What does this jumper between clipping paths do?

Theoretically not much. If one set of diodes is forward biased, the other is reverse biased with or without the bridge. There is a little junction capacitance added, but it's on the order of 4pF for 1n4148 and 15pF for 1N4004.

Paul Cochrane, creator of the original Timmy pedal claims there is a subtly audible difference. Did you end up breadboarding to see if you heard a difference? I don't hear one if I add/remove a jumper, but I'm in my 60s and my ears are kind of shot anyway.
The first place saw this was in a Timmy/Timmy clone schematic where it allowed use of a SPDT with open center position to provide 2 options:
1) open - 2 diodes in each direction
2) short out a diode pair for 1 diode in each direction
3) switch in a single diode in one direction for asymmetrical clipping.

Search "Timmy clone Super-Freq schematic" for a drawing. There is also a bit of discussion in the various DIY forums and PaulC participated at times.
 
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If you see how the original Timmys were made you'll see that it was easy to solder one end of each diode to the board and just twist all the other ends together and solder 'em together. Maybe it was a time-saving thing that sounded "subtly better"?
 
paulc said:
That jumper was used to short out 2 diodes - nothing more. Fsb was kind of brutal towards me back in the day. When they started talking about that link I played along with the stupidity and played it up. Lollar and other builders included it which had me thinking they really didn’t have a clue
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I am not sure this is correct (the diode clippers still work) - 'That jumper was used to short out 2 diodes'. Robert or Chuck or others who have that level of knowledge, care to contribute?
 
paulc said:
That jumper was used to short out 2 diodes - nothing more. Fsb was kind of brutal towards me back in the day. When they started talking about that link I played along with the stupidity and played it up. Lollar and other builders included it which had me thinking they really didn’t have a clue
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Well that makes a lot more sense - I've never seen anybody include the switch to short out the diodes!

I've seen years of people stating including it (sans switch) lead to tonal differences that only they could hear, and used you as their evidence for it :LOL:
 
DDad, in the first post you did, the link does essentially nothing. Both clipping paths still function. Why is it there? paulc put it in the Timmy to allow changing the clipping diodes with a switch (as per the later diagrams), and it got propagated into other designs (at times without the switch) for "reasons".

Paul noted that the comment that he heard a subtle difference was because he "played along with the stupidity and played it up" on FSB when he was nice enough to provide info on the design, in a pedal cloning forum yet. Good for him. LOL

Paul - appreciate your participation here and your contributions to guitar pedal history!
 
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