RM octavia

[Sody54]

WOOHOO!! RM Octavia worked on the first try!!  It's got a pretty weak octave signal, but it's clearly there!  I didn't have any MPSA13's so I subbed in 3904's.  Afterwards I went through and learned how to match them, so now I've got 3 of them at right around 160 Hfe that I'm going to put in IF I can pry it out of my lead players grubby mitts long enough to make the swap!  Also had to sub a couple resistors I didn't have in my stash.  The 180K and the 820K's.  I used the layout in TCobretti's gallery.

Going to place a Mouser order this afternoon to get the correct parts,  unless I can find the MPSA13's on smallbear.  Haven't looked yet.

And now back to your regular programming.....

[tcobretti]

I'm glad the layout worked for you.  I recently went back and played with swapping transistors in mine, and found that you definitely want the MPSA13s, but for Q1 I used a Ge PNP.  After some experimentation I discovered that the darker sound of the Ge transistor helped bring out the octave, sort of like like rolling your tone back a bit.  If you'd rather use an Si transistor, I'd pick one that is low gain and I'd put a <100pf cap from it's collector to base.  This cap will help muffle the high freqs just a little and mimic what the Ge transistor does to my circuit.

Also, you get more octave the lower the gain pot is set.  I run mine with the gain pot all the way down for octave and higher if I want more of a fuzz sound.