Nothing like steam explosions. Heheh  xP

I've considered doing pedal cases, too. I've read on one site about using zinc with aluminum as a strong alloy. Actually, I may have read this from one of the Gingery books. Making a wooden model would be fairly easy. Whatever I do, I'll try to remember to post the results however good or bad they may be. (hopefully no hospital trips from shrapnel)

One thing I'm thinking about doing with a spare computer case I have is it use it to house breadboarded amp circuits. A computer case can hold several solderless bread boards, and can shield large circuits from noise.

There's actually A LOT of guys who do their own sand casting. There's a lot of stuff on instructables.com about it.  Check out this example: http://www.instructables.com/id/Ultimate-Guide-to-Making-a-Cheap-but-Effective-Alu/ I've got a large and small coffee can and some quickcrete saved up. I still need to get the stuff for the mold.

Quote from: phatt on December 10, 2010, 03:36:40 AM
Sand Casting,, jeezz mate long gone :lmao:

If you ever see how fast Ally comes out of an extrusion machine you will instanly see the folly of the idea.

Casting Only used now for specialised applications.

Trust JMF to try it,,,   Somehow that does not suprise me as he has been known to try the impossible.  :lmao:

Re Fans,
= Cheap crap in my opinion,,, If one cares to look at almost any industry a proper heat sink is not cheap and in this day Fans are proly 10 times cheaper that a heat sink.

A fan might look trick but WILL ONE DAY STOP!!! Whereas a correctly designed heat sink will NEVER FAIL.
Phil.

If only we all had extrusion machines.

As silly as it might be, I might give sand casting a go. I've been looking for an excuse to sand cast something anyway.

Well, I might only dream about it. School is eating up all my free time. Next week, I have to take a calc II final exam that is big enough that I have to show up on two different days to take it. Then, it'll be time for two more classes, including Calc III.

If I ever do give it a go, I'll set up a power transistor whose only job is to get hot, and I'll try to measure it's effectiveness. If I can't get a flat enough surface for mounting, it'll no doubt get warmer than it should.

Quote from: J M Fahey on December 10, 2010, 12:11:26 AM
Well, in fact I *did* something like that, back in the Stone Age.
There were extruded heatsinks available, but fins run along the extrusion axis, and I needed transversal ones, to make my own vwersion of "big" US/Japan rack power amps, where they were used as the sides of the rack cabinets.
*Huge* heatsinks !!!
I made a wooden model, sandcast them, cleaned the very rough surface by airsanding (casting sand adheres to the surface) and last but not least, had to find a guy with a machine that mills aluminum engine blocks, I needed *one* surface quite flat to mount transistors.
Truth is: a lot of work, and the engine block guy charged more for his work than al, the other costs put together. Not worth it.
What I still do, is cut, bend and rivet 1/16" aluminum sheet, to build quite fancy heatsinks.
That *is* cost effective.
PC 12V fans have made the problem much smaller; any heatsink is 300/400% more efficient if blown cold air, and PC fans are very cheap and reliable.
Sometimes I buy surplus CPU fans and heatsinks and bolt them to existing amps (think Bandits, Fender M80, etc.) which use the chassis as heatsink.

You rock, JM, you've done everything!!!

You could flatten the mounting surface afterwards. Or better yet, build a mold template and use lost wax casting.

Has anyone tried sand casting aluminum heatsinks? DIY aluminum sandcasting is supposed to be pretty easy.

That might have more to do with that specific speaker than with speakers that size in general.  Also, like I said earlier, you should really get a speaker suitable for guitar. Something comparable to a Mod 8. Weber makes some really affordable speakers, too. Using a larger speaker with a ruby will probably make a bigger difference volume wise than using a more powerful amplifier with the small 5W speaker.

Ditto what JM said. LM386 is great for not too loud (though I can still manage to piss my wife off with a ruby amp, especially with a 2 x 12 cab). If a single lm386 doesn't do it for you, go with a more suitable chip.

In many cases, a stompbox is a preamp. This is certainly the case with the "Grace" from ROG. There is also a Distortus Maximus schematic floating arround which uses an LM386.

Actually, I really do not think it is. ROG probably want's a license fee for using their designs, but they are not patented. (Still, it would be damn nice to send them a cut of your sales if you use their designs.) Also, there's really not that much difference between their ruby/little gem designs and the reference design in the data sheet for the lm386. You can use the reference design as a starting point. Use a little different tone stack. Or maybe a very different tone stack. The real mojo in the lm386 designs comes from how the lm386 sounds when overdriven.

I really like the way my ruby and little gem MkII sound with a tone stack and booster in front of them. Maybe you could try combining such things into one amp. Maybe combine the tonemender (see ROG) and the ruby or little gem.

Check out my Little Gem MkII build: http://www.ssguitar.com/index.php?topic=1456.msg9232#msg9232

If you have sockets for the lm386's and a nearby radioshack that keeps them in stock, just give it a try. If you fry them, you can fork out $3 and pop in some new ones.

I built a Little Gem MK2. It's not bad. At 12V, it is plenty loud enough for a practice amp. Put a booster and tone control in front of it, and it sounds pretty cool. I suggest using a cheap 8 inch guitar speaker, like a Jensen Mod 8 or something comparable. Build it and see if it is loud enough for you. I can piss my wife off with mine. If you need more power than that, go with JM's suggestion. There is only so much you can expect from an LM386.