Review: Yuji BC Series A14 & A60 E27 LED Bulbs (3000K, 4000K, 5000K)

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maukka
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Review: Yuji BC Series A14 & A60 E27 LED Bulbs (3000K, 4000K, 5000K)

Yuji sent me four of their E27 socket LED bulbs in two sizes (A14 & A60) for testing.
Disclaimer: I did not pay for these review samples

The models tested are:
BC Series A14 High CRI Remote Phosphor LED Bulb in 4000K and 5000K
BC Series A60 High CRI Remote Phosphor LED Bulb in 3000K and 4000K

The A14 also comes in 3000K and the A60 in 5000K but they weren’t in stock at the moment of writing.

The main specs by the manufacturer:
-Very high color rendering
-CRI of 95
-Flicker free, no distracting PWM
-A14: 380-420 lumens, 6 W power consumption
-A60: 840-940 lumens, 10 W power consumption
-AC voltage range of 100-240V
-No mention of E26 compatibility
-Not dimmable
-25k hour lifetime and 2 year warranty
-30-Day Return & Exchange Policy (in non-warranty cases buyer pays return and reshipping)

All the bulbs have lots of heatsinking material as their weight is higher than normal. The 155 gram A60 weighs almost 4 times as much as the Waveform lights tested earlier. This also at least partly explains the lower base temperature.

Measurements

Measurements were made in a 50cm integrating sphere with an x-rite i1pro spectrometer after the bulbs had warmed up for 1 hour. Intensity (lux at 1 meter, candela) was measured outside the sphere at 1 meter. To save time tint shift measurements were made after a 5 minute warm-up.

The bulbs were connected to mains power, which is why the input voltage varies some (223-226V).

At 1 hour all the bulbs exceeded their lumen output ratings. Power consumption was significantly lower than advertised on the A14 models. For some reason the bulbs themselves say 5W while the packaging and specs say 6W. Actual consumption was 4.4W. The 10W A60 bulbs were closer to their spec at 9.5-9.6W.

After 1 hour the output decreases 6% for the A14 and 13% for the A60. Efficiency is good at 104-109 lm/W for the A14 and 90-95 lm/W for the A60 models. The base of the bulb stayed rather cool at 62°C, especially compared to some other bulbs I’ve tested before (Ikea 100°C, Waveform 78°C).

Color rendering

The CRI data was measured integrated after 1 hour of warm-up.

All of the bulbs meet their spec of CRI (Ra) 95 except for the A14 5000K which falls just a bit short at Ra 94. The deep reds are produced beautifully, but looking at the TM-30 index, the color rendering isn’t exceptional over a wider variety of samples.

Overall, the A60 3000K is the winner when it comes to CRI. It’s pretty similar with the Waveform 2700K bulb but offers better deep red rendering (R9 91 for the Yuji vs. 76 for the Waveform).

For the 4000K models, the A14 performed better than the A60 with a higher TM-30 fidelity and color gamut. Neither one is as good as the Waveform 4000K which scored Rf 94, Rg 101.

Tint

The tint is mostly slightly below the black body line, so the overall tint is slightly magenta. The 5000K A14 was practically spot on at the BBL. The tint is very pleasing on all of them.

The diffuser for the A60 models works very well and there’s very little tint shift. The A14 diffuser is less effective and the LED phosphor is visible through it. It’s not too visible in real life, but the bulbs might work better in a light fixture with more diffusion or when bounced.

Load IES TM-30-18 Color Rendition Reports by clicking the thumbnails:

Flicker

There’s zero flicker/ripple on the output of the A60 models with the high power factor. The A14 models have a slight ripple at the output, but it’s at such a high frequency (67kHz) that it will not be visible under any circumstances. Snob index of 0% guarantees this.

Electrically the bulbs behave differently. While the A14 draws current to charge its input capacitors in short burst near the peak of the voltage waveform, the A60 has power factor correction which makes it act almost like a resistive load. This might be an important thing for some commercial or government clients who have to adhere to regulation or pay for apparent power.

A14

A60

Cyan line: mains line voltage
Yellow line: current draw of the bulb
Violet line: power draw (voltage * current)

Verdict
The Yuji BC series of E27 bulbs offer good color rendering and a solid build quality. The A60 has an advanced driver circuitry with no ripple and a high power factor. This and the higher power might also be the reason for the slightly lower efficiency compared to the smaller A14 models. The A60 diffuser works great while the smaller and more transparent A14 diffuser causes some tint shift especially on the 4000K variant. For some reason the 5000K has less shift.

The A60 3000K warm white variant achieves good measurements on all metrics and is very pleasing to look at. The 4000K and 5000K models are nothing to sneeze with their beautiful tint and good color rendering, even though they aren’t at the absolute top when it comes to achieving near perfect spectrum or vibrant gamut. Which at $20 a pop they should be.

Edited by: maukka on 11/12/2019 - 15:05
fneuf
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Thanks for your test maukka, I'll add those results it in the BLF High CRI Bulb thread.

The A14 bulb, 4000K flavour, was also tested by djozz. How do you think should we cope with the differences? Is it most likely due to industrial dispersion, or to the measuring material?

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maukka
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Since there’s significant tint shift on the A14 bulb, it measures differently integrated and outside a sphere also depending on the reflector or light fixture used. Also the warm-up time has a big effect. To me the numbers seem close enough. Here’s mine directly below the bulb without a reflector and not fully warmed up. CRI number are pretty close to djozz’s.

djozz
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Thanks for the tests!
My bulb was bought in feb 2015, 4.5 years ago, when Yuji was maybe a bit smaller and younger. They may just have changed the production process a bit since then.
And, as maukka pointed out, the angle may have an influence, I measured roughly straight under the bulb, without thoroughly warming up, but also the bulb was in a small white lamp shade, so some reflected light coming from other angles will have hit the detector as well.

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Thanks for the explanations!

Then if it's ok with you djozz, I'll use Maukka's results for the A14 bulb in the table, to reflect. At first I thought of keeping the "worst" CRI values (all things relative) to be sure not to oversell some bulbs, but I believe you are right. Changes on the product and its manufacturing processes are most likely to have happened in those 4,5 years.

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Looking back at the closests thing I found to be "manufacturer specifications", all those bulbs seem pretty adequate apart from one point. R12 value. Yuji was supposedly aiming 94ish. One probable explanation could be the fact that this "advertising image" I'm refering to is done on Yuji dies, not bulbs.

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Where do we buy these or indeed the waveform?

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There are links included in the opening table from the BLF High CRI Bulb thread to buy the bulbs from Europe or USA. Maukka also included links to the non-EU shop at the start of his review.

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fneuf wrote:

There are links included in the opening table from the BLF High CRI Bulb thread to buy the bulbs from Europe or USA. Maukka also included links to the non-EU shop at the start of his review.

The table is blank for me, perhaps because I’m on mobile? Edit; got it, thank you

Maukka’s link gives me $102 per lamp, bit out of my budget I’m afraid, my dining room light would cost over 500 bucks alone Crying

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Jinx wrote:
Maukka’s link gives me $102 per lamp, bit out of my budget I’m afraid, my dining room light would cost over 500 bucks alone Crying

It’s $102 for 6 pcs A14 or $80 for 4 pcs A60.

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I have a few waveform. these seem better.

Jinx wrote:
Where do we buy these or indeed the waveform?

Virence ArmyTek Viking Pro Quadtrix 9080 E21A 5700, Virence Skilhunt H04 Quadtrix 9080 E21A 5000k, Virence Jetbeam AAA 9080 E21A 5000k,
Virence Jetbeam AAA Nichia HCRI Red Led.

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malkoffdevices wrote:
I have a few waveform. these seem better.
Jinx wrote:
Where do we buy these or indeed the waveform?

Where did you buy them malkoffdevices?

-

maukka wrote:
Jinx wrote:
Maukka’s link gives me $102 per lamp, bit out of my budget I’m afraid, my dining room light would cost over 500 bucks alone Crying

It’s $102 for 6 pcs A14 or $80 for 4 pcs A60.

Ah that sounds better, i missed that, thanks Maukka.

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https://www.waveformlighting.com

Jinx wrote:
malkoffdevices wrote:
I have a few waveform. these seem better.
Jinx wrote:
Where do we buy these or indeed the waveform?

Where did you buy them malkoffdevices?

-

maukka wrote:
Jinx wrote:
Maukka’s link gives me $102 per lamp, bit out of my budget I’m afraid, my dining room light would cost over 500 bucks alone Crying

It’s $102 for 6 pcs A14 or $80 for 4 pcs A60.

Ah that sounds better, i missed that, thanks Maukka.

Virence ArmyTek Viking Pro Quadtrix 9080 E21A 5700, Virence Skilhunt H04 Quadtrix 9080 E21A 5000k, Virence Jetbeam AAA 9080 E21A 5000k,
Virence Jetbeam AAA Nichia HCRI Red Led.

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*Yuji BC A60 4000K
CRI_Grade = B
Duv = -0.0024
price = $20

*Yuji BC A60 3000K
CRI_Grade = B+
Duv = -0.0016
price = $20

They aren’t anything I’m excited about.

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malkoffdevices wrote:
https://www.waveformlighting.com

I checked that out but it’s nearly £50 shipping, sod that!