Malkoff M61 Modded Some More

After I put in a 3 mode 1.4 A driver in my Malkoff Devices M61 drop-in, I wasn’t too happy with the yellow/green tint of the Cree XP-G LED. I found a cooler tint XP-G and applied some Arctic Silver 5 Thermal Compound to the back of the LED board and used some Arctic Alumina Thermal Adhesive to hold the assembly in place.

Malkoff M61 with cooler tint Cree XP-G LED

Before I reassembled the drop-in, I wiped some hazing off the reflector with some chrome polish and inadvertently removed some of the reflective finish. I needed a new reflector.

Modded Malkoff M61 and McR-20 Seoul reflector

I searched for reflectors for the Cree XP-G and found positive comments about Don McLeish’s McR-20 Seoul reflector. I ordered one from the Sandwich Shoppe and it was delivered in 2 days.

There is a recess around the top of the M61 heat sink that the top of the stock reflector sits in – that’s the flat part of the reflector. I put a GITD (Glow In The Dark) O-ring in the recess and it held the McR-20S reflector perfectly. The new LED is mounted on a thinner circuit board than the Malkoff board, which in this case helps with the reflector placement. The bottom of the reflector (with a thin insulator) rests on the LED board. The other end of the reflector is flush with the end of the heat sink.

The beam is very nice. Compared to a M60 or M30, there is less of a hot spot and more spill. The stock M61, IIRC, didn’t have as much of a hot spot compared to the McR-20S.

So far in this mod, I have destroyed the Malkoff M61 driver board and damaged the reflector. But now I’m happy with a drop-in that has a great heat sink, a great beam and three modes. It’s now in my current favorite flashlight, the Surefire C2.

Modded Malkoff M61 in Surefire C2

Malkoff M61 Mod

Malkoff Devices M61 Drop-in

I received my Malkoff M61 drop-in last week. The drop-in uses a Cree XP-G LED and it’s designed to replace the lamp assembly in Surefire 6P style flashlights. Malkoff Devices says, “the output is approximately 260 measured out the front lumens.” It is a single mode drop-in.

I bought the M61 with the intention of modding it with the Shiningbeam three-mode regulated circuit board (NLA). The Cree XP-G had recently noted an “increase of maximum forward current to 1500 mA for XLamp XP-G Cool White is retroactive and applies to all XLamp XP-G Cool White LEDs produced by Cree. The increase is the result of more extensive qualification testing that was performed after the initial product launch.” The Shiningbeam board output current is 60 mA on low, 440 mA on medium and 1.4 A on high.

First, I removed the potting and contact spring. In the process, I destroyed the Malkoff driver board. I used a Dremel to reduce the diameter of the Shiningbeam board so it would fit inside the drop-in.

Modded Malkoff Devices M61 Drop-in

The Shiningbeam board works as advertised – I measured 1.4 A on high, 450 mA on medium and 65 mA on low. I’m not enamored with the yellow-green tint of the LED; maybe I’ll replace it down the line.

I have also used the Shiningbeam board in a DealExtreme XP-G R5 drop-in (SKU 32954). The result, compared to the Malkoff, is a little more throw and a lot less spill. The tint of the DealExtreme LED is also cooler – more blue.

After disassembling the M61, it’s clear that this is a most robust, superbly constructed drop-in. I can see why a professional would be able to rely on this drop-in in a life or death situation. But flashlights for me are a hobby, which is why I wanted to mod this drop-in to have (a more useful for me) three modes. (Note: Malkoff Devices now makes a three mode M361 P60 style drop-in that has an input voltage of 3.4-6 volts)