Monday, September 24, 2012

Steve Ku Quantum DD Review

You are not used to this:

But, you know exactly what to do with it:

That is the difference, in visual terms, between the 40DD and the Quantum DD.  Unlike the two steering wheels above, the difference in performance between the two lights is insignificant.  The Quantum is just a much more consumer-friendly package and one hell of a light.  Its not impossible to think that this light should cost upwards of $150, what a similar package would cost you elsewhere in the high in light world (Lummi, for example, though that is the epitome of buyer beware).  But it won't even cost you $100.  And since this is a Steve Ku light and all of them have gone on to be collector's pieces that appreciate, it behooves you to track one down now before you have to resort to getting one on the secondary market.  This light is an unprecedent good deal.  You can read the rest of the review if you want, but I'd recommend you go buy the light first and then come back and finish this piece to whet your appetite while you wait for it to arrive from Hong Kong (which, as a total aside, has the most elegant looking package mailers I have seen).  If you are looking for a super small light and can't afford the Ti Aeon Mark 2, this is a more than suitable substitute.  Can you tell I like it?

Here is the Quantum DD product page.  Here is the one of two places to buy them, and here is the other.  Here is an excellent forum review over at CPF.  There are no video reviews.  Steve contacted me directly and asked if I'd like to review the light.  Obviously, I agreed (feeling a little like the editors of Motor Trend when Ferrari comes and invites them to test drive a new red beast of a car).  Here is the model I got for review:   


Design: 2

The original 40DD is a super small light that uses high technology, like Quantum Tunneling Composite (QTC), to give you infinite variable brightness in a thumb sized package.  Steve puts his usual touches in the light, adding two tritium inserts to the tail so you can find the light in the dark.  The light itself is finished with a satin stainless steel, unlike the 40DD which was a matte stainless steel.  I really liked the Boba Fett look of the matte stainless, but the satin finish is equally useful.  The rechargeable only battery is capable of pumping out a ton of light for its size, hitting 100 lumens.  The Quantum package includes a very nice USB charger for the incredibly small 10180 cells, something the 40DD did not.  The charger is amazing and I wish Steve would sell it independent of the Quantum.  I can make do with my Cottonpicker charge, but I'd prefer the Quantum unit.  The long slots down the side of the light aid in grip and are deep enough to use as a flat facet to stop the light from rolling.

You can't really get a sense for how small this light is until you see it next to something else.  Here is a size comparison with a Zippo lighter on one side and a Mini Mag AA on the other:


The light's ratios are, as you can imagine, unusual given its size.  The light weighs next to nothing at .64 ounces with the battery in.  The lumens:runtime is 12.5 (100 lumens for 8 minutes), which is not so good.  The lumens:weight is 156.25, a ratio that will probably remain unchallenged for a long time.  This is not a light designed to illuminate the side of a building for an hour, but if you need a short burst, it can still give you a decent amount of light, irrespective of size. 

Fit and Finish: 2

The QTC thing only works well with smooth threads and this gem has as smooth a set of threads I have ever seen on a light.  They are in the McGizmo range.  The external reflector fins for the tritium tubes are crisply cut as well.  See here:


Everything that Steve did in this light or had his machinist do is perfect.  One issue I did have was with the 10180 cell.  No matter what I did I could not get it to fully charge or put out the 100 lumen hit, one or the other.  This is something that Steve did not make, so I can't really blame him.  I contacted him about it and he was really great.  There were only two errors out of the initial batch of 500 lights, so I wouldn't worry about it.  Rechargeable batteries can be finnicky and I can hardly hold that against the light.  Replacements are pretty cheap, clocking in around $5 on various internet sites.

One thing you should know, with a little this small and a battery this absolutely teeny, you might have a difficult time getting the battery out using traditional methods.  I have three suggestions, though Steve tells me he is improving this for future runs.  First, you can use the old "tape" grappling hook.  Take a piece of tape and just stick it to the top of the battery and pull.  Second, you can hold the battery compartment in one hand and tap the back with your other, using your index finger.  Finally, you can use a magnet to pull it out.  Personally, none of this is an issue for me as I could extract it with ease every time.  I am not sure I'd wait for the second run as this seems like an improvement for sausage fingered people only.  

Grip: 2

One of my big concerns with the original 40DD was that it was just too small.  This light is not huge by any means, but it is a bit fatter and that makes a huge difference.  Additionally the matte finish, which looked great, did wear a bit and became smooth.  The satin finish doesn't show anywhere near the wear and is actually probably equally grippy.  The long slots however crush the facets of the 40DD in terms of grip.  They are, again, precisely and crisply cut and therefore dig into your fingers a bit when you twist the light.  Here they are up close. 


Really an outstanding job making something so small so tactile.  I had simply assumed it was too small to be grippy.  Steve proved me wrong with a few small adjustments.  Great upgrades.  

Carry: 2

Three quarters weigh about .61 ounces.  Have you ever felt encumbered by three quarters in your pocket?  Right.  The light is small and featherweight.  There is no reason not to carry a light when you could carry this thing. 

Output: 2

The Hi CRI version I have in my 40DD is not available, but nonetheless, the tint here is fine.  The high is very good, especially for a light this size.  The low is awesome, rivaling the low on the RRT-01.  All that versatility in a light this size for this price is just STAGGERING.   Love it. 

Runtime: 2

Okay, so you only get 8 minutes on high.  That is not so good.  But what did you expect?  This thing is the size of your thumb nail.  There is only so much current you can pass through a battery this size.  I would have dinged it severely for the 8 minute high had that been the only mode, like on the Lummi Wee, this light's closest competitor.  But with the QTC in place, you can use the light in real world conditions for a very, very long time.  I went about two weeks between charges carrying it daily and using it three or four times.  Excellent job.

Don't let the 8 minutes bother you too much.  Compared to similar sized lights, such as the generally awful Photon-style lights, you will get neither the 100 lumens output or the 8 minutes at that level.  In fact on those lights your lucky to get 10 lumens.  On the other side of the price tag, compared to other high end options, again like the Lummi Wee, you get the same runtime, but you can't choose the output level.  For lights of this size, there is nothing better.   

Beam Type: 2

Do not expect any throw at all.  There is a reflector, which is kind of incredible, but the lens is cover with a diffuser film of some kind and it makes the light's output smooth and pure flood.  Here is a picture of the film over the perfectly centered emitter (which is an XPG emitter).


Beam Quality: 2

Perhaps its the diffuser film, but the 40DD didn't have any film and it too produced a wonderful and full blanket of light.  Again, its pure flood, but it is a very nice floody beam.  There are no rings, holes, or shadows in the beam at all. 

UI: 2

I am a fan of simple UIs and it doesn't get simpler than this: twist to turn on, twist more for more light.  Best you can get, in my opinion. 

Hands Free: 2

The long slots allow the light to sit still (as evidenced by my two pictures of it sitting on its side).  It is not all that rooted in place, but it can do it, something the 40DD couldn't manage all.  It also tailstands very well thanks to a perfectly flat bottom.  Excellent and a small change that made a big improvement.  Here is a picture of that flat bottom.


Overall Score: 20 out of 20, PERFECT SCORE

The differences in design fixed all of the problems this light had in its "prototype" run the 40DD.  A few more millimeters of girth and different grooves on the exterior made all of the difference.  This is a just a better light than the 40DD.  I still like the Fett-like matte finish on the 40DD, but in every other regard, especially those that count, the Quantum is the superior light.

This is one of the finest lights I have used, of any size for any price.  This is an amazing piece of tech. Now that we know the 40DD was a prototype, its clear why this light is so great--the starting point was nearly perfect to begin with.






  1. How does this finish compare to hard anodizing? After a couple of years my HAIII edc light (on my keychain) is pretty beat up.

    1. it's STAINLESS - HA III is for ALUMINUMS. Stainless is so much more hardcore and doesn't need such attributes.

  2. Ordered. I almost ordered one as soon as you said you were going to review it to beat the rush :)

  3. Craig @ Illumination Supply here. great review! I would just like to mention that if you ever have any sort of problem with a battery or charger I will replace it!

  4. I already had this on my wishlist, but dang, now I really want to pull the trigger.

  5. Also, anything specific you could compare with this and the 44dd? Is this also better in the same ways it's better than the 40dd?

    1. 44DD is Titanium, 5-6MM longer (measured when current starts to flow) than the Quantum which in turn is just under 2MM shorter than the 40DD. It's about 38.5mm by my measurements. YMMV. Otherwise it's very similar. Anodizing by ukmidnite on the 44DDs has been quite nice!

  6. THAT settles it! I had my eyes on this one before, but this was the final drop. Just like with the Aeon :)
    Craig; you're getting an order of 4 lights tomorrow :)

  7. Just placed my order, thanks for the heads up! Can you quickly rehash again the key differences between this one and the 40DD? I'm also seeing a bunch of people online referring to this as the "budget" version of the 40DD, but it's only $5 that right?

    1. 'budget' may not be the right way to put it, but as a high end, low cost production light these won't only be available on the secondary market for inflated prices any time soon. The idea was ensure everyone could enjoy Steve Ku's work.Now it's easy to own a unique and high quality Veleno Flashlight. Great job guys, this one is a grand slam!

  8. This sounds like an awesome light. The review is a little choppy in a couple of places, likely a reflection of your excitement. After re-reading with care, I think I'm clear on two points that were unclear on the first read:

    1) The light under review does have the same infinite variable brightness twist control as the 40DD. That is why you're not too stressed about the miniscule 8 min runtime on max output. There is a whole spectrum of useful outputs below the 100 lumen high, with much longer runtimes, including a firefly low.

    2) Your Quantum had functional problems when used with the rechargeable battery that shipped with it, but you replaced the cell with another rechargeable battery of the same type and the light then functioned perfectly.

    Rock on. I'll probably order one of these little guys when the budget allows, next month.

    PS: Unrelated -- thanks to your heads up a couple of months ago I got one of the last Aeon Mk 1s from Enrique, it is the bomb. Splendid little light. Thank you for the reviews and the tip.

  9. I have to get one of these (I have an e05, but I have a feeling that it won't be good enough, after reading this review). As soon as I get a job...

  10. Purchased. Thanks for another great review.

  11. Best Keyring light ever.

    Any light from Steve is a winner.

  12. Trits are not included, but totally worth the added expense. Battery holds onto its charge when not in use. The lens is described as "sapphire" which, if like the watch crystal of the same name, should be bullet-proof. A remarkable light!

  13. Great review and thanks for linking mine! I made a brief video showing how to manage removing the battery a few weeks back. It should give folks an idea how I do it. Also, a magnetic lead like from a CP charger does the trick as well.

  14. As always, great review! Can you turn it on with one hand?

    1. There is no way to get a purchase on the body with your hand while turning the head with two fingers. I'd sure like to see a video of folks trying. I imagine you'd have to somehow hold the body between two fingers while using two more to turn the head. "no" is my answer. I get bored.. I've tried... :)

  15. Just got mine. Amazing! It's replacing a Fenix E05 on my keychain. Here's why it's better than the E05:

    * awesome metal construction, far more durable
    * less than half the length
    * easily twice as bright
    * USB charging is pretty handy
    * the variable brightness is big plus
    * it's more floody, which I consider a plus for a keychain light

    The only complaint I have: I like it so much I wish I could get one in the Bofa Fett finish like the 40DD.

    Planning to add tritium inserts as soon as I figure out how to order them.

  16. This comment has been removed by the author.

  17. If you use it as a keychain light (I do) then you can turn it on one-handed. Turning it off, not so much, but that is a bit less important, in my view.

  18. Just pulled the trigger on this; you are costing me a lot of money!

  19. Just bought one myself...actually purchased the D2 from directly for a good price with tritium viles pre-installed! Can't wait for this to show up!

  20. Any thoughts on the D2 compared to the DD? Is it basically the same thing?

    1. i can't compare the two as i don't own a DD but the D2 is a very nice piece of kit. Looking through this review and others of the quantum DD, these are the main differences i found:

      1- the finish. The D2 stainless is polished rather than satin which is a bummer for me. it is not nearly as polished as i feared though and i am still very happy with it. i have seen others who applied their own stone/coin wash and it looked great but as i said, i am happy enough with the finish as is.

      2- regarding the included USB charger, from this review: "I wish Steve would sell it independent of the Quantum". I noticed on the velenodesigns site he does now. I believe i read somewhere that the charger has been updated with the D2 but i don't know what, if anything, changed.

      3- regarding removing the battery, also from this review: "One thing you should know, with a little [sic] this small and a battery this absolutely teeny, you might have a difficult time getting the battery out using traditional methods". From what i understand, the QTC pill used to be at the base/bottom of the light. Since it is held in place magnetically, the battery would get "stuck". The QTC pill has now been moved to the top/head and is super easy to remove in my light. I don't know if it is due to the new placement of the pill but i have also read form others that removing the battery on the D2 is no problem.

      I read and watched a few reviews that made me worry about the QTC pill in general. It certainly does seem that there are some kinks to work out but i have had no issues yet. I was also happy to see that a spare QTC pill was included in my packaging along with the expected spare o-rings etc...

      Shipping did come from Taiwan but it only took about 5 days to get to me in California.

      I am very happy with the light and am glad it was so easy to get one at a good price.

    2. sorry- i should clarify for point 3- "The QTC pill has now been moved to the top/head and is super easy to remove in my light" i am referring to removing the battery, not the pill. the battery is a snap to remove. I have not had to remove the pill yet so i don't know about that :)

    3. Jason, thanks for the quick and detailed reply! Really appreciate it. I actually live in Hong Kong and will be going to Taiwan this weekend. Maybe I'll get lucky and find it out there somewhere and pick it up for cheaper.

  21. Anybody else had trouble with the D2? Difficulty turning/twisting head. O- ring that galled up and broke. Scratches to polished SS out of box. Lacking customer service in addressing problems with solutions, etc??? Steve seems to indicate if there is anything wrong with his light it is the customers fault.
    Tried light and could see all the attributes mentioned but don't think it is a very practical light for the long term.
    Hope to see better from this light maker in the future. It is a lot of a light for the money, but sent mine back. Bad experience.
    May have just received a lemon. Sometimes my luck goes that way...
    Anybody else had any of these issues?

    1. Just got mine - no scratches out of the box (although it didn't take much pocket time for some to appear). Head twists smoothly and it looks like the threads have some sort of lubricant on them). If my o-ring breaks prematurely, I will update this. But if it lasts 6 months or so, I think that's fair considering he includes a spare.

      Additionally, mine came with a spare qtc pill. I have seen others posting this save thing on different forums. That seems like a reaction to some negative reviews referencing bad pills and I appreciate that gesture from Steve.

      So far, very happy. Will update about the mentioned issues.

  22. how long does the battery take to charge?

  23. I've been EDC'ing the Quantum D2 around my neck for over a year now. A few months ago, I started having trouble getting my light to come on at full power so I contacted customer support at Veleno Designs. They got back to me very quickly and told me I needed to put in a new QTC pill. I ordered 4 along with a spare battery and spare battery case: the light is back to working at 100% and I couldn't be happier. The Quantum D2 is the ultimate upgrade to the LRI Photon's that I had been wearing around my neck for years: rechargeable battery, waterproof, orders of magnitude brighter (when I need it to be) and far more durable: I never go anywhere without it around my neck!