5000K). I decided to pick up my bulb there directly, and had the customer service desk cancel my order.

    Now that I’ve had a chance to test the bulb, I’m a little disappointed. I have 2 types of dimmer switches at home. One of which works well with these (Lutron Electronic Low Voltage), but the other results in a lot of buzzing noise at all levels (Lutron CFL/LED dimmers). I also noticed that despite the noise, the bulbs don’t dim nearly as well as some of the other bulbs I have. I have bulbs from other manufacturers such as Philips, Lighting Science, LEDNovation, Feit, and even some other Cree bulbs (CR6 and CR4) that dim to much lower levels.

    My other issue with these is the lighting quality. These definitely are NOT the “True White” bulbs I’ve come to get used to from Cree. The CRI for these bulbs is in the low 80 range (I think 81). It definitely shows, and the lighting quality isn’t any better than a standard CFL (of course, when it comes to full brightness :-) ). I did a test in a dark room lit only by a single bulb, alternating between an incandescent, high CRI LED (LEDNovation), CFL, and this LED. The CFL and the Cree had the same old dull colors that one would expect with a CFL, and the incandescent and LEDNovation bulbs brought back the colors in the room that were missing.

    Some of the features of this bulb are really great. I appreciate the design with the LED tower, which makes it appear like a filament. I also appreciate that this bulb is instant on – it actually comes on faster than an incandescent. I hope that Cree will eventually bring out a “True White” version like the one they announced a couple years ago. I know I would pay more for it. Otherwise, I simply have too many CFLs in my possession that easily rival this bulb’s color quality to keep it. Mine will be going back to the Home Depot on my next visit. $12.97 is a great price, but not for a bulb that doesn’t create a better ambiance than one of the CFLs that I already own.

  11. says

    Nice review. Happy with details provided such as power factor. The Philips Endura & L-prize winner fail here. Would like additional details such as Beam angle and CRI. Wonder why Cree did not employ its highest efficacy led chip of 270lpw? More importantly, I would like to know when the 220V version would be released.

  12. says

    >> Wonder why Cree did not employ its highest efficacy led chip of 270lpw

    I believe that will be restricted to the labs for some time! Cree has the XM-L2 @ 186lpw, which is their most efficient *commercially available* LED, or at least it was a few months ago. And then then these lpw numbers drop once you move from the rating for the LED itself to the rating for the actual lamp. Even more so when you factor in restrictions on a household lamp, like 2700K.

    This might be a flawed comparison but I tend to look at it like computer speeds – sure my gigabit ethernet is theoretically capable of x speed, but it doesn’t actually hit that in the real world. I’d love some more clarity on this whole issue though!

  13. Margery Conner says

    Another thing to keep in mind when specifying LEDs is lumens/dollar rather than just lumens/Watt, especially in a cost-sensitive application such as light bulbs (which will probably have every last cent wrung from their profit margin within a few years.) According to LEDs magazine, the Cree bulb uses Cree’s XT-E LEDs which cost well under $1 each in high volume, with Cree’s costs being far less than that. When the whole bulb sells for $13 and requires 20 LEDs, lumens/$ is probably paramount.

  14. Rohan Samsi says

    THD was 15% without a dimmer connected. Also curious why they used the L6561D not the L6562A which is the state-of-the-art IC. There was also a lot of current drawn when the lamp was “Off” upto 60mA on the input side, any thoughts?

  15. True Believer says

    Not sure the testing of the Bulb was completed fully. I would be wondering what the efficiency is if the L6561D is used in the Boost (Original PFC intent)
    And bring it up to 220VDC. In any Boost topology issue is efficiency so prove need to happen at this point. I would also wonder what efficacy number is for such large amount of LED’s in this design???
    Another question I would ask is how well Dimming on TRIAC works and that was not highlighted in the test set up, unless this is NOT dimmable Bulb.
    There are bunch of questions that still need to be answered…

  16. kweb says

    Hi. Some points to consider…How about trailing edge dimmers? Normally, these types of dimmers dont work well with LED bulbs. It will be interesting how the L6561 circuitry they used will deal with these kinds of dimmers.

  17. Chris says

    I believe it’s the leading-edge triac dimmers that are the problem. Bad for CFLs too as far as I remember.

  18. Kent says

    Where to buy these in the UK? The only ones I’ve found are older versions.

    Is there a better alternative for the 220V world?

  19. Robert says


    It was a trick question. The increase brightness perception as nothing to do with shadows and/or contrast.

    Brightness perception is not a function of the rods or cones, but of a third photoreceptor which is sensitive to shorter wavelengths.

  20. alzie says

    I have a problem with the 40 led strings.
    I think that its more like 80 leds in series total.
    Say we have ~3V per led * 80 leds = 240V
    as opposed to ~3V per led * 40 leds = 120V
    The 80 led 240V model fits better with the PFC output which
    must be higher than the 170V peak of the power sine wave.

  21. Joe says

    One more thing do you know if a e14 bulb is in the pipeline or is it going to be e27 only?

  22. Wyatt says

    I recently purchased and installed some of the 60W 2700K bulbs in a room with a simple Lutron Ariadni dimmer. At the darkest dimmer setting, my old incandescent bulbs would nearly turn off, giving me a nice dark room with just enough light to see my way around at night. With these Cree bulbs the room dims from noontime bright to about 80% of that. Its still amazingly bright, and I might as well not have a dimmer in the room at all. I want to love these bulbs, but although they don’t suffer from flicker…they don’t really dim either.

  23. Erik says

    Is Cree making any money on these bulbs? Seems like a lot of material cost: 40 LED’s, heat sync, Power converter, housing, Home Depot’s 20%… Any thoughts?

  24. germ says

    I bought a six-pack.
    There is a problem: The bulbs buzz when on a dimmer. It doesn’t matter the dimmer type (I tried 3 including dimmer specifically made for CFL/LED). 3 out of 6 bulbs buzz louder.
    No issues if you are not using a dimmer.

    This is a show-stopper.

  25. says

    Erik – I agree, this is an interesting question. The bulb uses XT-E LEDs which cost $1.50 in low quantities, and under a dollar in high volume. The general rule of thumb for an LED bulb BOM cost breakdown is a third each of the cost going to LEDs, electronic components, and heat sink/packaging. (Sometimes, and this is quite likely one, the mix shifts to the LEDs taking up 50% of the costs.) So, we’re left with thinking that Cree is subsidizing every LED bulb it sells — or that it makes a tremendous profit from its LED component sales.

  26. says

    germ – This is the first I’ve heard of buzzing in this bulb. Buzzing usually goes along with an isolated bulb design due to the transformer, so I’m surprised you have not only one but three out of six bulbs buzzing. Home Depot will return your money, or you can contact Cree directly. Or better yet, send one to me and I’ll tear it down. Email me at for shipping info. Thanks.

  27. adrian says

    I’m surprised you could not see any flicker. These bulbs have a quite distinct 120Hz flicker.

  28. says

    Is it UL approved?
    With it bing a non-isolated driver design and 220VDC feeding an LED array on an aluminum board…
    LED assembly mounted directly to the heat sing core.
    How did it do on a HI-POT test? Just wondering.

  29. adrian says

    I see the 120 Hz flicker without a dimmer. Also, my kill-a-watt showed a .92 PF, which dropped to .88 as the bulb warmed up. The kill-a-watt isn’t particularly accurate, so I’m not sure how much I trust those numbers.

  30. Chuck says

    Can anyone tell me definitively how any of these screw-in LED replacement lamps perform in recessed, IC-rated fixtures? Those are typically fully enclosed and in contact with surrounding insulation–there’s no significant place for heat to go. In addition, they’re all base-up, so any heat just accumulates at the base of the lamp.

    These fixtures are quite prevalent in homes built within the last 30 years. I’ve tried CFLs in them and find that lifetime degrades to the same as an incandescent flood in the same fixture.

    I cannot imagine that LEDs will perform much better, but does anyone have any solid data? Does using an LED replacement in the fixture void the lamp’s warranty?

  31. says

    Chuck, Cree doesn’t say what the maximum ambient temperatures are for the bulb. This is what the warranty states: “If this bulb does not operate for 10 years (based on 6 hours per day / 7 days per week of normal consumer use) from date of purchase when used as directed, return the bulb with proof of purchase, register receipt and your name and address to Cree, etc.” Nowhere does it state that it can’t be used in an enclosed fixture. On the other hand, an omni-directional bulb is not the best choice for a can fixture – a directional light would be a more effective use of the lumens. And you’d be using the bulb in an application it wasn’t designed for. On the *other* other hand, where else are you going to find a 10-year warranty?

  32. Marc says

    There’s one thing that the reviewer doesn’t mention: why does this bulb get so &^*( hot? I was looking for an LED bulb for my children’s room, and this is disqualified not only because of the high temperature, but also because it uses glass and high voltage. Are we paying too high a price for compatibility with old-fashioned dimmers? Aren’t LEDs cool by nature, so it’s the power supplies that are making these bulbs so hot? Why are some LED bulbs cool and other hot? Has anyone compared LED bulbs in terms of how much noise they add to the power line, for those of us who use powerline over ethernet adapters?

  33. Allan Marcus says

    I just got 6 from HD. Audible buzz from 4 of the 6 in the same fixture. I guess there might be some QC issues, or some are just better than others. I will return 2 to HD (two are in a place where the hum doesn’t matter), and buy ten more. I’ll just keep trying until I get some that don’t hum.

    Once point not mentioned: the packing is not reusable. By that I mean you have to rip the packaging to open the bulb. I guess this is good since HD can’t resell the bulbs as new, but it’s wasteful.

  34. Mike says

    Definite audible buzz with the three that I installed (purchased several weeks apart). I didn’t notice with the first one, but after installing two more in the same fixture, the buzz is quite noticeable. It’s coming from all the bulbs.

    Works fine with standard dimmer and light quality is good.

  35. says

    Margery Conner,
    Why has the price of LED bulbs in the USA been dropping significantly lately and the price remain high up there in Europe? What is the plan to release the 220V European version of this bulb and the Philips 11W Endura/MasterLed bulb?

  36. Geoff Mundi says

    G’day, I was about to buy some of these to use in home Australia but we are on 240 volt, I can’t find or get an exact answer if they will work here on 240 volt sockets. Do you know the answer?
    Cheers from Down Under

  37. Kelly says

    I have started to convert all my incandescent and CFL lighting to LED using the CREE bulbs due to their great price point. In my experience these lights have a definite buzz on any dimmer setting and will not dim to less than 25%. Anything on a non-dimmer switch is quiet and the light is great.
    Is this buzzing and limited dimming a CREE specific issue or is this a general LED phenomenon?

  38. Jay R. says

    I’m getting a slight buzzing noise from two 60W Cree’s that I bought at Home Depot today. I’m also monitoring the heat output since I bought them to reduce heat in a non-air conditioned home office.

  39. says

    In regards to the comments on flicker above.
    I measured the output of the Cree bulb with a photodiode & Oscilloscope, without a dimmer. The bulb does in fact flicker at double the mains voltage frequency. It isn’t nearly as bad as some LED lights however. If you notice this or not probably depends on how sensitive you are to flicker.

    You can see a screen grab from the Oscilloscope here,,+Inc.+9.5W+Dimmable+WW+Globe

  40. Isaac Lau says

    I brought this bulb from the USA planning to use it in Hong Kong. Rights after I got back, I realized that the US uses 120 volts and we use 220 Volts in Hong Kong. This did not cross my mind when I brought it. Will if be dangerous if I attempt to use this 120 Volt bulb with a 220 volt socket.

  41. Jay R. says

    As a follow up to my post, I removed the 60W Cree’s as they gave a brighter (and harsher) light than what I was expecting (more like a 75W equivalent; also had a greenish hue), and the buzzing sound was too loud.

    I replaced them with 40W Cree’s. Still a slight buzzing noise but the light is more pleasant and the dimmer can reduce the light more. Neither the 60W or 40W dim very low though.

  42. Mark Krueger says

    I purchased 7 of the 40W equivelent Crees for a fixture connected to a Lutron Maestro dimmer. 5 of the 7 buzzed. I’ll be returning those and buying a bunch more to try to get a set of 7 that don’t buzz. I wonder what percentage of these bulbs have the buzzing problem? I love them otherwise. Great color and low dim capability.

  43. Kris says

    I am surprised to hear that you could hear a buzzing at all, And the last commenter said he had 5 of 7 that buzzed. That’s quite odd. I have pretty good hearing and I can usually pickup on sounds that my friends and family don’t notice. I have bought about 17 of these and I have only had 1 that buzzed. The buzzing wasn’t very loud, and you could hear it easily within about 1 foot. I replaced that particular bulb and couldn’t hear anything until I was within a few inches.. I am quite impressed with these bulbs. The only way people have been able to tell the difference in light is by looking directly at the bulb while it’s on. Then the light is slightly different at the top of the bulb, It still disperses the same none the less..

    Love em, going to get more.. I will eventually have these replacing all of my standard bulbs in the house (somewhere over 36)

  44. Mark Krueger says

    Yeah, the buzzing problem is really a mess. Must only effect some batches. I have purchased 4 more (costco was sold out) and all 4 buzzed to varying degrees. One was almost good enough. But if I can hear it from my Sofa 5 feet from the hanging fixture it’s too loud (especially when bulbs are going to last 20+ years). I actually don’t have that great of hearing anymore (42 year old here) — so it’s not like I’m some kind of sound nut :-)

    So 2 out of 11 are acceptably quiet. Note that NONE of these bulbs buzz when used without a dimmer circuit. I’m using a Cree approved dimmer unit (Lutron Maestro). In a regular desk lamp they are quiet.

    Hopefully the next batch Costco gets in will not having this problem.

  45. Sheng Lee says

    This Cree lamp flickers actually, though milder compared to other cheap designs. It’s a consequence of using one-stage PFC that can’t be eliminated regardless of the filtering capacitor size across the LED. It occurs even without dimming. Please use a flicker detection device rather than your eyeballs to detect it. An alternative is to use a smartphone to record a video. Since the line frequency and recorder’s frame rates are not synchronized, moving light stripes will be visible at the beat frequency. Make sure the camera is close to the lamp to expose the flickers clearly. Smartphones are popular, so it’s only a matter of time before the general public use this trick to weed out flickering lamps.

  46. mark says

    It would be useful to test for RFI [radio frequency interference] with a nearby AM radio tuned between stations. Switch the bulb On & Off, see how much the noise changes in the radio. The Homedepot house brand EcoSmart LED bulbs have been awful RFI generators. I tried several, returned them all.

  47. Jim Christensen says

    Do you have any idea what adhesive they are using to glue the glass covers to the housing. Most manufacturers are using the same stuff, and your 200 deg. trick works like a charm, but I have tried to find out what type of adhesive they are using.

  48. Pat M. says

    A question…. I have a couple of old wall-mount lamps that use “clip on” shades…you simply slide the mounting clip onto the bulb…. Can you use such shades on LED bulbs like the Cree?

  49. A. Peon says

    re: Clip-on shades – I don’t think they should be a problem except that the safety coating on the Crees is very sticky to the touch (will be interesting to see how it ages). You might want to hold the clips apart with waxed paper or something if it avoids leaving fingerprints etc. and actually lets them snap on without getting ‘stuck’ (think trying to put the clip on a regular bulb covered with a rubber glove, you’d want to hold it apart and try to let it clip in one motion rather than just sliding it on).

    At worst the clip will dig into the coating over time and need to be peeled out / leave a line in it if you move the bulb, but it’s just on there to hold the glass together if you drop it. The Crees are cheap and look really good in shaded fixtures so I’d certainly go for it. The similar-price-point Philips are a hair less yellow / more good-quality-CFL-like in tint and have smooth glass, so as long as the clip can hug the sides of the the ‘snubbed’ glass shape those will work fine too.

  50. Dan Przybyla says

    From Home Depot I purchased 4 CREE soft white 60w replacement bulbs for my Casablanca fan light. I have a combination fan switch / dimmer switch from Casablanca. The dimmer worked fine with 60watt incadesent bulbs. The CREE package claimed they were DIMMABLE but yet when I turned the switch for the first time a loud pop came from the fan/light unit and now the dimmer is either on or off. I tried the bulbs that I took out and again, on or off. Now I’m out a dimmer combination fan speed control. Is there a combination fan/light control that works?

  51. Mark Krueger says

    You need to buy an LED compatible dimmer. I use the Lutron Maestro and it works well. It has the Cree bulbs in supported list.

  52. Jim says

    I’m wondering if you might do a updated tear down of the Home Depot Cree soft white 9.5 watt A19.
    They changed the package label from warm to soft,it has a new heat sink and it uses different LED’s, ten instead of twenty.

  53. Marty Wayne says

    There have been many reports in the ham radio community that LED lights cause interference with ham radio communications. Has EMI/RFI testing been done? If so, what are the test results? What freq ranges were tested? What EMI/RFI suppression has been implemented?


  54. says

    Marty – I have asked the power IC manufacturers about radio interference in the past, but we couldn’t come up with specific examples of problems. It sounds like there’s a discussion thread out there that they don’t know about. Can you please give me the link?

  55. Marty says


    Although I am sure there may be an on-line discussion on this topic, I don’t know about it. I have heard and been in conversations in the SFO Bay Area ham community about LED lights (CFLs too but I’m not interested in them). It may just be circumstantial evidence from these people. I was just wondering if there had been rigorous testing for EMI/RFI on any manufacturer’s LED replacement bulbs.

    I can do research on a few ham chat networks and if I find a link on this, I will certainly forward it to you.

    Thanks for your reply.


  56. craig says

    The Cree bulbs do put out good soft white like an incandescent but they are not dimmable. Perhaps it’s a manufacturing glitch since some users have had success. The list of compatible dimmers isn’t accurate and I’m not going to take the time to switch out dimmers to match bulbs that are supposed to be dimmable.

    I agree with previous posts that it doesn’t make sense to take a step back to take one forward. The dimmable issue is indeed a deal breaker. Don’t both with LEDs unless you are using a standard switch.

  57. says

    I have a total of 61 Cree LED bulbs in my home. Most are on Lutron Maestro dimmers of one type or another (digital dimmers, IR-controlled digital dimmers, occupancy/vacancy digital dimmers), except the 24 BR30 5000K ones in the garage which are controlled by a Leviton commercial-grade motion sensor on the ceiling. I have had no buzzing or any other issues with the regular Cree A19 and BR30 bulbs, and they dim just fine (not as well as an incandescent, but very respectably for LED bulbs).

    The Cree TW series are a different story. I have 6 of them, in groups of three on a pair of dimmers. If they’ve been off for a while, when the dimmer starts up, the bulbs flash and then go off. A second later, the dimmer ramps them up. I haven’t looked for a teardown, but I assume there’s an inrush current (capacitor charging?) that causes the dimmer to activate some sort of protection, then when the dimmer retries, the inrush current doesn’t happen (capacitor already charged?). I just installed the TW bulbs tonight, and was really looking forward to the higher CRI, but it looks like I might have to delegate them to circuits without dimmers. I’ll poke at them a little more this weekend.

  58. Joe D says

    Hello, I purchased a 24-pack of the 60 watt A19 bulbs. I did this after I loved the 6-pack that I purchased as a test in my chandelier fixtures. Well, 60% of the fixtures in the rest of my house have ceiling globes that are enclosed. I have been reading up on whether these bulbs are OK for enclosed fixtures. (Including the previous posts)

    I am curious:

    #1 if anyone can guess about how much the life of the lamp would be degraded.
    #2 if there’s any fire hazard by having them in an enclosed fixture.

    I am MUCH more worried about the fire hazard, if there is one. Thanks!