Aw man! This rocks!
Great stuff so far, O-L! Really like what you did with the host. Looking forward to you wrapping it up and turning it on. 8)
More photos, including a wiring diagram, in the first post.
great job on the soldering and wiring diagram. BTW, you don’t have to solder both the centre leg and the back leg of the AMC chips as they’re electrically identical.
Easiest way for me to understand the Master-Slave thing is this. The AMC chips are simple current sinks - switch ’em on and they pass whatever their rated current is, from the LED to the battery. To switch them on, they need a certain voltage on their Vdd pin (either the left or right front pin, I can never remember), 3V or thereabouts I think. So, simple single mode boards just have a diode or resistor between the B+ and the Vdd pin whereas multi-mode boards have an MCU that switches that pin on and off very quickly (PWM) to control the amount of current sunk through the chip over a certain time.
So, what you’re doing with the Master-Slave set up is making a couple of single mode boards (the Slaves), then wiring their Vdd traces to the Vdd trace on the Master board, et voila, mahoosive multi-mode current! Another way of doing it would be to just start with single mode boards as Slaves to begin with, but I don’t think you can get them in 8xAMC formats (only 4x boards as far as I’m aware).
Hope that wasn’t condescending, it was quite a revelation for me when I figured it out!
1 question. Will you be making some to sell?
Not condescending at all.
I soldered the back, just for stabilization and for another heat path.
I have found that Arctic Alumina does not like heat! What the heck is that? AA is supposed to be good for heat, but I'll tell you what, I have had many instances where I soldered something like these chips and the chip came loose from the AA. I've seen it on led stars too, when soldering the wires on. I am not very happy about AA and if it is the best of the bunch, I can see why stars should always be screwed down instead of using thermal compound.
Sorry, had to rant....... just had to.
You mean drivers or lights?
If it's drivers, no, I would not be making any for sale. It's too much stress, LOL.
Seriously, for me, it's very hard to do these, so I try to do them only when I have to.
What do the hardcore computer people use on their heat sinks ??
They use thermal grease, not adhesive and they use all different types of clamping methods, to hold the heat sinks on. They don’t use adhesive because they can’t take if off easily and because clamping or hold downs are the only real way to hold two pieces together. We just don’t have that kind of room in a flashlight.
AA needs pressure and a lot of it to work properly as it’s not an adhesive - alumina adhesive would be what you’re after AA on newegg Plain AA works fine on CPU heatsinks as the clips/clamps/screws provide an enormous amount of pressure, but wouldn’t be any good for a component left floating around 
I’ve always screwed my LEDs down on all of my builds, although I tend to have more room to play with. You can get sweet little allen cap screws with 4#40 threads that fit within the holes on the star, those might help. I have a draw full of them (scavenged off an old microscope filter wheel) if you want any - I’d have to build 20 or 30 lights to use all of them, which, you know might happen {tick, twitch}
I have 3mm screws. I just hate to do it. It's such a PITA. I will be using screws on the SST-90 instead of AA.
AA is good to 150c, but unfortunately, that is lower than the 185c-190c of 60/40 solder. No wonder it never works. So, that means solder before, glue after. Another PITA.
I think maybe it's just the 100+ degrees every day that's a PITA and it makes everything else seem to be. 
I dunno, it only adds 10-15min to my builds. Mark, punch, drill, tap, blast with compressed air and you’re done. 100% reproducible top notch thermal junction everytime plus replacing the LEDs with the next model out is a piece of cake.
Epoxy sort of has a “memory” for the highest temp that it has seen. Heat it above that and it softens. There is (somewhere) an article on boat repair on the Gouegon.com web site that talks about it. Gouegon makes the West Marine epoxies.
Real high temp epoxies have to be baked to set the epoxy and get the high temp capability.
Blown away again. How do you get your soldering so neat? Lots of practice and ability I suppose. If I did what you have done with those drivers there is a 100% chance that they would never work again. The close up picture's aren't bad either.
Truthfully, I get nervous every time I have to go near something like that. I hate soldering those things! I have a table top light that has a big magnifying lens in it. I can pull it over top of the work area. I also have to position the boards in a small vise, where they cannot move and where I can rest both hands on it. Otherwise I can’t hold still enough. It’s hit or miss and y’all don’t get to see the mistakes, LOL, but mistakes, they are a plenty, believe me.
I would love to buy a real micro soldering gun or station, but the good ones, with the really thin tips, are way too much money. I usually file my tips to a finer point, even though it ends up ruining the tip much quicker, but I can't solder that stuff with a regular tip. I know one thing, you want a good, hot iron. At least 40 watt or more. It is so much easier to just hit the spot for a second, rather than to have to hold in place, waiting for things to get hot. I never knew that, till I read it from another member. It works!
If I may ask what mixture of lead/silver, flux or resin cored and thickness solder do you use. The array is amazing.
I use 0.032" solder, 60/40 rosin core. I get it from Radio Shack in spools and wrap a few yards at a time on a 3/8 rod, so I only have to hold the small coil when I’m soldering.
That looks to me like some very fine soldering work. Mine is improving but not yet ready for prime time.
Hi Oldlumens,
I have to say I am very impressed. Even at a glance the level of quality you are able to produce without the benefit of expensive equipment is clear. The amount of patience shown in your work is admirable.
I think the upgrade to the battery carrier is probly the most creative part, it has a professional look about it too.
This is not a criticism, merely an observation based on my experience. The addition of those extra chips being soldered on top of each other is probly going give you the opposite effect of what you are looking for.
Heat is a very serious issue with these 7135 circuits ( as you probly know). Piggy backing those chips like that will compound the issue. I have found without exception when these boards are slaved it also causes a heat issue.
My personal SST-90 mglite is powered by a set of 3 drivers like that ( not as pretty as yours 
), but in order to keep the current stable I had to heat sink both sides of the boards to fairly thick aluminum plates that touched the outer light wall. Without this the current will fall like a rock around the 1 minute mark till it bottoms out at like only a couple of amps.
Thanks for sharing man.
My admittedly limited experience has been that the thermal issues can sometimes be attributed to excess heat from the LEDs. If the led sink is capable of maintaining a constant temperature then you could be okay. If the sink gets hot then the chips will get hot even if they are not being overdriven.