One thing to consider: the output impedance of your phone is probably not the same as your guitar. Some pedals care a lot about that (Cot-50, fuzz face, etc.). For debugging, this is no big deal, but if you want to tweak values on any pedal that sees the guitar directly, you might consider making a circuit with a buffer feeding a pickup simulator to go between the phone and the input. This will give you a more guitar-like signal. (This works well for re-amping in general, for those who like to record a dry signal and experiment with different amps/effects. Kind of like an analog version of Amplitube.)
Watch the input levels too. Passive pickups put out a pretty small voltage signal.
I tend to use Alpha pcb pots (pins for lugs). On a breadboard these slot in nicely over a 5 row span. If you look at the bottom of my breadboard you can see rows running vertically. This allows me to put all my pots on the bottom of the circuit for easy access when tweaking. I just jumper from the circuit to the relevant pot.
When I'm happy I then transfer all to stripboard, wire in all pots but connect the rest to the breakout box and test the board for errors. If all good I start boxing.
I'm only new to all this but I can deffs say this interface is great tool. Go for it!
I've already started retrofitting a transformer AND Adstrums speaker terminals.
Got the idea last week from this http://pcb.delyk.com/utility-boards/9-effects-tester-kit.html and decided to make one for myself.
You have to actually build the vero first, and then try it. It just includes all the wiring except the board and any pots/switches. Here is a pic of mine (kinda ashamed after all the neat things you all posted)
Here you can see it hooked up, and you can also see how I test pots and switches before soldering.
Also includes a humminator (search the forum for it), and finally here's how it's wired.
Took awhile but I finally finished my new Test Box based on Miro's V2. Only I added a few extras. It can now do the following...
Supply a test build with 9V or 18V (Zach's switchable Charge Pump)
Input a simple 555 square wave for debugging/probing purposes (my own layout below)
Switch in a simple JFET Input Buffer Switch in a simple JFET Output Buffer
Connect/switch in an Audio Probe
Hook up Test Build without any tools (finally!!!)
The switches top Left to Right. 9V/18V, Oscillator Power, Osc/In Jack, In Buffer, Out Buffer
Bottom Main Bypass, Audio Probe
Haven't had a chance to use it yet but everything functions as expected. I was concerned the oscillator would bleed through hence the power switch for it. I wasn't concerned with LEDs but for anyone who may ask, just add a pole to each switch and wire an LED in the usual way.
I've spotted an error on the oscillator. Output should come from Pin 3 not from Pin 2. I drew this from memory and misplaced it sorry. I checked my build this morning and confirmed that everything else on the layout and wiring diagram is correct. I'll update the OSC layout tonight when I get back to the house.