Author Topic: King of Tone High Gain Mod  (Read 2939 times)

sonnyboy27

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King of Tone High Gain Mod
« on: June 17, 2020, 03:12:49 PM »
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.
« Last Edit: June 20, 2020, 01:20:38 PM by sonnyboy27 »

Aentons

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Re: King of Tone High Gain Mod
« Reply #1 on: June 17, 2020, 05:42:58 PM »
Cool, Thanks. Are the IC's 4580D? I have seen there are occasionally different diodes as well. We're gonna need some pics  ;D

sonnyboy27

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Re: King of Tone High Gain Mod
« Reply #2 on: June 18, 2020, 01:17:21 PM »
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

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Re: King of Tone High Gain Mod
« Reply #3 on: June 18, 2020, 01:54:08 PM »
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

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Re: King of Tone High Gain Mod
« Reply #4 on: June 18, 2020, 04:41:46 PM »
This is right on time. I have a pedalpcb kot board I'm putting together soon, thanks for the insight!

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thesmokingman

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Re: King of Tone High Gain Mod
« Reply #5 on: June 18, 2020, 06:35:05 PM »
optional c12?
once upon a time I was Tornado Alley FX

sonnyboy27

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Re: King of Tone High Gain Mod
« Reply #6 on: June 19, 2020, 08:50:47 PM »
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

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Re: King of Tone High Gain Mod
« Reply #7 on: June 19, 2020, 08:54:56 PM »
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

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Re: King of Tone High Gain Mod
« Reply #8 on: June 23, 2020, 12:54:59 PM »
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

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Re: King of Tone High Gain Mod
« Reply #9 on: June 24, 2020, 11:01:40 AM »
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

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Re: King of Tone High Gain Mod
« Reply #10 on: June 24, 2020, 01:12:02 PM »
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

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Re: King of Tone High Gain Mod
« Reply #11 on: July 28, 2020, 03:33:36 PM »
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

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Re: King of Tone High Gain Mod
« Reply #12 on: July 28, 2020, 05:13:13 PM »
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

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Re: King of Tone High Gain Mod
« Reply #13 on: July 28, 2020, 05:39:05 PM »
I've always assumed it was a decision not to put an electrolytic in the signal path or source a large value film cap
once upon a time I was Tornado Alley FX

pedrohead

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Re: King of Tone High Gain Mod
« Reply #14 on: September 25, 2021, 03:51:32 PM »
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?