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

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 :cry:

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

I have a few waveform. these seem better.

Where did you buy them malkoffdevices?

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

*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.

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

Hmm, A60 3000K is really 2700K bulb.
For $20 per bulb Yuji may work better.

Those bulbs are actually not made by Yuji LED. They are OEM bulbs from LEDISUN which I have several of them myself (5 watts version only). It was out of stock for a long time for unknown reasons (I saw some report that they have no profit for several years already). LEDISUN’s spectrum is rather mediocre comparing to other Ultra High CRI LEDs however they have several patents in Quantum Dot LEDS and they have acquired license from CREE for the “remote phosphor” technology. Combination of Quantum Dot and “remote phosphor” would considerably improve the expected lifespan for LEDISUN lightbulbs (in theory of course, and the main reason that LED bulbs die is the crappy drivers).

I am so upset :person_facepalming: But it was this company and SORAA that were the inspiration for the creation of my light bulbs for eyes in 2017! And now YUJI is releasing shit with a blue peak :rage: This is outrageous and offensive!

Here I described the reasons why led light bulbs burn out. Article in rus, use translator — https://sundaylamp.com

In short, if at least 1 of the 4 components of the light bulb is shit, then the whole light bulb is SHIT =(

Thanks Sunlike, I already read your article. So one quick question regarding Qihan power supplies: the manufacturer told me that 12-20w BP cannot go under 400ma while output 36v however it looks like you managed to make them work with around 350ma (correct me if I am wrong). Are they working fine with 350ma output?

what 20w led driver you mean? 20w dimmable only 300mA, and it can be 400 and 250mA. All my tables you can find here — Telegram: Contact @resistorSunLike

The non dimmable 20w (QH-LO20-5-13x2). By the way, I have modified a TRIAC compatible LED driver myself.
Here are the pics of modified:





Original:



Should put the resettable fuse on the Hot (Line) side, will fix that later.

Looks nice :+1: . But I advise you to abandon from ceramic capacitors completely. It happens that they go into a short circuit =( CBB much more reliable

For reusable fuse change varistor to 1.5-350CA supressor.

And add cbb to the output. 2.2uf or 4.7uf (63-100-250v)

I agree that CBB are much more reliable but I had to live with the limited space inside the radiator. Besides I use MLCC to compensate for the capacitance required and technically they have much longer lifetime comparing to Electrolytes. (Of course, X7R and plus). Add CBB to the output is probably OK but definitely not 2.2uf or 4.7uf ones since the output stage is a one-stage Valley Fill Passive PFC circuit which I still do not understand how that works. https://www.ti.com/lit/ds/symlink/lm3445.pdf
From page 19-20 typical applications. The is the detailed data sheet for LM3445, which this driver uses

there is space for CBB 1uf 63v and for 1uf 400v

I tried many of X7R and X5R. And now I try to do not use it by 100%, or use 50v10uf with 12-16v only

For the first pic the output capacitor has to have a voltage rating over 400v (valley fill circuit requirement) so may be I can parallel 0.47uf CBB next to the output electrolyte. For MLCC next to the input caps I used 630v rated ceramic and never expect them to have the same capacity under load. (As long as they do not explode I am happy with then). I usually mod High Power Factor LED Drivers (CE rated of course) and put a modded ripple remover in between. Perfect solution for both Power Factor and flicking.

For Ceremic capacitor you ONLY want to use X7R since they have higher temperature range –55 to 125 degrees and way less capacitance drift compared to X5R. But you still need to at least double the capacity when substituting electrolytes for MLCC. Like 20uf ceramic for 10uf electrolytes. TDK did some experiments regarding all ceremic capacitor LED drivers and they find that they need at least double the capacitance in order to completely remove the flicker. (It has something to do with the response curve and capacitance drift, anyways it is very complicated)