SWTC in a Big Daddy from ROG

[ItZaLLgOOd]

Alright, with a few successful "color by number" DIY projects I am going to experiment a little.  I want to add an SWTC to the Big Daddy from ROG.  My thought was to place it after the Jfet and before the 386 chip.  Would this be a good place to start or should I put it after the 386?  Is there a rule of thumb to go by as to were to put a tone stack or is it a trial and error thing? Thanks for any help, john

[Mark Hammer]

You,re using it to trim the high end off the distorted sound, so it should go just before the volume pot, the same way it does on circuits that don't use a 386.

On the other hand, I'm curious about whether it might be an interesting control if placed in the feedback loop.  In other words, you get yourself a 1-5k pot and wire up the two outside lugs between pins 1 and 8.  The wiper of the pot goes to a cap and then ground.  Since I don't know how the 386 might handle a cap to ground directly from pin 1 or 8, it may be best to start with a 1k pot that goes to a 220-470R fixed resistor on each side and THEN to pins 1 and 8.  That way, there will always be some resistance between the cap and the IC pin.

Note that the 1k pot between pins 1 and 8 determines the amount of feedback.  The suggested control would keep the overall amount of feedback/drive constant, but alter how much feedback/drive there is across the overall spectrum.  As the combined resistance between the wiper and pin 8 increases, there will be less feedback/drive in the treble range.

[ItZaLLgOOd]

Would this an additional pot to the 1k already there or a substitute pot. The 386 chip is only only $1.50 for 2 at my local Rat Shack.  Not much to lose.  I think I'll give it a try.

[ItZaLLgOOd]

I did this for the SWTC. Hows it look?  This will be my first try so be gentle