I am trying to create my first guitar amp on a hopefully simple circuit!
Here is the schematic
http://www.redcircuits.com/Page96.htm
Although, with a dummies guide, I am trying to learn about reading schematics, components etc.. I did cheat and found this veroboard layout
http://2.bp.blogspot.com/-Oo0fOO7BWTY/T6icNKtTqeI/AAAAAAAACVw/QoVP4avH-As/s1600/MiniGuitarAmpVero-01.jpg
From this blog
http://diystrat.blogspot.co.uk/2012/05/how-to-make-kids-portable-guitar.html
My question, is the veroboard layout correct??
I have done it exactly the same triple checked and referenced and all I get is a slight crackle when I turn the volume on my guitar!?!
Not to rain in your parade but "Red Circuits" are *notoriously* unreliable.
Better check the datasheet and build the "official" suggested schematic.
EDIT: I suggest you build a "little Ruby" or even better, a "Smokey" clone, based on an LM386 and count'em: 2 (two) electrolytic caps .... and *nothing* else.
Volume/distortion and tone controls are those in your guitar.
Sound?:
http://youtu.be/creY959fH8c
or if you are not into versatility but just love MEEETTTAAAAAAAAALLLLLL !!!!!!
http://youtu.be/pdWKAAL9qco
Oh.... It is all a learning curve I suppose! We check out the ruby and smokey projects, cheers :)
Although circuits from that website may be rumored to be unreliable, this particular one is closely based on what is in the datasheet for that TDA chip.
Basically the only contribution of this circuit is the use of the switching jacks.
They also changed the input resistor from 5K (datasheet) to 22K. This is a feeble attempt to provide a higher input impedance needed for guitar. Unfortunately, it is nowhere high enough; you need a minimum of 500K.
The raw input impedance of the chip is specified 100K, so it's best to try to preserve most of that. You need to provide a DC return resistor for any bias current flowing out of the input; perhaps a 500K resistor to ground for R1 could do the job. It's worth experimenting with, anyway.
Forget the verboard layout; make your own and carefully ensure that it's correct.
There is some Windows cad program for doing layouts on veroboard. It's called VeeCad. I've never used it; but if strip boards are your circuit building too of choice, it behooves you to check this program out!
"Like a PCB layout program, VeeCAD takes a schematic generated netlist and assists you to build a layout - on strip (Veroboard), matrix, donut, tripad, Atarado Smart, and other prototyping boards. "
Sounds good.
To which I would add; I have long considered one megohm to be the minimum input resistance for guitar, but after some recent experimentation with buffers I have found that values for 3 to 5 megohms give even better results with passive guitars.
An easy way to get such high values is to put a simple FET buffer in front of the input, like this one from AMZ;
(http://www.muzique.com/images/buff11.gif)