Egghead!

[patrickbrose]

Built up my egghead board today. Very cool little OD.  Some things to note:
1. The 120pf cap value is not too important. I believe this is a smoothing cap for the diode clipping and honestly, I hear no difference between 100pf, 120pf and 150pf. I used all ceramic caps since I don't have any silver mica, but I doubt there would be much difference. Honestly, I hear little difference with the cap completely out of the circuit. I know the portion of circuit works because if you stick a .01uf in there the tone changes drastically.
2. Using a 100K pot for presence works fine, below about 40% there is little change to the tone. I compared it to a 25K that I had and the tone didn't change, just the useful range is in the top 40%.
3. Used a 100K for the volume since I didn't have a 500K. Not sure what effect this has on the circuit, but I can't image much.

Let me know if there is something that I am missing. Once I get it boxed up, I will try out some other IC's to see if there is any change.
Very cool circuit Brian!
-P

[madbean]

Yeah, there won't be much if any audible difference under normal listening conditions between a 100pF and 120pF cap, so that's no sweat.

For the Presence knob, mine is basically set and forget. With my Strat and Champ, which was my testing equipment for this, I just dialed it to the right spot and left. It really made the Strat sing, esp. in the 2nd position which is my favorite.

The difference between 100k and 500k vol pot is output impedance/volume. IOW, with a larger pot you get more volume out...but, also more potential noise. There is nothing wrong with using 100k.

Glad you like the Egghead!