Matt T.
12-18-2006, 02:43 PM
I just built a BSIAB II using the PCB from General Guitar Gadgets. Schematic is here. (http://www.generalguitargadgets.com/pdf/ggg_bsiab2_sc.pdf) The circuit works and sounds pretty good...the distortion comes on really quick but I used a linear taper 500K drive pot so that should explain that. All other values were per the layout/schematic except I used a 100ohm source resistor instead of 120ohm on Q3.
My question is on some slightly strange voltages on two of the trannies (based on the BSIAB II build instructions (http://www.generalguitargadgets.com/pdf/ggg_bsiab2_instruct.pdf) on the GGG site). Q3 has the exact same voltage on the source and drain (about 1/2 V+) with very low voltage on the gate. Q5 also has the same voltage on the source and drain (adjustable through the V+ range with the 100K trim-pot) with about 1.1v on the gate.
The unit doesn't sputter, it distorts pretty well...and a lot, tonality is good, it has plenty of drive and volume...plenty, and it decays well...no 'fizzing out' when a note decays.
Are these voltages anything to worry about? It does seem to work fine but I'd hate to not see the full potential because of some mistake/problem. Any help appreciated. Thanks.
My question is on some slightly strange voltages on two of the trannies (based on the BSIAB II build instructions (http://www.generalguitargadgets.com/pdf/ggg_bsiab2_instruct.pdf) on the GGG site). Q3 has the exact same voltage on the source and drain (about 1/2 V+) with very low voltage on the gate. Q5 also has the same voltage on the source and drain (adjustable through the V+ range with the 100K trim-pot) with about 1.1v on the gate.
The unit doesn't sputter, it distorts pretty well...and a lot, tonality is good, it has plenty of drive and volume...plenty, and it decays well...no 'fizzing out' when a note decays.
Are these voltages anything to worry about? It does seem to work fine but I'd hate to not see the full potential because of some mistake/problem. Any help appreciated. Thanks.