# Prince of Tone (Pauper) Question



## sonnyboy27

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.


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## Robert

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.


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## sonnyboy27

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.


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## sonnyboy27

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.


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## Robert

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.


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## sonnyboy27

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?


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## Boba7

Thanks for your work!

Yes it was confirmed on the freestompboxes 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?


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## Boba7

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!


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## Boba7

sonnyboy27 said:


> 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.


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## sonnyboy27

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

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  (like the H he writes on the chip and output capacitor)


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## zgrav

...hmmm  maybe a 75P cap?  "751" seems very odd


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## Robert

It could be 152 (1n5) and we're looking at it upside down...


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## Boba7

Seems very odd to me, there are a few pictures showing clearly a 100pf for C22. 
I have no idea


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## Boba7

@sonnyboy27 could you post a close up pic of C4 too?


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## zgrav

very interesting to see how this resistor color code was changed in this picture from the other thread  -- red stripe painted over the yellow band:





link: https://www.freestompboxes.org/viewtopic.php?f=7&t=382&start=440


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## sonnyboy27

Here's the other capacitor. Had to take a picture through a magnifying glass because my camera isn't the best closeup.


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## Boba7

sonnyboy27 said:


> Here's the other capacitor. Had to take a picture through a magnifying glass because my camera isn't the best closeup.



Thanks! Even more confusing, it’s easy to read 152, so 1n5...


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## sonnyboy27

Boba7 said:


> 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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## BeeSharp

I have a newly built KOT (July 2020) and an older one (recently sold) from 2015-16.  I"ll find the pictures of the boards when I get home.  The older one is high gain of the red side and the new one is high gain on both sides.  I went for high gain on the yellow side because I found my self cranking that drive as well.  I do remember that there is a large cap with an "H" and the IC has "H" on the high gain side (s).


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## Boba7

BeeSharp said:


> I have a newly built KOT (July 2020) and an older one (recently sold) from 2015-16.  I"ll find the pictures of the boards when I get home.  The older one is high gain of the red side and the new one is high gain on both sides.  I went for high gain on the yellow side because I found my self cranking that drive as well.  I do remember that there is a large cap with an "H" and the IC has "H" on the high gain side (s).



Great thanks a lot! 
It would be especially useful to have detailed pics of C4 and C22 on the two pedals!


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## Robert

sonnyboy27 said:


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



Are there, by any chance, any markings on the OTHER side of that cap?      

I'm tracing a circuit today and ran across a random cap value that didn't make sense.    Looked on the other side of the cap and it was marked 101. (100p)


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## Boba7

BeeSharp said:


> I have a newly built KOT (July 2020) and an older one (recently sold) from 2015-16.  I"ll find the pictures of the boards when I get home.  The older one is high gain of the red side and the new one is high gain on both sides.  I went for high gain on the yellow side because I found my self cranking that drive as well.  I do remember that there is a large cap with an "H" and the IC has "H" on the high gain side (s).



Curious to see the pics!


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## BurntFingers

I was just looking at the schematic posted earlier on in this thread. What's with the parallel caps at the output?  2 x 1uf caps, one electrolytic, not bipolar, in parallel before the output so making 2uf total. 

The parallel layout seems odd. Could a 2.2uf electro do the same thing?

There's something similar happening with resistors closer to the input as well.


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## Boba7

BurntFingers said:


> I was just looking at the schematic posted earlier on in this thread. What's with the parallel caps at the output?  2 x 1uf caps, one electrolytic, not bipolar, in parallel before the output so making 2uf total.
> 
> The parallel layout seems odd. Could a 2.2uf electro do the same thing?
> 
> There's something similar happening with resistors closer to the input as well.



There’s no parallel resistors in the schematic if you look closer 

The parallel caps at the output don’t make much sense. A single 1uf film cap would do the job (providing the same amount of low end as a larger value, I believe)
Maybe Analogman wanted a 2.2u for whatever reasons, but didn’t want an electro in the signal path, and a 2.2u film cap was more expensive or rare, so he went for a 1uf film cap and a 1uf electro.
I dont know.

I think some VFE pedals use the same output cap configuration, so maybe there’s really something to it (I trust VFE pedals much more than most other builders!)


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## BurntFingers

Ah yes you're right, there's some 10nf cap action going on. Still, I reckon that whole section can be streamlined. 

I wonder if something to do with esr in the signal path, like sticking a 220uf and 100n in the power section.


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## sonnyboy27

Robert said:


> Are there, by any chance, any markings on the OTHER side of that cap?
> 
> I'm tracing a circuit today and ran across a random cap value that didn't make sense.    Looked on the other side of the cap and it was marked 101. (100p)



Just opened it up and checked again. Nothing on the other side. Those were the only markings on either of my MCC caps.


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## Boba7

sonnyboy27 said:


> Just opened it up and checked again. Nothing on the other side. Those were the only markings on either of my MCC caps.



Love the dedication! What a great team! 
Now we can only wait for @BeeSharp pics!


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## BeeSharp

I was out of town, sorry for the delay

2017 KOT (sold this one, high gain red side)


















2020 KOT (both sides have, high gain)


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## Boba7

Thanks a lot @BeeSharp!

So here we have the usual 100pf on both lower and higher gain sides. Great!


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## Antilog

I just spent 3 days on the PCB of my original POT bought on Analogman.com 2 years ago and here are my results.


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## Antilog

Many changes from the original KOT actually.

- No Distorsion clipping diodes. Vref to OD Diodes

- The high gain mod is 100k from gain 2 to gain 3 and 100k coming from Gain 1 (instead of 10K).

- Turbo mode (even higher gain) only on the POT is 5k after gain instead of 10k. Actually it's 2 10k parallel (1 is swichable internally) which gives 5 k.

- switchable multilayer ceramic 1Uf parallel to the grounded 10n to modify the low mids 

- 100n and 1k carbon comp added after OP amp lug 7

- the power supply adds several components. The 47n bitween the LED and the footswitch is quite strange, never seen that before. Maybe to prevent from pops.


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## Chuck D. Bones

I think there might be a couple of tiny errors in your trace.  

The way the LED is hooked up in your schematic, it won't stay lit for more than a few ms.

The clipping sw hookup is questionable also.


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## Antilog

As I was saying, the led wiring seems strange. I’ll double check but I already spent many time on this part of the circuit and got those results.

What seems wrong with the clipping switch for you ?
This part looks like the same found for the Pauper to me.


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## Chuck D. Bones

LED: It needs a DC current path.  That 47nF cap is blocking DC. 

Switch: There is something wrong with the wiring to the two bottom terminals or the right middle terminal.  Try drawing that part of the schematic with the switch hardwired in the up position.  See if that schematic makes sense.  Then draw it again with the switch in the down position, see if that makes sense.


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## ntuncer

Hello,
is there any reason to use different C1 and R3 values in Pauper and Paragon schematics? Do I need to use both 22n for C1 and 1K for R3 for low gain both pedals?


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## sonnyboy27

ntuncer said:


> Hello,
> is there any reason to use different C1 and R3 values in Pauper and Paragon schematics? Do I need to use both 22n for C1 and 1K for R3 for low gain both pedals?


No. The resistor change is the only requirement for the high gain mod. 

The pauper was traced from a prince of tone which had a different input capacitor than my king of tone (which had a 22n). Strangely, my king of tone seems to be an outlier with most having a 10n input capacitor. It won't make a huge difference but feel free to try socketing the capacitor if you want to compare them.


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## jcrhee

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


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## ntuncer

sonnyboy27 said:


> No. The resistor change is the only requirement for the high gain mod.
> 
> The pauper was traced from a prince of tone which had a different input capacitor than my king of tone (which had a 22n). Strangely, my king of tone seems to be an outlier with most having a 10n input capacitor. It won't make a huge difference but feel free to try socketing the capacitor if you want to compare them.


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.


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## ntuncer

jcrhee said:


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


Indeed, this is the origin of my question which I try to figure out what are the differences...


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## sonnyboy27

jcrhee said:


> 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.


ntuncer said:


> 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).


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## 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.


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## sonnyboy27

ntuncer said:


> 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).


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## ntuncer

sonnyboy27 said:


> 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.


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## sonnyboy27

ntuncer said:


> 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.


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## ntuncer

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


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## 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


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## Coda

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


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## Boba7

Coda said:


> 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.


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## JamieJ

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


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## Boba7

JamieJ said:


> 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


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## 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.


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## 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.


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## 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.


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## giovanni

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


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## Robert

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







giovanni said:


> 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.


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## giovanni

Robert said:


> 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!


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## ntuncer

Robert said:


> 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?


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## 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


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## Cybercow

Wavelength said:


> 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.


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## Wavelength

ntuncer said:


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


Those look like 1N914 to me. Mixed reviews with those that have both the POT and MXR.


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## benny_profane

Wavelength said:


> 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


There’s no dc potential across the volume pot. It’s tied to Vref as well. 

It’s an inverting stage. There’s no voltage potential differential at the inputs.


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## Wavelength

Cybercow said:


> 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.


Actually the AC ground is the same and remember the opamp output is already centered at Vref.


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## Wavelength

benny_profane said:


> There’s no dc potential across the volume pot. It’s tied to Vref as well.
> 
> It’s an inverting stage. There’s no voltage potential differential at the inputs.


C14 blocks the DC from the volume control.


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## benny_profane

Wavelength said:


> C14 blocks the DC from the volume control.


Ah, the tone and volume controls are both dc isolated. The two blocks are ac coupled and don’t have dc potential across the pots. Neither pot is tied directly to ground.


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## Cybercow

Wavelength said:


> Actually the AC ground is the same and remember the opamp output is already centered at Vref.


But for the opamps, VRef is used as the signal (AC) ground. The opamps are being offset so the signal zero-crossing is centered. Setting the hard-clipping elements to ground will present an offset 'zero reference' to the signal, swinging the clipped signal towards ground instead of 'zero reference' (VRef). If examined with a scope, grounded hard-clipping will look different than hard-clipping to VRef.


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## Robert

Wavelength said:


> But why would you want to put the diodes to Vref?



Lug 1 of the volume control goes to VREF, not ground, so the potential difference across the pot is near zero.


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## ntuncer

Wavelength said:


> Those look like 1N914 to me. Mixed reviews with those that have both the POT and MXR.


Hmm interesting. But I could at least say my POT has ma858s.


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## Robert

Wavelength said:


> C14 blocks the DC from the volume control.



C14 doesn't block the path of VREF through D1 / D2, but the volume pot is already at Vref potential and all other paths are AC coupled.


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## giovanni

I think the circuit would be theoretically equivalent if all Vref after C14 were ground instead, since that’s the job Vref is doing for the signal path. I wonder if there’s a reason to use Vref at all: could it be to improve the noise floor?


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## Wavelength

Robert said:


> C14 doesn't block the path of VREF through D1 / D2, but the volume pot is already at Vref potential and all other paths are AC coupled.
> 
> 
> View attachment 33664


Thanks, I missed that!
Gordon


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## Wavelength

giovanni said:


> I think the circuit would be theoretically equivalent if all Vref after C14 were ground instead, since that’s the job Vref is doing for the signal path. I wonder if there’s a reason to use Vref at all: could it be to improve the noise floor?


I have to agree with this. One of the reasons I missed the Vref at the pots instead of ground.

Really put the diodes to feedback or ground after C14 and then all the pots to ground. Then loose C8/C9 and go wiper out. Though not a fan of using 100K wiper to an output as that can have an effect on the next pedals response.
Thanks,
Gordon


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