King of Tone High Gain Mod

[sonnyboy27]

Hey everyone, my name finally came up on the KoT waitlist and I got mine in the other week. Naturally I pulled it apart to see what the famed high gain mod actually was. Turns out the drive pot is the same value as the standard but the resistor in the feedback loop changes values.

I'm attaching the schematic I came up with from tracing mine. Certain resistors in each side where carbon comp as well so I've noted that in the schematic with CC.

Hope some folks find this informative. This community has been super helpful to me so I wanted to pass this info along.

Edit: Updated the schematic to include the serial number, IC value, and fixed the clipping diodes sections.

[Aentons]

Cool, Thanks. Are the IC's 4580D? I have seen there are occasionally different diodes as well. We're gonna need some pics 

[sonnyboy27]

Yes it does. High gain side is the same chip (I believe) just with a big H painted over it for some reason.

Here's a gut shot. My phone can't get close up shots so I don't have good ones of the diodes.

[Aentons]

Yes it does. High gain side is the same chip (I believe) just with a big H painted over it for some reason.

yep, I think he does the "mystery" H as big joke.
Interesting, it looks like he has switched to Vimex pots

[Thewintersoldier]

This is right on time. I have a pedalpcb kot board I'm putting together soon, thanks for the insight!

Sent from my moto z4 using Tapatalk

[thesmokingman]

optional c12?

[sonnyboy27]

I hadn't thought to check before now but C12 is a cap between lugs 2 and 3 of the drive pot. I don't know if the optional refers to the cap or the resistor that's right there (it's R5 on the board).

[Aentons]

I hadn't thought to check before now but C12 is a cap between lugs 2 and 3 of the drive pot. I don't know if the optional refers to the cap or the resistor that's right there (it's R5 on the board).

https://www.thegearpage.net/board/index.php?threads/analogman-grounding-issues.2039391/
"C12 is optional (we never used it though), R5 needs to be there"

[Boba7]

This value for C3 (750p) still seems a bit odd to me, compared to the one usually found in this circuit (100p), so I wonder if Analogman is not playing with us geeks there...

[sonnyboy27]

I actually tried out a 680pF in parallel with a 100pF in my pedalPCB Pauper (Prince of Tone) and it sounded really close. Adds a nice midrange emphasis and cuts down on noise but it wasn't the most in depth test (looper into the pedal while putting the cap in and out of circuit repeatedly).

[Boba7]

I actually tried out a 680pF in parallel with a 100pF in my pedalPCB Pauper (Prince of Tone) and it sounded really close. Adds a nice midrange emphasis and cuts down on noise but it wasn't the most in depth test (looper into the pedal while putting the cap in and out of circuit repeatedly).

Interesting, thanks, I'll keep that in mind!

[Flying]

What is the affect / benefit of having a 1uF metal film cap with a 1uF electrolytic cap in parallel on the output, why not just a 2.2uF Cap?

[somnif]

What is the affect / benefit of having a 1uF metal film cap with a 1uF electrolytic cap in parallel on the output, why not just a 2.2uF Cap?

Hmmm... Could be a resistance thing (a couple small caps has a lower ESR than a single large cap)? Granted at typical pedal voltages/frequencies that is mostly a non-issue, but "thou shall not question the mojo" I suppose.

[thesmokingman]

I've always assumed it was a decision not to put an electrolytic in the signal path or source a large value film cap

[pedrohead]

Hey everyone, my name finally came up on the KoT waitlist and I got mine in the other week. Naturally I pulled it apart to see what the famed high gain mod actually was. Turns out the drive pot is the same value as the standard but the resistor in the feedback loop changes values.

I'm attaching the schematic I came up with from tracing mine. Certain resistors in each side where carbon comp as well so I've noted that in the schematic with CC.

Hope some folks find this informative. This community has been super helpful to me so I wanted to pass this info along.

Edit: Updated the schematic to include the serial number, IC value, and fixed the clipping diodes sections.

Had a question I don't understand. It doesn't look like the R# numbers for each resistor match from your trace to the PCB numbering. is there a reason for that?