OD Mod on Kingslayer II

[Droogie]

Was wondering if it's possible to insert the OD switch with a pair of diodes into the KII. I know this feature was left out of the new version, but I really dig it and am not worried about space issues for the extra switch.

Thanks!

[madbean]

Yes, although you will likely need to do additional modifications. The KS1 used alternative resistor values to crank up the gain a bit for the soft clipping OD. While you could use the stock values in the KS2, which are essentially the Klon values, you might get more bang for your buck using something closer to the KS1.

Fist, you will need to arrange your back to back diodes used for clipping. They need to go in parallel with C9/R11 and with a switch so that one side of the diodes can be lifted to disengage the soft clipping.

Make R11 a 1M resistor. Socket R9. Start with 2k there. Test out the range of overdrive using the soft clipping then the hard clipping. You want to minimize any oscillation you get when you start cranking up all three knobs in parallel. You will likely get this oscillation when you bring up the Tone pot when the Volume and Gain are cranked. To minimize this, increase the value of R9. Start with 4k7 and go up to 10k until you minimize or eliminate the oscillation.

Keep in mind that the KS (and Klon) is really a "two up one down" kind of overdrive. Cranking all the knobs up full is not really how to get a good sound out of it. The most useable tones and OD you get out of them are by having two knobs up some and one knob down, in different permutations. For example, the Gain and Volume up pretty high and the Tone rolled down, or the Gain down and the Tone and Volume up, etc. You get the idea.

BTW, the reason I'm going through all this detail is just to illustrate the necessity of "design balance". IOW, adding in mods sometimes can break other things so you often have to fiddle with things a bit to get the best compromise across all features.

[Droogie]

Awesome! What would be the best place to connect the switch? I'm looking at one leg of C11 for Sw1a and the junction of R9 and 10 for Sw1b (dpdt).

[Droogie]

In case anyone else is interested, I took the Bean's advice upthread re some part value substitutions and connected the diode pair as mentioned in the previous reply. It works like a charm! For the hard clippers I used the stock 1N34a for the first pair and the other are mosfets G+D - S with 1n34a cathode to S—my favorite clippers so far. I find them, along with soft clipping, to yield a much larger use range on the gain knob. With LEDs and no soft clippers, the upper end always struck me as a bit harsh—this really tames it.

As for oscillation, I cranked tone and gain with excellent results; didn't crank the volume. Yet...