Author Topic: Ampeg Scrambler - Which layout is right?  (Read 2498 times)

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azrael

Ampeg Scrambler - Which layout is right?
« on: December 15, 2009, 05:11:22 PM »
Why are there two diodes on this layout:
http://ustomp.com/?p=9
and five on this one:
http://www.tonepad.com/getFileInfo.asp?id=31

Which is the correct Scrambler?

PRR

Re: Ampeg Scrambler - Which layout is right?
« Reply #1 on: December 15, 2009, 05:49:30 PM »
Read the PDF on the TonePad site:


azrael

Re: Ampeg Scrambler - Which layout is right?
« Reply #2 on: December 15, 2009, 10:24:04 PM »
Oh, thanks for clearing that up. Missed that detail. I used the uStomp layout, so I was a bit worried haha.

Jarno

Re: Ampeg Scrambler - Which layout is right?
« Reply #3 on: December 15, 2009, 11:08:58 PM »
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).

MikeH

Re: Ampeg Scrambler - Which layout is right?
« Reply #4 on: December 16, 2009, 11:46:45 AM »
Honestly it doesn't sound that different with the extra diodes.  Sounds like doom either way.
"Sounds like a Fab Metal to me." -DougH

PRR

Re: Ampeg Scrambler - Which layout is right?
« Reply #5 on: December 19, 2009, 01:50:49 PM »
> 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.