# Finishing Kilimanjaro - Measuring / Biasing



## joelorigo (Sep 16, 2021)

I have a Kilimanjaro that I am trying transistors on. I have a "3 knob Tone Bender PNP" setup from Small Bear that I am trying. These:








						Transistor Set - 3-Knob Tone Bender PNP Generic
					

Small Bear Electronics DIY Parts




					smallbear-electronics.mybigcommerce.com
				




Obviously I am not sure these transistors will work but I am confused about what steps to take to find out. I have the transistors inserted and now what exactly?


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## joelorigo (Sep 17, 2021)

Hi, just bumping this


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## JamieJ (Sep 18, 2021)

How does it sounds with those transistors?


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## Barry (Sep 18, 2021)

I'd plug it in and try it, probably set the bias pot half way and tweak by ear


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## joelorigo (Sep 18, 2021)

Depending on where the knobs and the trimmer is, it either makes no sound or a sustained "buzz" 

Where should I have the pedal knobs?


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## Barry (Sep 18, 2021)

I'd start at or just shy of noon, did you check pin out on the transistors? Tabs do look to be lined up correctly


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## joelorigo (Sep 18, 2021)

I think so. I asked for confirmation on that first in this post:





						Small Bear Germanium Setups Question
					

I was able too pick up a 3 knob tone bender setup from Small Bear a few weeks ago: https://smallbear-electronics.mybigcommerce.com/transistor-set-3-knob-tone-bender-npn-all-american/  I have a Kilimanjaro that I have been working on and off on for a while and none of the small amount of...




					forum.pedalpcb.com
				




The way I have them inserted is each lead in the triangle shape matching the triangle shape of the pads. No crossing leads. If that makes sense.


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## Barry (Sep 18, 2021)

joelorigo said:


> I think so. I asked for confirmation on that first in this post:
> 
> 
> 
> ...


There's a little tab on the transistors that should line up with the tab on the PCB silkscreen, there are a few manufactures who put that tab on a different leg I think, so might not hurt to look at data sheets


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## joelorigo (Sep 18, 2021)

I have the tabs of the transistors lined up with the tabs on the PCB. The transistors don't have any identifiable markings so that is why I asked in that thread about the pinout.


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## JamieJ (Sep 18, 2021)

If you Google the data sheet for that transistor that will tell you the pin out.


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## joelorigo (Sep 18, 2021)

How do I do that when they are "Three unbranded, unmarked, PNP germanium devices." per Small Bear?


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## fig (Sep 18, 2021)

I believe you can determine with a DMM set to DIODE mode. There is a center pin, that is where you attach the BLACK lead. Touch each of the others with the RED lead and record the readings. The higher reading is the base-emitter junction. As others said, the emitter is typically the tabbed pin.


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## joelorigo (Sep 18, 2021)

Got It!


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## danfrank (Sep 18, 2021)

The Kili is an offshoot of a Tone Bender MK1/Zonk Machine. This circuit is finicky with transistors.
Here are my observations on TB MK1 transistors:






						Tone Vendor/Bender MK1... Some Observations
					

Hi everyone. I ordered a Tone Vendor MK1 board a bit ago. I've made most of the fuzz box types in the past except for this one. I was happy to see  that PedalPCB offered a board for the MK1. I've read most everything I could find on the internet about the MK1 and the data and opinions about the...




					forum.pedalpcb.com


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## joelorigo (Sep 18, 2021)

fig said:


> I believe you can determine with a DMM set to DIODE mode. There is a center pin, that is where you attach the BLACK lead. Touch each of the others with the RED lead and record the readings. The higher reading is the base-emitter junction. As others said, the emitter is typically the tabbed pin.


All the transistors have larger readings on the base pin and tab pin versus the base and non-tab pin.

Q1 .210 vs .206
Q2 .182 vs .179
Q3 .177 vs .170

So it seems like they were inserted correctly


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## joelorigo (Sep 19, 2021)

danfrank said:


> The Kili is an offshoot of a Tone Bender MK1/Zonk Machine. This circuit is finicky with transistors.
> Here are my observations on TB MK1 transistors:
> 
> 
> ...


I also have done a bunch of research on the mkI. I first tried some transistors I already had based on that research.
These are what I got from Small Bear.
Q1 63 leakage 35
Q2 79 leakage 84
Q3 108 leakage 100

Some of the numbers match with what worked for you, but not all of them.


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## danfrank (Sep 19, 2021)

Yeah, what you bought from Small Bear is a set for a TB Mk3 or 3 knob TB which is a different beast. Out of that set you bought from SB, try switching Q2 & Q3 around. For Q1 use something with gain of 60-80 and leakage of 200-350ua, maybe more. You could use the Q1 from that SB set but you will have to add a resistor from Q1 collector to Q1 base, like a 1meg or so.


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## joelorigo (Sep 19, 2021)

danfrank said:


> Yeah, what you bought from Small Bear is a set for a TB Mk3 or 3 knob TB which is a different beast. Out of that set you bought from SB, try switching Q2 & Q3 around. For Q1 use something with gain of 60-80 and leakage of 200-350ua, maybe more. You could use the Q1 from that SB set but you will have to add a resistor from Q1 collector to Q1 base, like a 1meg or so.



Ah I see. The reason I bought them for this is because Small Bear told me that their 3 TB work "well in a MK I type build." 
I will try swapping Q2 & Q3. For that Q1 suggestion, I have 1M resistors, what does the resistor do? Do I wrap the resistor leads around the transistor leads and solder? Can I try without soldering first to see if it works?


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## Barry (Sep 19, 2021)

joelorigo said:


> Ah I see. The reason I bought them for this is because Small Bear told me that their 3 TB work "well in a MK I type build."
> I will try swapping Q2 & Q3. For that Q1 suggestion, I have 1M resistors, what does the resistor do? Do I wrap the resistor leads around the transistor leads and solder? Can I try without soldering first to see if it works?


I think you'd get an idea if it works without soldering first


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## danfrank (Sep 19, 2021)

The 1M resistor is just a starting place. Your Q1 has very little leakage and Q1 in a TB Mk1 needs leakage in order to pass signal and work. Same with the Kilimanjaro circuit. The 1M resistor simulates transistor leakage for Q1.
This is where breadboarding the circuit would come in handy... Build up the circuit on breadboard and that way you can test it out and modify it to your liking before committing it to the soldered PCB.


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## joelorigo (Sep 16, 2021)

I have a Kilimanjaro that I am trying transistors on. I have a "3 knob Tone Bender PNP" setup from Small Bear that I am trying. These:








						Transistor Set - 3-Knob Tone Bender PNP Generic
					

Small Bear Electronics DIY Parts




					smallbear-electronics.mybigcommerce.com
				




Obviously I am not sure these transistors will work but I am confused about what steps to take to find out. I have the transistors inserted and now what exactly?


----------



## joelorigo (Sep 19, 2021)

danfrank said:


> The 1M resistor is just a starting place. Your Q1 has very little leakage and Q1 in a TB Mk1 needs leakage in order to pass signal and work. Same with the Kilimanjaro circuit. The 1M resistor simulates transistor leakage for Q1.


Ok. And if it isn't sounding good start going higher and lower with the resistor values?  For going higher I currently have 1.2M, 2.2M, 3.3M & 10M. For going lower (lower would be in the "k" measurements right?), the highest I currently have is 470k.


danfrank said:


> This is where breadboarding the circuit would come in handy... Build up the circuit on breadboard and that way you can test it out and modify it to your liking before committing it to the soldered PCB.


I see. I haven't ever breadboarded, but I see what you mean.


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## joelorigo (Sep 20, 2021)

danfrank said:


> Yeah, what you bought from Small Bear is a set for a TB Mk3 or 3 knob TB which is a different beast. Out of that set you bought from SB, try switching Q2 & Q3 around. For Q1 use something with gain of 60-80 and leakage of 200-350ua, maybe more. You could use the Q1 from that SB set but you will have to add a resistor from Q1 collector to Q1 base, like a 1meg or so.


I tried swapping Q2 & Q3 and a 1M on Q1. Nothing really useable I can get turning the knobs and trimmer.

Question: if I get transistors that fall into your Tone Vender Observations specs, is it the case that they should work in a mkI? Or is the circuit picky enough that one might have to go through different transistors  that have those specs to get it working?


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## fig (Sep 20, 2021)

It's all about the gain and leakage. If those are in the target range, the pedal will have much better results.


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## joelorigo (Sep 23, 2021)

I am out of my element on this one. I don't have a transistor tester, I don't have a lot of transistors. Would anyone who has the experience and transistor stock want to get it working? I'd pay you for your time.


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