Something louder than a Ruby?

Started by gutsofgold, October 05, 2009, 10:37:19 PM

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davidallancole

Do you have a schematic or more details of how you did that earthtonesaudio?

Nasse

There was a note on old lm380 datasheet that for maximum heat sinking you should have somewhat biggish copper areas on the pcb and you should solder it directly with no sockets.

Dunno if it works for 386 too

I had a TAA300 (discontinued Philips 1 watt chip) chipamp and it sounded damn good, and with my super efficient 2x12" cabinet it was very loud. It sounded so good that I burned the chip twice, and after that never fixed it till the chip was obsolete. It had an add-on small heatsink thingie, perhaps i had it attached not properly

Perhaps we should have a temperature alert on the chip, just turn it on more and more till the smoke comes out, and then back off a little bit
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earthtonesaudio

Quote from: davidallancole on October 09, 2009, 11:59:23 AM
Do you have a schematic or more details of how you did that earthtonesaudio?
Much simplified:


For better operation this should have a buffer in front and an LC lowpass filter before the speaker.  Otherwise you could damage the speaker.  Check the LM386 datasheet for the "Square Wave Oscillator" application for example part values.  For the LM380 the primary difference (other than power dissipation) is the input resistance, so you need to take that into account.

davidallancole


puretube


Mark Hammer

Quote from: Nasse on October 09, 2009, 12:01:55 PM
There was a note on old lm380 datasheet that for maximum heat sinking you should have somewhat biggish copper areas on the pcb and you should solder it directly with no sockets.

Dunno if it works for 386 too
The 380, like a number of other 14-pin DIP amps from that same development era, has 3 pins on the middle of each side that go to ground.  Consequently, by simply soldering those 6 pins (3 per side) to a ground plane, you direct heat away from the chip, without the need for a heatsink.  In the case of my mini-amp, I used a heatsink because I didn't have a lot of ground plane, or at least not as much as I thought I should have.

An alternative, for those who might build on vero or perfboard (where there would be no copper ground plane to work with), is to bend the 6 ground pins upward so they are perpendicular to the board (like "wings" on the chip), and solder them to a piece of copper or brass shim material on the top of the chip, making sure to run a lead from that whole assembly to ground.