help me understand Burn in/Dedome?

Hey guys. So, after my last thread a few days ago about my SRT7 getting stolen out of my car with not one scratch on her, I am ready for a new light. And, like I said I wanted to blow the Srt7 out of the water if possible, for the principle of it. Plus, I did love the srt7, but did feel like it could use a bit more punch.
So, I think I am going to go for the TK75. Now, I am specifically looking at Vinh's TK75vn, since it seems to blow the stock 75 out of the water. But, he gives different options. He offers a 6500k dome on, 5000k dome on, and a 6500k Dedomed, Killer throw burn in edition for a bit more.
Now, I understand that de domed means better throw but I have a few questions.

First off, I am aiming for a nice neutral tint, even a bit slightly warm. I do seem to shy away from the cool tints, because to my eyes outside everything just looks grey/blueish, and the warmer ones seem more natural like daylight to my eyes. So, from the pics on Vinhs page, the 6500k dome ON, looks way to cool to me.

So, I am probably going to go with either the 5000k dome on, or the 6500k Burn in, if I can understand the difference.

Does the burn in one give better throw with a smaller hotspot, and also less spill? It seems that way in the pic, and I really do love the spill also, since I will be using this light for mostly S&R in very large fields and the spill/flood really comes in handy for me. But, the throw is of course so important too. So, if the de dome burn in means tight spot with less flood, then I won't go for it.
On the other hand, in the pics, the 5000k seems like a nice natural tint on objects outdoors, and with the dome on seems to show a great deal of spill too, which I love.

Ok. Enough of my talking in circles. Its late and Im getting anxious to buy a new light!

Help me understand the differences please, as right now it is unclear to me. Especially in this case with the TK75vn, since that is probably what I will buy unless for some reason I shouldn't. Don't hold back, if you feel one or the other is better for me, please tell me. I am not as technically advanced as some of you guys, especially with understanding lights to the degree that some of you guys do, but I do get the basics.

Thanks in advance for any suggestions/advice/help you can give me. I think I may be starting to become a flashaholic....

Dave

d.weglarz13 said:

Does the burn in one give better throw with a smaller hotspot, and also less spill? It seems that way in the pic, and I really do love the spill also, since I will be using this light for mostly S&R in very large fields and the spill/flood really comes in handy for me. But, the throw is of course so important too. So, if the de dome burn in means tight spot with less flood, then I won't go for it.
On the other hand, in the pics, the 5000k seems like a nice natural tint on objects outdoors, and with the dome on seems to show a great deal of spill too, which I love.

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Burn-in just gives you a little bit brighter light...I'm not sure exactly how Vinh does it, but basically it involves pushing a lot of current/heat at the LED for an extended period. Not sure what exactly the physics of the process are, but the end result is that it becomes more efficient, so at the same current, it pumps out more lumens. It doesn't change the beam profile at all...it will increase the throw a little bit, in proportion to the lumen increase, and the same goes for spill. More light total = more throw and more spill. I don't know if you would be able to tell the difference in practice...but if you have extra money, it gives you a little more performance. How much exactly will vary from LED to LED.

De-doming a 6500k XM-L2 LED usually results in a color temperature 1000-1500k lower than where you started. So a 6500k de-dome is USUALLY going to end up in the 5500-5000k range. But there are exceptions - again, it varies by LED, and how clean the dome comes off, and how close it was to the rated color temperature in the first place. If tint is important to you, might want to ask for the PDTn option. Premium de-dome tint, neutral. That way, Vinh will pick LEDs that offer the tint you want AFTER de-doming, so you will definitely get what you want (assuming you both share the same preferences, it is subjective). And he also won't send out a PDTn that has a green tinge to it, for example, which can be another issue with any kind of XM-L2 LED.

I originally sent my TK75 in for just a current boost, because I was afraid to lose the spill. But I was underwhelmed with the change - unless you compare lights side-by-side, the difference between 2900 lumens and 4000 is not very large. I sent it back to de-dome, and THAT made a clear difference. It really just makes the hotspot and corona a little tighter, and in so doing DRAMATICALLY increases throw. I really don't feel like you give up anything in the spill department...the lumen increase more than offsets any losses from the de-doming. If you want a flood light, you should consider not getting the TK75 at all. It is a balanced light, but a true flood light will put it to shame in that department. But if you want a hell of a thrower, which is decent at flood too, then the de-domed TK75vn would be my choice. Personally I wouldn't go with the burn-in option...you are unlikely to notice the difference anyway, unless you have a light meter and can accurately test it.

So, those are my thoughts. You may have different priorities, but I hope this at least helps you decide. Good luck!

wow, thanks for that explanation. I think I get it now. I am going to email Vinh again i think. I really want a nice neutral, even slightly warm tint. I was hoping that the spill wouldn't be changed, so thats good news.

Just curious, as I never had one of Vin'hs lights yet, but is the TK75vn really WAY more powerful than the stock one? This is getting to be very expensive! But, i really do want this light, and am still undecided now that you say the de doming really made that much of a difference. When I asked Vinh, he said that the spill gets lost just a tiny bit, but will throw TWICE the distance with the dedoming. And then he said the dedome could also have a green tint, so I think I will ask about the PDTn option. Thanks again for the help Doc.

My eyes are weird I guess. A lot of the tints that some of you guys love, are a bit too cool for me. I can't really stand anything cooler than pure white. And, definitely don't want green.

I didn't think this would be this hard a decision. In the pics of Vinh's Tk75 different options, its hard to tell for me. The 5000k dome ON, seems to have the nicest color and spill, but then when the gif changes to the pic with the TK75 6500k Dedomed vs. the K40, the tint really looks nice but seems to lose the spill some, so its hard to choose.

And, I don't plan on using as a flood light, but I do seem to enjoy the spill a great deal when I am outdoors and looking for something. The lights with the tighter hot spots usually don't call my name.

Thanks again guys for any help/advice.

dave

d.weglarz13 said:

...but is the TK75vn really WAY more powerful than the stock one? This is getting to be very expensive! But, i really do want this light, and am still undecided now that you say the de doming really made that much of a difference. When I asked Vinh, he said that the spill gets lost just a tiny bit, but will throw TWICE the distance with the dedoming. And then he said the dedome could also have a green tint, so I think I will ask about the PDTn option.

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Well, the easy answer is it will be about one-third brighter with the boost. But it won't SEEM that much brighter unless you have a bunch of targets at various distances, so that you can truly gauge how much more light it is putting downrange. As I said, I was not impressed with just the current boost. I know it is brighter, but the change in throw is dramatic - the lumen increase is not, at least by itself. I should also clarify something - it will not double the throw. It will double the beam intensity (candela) but you need four times the candela to double the throw. So it won't actually double the effective range. Many people, including Vinh, are careless about discussing candela vs. throw. But rest assured, de-doming will make a large and obvious difference. If you chose to make only one change, that would definitely have a larger impact than anything else.

d.weglarz13 said:

My eyes are weird I guess. A lot of the tints that some of you guys love, are a bit too cool for me. I can't really stand anything cooler than pure white. And, definitely don't want green.

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Hah, not at all. Many people on CPF share your dislike for cool white. Definitely sounds like PDT might be for you...if a tint bothers you, it can make an otherwise ideal light a disappointment.

d.weglarz13 said:

I didn't think this would be this hard a decision. In the pics of Vinh's Tk75 different options, its hard to tell for me. The 5000k dome ON, seems to have the nicest color and spill, but then when the gif changes to the pic with the TK75 6500k Dedomed vs. the K40, the tint really looks nice but seems to lose the spill some, so its hard to choose.

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It will have a narrower corona and hotspot, no doubt about that, but it will still have lots of spill. By definition, spill is unfocused light, and as such it is less affected by de-doming than either the hotspot or corona, which are both focused light.

d.weglarz13 said:

And, I don't plan on using as a flood light, but I do seem to enjoy the spill a great deal when I am outdoors and looking for something.

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In that case, and given your priority is throw, with spill as a bonus, I would still recommend the de-dome option. It is a natural for the TK75.

Still waiting on others to chime in - the TK75vn is a very popular light, and I'm surprised I'm the only one to respond thus far.

haha, yea I know what you mean. But, so far you have been a GREAT help to me. I think you sold me on this one Doc, and I think Im gonna shell out the extra cash for the dedome. Vinh didn't mention anything about the PDTn version, so I asked him and waiting for his reply. I do think that is the best decision for me, thanks to your help, good Sir. I am pretty darn excited now. From some vids on youtube, i saw a Killer throw edition that just looks crazy bright. Hopefully Vinh will let me order a KT option with the PDTn!

Cheers,
dave

Glad I could help. No matter what version of the TK75 you get, I'm pretty sure you'll like it. Definitely a fan favorite, even for people that have dozens of high-end lights to choose from. A good, balanced, capable, all purpose light. You can get a light that is better at any one particular use, but the TK75 does multiple jobs better than most.

Ok great. I actually was a bit blown away by the prices of the modded tk75, especially with the PDT option, but maybe thats because I'm so broke.....I am really loving the KT with the PDTn, like you suggested, and trying to get the nerve to pull the trigger on that, plus batteries. This hobby is getting expensive now!

dave

The burn in raises the forward voltage of the led, but at higher powers, it gives more light. So lights with moonlight, or a super low low, may lose that mode. This isn't a problem with the tk75vnkt because low is still a bit bright.

The stock tk75 has around 100kcd, the tk75vnkt has around 300kcd. That's a very large increase.

As said the dedoming will make you loose a bit of lumens. The tk75vn will have around 4400lm, and the dedomed around 4000lm or something close.

Being a triple emitter light, you will always have good flood /spill matter how you modify it, so the kt option has more benefit than anything imo.

I got a tk75vnkt as my first Vinh light. 20 lights later, nothing can compete with it as far as it's ability to perform in any situation.

It can throw with the big boy dedicated throwers, it can flood like multi emitter lumen monsters, and it's a compact perfect size.

If you go with domes, you'll always wonder how much more throw you could have had. If you go kt, I highly doubt you'll be wishing for more flood because the triple emitters ensure good flood even dedomed.

Another must have is the tk75vn,especially as said the KT version if you like more throw and not as cool.

I prefer cooler in general(come on there has to be 1) :laughing: so i went for dome on . I also was not too bothered about the extra throw as i have a tk61vn for that when needed. I will admit the better option is KT but i was not that bothered personally.





Mad as a monkey not to get one :naughty:

Ok great. Now the choice is probably the KT obviously, but if I should go with the regular KT which Vinh said does have some green tint to it which kind of turns me off, or the KT with the PDTn option for an extra 45 dollars or something like that. So yea, trying to decide what I need without spending more than I have to since funds are limited on this one, but at the same time I hate to spend like 300 bucks just to be unhappy with a great but green tint light.

Oh man, so many decisions!! I'm about to pull my hair out now!

and side note, should I order the eagletac batts? I know they are expensive but I still have 1 from my stolen srt7, and I hear they are best. But, I am also using a nitecore i4 charger. So if you guys have any recommendations for batts too I would love to hear.

i can't let my fiancée know about this new light, so talk quietly.


thanks guys
dave

The tk75vnkt can use mist any battery. I like unprotected Panasonic 3400mah. Looong life, plenty of power for this light. High drains aren't necessary.

My tk75vnkt was not PDT or anything, and I've never noticed any green what so ever.

There are some variances in led, so some may be green, but mine is perfectly white. It's even a bit cool still. The 6500k dedomed still leaves the leds on the cooler side of neutral.

Man, Im pretty excited now. Im definitely going with the KT version thanks to you guys. Just curious, what would Vinh charge just to mod it if I bought the light somewhere else? I did see a good deal on another site, plus it would sure be cool to see the before and after. But really, just trying to save some bucks if possible. Maybe after all, I don't need the PDT version. Like I said, I do prefer a nice white neutral tint over a cool one or greenish though, but from what I am hearing it may be fine either way. Oh man, my head hurts....I know I know, just pull the trigger on one already! haha

dave

thank you guys again I am learning a lot from this thread so far!

There is still a little confusion in taking about the different variants, I think. You can get it de-domed without it being a KT version...the burn in will not make a large difference. The current boosting and de-doming is probably 90-95% of max performance, and the burn-in takes you that last 5-10%. Personally, I'm not sure it is worth it. Not sure how much extra he charges for it, but unless it is pretty cheap, I would pass - you are unlikely to ever notice the difference.

I went with a non-PDT version as well, and am happy with it. No green. But it is still somewhat cool (which I personally prefer) so if you want it to be on the warm side of neutral, you'll need to either start with warmer LEDs, or go with the PDT version. If you go with the standard build, you probably will not find the tint to your liking. The only real benefit I see to the PDT versions is you won't get a greenish tint - but the majority of LEDs are fine, and even those that are a little off aren't so bad they bother me. But the nice thing is, if you do decide to go PDT, you know you won't have to worry about it, even if you are more sensitive to tint issues.

It is definitely substantially cheaper to buy straight from Vinh. The shipping cost is a factor, but even if you exclude that, it will still cost more. I am reluctant to give you any hard numbers, because as you are aware, it depends on the options, and Vinh's prices have probably changed since I had mine sent in anyway. But unless you find an awesome deal on the stock version, chances are very good you'll save by buying direct.

I would definitely not buy the Eagletac cells. They are among the most expensive...and they are the same cell underneath the wrapper anyway. This isn't a light that asks too much from the cells, typically. Because they are arranged in series, though, I would recommend protected cells. The SoShine 3400mAh would cost you $40 for four, and give you essentially the same performance. They are, like the Eagletacs, shorter than most protected 18650s, so compatibility is good if you ever decide to use them in another light.

Better to take the time to learn about the issues now, then to have to send it back later. You're taking the right approach. I've bought lights on impulse before, and often regretted it later.

Dave, where are you located? Are you in the USA?

Yes Doc, I am in NY, on long island. And yes, it must be that apparent what a hard time I am having.

The choices Vinh has listed is as follows:

A. 6500k Dome on......$215
B. 5000k Dome on......$240
C. 6500k DeDome Burn in Killer Throw Edition....$280

Now, normally for one of my new toys, I buy best I can. However this time around money is a bit tighter, although it is still very important to me that I feel inside like I made the best choice in the light, not my pocket.

Then, for the PDT, its i think 15 bucks per led, so 45 total.

From the pics, vids Ive seen, and of course from your suggestions, I am very much wanting to go with the KT, but you are correct in assuming that if the burn in only gives me that last 5%, then it is no big deal especially if it can save me some money. I do want a substantial upgrade, but 95% is more than fine.

Perhaps I should ask Vinh about this, I just hate to keep asking him questions. I feel like I have already started to get on his nerves. And yes, I guess I am a bit overbearing when it comes to making delicate choices like this.

Thanks again for helping me to understand this whole thing better. I am starting to get it I think. Its funny really, up until very recently, I never cared that much for tint either way. But since getting into the better lights these days, I really do prefer a nice tint on my eyes, and going back to older lights I have, now I can't really even look at their silly blue beams...


I think I will ask Vinh one more question, about whether I can go with something like Dedomed, Current boost, with OUT the burn in, if possible to save some money. The PDT thing.....well, yea, still thinking about it I guess. I am trying very hard to study up on this one before buying, like you said I have impulse bought MANY things in the past that I do regret.

I very much appreciate all the help and advice, really. It sure helps me out a lot.

dave

You'd have to try very hard to get on vinhs nerves. He's a very easy going guy like many of us.


Sounds like you've got it figured out very well.

All I knew when I bought mine was it had 3 leds and was strong....... Luckily later I found it is one of the best lights around.