Switchable Clipping Diode

[MetalGod]

ok. I will solder the cap across D4 legs - so I guess this should be the "lonely" diode.

I guess I didn't understand your mod correctly - does it do what I want? add/remove the diode? and is it the right diode to add/remove for this mode? because it seems to have just one position. If it does, I'll kiss you.

yep, it switches one of the series diodes (D6) out of circuit - one of the switch lugs is not used because the diode will conduct in this setting on the switch.  In the 'other' position the diode will not conduct because the wire presents less resistance than the diode (path of least resistance rule).  I'll pass on the kiss if it's all the same 

I would like to change the diode to mosfet anyway so I have to desolder it.

have a play round with the clipping diodes if you must - I wired up a 6-position rotary switch with various configurations and like a pair of 1N4148s best (stock TS-9 config).

using a Germanium transistor wired as a diode sounded quite 'squishy' - worth a shot (I believe this is one of the mods Keeley offers)

[Tamir]

THANKS! realy. now I finally understand everything.
so just for dessert, can you list some diodes/components as diodes that sound best for you?
I have here a BS170 that I am going to try, a silicon diode and maybe a fet or led. I have already read about those but I just want recommendations

thanks again everybody!

[petemoore]

1  Si>Si>
   <Si<  Assymetric
-----------------------
2  Ge>Ge>
  <Si     Alot like 4       
-----------------------
3 Si>Ge
   Si>Si     ...High Output, 'still assymetric
-----------------------
4  Si>
   <Si    Symmetric
 
  Really depends on the circuit and everything else.
  If the clipping threshold is high [like 3], boosted signal level hitting the diodes may exhibit harder clipping again.
  I measure lotsa diodes, for symmetric...equal threshold voltages, but that also depends directly on how far the +/_ signal voltages swing...it was hard for me to discern tonal difference between exact matched diodes and ones of the same type but farthest from each other threshold wise...tending later to opt for diode type swaps which exhibit clipping characteristic differences I could actually hear.
  Here's how I suggest it can be decided by you and your rig.
  Picking a couple types of configurations like 2 and 4, with one of the choices socketted through the switch that chooses between 2 configs, then playing the box with the switch in an arbitrarily chosen position, for some time, trying different settings on the clipping circuit [gain tone vol] as well as revoicing the clipping diode HF rolloff cap, trying settings on pre-boosters etc. until I 'get to know' what that switch setting 'does', then hit the switch and repeat full length testing in that position...then like it and leave it or..decide which of the two Sw. positions is a keeper, put those diodes in the 'semi permanent' soldered in position, try a third config in the socket.
  I used socket, it may be possible to easily solder them 'floating' on offboard wires or on the switch?..