Introducing not a new build, but a rebuild:
I've been working on this amp lately, finally got around to post my 6+ months old project on the forum;
TDA7293 can be connected in parallel to drive low impedance and to increase output power especially at high voltages.
Furthermore the paralleling of chips reduces the total thermal resistance of the system and therefore reduces cooling demands to a level which is more likely to be handled correctly under all operating conditions.
Heat sinking is critical, of course, If you can, use the heat sink extrusions as structural pieces of your enclosure.
Nice feet from DIYaudiocart.
Compared to the prototype, made some improvisations in chip mounting and layout:
* Bigger enclosure to facilitate rack mounting.
* Amp boards and PSU were moved from one-above-the-other to side-by-side.
* Chips mounted directly on heat sink to decrease thermal resistance.
* To turn individual channels on/off I use switches placed between the transformer and the power supplies.
* Im using a copper braid to shield the signal wires.
Top cover holes drilled using an old UPS side panel as jig.
To mount chips directly a groove is required on the heat sink so, decided to use standard carbide tipped wood blade on a regular circular saw.
It cuts pretty well, if you are not too pushy I don't even think it loads the saw too much worse than a sheet of three quarter-inch plywood, despite this dry cutting, the saw blade did not load up with aluminum,
although some lubricant like WD40 would probably be a good addition, but the potential is certainly there.
The job I did was not planned out in advance, so my only choice was to grab the nearest 40T blade available.
I don't know if they make one, but a carbide tipped blade with about 50 or 60 teeth and a triple chip grind would be the ultimate blade to use for this application.
Everyone has a circular saw, so they can't be that dangerous, right? Maybe that's the problem the tool lures you in with its apparent ease of use, but could take your hand off with its ferocious kickback.
Circular saws have faster blades than table saws, with an outer edge spinning at about 120 mph, and they can cause some serious damage if used incorrectly or recklessly.
Safety Tips:
* Clamp your work piece so you can keep both hands on the tool.
* Make sure to wear safety glasses, gloves and other appropriate clothes, the aluminum chips seemed to fly in all directions with a great deal of force,
and they are both very sharp edged and extremely hot! can and will get everywhere.
Build to continue...
