The objective here is to build a portable guitar preamp that I can carry around and gig with different people. It can also replace the preamp section of my guitar amp, which is a Peavey, and borrow the sounds of Fender/ Marshall/ Vox from its tonestack.
Step 1: Schematics
I then borrow the tonestack from the Tonemender that is found at www.runoffgroove.com . The Tonemender is a booster with a very flexible tonestack, which can re-create the Fender, Marshall and Vox responses.
Details of these schematics can be found at the links above, which explain clearly what these circuits do and how they work.
Step 2: Layout
It took me some time to draw the layout (which was my first time), but it actually saved a lot of time for me to build the board.
I also matched the FETs by following the instructions found here:
Step 3: Building the Preamp
Not much to explain here. Just solder the parts according to the layout. It is always a good idea to test the board before putting the off board parts all together.
I used shielded wires for the signal path. More work and time is needed in soldering and grounding, but I think it surely worth it.
The preamp can be powered by 18 volt. The 18 volt battery clip is made by using some old 9V batteries.
Step 4: Finishing
Just put all the wires nicely and carefully into the box. Use some cable ties whenever suitable. Label the switches and knobs. Yes. I am a Dymo lover!
Step 5: Testing
I also tested the preamp using a pair of headphones and it worked fine for me, so it can also be doubled as a little practice headphone amp. A bonus.
The only problem I found with this preamp is that it has too much gain, so only about 1/5 of the volume knob is usable in my settings and adjusting the volume to level with others' instrument could be a problem. But I also doubted that it depends on the power amp, so I have not made any changes to the part values yet. Any suggestions on this are welcomed.
I hope that you would find this instructable useful!