ImA4Wheelr,
I appreciate the encouragement. Actually, I’ve “resumed” a couple of times, and then I remember :)… Just kidding. Still enjoying it here, so I think that’s a good (or maybe bad, depending…) sign.
>>>>> put the $3 nanjg 105c from FT in mine. Added 4 amc7135’s.
Yeah, a new driver will be the next step I think. Hopefully it won’t be another case of spending time and money to gain 100 lumens that you can’t see. 
Been there done that.
I did the 18650 spacer mod to 3 HD throwers (HIGHLY recommended) and the Leica coated lens to two. Now that made a HUGE difference, much more than the U3. Didn’t think it would, but then I read some of the stuff posted by BLFers about light loss from uncoated optics. Been a photographer all my life, always concerned with coated lenses, but never thought about the effect in a flashlight, where of course it’s just as important.
>>>>My problem is that my experience is somewhat limited,
>>>>>and I had purposely avoided getting into modding for
>>>>>>some other reasons (bad eyes, for one),
Don’t mean to stick my nose … But you may want to check out the various lumen lists floating around on BLF. They take a lot of guess work out of picking the best and brightest over the third-place dogs … and also a great help in taking the guesswork out of choosing some of the really good lights.
And there are some surprises in those lists, real sleepers not much talked about on BLF, like the Trustfire F15-T6 and of course the Keygos Ke-5. Both of these can be improved with say an U3 emitter, but they are pretty darn good by themselves, especially the ke-5.
As for the bad eyes, I’m in the same boat. I solder every day in my business, but soldering leads on those tiny bleeping driver solder points. Forget it. I can do it sometimes, but I wreck as many drivers as I succeed on. BUT the Fasttech (and others) drivers with the wires already soldered in place means you only have to solder the leads to the emitter, which are MUCH easier to see, and the solder points usually are MUCH easier to do. Also a thin soldering tip makes all the difference in the world.
Good luck!
Are those lenses still available? I thought I’d read that you couldn’t get them anymore?
Also, lazy man here: I have one of the FT Convoy C8s coming in, one with 8*7135 already. Could the DST driver be replaced by the one from the Convoy C8?
If you run across those lists, let me know (maybe PM me) if you remember?
Yes, the soldering is a pain. I use to love doing it, and was pretty good at it… kind of therapeutic, like get your mind off things, but when I tried soldering on the leads to an emitter last week, it was more like close my eyes and hope that the soldering iron tip touched the right place on the PCB :(. I have some head-mounted loupes coming in, and will try those next time.
I’m kind of surprised that you said the emitter leads were easier. Actually just soldering the leads to the emitter was not hard, but trying to get the joint to be “flat” was hard. The lead wire just seemed to have its own mind, bending the wrong way :). Plus, now garry is recommending 20 AWG, which’ll be even more stubborn :(…
By the way, I used the word “wasted” above. That too was not intended specifically to anyone. I actually needed to use a different word or phrase, but I still can’t quite think of the right wording. I guess I meant I have purchased a bunch of stuff that ended up not being needed. I think that is unavoidable to some extent. You have to build up a critical mass of a bunch of small supplies and such to really mod/build. That takes time, patience, and money.
This is a hobby and I haven’t had a hobby yet that doesn’t cost me all three.
>>>>>Are those lenses still available? I thought I’d read that you couldn’t get them anymore?
Yes, you are correct. The lenses are already gone. I got two way back when.
>>>>I’m kind of surprised that you said the emitter leads were easier
SO much easier that soldering a big hunking wire to the LEG of a 7135 on a driver. I’m glad that others around here can do it. I can’t. Well, I can do it. I have done it. Just not with any regularity. Failed 50% of the time. More places like fasttech are getting drivers with the wires already attached. What really helped though was getting a REALLY skinny skinny tip for my Weller. The one I started with was pretty small I thought, but not compared to the skinny ones I have now. Work SO much better.
And USE FLUX. Guys here on BLF recommended it and it REALLY helps. No long heating period to get the solder to stick now and even then it would still pop off 25% of the time. So I got a little bottle of flux on ebay with a pipette applicator and now you just have to barely touch the lead and solder pad witha little ball of solder and i am done.
Good luck!!!
I will see if I can find some of those lists. Just saw one. But where is the question.
[I hope the younger folks reading this don’t laugh at the following…]
Ubehebe,
Re. the “eyes” thing, I’ve been experimenting with a couple of things to help with soldering, and I just got these in:
http://www.amazon.com/gp/product/B00155BSHI/ref=oh_details_o04_s00_i00?ie=UTF8&psc=1
Ok, it looks kind of funny, but at least from initial try, it seems that they might be helpful!
I clip it on the outer side/edge on my dominant eye, and you can swing it out of the way when not needed. The loupe part is held in place in a spring steel loop, and you can pop the loupe part out and flip it over. I think that it seems to have a different magnification/power for different sides. I haven’t actually tried soldering while using it, but seems to do a good job just by looking at some stuff through the loupe.
Here’s another thing I found on FastTech that I find useful, not for soldering, but just in general:
https://www.fasttech.com/p/1244005
I reviewed that, and as I said, I’ve almost always carried a 10x loupe with me (EDC?), but then I got this, with the two LED lights, and it’s very nice for looking at chips, solder joints, whatever.
Later,
Jim
I did some resistance checks on the Defiant and A8 clone switches using one of my HP3458A multimeters (reads to 8.5 digits).
The Defiant switch is actually rather good. They show less than 5 milliohms of resistance.
The A8 clone switch is rather awful. The best reading that I could do was around 70 milliohms… and that does not include the spring and brass spring cap. It was tough getting readings less than 120 milliohms. At 3 amps you are losing at least .35 volts in the A8 switch and only 0.015 volts in the Defiant switch.
If you are going to mod the Defiant with an A8 tube, I would highly recommend using the Defiant switch and bypassing the A8 switch with braid, copper strip, etc.
When I had mine all tore apart, that’s the impression I had of the switch. I wouldn’t call it a quality switch but the area of contacts and the pressure used seemed very good to me. Didn’t see any need to upgrade.
Thanks for the posting your voltage drop measurements texaspyro. 
Hi,
For a non-permanent workaround, would shoving some aluminum foil into the A8 tailcap work?
Also you said that your measurements were for the A8 “clone” tailcaps. Do you have any idea what the “real” A8 tailcaps would be? Do I just measure resistance between say the spring and some uncoated part of the tailcap?
I did some more testing on those clone tailcaps. They are MUCH worse than I originally thought. When I just tested the switch, I could get readings of 70 to 100 milliohms. Assembled they measure over 0.5 ohms!!!
I did a quick fix by just putting a strip of 10 mil copper across the switch tabs, unsoldred. The resistance of the assembled tailcap went down to 0.063 ohms. With the original tailcap I got 500 lumens. With the kludged one I got 650 lumens.
I then tried an easier and kludgier fix… I put a W shaped piece of 5 mil copper over the tailcap spring/brass cover and crammed some aluminum foil into the V’s of the W shape to force the copper against the sides and bottom of the tailcap and got very similar lumen readings. The meter showed the kludge had a resistance of around 0.010 ohms, so not much to be gained by mucking with braid and solder, etc.
Sure, if you have a $10,000 meter that does 4-wire Kelvin connection resistance measurements down to a micro-ohm. Your average DMM is pretty useless for resistances less than a couple of ohms.
Who knows what the switches and tailcaps in other A8’s look like, but I suspect they all come out of the same vat and perform much the same…
For those wanting to use a tail switch, the new question is whether there is a satisfactory replacement switch?
I think I’m not understanding correctly. Sounds like you were basically taking the spring’s resistance out of the equation. Wouldn’t there be a lot to be potentiall gained by copper braid if that got you down to .01ohms?
EDIT: I’m referring to the Kludgier mod. I know you will still have a bottle neck in the switch you talk about higher up.
EDIT2: Oh, I think I understand. You were talking within the switch. Is that correct?
I test springs and switches by driving 6A through them and measuring the voltage drop. From that I can get the resistance. You need a current limited supply though…
Yes, the resistance within the switch itself is in the 0.065 to 0.080 ohm range. Once you factor the spring, spring cap, and contacts the body the resistance of the tailcap assembly can be over 0.5 ohms.
So, you are far better off totally bypassing that tailcap to control the power and using the switch that came with the Defiant… it is a very good switch with a resistance of around 0.005 ohms (100 times less than the A8 tailcap).
so im finally thinking of getting one of these defiants super throwers, but it needs to be on par or better than my hd 2010 to make it worthy of buying.
can you guys tell me if it throws as far as a hd2010, and which one is floodier with more usuable spill?
The Super Thrower throws further, but it’s hot spot is smaller diameter. Not sure about the spill. The HD is more usable for typical usage as I can generally only see so far due to all the vegetation down here. To me the HD is more of a mid-range thrower. Gotta love that big ol hot spot though. The Super Thrower is better when trying to peer between trees.
EDIT: I got off my lazy a and took both lights outside. The spills are about the same brightness, but the Super Thrower’s is narrower and starts about 20 or so out. Estimating because I was on an elevated deck. The HD’s spill starts about 8 feet out and may be a tad brighter. The HD has a more defined hotspot. The Super Throwers beam gradually intensifies to the center. That and the narrowness improves peering into the forest.
texaspro,
Did you buy the A8 clone from “work4best” on Ebay per that link?
I ordered 2 from him/her, got a tracking #, but it is still not working after almost a week. Messaged him/her via Ebay yesterday, but no response. I was checking his/her feedback, and seemed to be a lot of negatives in the last month…