Semileds 4-core True Violet LED on a copper Noctigon MCPCB
Version 1.0 Product code: 4xU-N


Availability:  Out of Stock

Improved version of this goods. Differs in that the LED is placed on a copper metal board Noctigon with direct heat path. As a result of improved thermal LED mode as a consequence - its radiation quantity is increased. Also increases the probability of the use of LEDs at high currents without overheating.

   Custom-built 4-core violet LED Semileds N5TL-U2-AM

The LED is placed on a patented SinkPADTM MCPCB which provides an improved heat conducting path.
Color Max. current Max. voltage drop on the chain Wavelength LED emitter type
Requires soldering. Connect the "+" pad to the positive wire from driver, and "-" to negative.
Violet, near to UV
Violet, actinic spectrum
Violet ("indigo")
1000ma 14.5V 405-410nm
Semileds N35L-U 405-410nm 
Semileds N35L-U 415-420nm 2pcs.

Semileds N35L-U 420-425nm


Total power consumption, W:  up to 14.5
The МСРСВ dimensions, mm:  matches the standard 20mm “star”
Completely solderless NO



  • Best way to complement your existing LED fixture with True Violet actinic radiation to provide for best coloration, fluorescence, and coral growth *
  • Unique LED that was custom-designed and manufactured by TSLC specifically for ReefLedLab
  • Newest and most efficient N35 crystals*
  • Advanced Noctigon metal board with improved heat path (up to 400W/mK), can be used with passive cooling heatsinks to achieve a most reliable fanless solution
  • Our custom LED can use any optics designed for the popular XM-L LED by Cree
  • 100% quality control for all LEDs and the assembly



“*” no competing solutions were available on the market by March, 2016.

This unmatched LED was custom-built based on ReefLedLab’s design and is solely manufactured on our order, using the most efficient crystals existing at the time of manufacture. An official reference by Semileds provides the parameters for crystals used in the manufacturing of this LED.


Our custom-LEDs are manufactured using as base the TSLC N5050U-UNx2


TSLC states that by maintaining an LED crystal temperature of less than 75C, one can use the LED at a current greater than 700ma as is described in the technical document for the basic option of the LED. Since the LED is installed on MCPCB with the SinkPADTM technology using a heat sink with passive cooling, it is possible to use it up to 700ma. Also, our research shows that when using active cooling of the LED heat sink, if  the crystal temperature is kept less than 75C, it can function up to 1A.

We do not recommend using the crystals at currents above 700ma without checking the crystal temperature using thermal vision or a pyrometer.

Semileds informs that radiation power must be multiplied by 18-20% for the package factor. The radiation power of our LED, depending on the supply current, is given in the table below:

Current, ma Radiation, mW (@ 25оС) Voltage drop, V
350 2150 13
700 4200 13.8
1000 5800 14.5

Thus, the real quantity of radiation received from one LED is up to 5800mWt, it is 10-20 times more than the cheap single-crystal violet LED's that are commonplace on the market. 

NOTE: This LED produces a large quantity of short wavelength radiation which can be very dangerous for your eyesight! It is forbidden to look at the LED radiation from a short distance or in the darkness.

Customers who bought this item also bought:

Make a DIY LED fixture using our LED assembly: Video Tutorial:

Note: – the tutorial was made using rev. 2.2 of the 6-channel LED assembly and a different connector. You can also watch our video tutorial on how to use the new connectors.

Using the KRP crimper tool:

Theoretical and practical aspects of LED lighting

What type of light is available to corals in nature? What type of light do corals require for growth and for best coloration? Under what spectrum will your reef tank look its best? You will find the answers to these questions in this section.

All you need for DIY

Do you want to build a DIY LED fixture that would best fit your tank’s requirements, using the state of the art technological achievements and the highest grade components? You will find the answers to these questions in this section.


Building a DIY LED fixture has never been so easy! Find the answers to many questions that hundreds of others have asked. Everything you want to know about building DIY LED fixtures is available in this section.