Klon KTR mods - the JHS "Shamrock" Klonspiracy

[coltonius]

Curiosity is getting the best of me, so I'm making an appeal to the community.


The JHS Shamrock Mod adds two toggles to a Klonlike circuit: Gain (3-way clipping) and Punch (appears to be a DPDT swapping a resistor + adding red LEDs). The former is pretty straightforward, and the latter appears to be swapping out R9. No clue what the red LEDs do, unless they're adding soft clipping somewhere? It works independently from the Gain toggle.

Any guesses what's going on with the LEDs? Perhaps @Robert or someone who's familiar with the KTR parts designations can tell us where R9 lies in the circuit.

Resources: Kliche build doc

 

[coltonius]

A shot of the Shamrock mod on a Soul Food with a better shot at the "R9" resistor values:

 

[benny_profane]

Oh cool. They outsource their drilling to LWA.

 

[Harry Klippton]

Oh cool. They outsource their drilling to LWA.

Didn't he change his name to void something or other?

 

[jimilee]

Curiosity is getting the best of me, so I'm making an appeal to the community.


The JHS Shamrock Mod adds two toggles to a Klonlike circuit: Gain (3-way clipping) and Punch (appears to be a DPDT swapping a resistor + adding red LEDs). The former is pretty straightforward, and the latter appears to be swapping out R9. No clue what the red LEDs do, unless they're adding soft clipping somewhere? It works independently from the Gain toggle.

Any guesses what's going on with the LEDs? Perhaps @Robert or someone who's familiar with the KTR parts designations can tell us where R9 lies in the circuit.

Resources: Kliche build doc

View attachment 47504

Clippers,

 

[coltonius]

Clippers,

I’s smart enough to work out that the Gain toggle does that. My question is about the Punch toggle (which also seems to feature clipping of some kind).

The Punch works separately and independently from the Gain toggle, so my guess is those red LEDs are in the negative feedback loop of one of the gain stages, in addition to whatever shift the resistors are causing.

 

[cdwillis]

Didn't he change his name to void something or other?

Void whetever is his synth branch of his company. Lone Wolf Audio is still making metal oriented guitar stuff and I'm sure the build quality is still on point with a third graders first science project lol.

 

[bakelite52]

Hey was just wondering if you ever resolved this and figured out what the punch mod does. Has anyone been able to identify what is being switched out?

 

[FlyingV55]

May have figured out some of the Punch mod. The resistors appear to switch between 2k (stock value of R9 in the Kilche build doc) and 470k (I have Yellow Purple Black Brown and dark brown for tolerance, although the brown after the black is murky). The LEDs appear to be hard clipping to ground, connecting to the other diode side in the KTR shot.

 

[LunarModule]

I think FlyingV55 has it mostly correct. If you follow the wires it’s pretty clear the LEDs are connected to the diode switch and ground, so they are hard clipping. I read the two resistor values as 20k (red, black black red) and 47k (yellow purple black RED brown). I could be wrong but to my eye the multiplier bands look different than the brown tolerance bands, so I think they’re red.

Now obviously 20k doesn’t match the 2k stock value of “R9” on the kliche build docs. Which got me wondering how everyone concluded that the R9 on the KTR and soul food PCBs correspond to R9 on the kliche. I couldn’t find a specific schematic for the ktr, but the soul food specific schematic I’ve attached has R9 labeled as the resistor connecting the clipping circuit’s out to the summing stage, with a value of 47K stock (R15 in the kliche). Switching that to 20k would probably accomplish what JHS says the mod would do, namely make the clipping stage a lot louder and add some more midrange. The LEDs seem to kick in with the 20k resistor. Given that they are in parallel with the other LEDs I don’t think they actually do anything unless you have the clipping set to “open” and the punch on.

Sorry if my formatting is a mess, I usually don’t post here and I’m on mobile.

 

[coltonius]

I think FlyingV55 has it mostly correct. If you follow the wires it’s pretty clear the LEDs are connected to the diode switch and ground, so they are hard clipping. I read the two resistor values as 20k (red, black black red) and 47k (yellow purple black RED brown). I could be wrong but to my eye the multiplier bands look different than the brown tolerance bands, so I think they’re red.

Now obviously 20k doesn’t match the 2k stock value of “R9” on the kliche build docs. Which got me wondering how everyone concluded that the R9 on the KTR and soul food PCBs correspond to R9 on the kliche. I couldn’t find a specific schematic for the ktr, but the soul food specific schematic I’ve attached has R9 labeled as the resistor connecting the clipping circuit’s out to the summing stage, with a value of 47K stock (R15 in the kliche). Switching that to 20k would probably accomplish what JHS says the mod would do, namely make the clipping stage a lot louder and add some more midrange. The LEDs seem to kick in with the 20k resistor. Given that they are in parallel with the other LEDs I don’t think they actually do anything unless you have the clipping set to “open” and the punch on.

Sorry if my formatting is a mess, I usually don’t post here and I’m on mobile.

I agree with your assessment of R9 on the KTR and Soul Food and knew it was unlikely to match up to the Kliche, so I’m not sure where that came from either.

As for the LEDs, I think you’re right about hard clipping to ground. The angle makes it hard to tell whether they’ve used the ground point of the original diodes on the PCB, though. There’s a twisted pair of black wires coming from the clipping toggle to somewhere beneath the board and a second pair of twisted wires coming from the LED side of the toggle to beneath the board.

I just found this photo of a different KTR with a better angle on the LED toggle:



This only leaves the mystery of the silicon-looking diodes on the clipping toggle! I’ve seen several different parts in that packaging, from the “basic bitch” 1N4148 to Schottky BAT42 and other more exotic parts.

And also, why the f*** did they use 4 diodes (1 parallel pair in each direction) when 2 would’ve done it?! No way it’s due to the pedal’s current draw requirements.

 

[jimilee]

I agree with your assessment of R9 on the KTR and Soul Food and knew it was unlikely to match up to the Kliche, so I’m not sure where that came from either.

As for the LEDs, I think you’re right about hard clipping to ground. The angle makes it hard to tell whether they’ve used the ground point of the original diodes on the PCB, though. There’s a twisted pair of black wires coming from the clipping toggle to somewhere beneath the board and a second pair of twisted wires coming from the LED side of the toggle to beneath the board.

I just found this photo of a different KTR with a better angle on the LED toggle:

View attachment 61136

This only leaves the mystery of the silicon-looking diodes on the clipping toggle! I’ve seen several different parts in that packaging, from the “basic bitch” 1N4148 to Schottky BAT42 and other more exotic parts.

And also, why the f*** did they use 4 diodes (1 parallel pair in each direction) when 2 would’ve done it?! No way it’s due to the pedal’s current draw requirements.

If two are distortion, 4 must be moar distortion.

 

[mdc]

And also, why the f*** did they use 4 diodes (1 parallel pair in each direction) when 2 would’ve done it?! No way it’s due to the pedal’s current draw requirements.

I would assume because he liked the clipping characteristics of whatever diode that happens to be but wanted a lower clipping threshold to better match the Ge pair.

(I've never tried running multiples in parallel, so I actually don't really know if that would work)

 

[juice886]

The effect of such diode configuration is quite subtle:

 

[coltonius]

The effect of such diode configuration is quite subtle:
View attachment 61535
View attachment 61536

That's what I thought! Then I stumbled across your data in another thread.. I'm sure somebody can hear a difference, but to me it looks like tolerances between a single opposing pair could easily make up the difference. After all, why use 2 extra parts when the result isn't 2x more good?

 

[juice886]

That looks like a secret "boutique" mojo. Though it would be interesting to check the difference by ear.