LM380N based practice amp

[Aharon]

I was checking the amps at GGG and there's a few interesting ones.Some are based on chips that are no longer available.
I have an amp based on the still available ($0.65 from NAtional AFAIK)LM380N.
I have taken the amp appart ansd if there is interest I could take a picture of the PCB from both sides so it can be reproduced.
PArt count is low,around 20 easy to get and cheap.
The controls are Volume and Tone.
Let me know if there's enough interest,never done it before but I have a camera that can shoot macro(closeups,I hope).
Take care
Aharon

[Mark Hammer]

An octet of C-cells and a 380 can actually deliver a surprising amount of volume for a pleasingly long time.  Just make sure you heat sink it for protection.  Normally, what you see recommended is the connection of the middle 3 pins on each side to a big ground plane, but you can get heat sinks that fit chips or make your own.

I have the schem for my little amp posted here: http://ampage.org/hammer/files/Miniamp.png
The accompnaying zipfile has some pictures of the amp and board, including a nice closeup ofthe heat sink, but unfortunately I can't access it (and neither can anyone else)

[D Wagner]

Aharon,

Sure, lets have a look.  I have two LM380's in my parts drawer, looking for a home.  All that I need now is a suitable heatsink.  From what I remember, the pins in the center of the IC are soldered to a large copper area on the PCB, to act as a heatsink.  Extra abuse and voltage would require an additional finned or "winged" heatsink mounted on top of the IC.

Derek

[Aharon]

Yeah,the pins in the center are all soldered together,it's a 14 pin IC,aside from that there's no other heat sinking on this one.All resistrors are 1/2W,there's 4 electros and 5 polys plus a 2N3904.

Aharon

[littlegreiger]

I was checking the amps at GGG and there's a few interesting ones.Some are based on chips that are no longer available.
I have an amp based on the still available ($0.65 from NAtional AFAIK)LM380N.
I have taken the amp appart ansd if there is interest I could take a picture of the PCB from both sides so it can be reproduced.
PArt count is low,around 20 easy to get and cheap.
The controls are Volume and Tone.
Let me know if there's enough interest,never done it before but I have a camera that can shoot macro(closeups,I hope).
Take care
Aharon

I take it that you're talking about the LM383 amp? Well you can still get an LM383T from a few places and I believe that it is an exact replacement.