Analogman - King of Tone [traced]

[modman]

The mystery capacitor in another KOT gut shot

[Seiche]

do you know how old this pedal is?

[Bolsyo]

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 !

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):

[modman]

do you know how old this pedal is?

Not yet, scored it on facebook, I'm asking the owner of the pedal.

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

Screen Shot 2020-05-23 at 17.10.28.png (220.05 KiB) Viewed 8311 times

[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 Never take the color coding for granted

[Boba7]

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 Never take the color coding for granted
King of tone.jpg

Haha that’s great, thanks! So it’s official, low gain is 1k and high 100k. Nice.

[Boba7]

- 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

[Boba7]

do you know how old this pedal is?

Not yet, scored it on facebook, I'm asking the owner of the pedal.

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

Capture d’écran 2020-06-19 à 13.38.38.png (11.53 KiB) Viewed 7887 times

[modman]

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!

viewtopic.php?f=7&t=382&p=271493#p271493
here's the correct schematic - what makes you think the diodes are interlinked?

[Boba7]

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!

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

[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.

[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.

[modman]

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!

[sprentiss]

Here's my traced schematic with the serial number and build date noted.

[rtcustom]

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

[sprentiss]

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.

[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!

[Boba7]

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?

[rtcustom]

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!

[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.