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Prince of Tone (Pauper) Question

sonnyboy27

New member
I just finished building my Pauper and noticed something interesting. In the schematic R15 is 100k but in every other schematic for the king/prince of tone that I've seen there's no resistor there. I was wondering if anyone had an idea of why this resistor was added. Maybe it's part of the PoT and not in the KoT?

Additionally, my name finally came up on the waitlist for the KoT and it just arrived in the mail. I compared my clone and noticed that the KoT is a little bassier so I naturally opened it up and here's what I've seen so far that's different.

Input cap: 22nF (Pauper 10nF)
Feedback Loop Cap: 750pF (100pF Pauper)

Only 1 100nF capacitor which is connected to an 82k resistor. I'll have to pull all of the guts out and do a proper trace of it this week. I'll update this when I've finished that.
 

PedalPCB

Administrator
Staff member
The Pauper was based on my personal Prince of Tone unit. It was one of the newer models.
Something else I think you'll find that is different is the clipping diode arrangement. Unless the KoT circuit has been updated, the dipswitches have a different function as well.

I can't comment on the accuracy of the other PoT or KoT schematics floating around. I assume they are correct, but I don't know much about their history or where they came from.... Were they both traced from original units? Did someone trace a PoT and assume the KoT was two of those, verbatim? Did someone trace a KoT and assume the PoT was exactly half of that?

I'm not sure. I'd certainly be interested to see what you find in yours. :)

It has always been said that the only difference in the high-gain version of the KoT is the Drive pot, but I believe more recently that has been found to not be true. This was mentioned here somewhat recently as well. I suspect the High Gain version might be closer to the "Turbo" mode of the PoT, but that's just a guess.
 

sonnyboy27

New member
I can confirm that the drive pot on my high gain side is only 100k. I think there's a resistor attached to it that's 100k on the high gain and 1k on the low gain. I'll know more once I pull the whole thing apart and can properly trace it. I'm very curious to see how well the PoT you traced matches up to the KoT High Gain side since that's supposed to be the inspiration behind it.
 

sonnyboy27

New member
Ok. I finished tracing my King of Tone and here's what I've found.

1) The High Gain mod is simply changing out the resistor in the feedback loop of the first gain stage that connects to lug 1 of the drive pot. In the low gain it's a 1k and the high gain is 100k.
2) The input cap is 22nF instead of the 10nF in the Prince of Tone.
3) The capacitor in the first gain stage is 750pF .
4) They seem to use Carbon Film resistors in certain portions of the audio path.

Here's the schematic that I built up from tracing my unit. Hope it's helpful to anyone building there own. The carbon comp resistors are noted by CC next to the value. There's only 3 of them.

Analogman King of Tone Trace - Schematic.png
 
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PedalPCB

Administrator
Staff member
Very cool! Could you post of a pic of that 750pF cap?

Folks are going to question it if I change it on the schematics. 😂

The connection between the D1/D2 and D3/D4 is interesting. I've never seen that on any of the KoT or PoT schematics, but I have seen it on some Marshall schematics.
 

sonnyboy27

New member
Sure thing. I also confirmed the value with my multimeter.

Yeah the diodes are all connected in this alternating pattern underneath which is pretty interesting. I guess in case one fails so the pedal still works?

IMG_12231.jpg
 

Boba7

Member
Thanks for your work!

Yes it was confirmed on the freesrompboxes forum a little while ago that the input cap is 22n
But it seemed that along with the resistor change (low gain 1k, high gain 100k) there was a change of capacitor in the feedback loop (low gain 50p, high gain 100p)

So your c22 is quite surprising! Is it the higher or lower gain channel? What’s its equivalent on the other side? Same value?
 

Boba7

Member
The best way to know for sure would be to measure the cap outside of the circuit... if you feel like its something you’re willing to do, that’d be great!
 

Boba7

Member
Sure thing. I also confirmed the value with my multimeter.

Yeah the diodes are all connected in this alternating pattern underneath which is pretty interesting. I guess in case one fails so the pedal still works?

View attachment 4865
On the freestompboxes thread, someone mentioned another odd value for C22 on the yellow side (a 505 marked capacitor, see here: https://www.freestompboxes.org/viewtopic.php?f=7&t=382&start=360)
I would think that 750pf is a bit much in that place, but maybe I'm wrong. I'd be very curious to know the value measured outside of the circuit.
 

sonnyboy27

New member
Mine is the same value in both sides. I'm not gonna pull the caps out just because there isn't enough lead to get them back with my skill and I want to keep it in good condition. It does seem like an oddly high value. I'm wondering if he's changing part values year to year based on availability and other changes. The larger caps in the link you shared look different than mine.

I can confirm that the hard clipping diodes are 1N914s just like that link states. I can also say that I screwed up the diode placement. They aren't linked in the center like I posted before. I had a continuity error with my meter. I just double and triple checked the diodes and they are not linked in between.

Thing to note, there's an unpopulated capacitor in the upperleft hand corner of the pcb that connects lugs 2 and 3 of the drive pot. It's not populated in any gutshot of the KoT that I've seen though so I left it out of my schematic. Analogman have stated in a forum post that they've never used it. Could be interesting to play with though.

You can see a full gutshot of my pedal on the madbean forum. File is too big to upload here. https://www.madbeanpedals.com/forum/index.php?topic=31448.0
 
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Boba7

Member
Thanks a lot!
I totally understand you dont want to remove the cap to measure it.
But since Analogman has painted some resistors in the past (see the fsb forums), i wonder if they would use fake capacitors... just to play with us geeks :D (like the H he writes on the chip and output capacitor)
 

sonnyboy27

New member
Thanks! Even more confusing, it’s easy to read 152, so 1n5...
Oh man. Maybe my eyes are bad but to me that image has the numbers upside down and reads 751 like the image of the other cap. The glare kind of makes it hard to read but my crappy photography skills are to blame for that.
 
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