Prince of Tone (Pauper) Question

[sonnyboy27]

This video was posted a couple of days ago. "That Pedal Guys" compared KoT with Prince of Tone. You can clearly hear the difference.

That was a really good episode. It was amusing to me that they seemed to forget that the prince of tone is the high gain version of a king of tone.

In the schematics, I expected to have same component values as prince of tone suppose to be half of king of tone that's why I am confused. Pauper has 10n for c1 and 10k for r3 but on the other hand Paragon has 22n for c1 and 1k for r3 when we are talking about low gain mod.
View attachment 11912

View attachment 11911

Yeah it's a bit confusing. The Pauper is set to the high gain mod (which is just changing out R3 for 10k instead of 1k). But it uses the same input capacitor as most production King of Tones. The Paragon schematic was updated after I provided the trace of my king of tone (which used a 22n input capacitor on the regular and high gain channels). But you can lower it to 10nf without much interference. I've gone back and looked at a bunch of traces and they all use a 10nf cap.

TLDR: The standard Prince of Tone and King of Tone use a 10nf input capacitor (high gain or not). But the most recent King of Tone trace used a 22nf (probably due to component shortages).

 

[ntuncer]

Hello, I am checking Pauper documentation thus schematic and pcb photo, for the distortion part I expect to see 1S1588s for hard clipping but there are only 4 MA856s as clipping diodes. Am I missing something?

By the way I just received my Prince of Tone and I read C3 as 100p and C1 as 22n.

 

[sonnyboy27]

Hello, I am checking Pauper documentation thus schematic, for the distortion part I expect to see 1S1588s for hard clipping but there are only 4 MA856s as clipping diodes. Am I missing something?

The King of Tone uses different diodes for the hard clipping and soft clipping portions. But in the prince of tone it uses the same four diodes for soft and hard clipping. The switch is implemented differently since it's a front mounted DPDT rather than dip switches inside.

If you want to use the same diodes then you could put 1s588s in the diodes slots instead of the MA856s but you probably won't notice much difference. Part tolerances are more significant than diode differences in my experience with these kinds of circuits (LEDs being a different story of course since they have a much higher forward voltage aka they're louder and less compressed).

 

[ntuncer]

The King of Tone uses different diodes for the hard clipping and soft clipping portions. But in the prince of tone it uses the same four diodes for soft and hard clipping. The switch is implemented differently since it's a front mounted DPDT rather than dip switches inside.

If you want to use the same diodes then you could put 1s588s in the diodes slots instead of the MA856s but you probably won't notice much difference. Part tolerances are more significant than diode differences in my experience with these kinds of circuits (LEDs being a different story of course since they have a much higher forward voltage aka they're louder and less compressed).

Thanks a lot for the fast response. In my Prince of Tone which is the latest iteration, when I check it, I think it is not same as Pauper schematic. There are totally 8 diodes 4 x MA858s and 2 different pair of other diodes as a first and rapidly check. And also I see C3 as 100p and C1 as 22n.

 

[sonnyboy27]

Thanks a lot for the fast response. In my Prince of Tone which is the latest iteration, when I check it, I think it is not same as Pauper schematic. There are totally 8 diodes 4 x MA858s and 2 different pair of other diodes as a first and rapidly check.

Take a picture of the insides and throw it up here. It helps us to know what you're looking at and let's us see if anything has changed between what pedalpcb traced in his unit and what's going on nowadays.

 

[ntuncer]

Sure I will try to add more detailed photos but it looks exactly like this which I found rapidly from the internet:

 

[João Nuno]

HI!
new to the forum.
So, there is any simple mod to make a PoT does cut to much low end?
I've been told that the PoT cuts slighly more low-end than the Kot.
While searching online i found this forum and read someone say that the input cap on the PoT is different than the KOT

 

[Coda]

I just caught up. So…Analogman paints resistor bands?…

 

[Boba7]

I just caught up. So…Analogman paints resistor bands?…

Yes! Isn't it brilliant? There was a picture on the fsb forums of a resistor that was very clearly painted.

 

[JamieJ]

No wonder the KOT list is so long if they are painting resistors and sanding down op amps.

 

[Boba7]

No wonder the KOT list is so long if they are painting resistors and sanding down op amps.

Yes, and writing the letter "H" on the sanded opamp (although it's the same as the other one) and on a cap (same)!
Such a smart move though haha

 

[scottosan]

The are 2 additional diodes outside of the 4 used on the switch and the power. They are labeled D81 and D82 to the lower left of the IC. What are these used for. If done this build, but for whatever reason the it seems to have too much bass, only in Dist mode. There is also no free switch lug as indicated on the schem.

 

[Wavelength]

Quick question as I think the schematics are wrong on the switch to the diode array. Why would the position go to Vref which is 1/2 of the input voltage? That would mean the volume control has DC across it. Why isn't that just going to ground? The opamp is already cap coupled at that point. Just got here from seeing the board for the new MRX version.

 

[giovanni]

I think the schematic is correct. The diodes are either in the opamp feedback loop net, or connected to Vb which is equivalent to ground for signal. I am not entirely sure if that will change the voltage at Vb, I’m having a brain fart on that right now.
Edit: looked again. If I read it right, in the up position the diodes are disconnected and so is the path from the feedback loop to them, with one of the resistors just floating. The diodes end up being connected to Vb, maybe to allow parasite capacitance to discharge? In the other position the diodes are in the feedback loop as I mentioned.

 

[giovanni]

Wait maybe I am misunderstanding wha this 3 position switch does?!?

 

[Robert]

The schematic is correct, and for the record, the Duke clips to VREF in Distortion mode as well.

Wait maybe I am misunderstanding wha this 3 position switch does?!?

It's a 3-position ON/OFF/ON switch.

Overdrive mode (up) connects the diodes across the feedback loop of IC1.2
Boost mode (center) removes the diodes from the circuit entirely
Distortion mode (down) connects the diodes to the R15/R9 junction, hard-clipping to VREF.

 

[giovanni]

The schematic is correct, and for the record, the Duke clips to VREF in Distortion mode as well.

View attachment 33540



It's a 3-position ON/OFF/ON switch.

Overdrive mode (up) connects the diodes across the feedback loop of IC1.2
Boost mode (center) removes the diodes from the circuit entirely
Distortion mode (down) connects the diodes to the R15/R9 junction, hard-clipping to VREF.

Ah there we go. That makes a lot more sense!

 

[ntuncer]

The schematic is correct, and for the record, the Duke clips to VREF in Distortion mode as well.

View attachment 33540



It's a 3-position ON/OFF/ON switch.

Overdrive mode (up) connects the diodes across the feedback loop of IC1.2
Boost mode (center) removes the diodes from the circuit entirely
Distortion mode (down) connects the diodes to the R15/R9 junction, hard-clipping to VREF.

Any idea which diodes are used in MXR as replacement of MA856s?

 

[Wavelength]

But why would you want to put the diodes to Vref? That puts dc across the volume control. You could do the same thing and ground then before the blocking cap and make it a hard clipper.
Ok will open mine and see put it on the bench.
Thanks,
Gordon

 

[Cybercow]

But why would you want to put the diodes to Vref? That puts dc across the volume control. You could do the same thing and ground then before the blocking cap and make it a hard clipper.
Ok will open mine and see put it on the bench.
Thanks,
Gordon

IMO, clipping elements to VRef make sense because the signal's relative "0" (ground) is VRef. VRef provides the signal's DC center reference for its ±v swings. The power supply ground is different from the signal (AC) ground reference.