Analogman - King of Tone  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
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modman
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Post by modman »

The mystery capacitor in another KOT gut shot
100102121_10215874081554971_2117144050560663552_o.jpg
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Seiche
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Post by Seiche »

do you know how old this pedal is?

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Post by Bolsyo »

Seiche wrote: 19 Mar 2019, 21:22 pretty sure, yes, which pictures are you referring to and which resistors?

I think they were brown-black-red (1k) and brown-black-yellow (100k), but it's not entirely clear on my pictures and I already flipped the pedal.
Nice find Seiche ! :thumbsup

The 100k gain resistor, while keeping the same pot value on high-gain side, corresponds somewhat with a quote from Analogmans webstite: "It increases the DRIVE knob setting by a few numbers, in any mode. It moves the ENTIRE range higher".

According to this gutshot from madbean, the 3rd band on a stock gain side seems red (1k) to me, and not 10k as was earlier assumed:
(The carbon FILM resistor going into lug 1 (J27) on the drive pot):
IMG_0222.jpg

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Post by modman »

Seiche wrote: 23 May 2020, 12:45 do you know how old this pedal is?
Not yet, scored it on facebook, I'm asking the owner of the pedal.
Bolsyo wrote: 23 May 2020, 13:08
Seiche wrote: 19 Mar 2019, 21:22 I think they were brown-black-red (1k) and brown-black-yellow (100k), but it's not entirely clear on my pictures and I already flipped the pedal.
According to this gutshot from madbean, the 3rd band on a stock gain side seems red (1k) to me, and not 10k as was earlier assumed:
(The carbon FILM resistor going into lug 1 (J27) on the drive pot):
Thanks for that old picture -- anything that is important to the discussion in this section, please please attach it to the post. External links always go dead.

Here's a close-up of the little rascal (from the same madbean unit)
Gain resistor of 1k in orginal KoT traced
Gain resistor of 1k in orginal KoT traced
Screen Shot 2020-05-23 at 17.10.28.png (220.05 KiB) Viewed 4369 times
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Post by Bolsyo »

This gutshot was posted of a high gain side. Look at the resistor going into lug 1 on the drive pot here. According to the new tracing, it's should be a 100k (brown-black-YELLOW), but here it is a 1k (brown-black-RED). Now look closely on the red band... It's clearly painted on there, and you can even see the yellow under the lower edge of the red stripe :lol: Never take the color coding for granted :D
King of tone.jpg

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Post by Boba7 »

Bolsyo wrote: 23 May 2020, 17:11 This gutshot was posted of a high gain side. Look at the resistor going into lug 1 on the drive pot here. According to the new tracing, it's should be a 100k (brown-black-YELLOW), but here it is a 1k (brown-black-RED). Now look closely on the red band... It's clearly painted on there, and you can even see the yellow under the lower edge of the red stripe :lol: Never take the color coding for granted :D
King of tone.jpg
Haha that’s great, thanks! So it’s official, low gain is 1k and high 100k. Nice.

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Post by Boba7 »

Seiche wrote: 07 Jul 2018, 13:39 - the input cap is 22n on both sides
- instead of 1s1588, this uses 1n914
- output cap of the high-gain red side has an "H" painted on it, but is the same value 105 as on the yellow side.
- the feedback loop cap on the yellow side ist a weird value. 505? The red side has the usual 101=100pF.

I haven't verified all of the resistors.

kot_v4_2018.pngfeedback_cap_yellow_side.png

So on the Pedalpcb forums, someone posted another odd value for C22 on the yellow side: 750pf.
See here: https://forum.pedalpcb.com/threads/prin ... post-27138

What do you guys think?
King of Tone C22 Yellow side
King of Tone C22 Yellow side

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Post by Boba7 »

modman wrote: 23 May 2020, 15:14
Seiche wrote: 23 May 2020, 12:45 do you know how old this pedal is?
Not yet, scored it on facebook, I'm asking the owner of the pedal.
Bolsyo wrote: 23 May 2020, 13:08
Seiche wrote: 19 Mar 2019, 21:22 I think they were brown-black-red (1k) and brown-black-yellow (100k), but it's not entirely clear on my pictures and I already flipped the pedal.
According to this gutshot from madbean, the 3rd band on a stock gain side seems red (1k) to me, and not 10k as was earlier assumed:
(The carbon FILM resistor going into lug 1 (J27) on the drive pot):
Thanks for that old picture -- anything that is important to the discussion in this section, please please attach it to the post. External links always go dead.

Here's a close-up of the little rascal (from the same madbean unit)
Screen Shot 2020-05-23 at 17.10.28.png
If you still have your unit, could you verify if the diodes in the feedback loop are connected like that (see attachment)?
Thanks a lot!
KOT diodes
KOT diodes
Capture d’écran 2020-06-19 à 13.38.38.png (11.53 KiB) Viewed 3945 times

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Post by modman »

Boba7 wrote: 19 Jun 2020, 11:40If you still have your unit, could you verify if the diodes in the feedback loop are connected like that (see attachment)?
Thanks a lot!
viewtopic.php?f=7&t=382&p=271493#p271493
here's the correct schematic - what makes you think the diodes are interlinked?
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Post by Boba7 »

modman wrote: 19 Jun 2020, 11:50
Boba7 wrote: 19 Jun 2020, 11:40If you still have your unit, could you verify if the diodes in the feedback loop are connected like that (see attachment)?
Thanks a lot!
viewtopic.php?f=7&t=382&p=271493#p271493
here's the correct schematic - what makes you think the diodes are interlinked?
Same thread on the Pedalpcb forums, the guy has traced his KOT and found the diodes are interlinked.

https://forum.pedalpcb.com/threads/prin ... post-27138

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Post by sprentiss »

Hey guys, that's my pedal that Boba7 posted. Both sides use the same cap in the feedback loop, marked 751. I've measured it in circuit and it's 750pf but my meter isn't the best.

I'll try and get you guys an under shot of the PCB so you can see the diodes being linked. May have traced that bit wrong myself but I'm pretty sure that's how they're set up.

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Post by sprentiss »

Ok. Just double checked the diodes with my continuity test and confirmed that they aren't linked in the middle that's my bad. Though it shouldn't make a difference.

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Post by modman »

sprentiss wrote: 20 Jun 2020, 01:43 Ok. Just double checked the diodes with my continuity test and confirmed that they aren't linked in the middle that's my bad. Though it shouldn't make a difference.
Thanks so much for reporting back.

Anybody tracing a unit, please make pictures and if there is a serial, mention it on the schematic. There may be differences betweens different hand built units, improvements or just mistakes by organic Japanese vegetable farmers!

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Post by sprentiss »

Here's my traced schematic with the serial number and build date noted.
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Analogman King of Tone Trace - Schematic.png

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Post by rtcustom »

So, due to the increase in the value of the capacitor, the new versions have less noise than the older versions?

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Post by sprentiss »

rtcustom wrote: 20 Jun 2020, 20:11 So, due to the increase in the value of the capacitor, the new versions have less noise than the older versions?
I don't know if it's because of that cap change but mine is dead quiet even at high gain settings.

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Post by rtcustom »

i think that cap reduce noise level of the unit. The increase is significant, primal pedals 100pf, latest 750pf. Analogman could increase the value of that capacitor to 1nF and would not drastically cut high. ;)
It's just a game! :)

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Post by Boba7 »

rtcustom wrote: 20 Jun 2020, 21:26 i think that cap reduce noise level of the unit. The increase is significant, primal pedals 100pf, latest 750pf. Analogman could increase the value of that capacitor to 1nF and would not drastically cut high. ;)
It's just a game! :)
Just a game, yes, for sure! :)
By the way, is there a way to calculate the low pass frequency in this kind of circuit?

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Post by rtcustom »

Boba7 wrote: 21 Jun 2020, 10:11 Just a game, yes, for sure! :)
By the way, is there a way to calculate the low pass frequency in this kind of circuit?
I don't have that much knowledge, although I believe that someone with a better knowledge of matter can define it mathematically!

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Post by FiveseveN »

The formula is fc = 1/(2πRC) as usual, where R is the gain pot + the 1K or 100K "high gain" resistor. You can use a calculator like electricdruid's.
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