18-05-2011, 11:50 AM
That's nice - these days that's exactly how I do my diagrams! The schematics on my website took *forever* to produce, and I'm too impatient to learn how to use a CAD package, although there are quite a few nice (free!) ones out there - TinyCAD looked quite promising and perhaps one day I'll put some effort into learning it.
The only thing that leapt out at me was a lack of decoupling. Admittedly the LM386 datasheet doesn't mention it, but I would definitely consider adding 0.1uF and 100uF in parallel between pins 6 and 4. The LM317 would probably appreciate it too. You might find that Rs isn't needed either (although it's not really hurting here) - bear in mind the impedance of the speaker will vary wildly with frequency, and will be comfortable above the nominal impedance for quite large chunks of the spectrum. As long as the IC doesn't overheat or go into current limiting, I'm sure it'll be fine.
As I say, very nice! It's given me an idea (although I wish you'd magically given me the time to try it
) - one day I'll come back with a bench amplifier that is completely different, but somehow the same.... watch this space!
Mark
The only thing that leapt out at me was a lack of decoupling. Admittedly the LM386 datasheet doesn't mention it, but I would definitely consider adding 0.1uF and 100uF in parallel between pins 6 and 4. The LM317 would probably appreciate it too. You might find that Rs isn't needed either (although it's not really hurting here) - bear in mind the impedance of the speaker will vary wildly with frequency, and will be comfortable above the nominal impedance for quite large chunks of the spectrum. As long as the IC doesn't overheat or go into current limiting, I'm sure it'll be fine.
As I say, very nice! It's given me an idea (although I wish you'd magically given me the time to try it
) - one day I'll come back with a bench amplifier that is completely different, but somehow the same.... watch this space!Mark
