bsiab2 problem...

[darron]

hey. i just built a bsiab2 using the GGG layout: http://www.generalguitargadgets.com/index.php?option=content&task=view&id=150&Itemid=178

it fired up which is good, but it's not working correctly. before i go and get my DMM out to measure all the voltages for C/B/E of the 5 transistors, I thought I'd ask incase someone has a simple diagnosis first (:

alright, the problem is a farty splattered sound. there will only be sound past a certain input volume also. im pretty sure that all of the parts are correct since i bought them all new for this purpose. the resistors came right out of the packets and the capacitors numbers all match up. only one capacitor is bipolar and it's just a power supply filter. all the transistors are correct and in the right way (as the diagram shows at least, without looking up the datasheets to confirm). the soldering is very neat and i can't see any shorts.

i found a semi-cure for the problem... when i touch one of the lines for the gain pot it operates in what seems a normal manner, except the gain is at full blast. if i remove my finger it stays that way forever and i can continue playing with it at full gain up till a time where i play a heavy chord and it goes back to being crap. i originally thought it must have been bad wiring or a pot there but i changed the pot and redid the wiring. is this a biasing issue? when i turn the bias (100k) pot all the way the effect doesn't work at all. every other setting on the pot though sounds almost the same at this point.

i planned on making two, one for me and one for a friend. i could make the other one and see if it does the exact same thing?

anyone got any quick ideas as to what this could be?

thanks heaps guys (:

darron

[Auke Haarsma]

sounds like a misbiased trannie. Time to get that DMM out

[darron]

sounds like a misbiased trannie. Time to get that DMM out

will do. thanks pong (: