uStack Desktop Amp.

[Holmes81]

Hello,

I'm looking to build a desktop practice amp, no bigger than a sheet of A4 (not set in stone on size).

The idea being to create a little practice amp which runs off a battery (pp3) or maybe a wall wart. I have a couple of speakers to use and am thinking of making a very simple amp. The question I have is Class A or Class AB?

I was thinking about a simple single transistor Class A setup with volume and no tone stack(use guitar for that).

Then thought about building a Class AB just for fun. Not really huge power just want to get a decent little amp for practicing on.


Both have same (approx) amount of comps, so any thoughts?

Many thanks.

 

[Mooly]

The words Class A and PP3 don't really go together The battery life would be measured in literaly seconds as it couldn't supply the current.

Best bet is a simple single rail chip based amp and suitable wall wart PSU.

 

[Holmes81]

OK,

I was thinking along the lines of a headphone amp to drive the speaker, ao it's not possible to make a desktop amp with a transistor(or two) a handful of resistors and a small speaker.

OP Amp version me thinks then!

 

[JMFahey]

Make an LM386 based one.
Google "LM386 guitar amplifier" and enjoy.
You'll even find direct transfer PCB designs, or perfboard/veroboard versions.
Good luck.

 

[Holmes81]

Just ordered some LM386, cheers.

 

[shanx]

One of the versions for practice guitar amp using LM386 that has had a lot of successful DIY builds is the Ruby Amp by ROG. It uses a simple JFet as a buffer between the guitar and chip amp. That will increase the input impedance of your practice amp, giving better performance. It will also warm up the sound a bit compared to going in direct. Lots of sound demos available, and it is only a few more components so it is easy to give a try.
Have fun!