ROG Big Daddy Question

[tungngruv]

I'm almost done with ROG's Big Daddy. I'm still new to this (4th build) and have a pretty basic question, I think. On the 1K gain pot, are lugs 1 and 2 connected together? I can't tell from either of the two diagrams. Sorry for such an ignorant question and thanks for any help.

[Peter Snowberg]

It's a good question that comes up every few weeks here.

You may connect lugs 1 and 2, but you don't have to. The N.C. next to pin 1 on the diagrams stands for "No Connection", but connecting the unused end to the wiper is a cleaner and better way to build the circuit. If you connect lugs 1 and 2 and the pot is slightly dirty, when the wiper doesn't make perfect contact the resistace will jump from the desired setting to the max value of the pot. If you don't connect 1 & 2 then the resistace will jump from the desired setting to an open circuit which can cause some nasty noise.

One addition that I would recommend making to that schematic would be to insert a 10uF or slightly larger cap in series with the pot between pins 1 and 8.  The + side of the cap should be connected to pin 8. If you don't use a cap, it ends up upsetting the DC bias on the input stage.

Best of luck on your build! I love 386 based amps.

[tungngruv]

Thanks Peter, I'll try the cap also.

[tungngruv]

OK, it's done and I have to let you know, this is one fat, crunchy, awesome sounding pedal!! When I read the "big tube amp" comments, I thought probably not. This one's my new favorite. I am now a total believer in RunOffGroove's projects (and the LM386). Thanks for letting this one out!!

[GreenEye]

I loved the sound clips of Big Daddy - thank for saying you like it, it's definitely on my list now...