I built a copy of the Foxey Lady 3 knob on stripboard and the sound is superb apart from a screech which occurs when the notes have died down. This occurs whether powered from battery or mains, using an amp or headphones and with 2 different guitars, it gets worse when nothing is plugged into the input socket. While actually playing it doesn't happen, it seems to come in as a slow oscillation once the notes have died away (which takes ages, the sustain on this pedal is phenomenal) and then builds up to a sound resembling feedback. I have checked the layout and cannot find any problems.
The board was originally built with some unnumbered Motorola transistors which had HFe readings of 300 to 450. I replaced these with BC184c units and have checked all the capacitors. Whatever substitutions I have made have not altered the sound. The only real difference from the circuit shown is that I used 0.1u caps instead of the 0.12u as I could not obtain them. I have made this substitution before with no problems.
The circuit is in a metal box and is earthed to this so it is not radio interference. All wires are as short as possible.
This will not prevent me from using the pedal but it has to be switched off pretty smartly between songs to prevent breakthrough of this sound.
I've had similar problems with different pedals. It turned out to be a bad input or output jack.......not enough tension on the "prong" or a bad ground connection.
Thanks for the reply. I don't think it's the jacks as I checked it on my test rig befre I soldered the jacks, switch etc. on to the circuit board and it still did it. I used it live for the first time last night and it's not too much of a problem, as soon as I hit a string it stops and there is no underlying sound while playing. It sounds similar to feedback so it isn't too noticable as long as I'm quick with the footswitch at the beginning of a song to prevent it. I have tried it with battery power through a battery amp so it definately isn't anything to do with the mains.
The sustain on this unit is incredible. When I drop out during a song and let the last chord ring it goes on and on, and I can hold a note in a solo for virtually as long as I want to. I was expecting a sound along the lines of my Big Muff Pi (genuine-not a home build) as I understood it to be virtually the same circuit, but in A/B tests it sounds quite different, the endless sustain is the same but it has a much smoother and richer sound, more like a Boss Metal Zone. It also fits very well in the mix of my punk band, unlike the Big Muff which is too harsh and overpowering and usually only gets used at home when playing along to St Vitus or Sleep.
Has anyone else built one on stripboard and had similar problems? My local supplier has run out of 0.1u caps and isn't re-ordering until next year so I can't build another board and try that to see if it's the same. I suspect that it may be due to some compnents being too close together on the board but I haven't had this problem before. I might try a different layout when I can get the parts.
