Thanks anttyj for posting this, I look forward to hearing how the preamp works out for you once it is fully built. Maybe even a pic and a sound clip?
Well, I've got it built now and it works nicely. I followed your parts placement otherwise to the letter but moved all other components but the IC to the non-copper side of the veroboard (as a slight mental exercise). In addition, the cutting of copper strip at c12 was indeed necessary, as indicated in my previous post.
I put the preamp into an aluminium diecast box together with a small 8-watt TDA2030 PA built from a kit. The latter provides plenty of volume for home rehearsing.
Overdrive works well, too, and you can see the red LEDs blinking when a guitar string is struck.
Having built a number of solid-state ham radio transmitters in the past, I was slightly concerned of eventual self-oscillations due to proximity of the input and output copper strips of the TL072 but these concerns proved unfounded. There is no sign of instability of any sort.
With my guitar disconnected from the input jack and with the lid of the box in place, the amp is amazingly quiet, no hum, no noise, not anything. Nevertheless, with the guitar connected, the sensitivity is more than ample for full-blast blockbuster operation.
I'm attaching a mediocre-quality picture of the preamp and PA in the aluminium box. The camera of my Nokia C5 mobile phone isn't very well suited for close-up work...
The two not-yet-connected jacks at the rear wall are for connection to an effects box (in my case the
t.c. electronic G-Major guitar processor).
The dual-voltage power supply is external and, it is heavy-duty enough to supply power for a TDA2050 power amplifier I'm planning to build for gig use. As the amp is now, I'll try it at our band's rehearsal location the coming Sunday.