Ampeg Scrambler - Which layout is right?

Started by azrael, December 15, 2009, 10:11:22 PM

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Why are there two diodes on this layout:
and five on this one:

Which is the correct Scrambler?




Oh, thanks for clearing that up. Missed that detail. I used the uStomp layout, so I was a bit worried haha.


I put in all diodes, and it's wonderful, a very nice octave up. Didn't have any darlingtons, so I piggybacked BC560's. There's also a layout somewhere, which is meant to be used with 560's (two sets of holes in the place of each darlington). But I used the tonepad layout, and it worked on first startup (just some biasing issues, which is to be expected when subbing transistors).


Honestly it doesn't sound that different with the extra diodes.  Sounds like doom either way.
"Sounds like a Fab Metal to me." -DougH


> it doesn't sound that different with the extra diodes.

I can't see why either one is necessary. I wonder if they were left-over from a previous idea, or were over-cautious design. The pair should never do anything, the single looks like unnecessary protection. Like the breadboard was copied to a PCB, then in final testing it was realized that the diodes were probably doing nothing, a waste of 6 cents. In mass production, 6 cents matters. Easy enough to tell the workers to omit them, not worth burning a new PCB mask until the first mask wears out. Since this thing seems to be rare, they probably never wore-out the PCB mask.