1st MTG2 Build

Panasonic 1.2uH 14.2A Power Inductor ETQP6F1R2HFA. Qty. 5pcs | eBay - around $1 each there, but retail at Digikey they’re $3.27 ea

Coilcraft 1.2uH 12.3A Power Inductor MLC1260-122MLC, RoHS, Qty.10pcs | eBay - $0.70 ea, but only $1.42 ea direct from Coilcraft

Since the boards are going to be available for anybody to build I'm trying to find a part that works well, and is easy for everybody to get, and also doesn't cost $5. An ebay seller may only have a finite supply and so they probably won't be available forever at those prices.

I did experiment with the cap across the L+/L- pads, and from L+ to GND (was pretty sure beforehand that's not a good place to put it), but both those did affect the LED while not doing much to reduce the noise. Where it ended up it's just a damper on the power supply to the attiny and doesn't affect operation other than making it quieter.

That’s really cool Comfychair. I think I have misophonia, to say I hate a whining driver is a huge understatement. Certain sounds really get me. I have ground keys down so that I can make a key pocket knife (not a knife but opens up like one) our dog in my avatar, her dog license, tags etc are all riveted to her collar so no rattle. So I like the quiet driver very mucho. :wink:

Are you sure you’re not related to my wife? We’ve already discussed the name thing, and now the sounds…she’s very sensitive to sounds, smells, and foul old men. Oh OH, might be onto something there…

I’m a true Heinz 57 American. (Ketchup advertised as being made from 57 varieties for those unfamiliar with the gringo phrase) Every where I go in every country and state I have been to people always are saying, “Look honey, isn’t he the spitting image of Some Guy ”. I would not be surprised if there was a Haggard in your family wood pile. :wink: I also like to joke that I come from a long line of people that have trouble saying no.

At work in the ER we often joke about having some degree of CDO. (That’s OCD but alphabetized so that it’s more organized and logical :wink: ) People with similar traits are drawn to similar work. From what you have said before, Dale, misophonia included I have to say your Mamacita sounds like a keeper. Just don’t scrape your silverware on the plate.

So I think for the build I will be changing it to fit in a Solarforce host. I like the Dorpmuller, Itinifni/ Vinz look of a P-60 in copper. Where to score 3/4 slugs of copper or a 3/4” rod cut down to 5mm slugs? I could get discs on Etsy and solder them together but that costs about as much as a 12” rod of 3/4” copper at onlinemetals web site.

I recently ordered some aluminum rod from Exact Metals on eBay. When the product arrived it came with a flier that said to contact them by phone or email for cut to size stuff. I don’t see copper in their eBay listing, but the flier did say all types of metal in full lengths ready to cut.

7/8” copper fit’s loose in a Solarforce head, I used a piece 1” long to put the triple Noctigon on. Wanted it to be closer to a press fit, but didn’t want to pay for the 1” and then turn 3/32” of it into dust.

onlinemetals.com is supposed to be offering USPS shipping to save on that shipping cost, but I haven’t noticed em doing it yet. UPS from them is just ridiculous! Check em out, if they don’t have it yet as an option throw a fit, maybe we’ll get it affordable to get small pieces yet!

(A small flat rate box is only $5.05 shipped anywhere in the US in 2 days, if it fits, it ships. They have a pound limit on that {forget what it is}but to get a 3” long bar of 1” copper would be sweet at $5 shipping)

I have never really found a good cheap source for copper. I usually just stroll around ebay until I find something reasonable.
If your looking for aluminum, the best place I have found is http://www.stockcarsteel.com/aluminum-round-bar/6061-aluminum-round-bar
I have ordered several times from them, the shipping charges and the per a foot price are a lot less than others I have found. If you make the phone call they should also ship the items usps for a reduced cost, if you ask.
They do send out 10% off coupons about every month it seems to my email box. Might try searching for one for a even sweeter deal.

Pre 1982 cents are brass, not copper. Brass has a conductivity of around 100. Aluminum is twice as good. Real copper is 4 times as good.

Argh! Well. Sheesh. Even the penny was wrong. Only direction is up from here. I guess I’m going to have to fall back to a variation of the Dorpmuller and Itinifni P-60 builds. The Itinifni use of a copper pipe/sleeve helped him get a good fit but I don’t intend on using the AA or brass pill bottom. Both appear pretty straight forward. I also would like to do the FET on a 105c trick as that just sounds explosively cool, but I’m not sure where exactly to put it. I need to see a picture as some of the descriptions on other threads probably make sense to people that can identify the parts of an IC. (Not me)

95% copper is technically 'brass', and I imagine under some unrealistic extreme tests you could find a measurable difference between 'brass' with 95% copper and C101/C110, but I doubt it would translate into anything meaningful in real-world applications.

FET is mounted upside down here, with the legs straightened out and then re-bent the opposite way to touch the PCB. In this pic, the outer leg is ground, inner leg is the gate (the PWM input from the MCU), and the black LED- wire attaches to the big metal pad on the upper surface of the FET (wire not shown in the pic).

I thought pennies had to be 1964 or older to be mostly copper? I will go look that up. I am no coin expert! lol

You might be surprised… even tiny changes in a material can radically affect it’s thermal conductivity. Thermal conductivity does not change linearly with to the ratio of the materials in the mix. For instance, pnly a few parts per thousand of phosphorus in a copper alloy will utterly kill its thermal conductivity.

On the other hand there are many different varieties of brass, ranging from 65% copper to 95% (pre-1982 pennies are 95%). I doubt all the varieties of brass have the same thermal properties.

EDIT: Found it:

Gilding Brass (95% copper). Looks like it has 60% of the thermal conductivity of pure copper.

thermal conductivity chart

Comfychair, that’s perfect! Thanks. The diagram is a huge help.

Are you set up to flash driver firmware? I don't know if any stock drivers will run the FET correctly, it has to use firmware written for the 9.4kHz 'phase-correct' PWM.

Hey, that's MY line!

So, like-for like test. 16mm copper MCPCB on a filed-down pre-'83 brass penny, 16mm copper MCPCB on an identical size/thickness C101 (or whatever) copper disc. Same power to both. How many lumens difference between these two materials with vastly different thermal properties?

I'm going to be bold, and predict the difference will be within the margin of error for the measuring equipment. :~

Comfychair, that’s perfect! Thanks. The diagram is a huge help. I think I can use the driver that I broke to make this work. Which would be kinda funny. Thanks.