The architecture of the little gem has been updated with an input buffer as found in the little gem mkii feeding the inverting input and the volume control changed from the output rheostat to the type and placement as shown in the datasheet application notes.
Ruby amp vero layout.
It is an enhanced version of the previous little gem amp also designed by runoffgroove.
Ruby is an enhanced version of the little gem battery powered amplifier.
I used a demo version of lochmaster to layout a version of the lm386 ruby amp.
The data sheet for all 78xx v r s suggest using two fairly large caps for the in and out to ground.
So it s good to go.
As you can see in the schematic below there s a lot going on inside that eight pin dip chip.
The 1000uf caps i have a kinda big so the board ended up being 11x6.
Also added a very small heat sink.
Although they are correct according to the schem.
Maybe overkill but i have made almost every 386 amplifier on the internet.
It has been used in a lot of popular amps like the smokey amp the little gem the ruby amp the marshall ms 2 and the noisy cricket.
The main improvements of the ruby amp vs the little gem are new the input buffer a renovated volume control and an updated gain potentiometer.
The main power amplifier stage is based on the lm386 audio integrated amplifier.
I was pleasantly surprised about how easy it was to use the software and i may well consider using it again in the future.
Verified ish the gain wires need to be switched around.
The lm386 is a specialized op amp that was designed for easy creation of various audio amplifiers.
It is a popular choice for low powered guitar amplifiers due to its low quiescent current and ability to run on 9v.
Mains failure alarm stripboard layout june 3 may 2 april 10 march 3 february 5 january 3 2013 27 december 1 november 3 october 1.
Simple dual led battery monitor stripboard layout.
It might be helpful to add a daughter board to the layout.
The lm386 chip amplifier.
I feel it is a little expensive for the full version the demo version is software limited no saving or post editing etc but it was just what.
The 1 lm386 chip amp does all the amplification in the ruby amp.
I have just verified this.
The ruby amp is an lm386 based guitar amplifier.