Old MN20 vs. new MN20 ...

Re: Surefire MN20 arrived!!!

js, thanks for your thoughts. Could SureFire have altered the gas mix as well? My understanding is that all the factors are a complex balancing act and that to change one factor other factors have to be increased/decreased to compensate(?)

I am not sure how valid comparisons are based on one sample. I wonder whether any changes SureFire have made will make a visible difference? For such a comparison I figure at least five of each lamp are required.

Re: Surefire MN20 arrived!!!

Jim,

Thanks!!

I am running an MN20 with 2 18650's in a 2x18650 tube from TranquilityBase with a KT1 head and it is very nice.

Bill

Re: Surefire MN20 arrived!!!

js,

Thanks much for your great insight into the new MN20 :rock:

Technical question: Assuming a regulated voltage supply with a soft start, what would you say is the ideal driving voltage for both the old MN20 and the new MN20? Right around 7.5-7.6 volts?

Will

Re: Surefire MN20 arrived!!!

Al,

Absolutely. Couldn't agree more. Yes on all counts.

Yes, lamp design is a complex balancing act, and yes, they may (and probably did) alter the fill gas. Next time I talk to Willie I'll see if I can beat it out of him.

And yes, definitely we'll need 5 samples and/or multiple reports of people doing old to new comparisons to be even remotely scientific and professional about this.

Still . . .

We definitely know that the new filament is longer than the old by two turns--only one sample is needed to ascertain that. And given this, and making some assumptions, and applying a few rules of thumbs and handy formulae, I stuck my neck out and ran a few numbers for fun. My neck may very well be the target of attack from a sharp instrument with a lot of mass behind the cutting edge (Luna? Luna, where are you?)

But it was worth it.

And even IF my back of the envelope calculations and assumptions are correct, it would still be a very small price to pay (18 percent loss of output is only noticeable in direct side-by-side comparisons) for a lamp which will not explode as frequently as the old MN20's seemed to be doing.

So, yes, for the record, I was talking out of my ***. Heck, I haven't even powered up the new MN20 yet! Why did I even post . . . ? Oh yeah, for fun

It is pretty much a certainty that SureFire knows exactly what they are doing and that they made the best possible choices in the re-design of the MN20.

Time will tell what the new vs. old comparison will turn out to be. As I said, I plan on making some measurements and doing some field testing, and will post back when I know more or less for sure what I am talking about.

Just couldn't resist playing with a few equations and making a few assumptions. :devil:

Sorry.

Re: Surefire MN20 arrived!!!

wquiles said:

js,

Thanks much for your great insight into the new MN20 :rock:

Technical question: Assuming a regulated voltage supply with a soft start, what would you say is the ideal driving voltage for both the old MN20 and the new MN20? Right around 7.5-7.6 volts?

Will

Click to expand...

Will,

I love the MN20 on 123's so much, and use the MN16 for the LOLA when running the M6-R pack, that I have never done careful current and voltage measurements of the MN20. You'd be surprised how difficult that can be in some cases. Not to mention that danger of damaging the LA you are testing--and my old MN20 is worth more than its weight in gold to me right now. Not keen on doing bench testing on it. Not without a lot of thought and setup work.

BUT, I'm pretty sure that andrewwynn has done this as part of his HD-M6 project. Drop him a PM and see what he decided on for the drive voltage of the MN20.

And, yes, if I had to guess right now, I would go with 7.5 or 7.6 volts DC equivalent regulated w/soft start, or direct drive from 2 Li-ion or 6 NiMH cells.

Re: Surefire MN20 arrived!!!

js, you have a lightmeter, so why not do some bounce tests in a small room such as bathroom, or closet, and compare the reading between the new and old MN20. This would be at least better than a subjective test, and would show which LA is putting out more lumens. At least give it a try.

Bill

Re: Surefire MN20 arrived!!!

JS, if you're right and there is a noticable difference then our old MN20's are to be hoarded!

Re: Surefire MN20 arrived!!!

Bullzeyebill,

I don't got no lightmeter. Don't like em. Don't trust em. I use me own eyeball for a ceiling bounce test. ARrrggh. blimee.

Plus, the first thing to do is to field test both. Then the next thing to do is to make measurements of voltage and current draws for both.

Al,

Yes indeed. That's a possibility. But, like I said, I was just taking some assumptions and an observation and making a guess. Could be that the output difference is negligible and not noticeable. The powers may not be equal. The fill gasses could be different. Etc. Etc. Plus, even if I am guessing right, the difference would be slight.

Re: Surefire MN20 arrived!!!

js said:

Will,

I love the MN20 on 123's so much, and use the MN16 for the LOLA when running the M6-R pack, that I have never done careful current and voltage measurements of the MN20. You'd be surprised how difficult that can be in some cases. Not to mention that danger of damaging the LA you are testing--and my old MN20 is worth more than its weight in gold to me right now. Not keen on doing bench testing on it. Not without a lot of thought and setup work.

BUT, I'm pretty sure that andrewwynn has done this as part of his HD-M6 project. Drop him a PM and see what he decided on for the drive voltage of the MN20.

And, yes, if I had to guess right now, I would go with 7.5 or 7.6 volts DC equivalent regulated w/soft start, or direct drive from 2 Li-ion or 6 NiMH cells.

Click to expand...

Jim,

As always, thanks much. I am always learning lots of good stuff from you :rock:

The reason I asked is that I found (and verified with Willie Hunt by email) a way to change the set point on the LVR regulators that I got from you, and I want to experiment setting one of them up for 7.5-7.6 volts to drive not only the MN20, but the MN15 and N2 bulbs that I now use in my "normal" 6.8V M6-R. Raising the equivalent DC voltage also raises the set point for the warning flashes (battery depleted), but it is probably worth playing with on the bench

I will report in a new thread once I have something concrete to report

Will

Re: Surefire MN20 arrived!!!

Will,

You change out a surface mount resistor, right?

Do you have a rework soldering station? Or do you have a way to do this somehow?

If so, maybe at some point I could send you one of my LVR's for you to adjust? Right now, I don't need that done, but I was thinking of the possibility of changing one of my LVR3K's to run at 8.0 volts instead of 7.2, so that it would run the stock Gen4 TL LA at super-drive levels and blinding whiteness. Bill says he like the Gen4 best on 7 NiMH cells. hehe. Crazy, isn't he? But 8.0 volts would be within reason, I think.

Re: Surefire MN20 arrived!!!

I am just wandering, all of the NEW MN20s that we all got recently, did all of yours come in the plastic tube with the foam or did they come shipped the old way with just the cardboard sleeve around it in the plastic bag?

The reason I ask this is I found some but need to know if they are the new or old style? Thanks for any responce.

Re: Surefire MN20 arrived!!!

hburner,

My new MN20 came in a plastic tube with foam and it had a cardboard tube inside the foam.

Re: Surefire MN20 arrived!!!

js said:

Will,

You change out a surface mount resistor, right?

Do you have a rework soldering station? Or do you have a way to do this somehow?

If so, maybe at some point I could send you one of my LVR's for you to adjust? Right now, I don't need that done, but I was thinking of the possibility of changing one of my LVR3K's to run at 8.0 volts instead of 7.2, so that it would run the stock Gen4 TL LA at super-drive levels and blinding whiteness. Bill says he like the Gen4 best on 7 NiMH cells. hehe. Crazy, isn't he? But 8.0 volts would be within reason, I think.

Click to expand...

Yes, just a simple resistor change. Here in this post I discussed how it was done

Thanks much for your help :bow:

It after reading all that you want to proceed changing yours, post on the other thread so that we do not high-jack this one no more :naughty:

Will

Re: Surefire MN20 arrived!!!

Yea that is just the way that mine came. I would like to try another of the old versions as long as it does not blow up on me!

I got today a new MN20, so I wanted to compare it to the old MN20 that I have.

Here is the old MN20. then the new MN20, and the N2. As you can clearly see, spotting the new vs. old MN20 is rather easy (Canon Rebel XT, Kit lens with EF25-II - "macro" setup):







The old MN20 shown here out of my M6 is being driven with primaries, and the new MN20 is being driven out of my regulated M6-R(7.5V) pack, so brightness might not be an apples to apples, even though the camera settings/exposure is the same. Camera was on a tripod for everything, but there might also be some minor holding/angle differences between the two times I took these pictures (only the new MN20 pictures are from tonight). I aligned the "wider" part of the beam along the horizontal axis for all shots to keeps things about the same

First old MN20/primaries, then the new MN20/regulated pack:












To me the new MN20 gives a slightly wider beam, although a little harder to see in the two shots at the trees. Both are pretty nice, but I kind of like the old MN20 a little bit better

Will

Re: Surefire MN20 arrived!!!

EDIT: admins combined the two threads - which makes perfect sense

Will

Will,

Nice work. I count 13 coils on your old MN20, but I count 12 on mine. Is this just an artifact of a partial turn or the POV of the camera or a trick of the light? Could you actually count the turns on your old MN20 and report?

Next, it looks as if the old MN20 is a higher CCT from the pictures. Would you say that is so? Also, I assume you were using fresh 123's for these pics, right?

In any case the comments you make about beam shape fall in line with a wider filament on the new MN20, I should think.

Anyway, good thread, good pics. Thanks very much for the report.

Re: Surefire MN20 arrived!!!

wquiles said:

I posted some "macro" pictures of the old MN20 vs. the new MN20 here

Will

Click to expand...

Nice skills!

Re: Surefire MN20 arrived!!!

Today I received my two MN20's from Surefire.

They have the cardboard sleeve and are inside the plastic bags.

Interesting the variations in the way they are shipping these b/o bulbs out.

hburner said:

I am just wandering, all of the NEW MN20s that we all got recently, did all of yours come in the plastic tube with the foam or did they come shipped the old way with just the cardboard sleeve around it in the plastic bag?

The reason I ask this is I found some but need to know if they are the new or old style? Thanks for any responce.

Click to expand...

Nice work Will and nice house too. I was hoping someone would do this comparison, Thanks.