# Which inductor for the newest version of Conqueror Fuzz?



## Champagneperfume (Jun 14, 2021)

Hey gang,

There seems to be a couple difference of answers for the Conqueror Fuzz inductor.  I purchased the pcb last week, which inductor model should I buy for it?  Thanks in advance.


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## varlogtim (Jun 14, 2021)

I am curious as well. On the build docs it says 500mH.

I purchased a TM013-R from small bear. I am currently trying to trace the circuit and figure out where I am supposed to solder the leads.

It would be great to hear from someone who as put this together already? Or perhaps I will just give it a go and update?


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## Robert (Jun 14, 2021)

The PCB is designed to fit several different style inductors.


For a fasel inductor you should install one lead into any of the green pads and one lead into any of the red pads.





For the 42TM013 you should install the primary side on the side marked Primary and made sure the secondary leads go into the unplated holes at the bottom.    Do not solder the secondary side.


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## varlogtim (Jun 14, 2021)

Robert said:


> The PCB is designed to fit several different style inductors.
> 
> 
> For a fasel inductor you should install one lead into any of the green pads and one lead into any of the red pads.
> ...


Perfect! I was just about to ask about the bare holes. The via around R16 (10K) was throwing me for a loop.


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## giovanni (Jun 15, 2021)

I liked the Supreme so much that I might build another. Is it basically the same circuit but with the distortion and filter always on? And I see 3 choices for the frequency instead of 4? Which one was removed?


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## Chuck D. Bones (Jun 15, 2021)

I bought five 42TM013 transformers from Small Bear.  Their inductance is around 1.9H, considerably higher than the 500mH - 600mH you find in wah inductors.  They'll work, but the tuning will be about an octave lower than the production pedals.



giovanni said:


> I liked the Supreme so much that I might build another. Is it basically the same circuit but with the distortion and filter always on? And I see 3 choices for the frequency instead of 4? Which one was removed?



The Conqueror Supreme is a Conqueror with the Distortion switching enabled and one more (higher freq) MRB setting than the Vox preamp on which those pedals are based.  The Mystery Box is based on the Magical Mystery Machine, which is similar, but not the same as the Conqueror Supreme.  The MMB is Castledine's take on the Vox preamp and it contains a much-needed gain recovery stage at the end.



varlogtim said:


> I purchased a TM013-R from small bear. I am currently trying to trace the circuit and figure out where I am supposed to solder the leads.
> 
> It would be great to hear from someone who as put this together already? Or perhaps I will just give it a go and update?


Those transformer leads are fragile.  You only want to solder them once.  Don't pull on the leads or twist them, else you'll break the lead loose from the winding inside.


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## giovanni (Jun 15, 2021)

Thanks for the insight Chuck! Which one is used in production pedals, the transformer or the fasel?


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## Chuck D. Bones (Jun 15, 2021)

Castledine winds his own chokes for the MMB.  I'd think any decent Wah inductor would do nicely.  Try and get something around 500mH - 600mH.  Don't spend too much money on it though...


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## giovanni (Jun 15, 2021)

Interesting. So the transformer (which is what I installed) may be giving me too high a frequency? Could I adjust some resistor value to scale it down?


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## Robert (Jun 15, 2021)

Chuck D. Bones said:


> Castledine winds his own chokes for the MMB.


Ahh is that a custom wind?   I assumed it was a stack of dimes type inductor but wasn't sure what type, that makes sense.

I'll measure the inductance tomorrow.


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## Chuck D. Bones (Jun 15, 2021)

giovanni said:


> Interesting. So the transformer (which is what I installed) may be giving me too high a frequency? Could I adjust some resistor value to scale it down?


Uh, no. The higher inductance results in a lower resonant freq.  It's an L-C circuit; the resonant freq is determined by that inductor and the caps selected by the MRB switch.  Give it a listen, you'll probably like it as-is.


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## giovanni (Jun 15, 2021)

Ah I should’ve looked that up. Still rusty. I do like the way it sounds now but I wonder if I would like the original better. So I could replace the capacitors to get the frequency closer to the original? Would that affect the Q of the filter?


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## Chuck D. Bones (Jun 15, 2021)

Going by the Conqueror Supreme build docs, these things affect the filter Q:
L1 inductance
L1 resistance
C10-C13 (assuming you're using the rotary switch)
Treble control setting
Bass control setting

If you can't get the sound you want by turning knobs, changing the inductor probably won't get you there either.


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## Feral Feline (Jun 16, 2021)

Chuck D. Bones said:


> I bought five 42TM013 transformers from Small Bear.  Their inductance is around 1.9H, considerably higher than the 500mH - 600mH you find in wah inductors.  They'll work, but *the tuning will be about an octave lower than the production pedals*.



BASS!  😻

Thanks for that titbit, and for the advice on the pins-soldering.

Hmm rotary to select between a regular Fasel and a 42TOM013... with a LPF clean blend ...


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## giovanni (Jun 16, 2021)

Chuck D. Bones said:


> Going by the Conqueror Supreme build docs, these things affect the filter Q:
> L1 inductance
> L1 resistance
> C10-C13 (assuming you're using the rotary switch)
> ...


I see, the circuit is pretty complicated. I do like the way it sounds already, I was just wondering how it would sound with the filter tuned to the frequency it was designed for.


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## giovanni (Jun 16, 2021)

I did some math on the resonant frequency. With 500 mH we get mid range frequencies between 500Hz and 1kHz. With 1900 mH we get between 250Hz and 500Hz, so barely getting to the mid range. I think I’m gonna try and swap that transformer for a 500mH inductor after all…


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## Chuck D. Bones (Jun 16, 2021)

I was going to save this for another LTSpice tutorial, but here's a teaser:

This is the Mystery Box's freq response with all stock part values, DISTORTION off, MRB on, BASS & TREBLE at noon.  Inductor is a Stack-of-Dimes.  Each trace is for a different position of the MRB rotary switch.




Same setup, but now with a 42TM013 transformer.  The resonant frequencies are shifted down about an octave and the Q is a little lower.




We can obtain a similar freq shift by changing the MRB caps.


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## Robert (Jun 16, 2021)

Robert said:


> I'll measure the inductance tomorrow.



594mH / 32Ω


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## Chuck D. Bones (Jun 16, 2021)

That's what I'd expect for a good quality wah inductor.


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## Kroars (Jun 17, 2021)

Robert said:


> The PCB is designed to fit several different style inductors.
> 
> 
> For a fasel inductor you should install one lead into any of the green pads and one lead into any of the red pads.
> ...


I didn’t even know this new design existed! I’ve got a handful of ME-6’s I bought when the original pcb came out and the next few I ordered had newer layout that didn’t accept them (easily anyway).  Thought they’d end up just collecting dust.  Now I need to order more Conquerors!  Thanks!


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## giovanni (Jul 12, 2021)

I’ve been wondering what would happen if I shorted pins 1 and 2 (or 2 and 3) on the primary of the transformer. Should give me about half the inductance correct? That would be an easy adjustment to get closer to the designed frequencies.


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## Chuck D. Bones (Jul 12, 2021)

No, it does not work that way.  Every turn of every winding is magnetically coupled to every other turn in a transformer.  Shorting one turn is pretty much the same as shorting all of them.  If you connect to only pins 1 and 2, the you have half as many turns connected to the rest of the Conqueror circuit.  Since inductance is proportional to the number of turns squared, you get one quarter of the inductance.  For example, a 1H primary winding would become 0.25H (250mH).  The inductance of inexpensive audio transformers is not well-controlled in the manufacturing process.  As long as a minimum inductance requirement is achieved, then the transformer meets spec.  This means that you can buy five 42TM013 transformers and get five different primary inductances.
If you want to nail a specific inductance in a circuit like the Conqueror, you are better off using a Wah inductor.  Those may have a 20% tolerance, meaning that a 500mH inductor could be between 400mH and 600mH and meet spec.  Not to worry though, the resonant frequency of an LC circuit is proportional to the square-root of inductance.  This means that if the inductance is off by 20%, the resonant freq is off by only 10% (in round numbers).


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## giovanni (Jul 12, 2021)

That makes perfect sense! Thank you for clarifying, Chuck!


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## DeeBattery (Aug 17, 2021)

Robert said:


> The PCB is designed to fit several different style inductors.
> 
> 
> For a fasel inductor you should install one lead into any of the green pads and one lead into any of the red pads.
> ...





Robert said:


> The PCB is designed to fit several different style inductors.
> 
> 
> For a fasel inductor you should install one lead into any of the green pads and one lead into any of the red pads.
> ...


Would this be correct for the 42tm013? 3 on the primary and the center on the secondary?


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