TUTORIAL Just Got Your Breadboard/Protoboard? Start Here! LPB1 + Some Dirty Mods!

BuddytheReow

Breadboard Baker
Just got your breadboard or protoboard in the mail and don't know where to begin? The Test Kitchen's got your back! Let's start with a classic and simple circuit: the LPB-1. This is a simple booster and a basic building block for many circuits out there. Here is a schematic taken from Coda Effects.
1631124631764.png
If you'd like to read their write up about this circuit check this out!
Coda Effects also does a good step by step of this circuit too on a breadboard here.

Let's set up our basics first: guitar input (I used an orange jumper wire), power (+ is red jumper and - is black jumper), the input capacitor C1, and a 2n5088 NPN transistor. Notice the transistor's flat side is facing left in the picture. The pinout for this as read from top to bottom is Emitter (E), Base (B), Collector (C). If you don't have a 2n5088 lying around try another NPN transistor such as a 2n3904 or similar. Just check to make sure the pinouts go this way and if not, simply rotate the transistor 180 degrees.
1631124768560.png

Next we need to add R1 and R2 and then connect that to the Base pin of our transistor. The schematic calls for 430k ohm and 43k ohm transistors, but I chose to use 1m and 100k for 2 reasons. First, I had these values lying around on my workstation and decided to be lazy :p. Secondly, the relationship between R1 and R2 matters more than anything else: R1 is 10 times the value of R2 so you can use nearly any values (just keep r1 pretty high) as long as the relationship stays.

R1 goes from power to the same row as the capacitor and R2 goes from that same row to ground. The result? This is a voltage divider and the "new" voltage created is approx 1/10 of the input. In this case about 0.9v. Yours may differ slightly due to the tolerances of each resistor, but it should be pretty close.

From the row with the 2 resistors and capacitor we jumper this to the base pin. Why do we need to add power to the base? It is called "biasing" a transistor. The transistor needs DC power in order to operate and your guitar signal is AC. So, we add both at the same time to "trick" the transistor into working.
1631125409483.png

OK. 3 more components and we are done with the basic circuit. Let's add R3, R4, and C2.

R3 (390ohms) goes into the row with the emitter (remember, that's the top pin mentioned above) and out to ground. This resistor controls the amount of gain in the circuit. 390 ohms tends to be the sweet spot here, but you can alter it to you liking. Anything above 1k doesn't really work but you can give it a go.
R4 (10k) goes into the row with the collector (bottom pin) and the other end to power (red strip). The body of the resistor is kinda blocking the picture below but trust me on this one.
C2 goes into the same row as the collector and down a few rows. From here you can add your "Boost" potentiometer (it's just a volume pot going to ground) or you can test your circuit by merely adding an output jumper wire. I chose a white one. Be careful: since it's a boost circuit it will get loud!!

If you're looking at the potentiometer with the knob sticking up, the pinout is 1-2-3. 1 goes to ground, 2 goes to your output jack or plug, and 3 goes to the end of C2, right where my white jumper cable is.

I don't have a picture of the Boost pot wired up since I will talk about mods below and you'll see why I skipped this step.
1631125706117.png

And that's it. The LPB-1!!

Let's talk MODS for a bit. You can alter the value of C1: lowering it allows less bass frequencies into the circuit. Going higher than 100n won't have as much of an effect since most guitar signal goes through with 100n, but of course try it and find out!

The write up from Coda Effects (link above) does a pretty good job explaining what each piece does and how you can alter it.

This can easily be turned into a fuzz/distortion pedal!! Let's see how!

If you want to turn this into a fuzz pedal, simply add a diode (I chose a 1n4148) from the collector to the base. The cathode side (it has the black end on it or if you're using an LED it is the shorter end) goes into the row with the base pin of our transistor.
1631126437394.png

When I tried this out I noticed that the fuzz effect doesn't last as long as I like when I hold notes for a period of time. That's simply because of the way diodes work: it needs a certain amount of input or voltage in order to transmit signal.

Want to make this a distortion pedal?

We can add a 1k resistor out of C2 and down a row or two and then add 2 hard clipping diodes: they go in opposite directions and 1 end of each goes to ground. The 1k resistor is merely to protect the diodes.
1631126675654.png

OK. Now were cooking in the test kitchen! I feel like something's missing. Hmm.....let's add a tone control to alter the amount of treble!

A tone control like I will show here is pretty simple. It is merely a low pass filter and you will need a 10k pot and a 22n capacitor. Pin 2 of the pot goes into the same row as our diodes and C2. Pin 3 goes into a different row and this row only has our 22n capacitor (I will call it C3) going to ground. Your output jumper can go here if you'd like to test out your new tone control! You can alter the value of C3 here to suit your tastes: increasing the value will reduce the highs that much quicker. Pin 1 won't be used here.
1631127007408.png

Now, you run over to your amp, hook up your breadboard and your guitar, and fire off a sweet power chord!

Wait a minute? I thought this was supposed to be a boost/dirt pedal. Why is it kinda quiet?
I'll tell you!

Tone controls and hard clipping diodes like this tend to suck out a decent amount of volume. That's just the way these work. So, how can we make this louder? How about we add a booster after it!! Add another LPB-1 circuit block directly after your tone control, keeping the input and output capacitors as well. After the output capacitor here you should wire up your official "Boost" potentiometer like in the schematic: Pin3 to the output cap (100n), Pin 2 to your output jack, and Pin 1 to ground. My output jumper is yellow here. For some reason I kept my white one still on the board.

1631127426529.png

Behold! I present to you an "original" circuit that I'd like to call the L-PB&J Sandwich!! Why a sandwich? Well, because there are LPB-1's in the beginning and end of the circuit and thinking about sandwiches makes me hungry! Once I'm done eating my sandwich I will whip up a schematic for this and post below.

Thanks for making it all the way to the end of this!

BuddyTheReow
 
Here's the schematic if anyone's interested. C4 seemed unnecessary as I was drawing this up, but I don't think it's hurting anyone:)
 

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I have to try this! Thanks!
R6 needs a label. Is it a pot or fixed resistor? Just had to look at the picture, duh fig, LOL
 
IMO this can/should be tweaked a little better than what's here. I was merely trying to whip something up real quick. Tone control mostly.
 
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2 things I think should be done. Change C1 to a smaller value, say, 22n. That makes the circuit more treble oriented. Then I would put a 47n or greater capacitor in the tone control to give a more pronounced treble cut effect.
 
Thanks for this. I’ve already successfully bread boarded a number of projects but had no idea what all of the parts were doing in relation to each other. This is a great start for me to tinker
 
Here’s another interesting add on. I was stumbling through Jack Orman’s site found this. Credit where credit is due.

Simply wire up an LPB-1 normally then flip the transistor around for some interesting clipping. By itself it’s not very loud but this sparked a couple of ideas. I’m currently cooking something up on my breadboard using LPB-1s and will circle back when I get something I’m happy with.
Wife and I are taking a vacation this coming week so I’m itching to get something up on here when I have some time to draw schematics, etc.
 
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Piggybacking on the post from above here's an overdrive using LPB-1s. The first one is a straight LPB1. The second one is nearly identical with the exception being that you flip the transistor around 180 degrees. A simple tone control right after there.

I call it the LPB Overdrive.
 

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Using LPB-1s I sought out to attempt to build a fuzz pedal. I realized that I can add a diode between the collector and base of the transistor to provide some clipping. See original thread. Make sure the anode is in the collector and cathode is going to base.

The first stage is just an LPB-1 with a 470p cap in the feedback loop. The second stage is an LPB-1 with a 1n4148 diode in the feedback loop. From here I put in a spdt switch to select whether or not you want a single clipping stage or double. The second clipping stage has a 1n4001 diode in the feedback loop (collector to base). From here it goes into a Triangle BMP tone stack and then into a recovery stage LPB-1 with the "Boost" control thrown back in there. When I fired this up there was a high pitch oscillation so I put in the 470p cap. Why? Well, if you take a look at this circuit it is essentially 4 transistor boosters. Unless filtered, it will boost ANY signal. The input and output caps take care of a lot of the low end and DC filters. I realized I needed to take the high end and found that the 470p cap does the trick pretty well.

No gain control is needed since your guitar volume will take care of that. If you've got hot pickups there will be a bit of gating if the volume is maxed out. One of the cool things I like about this circuit is that if you hold a note long enough you will eventually hear the clipping stage fizzle out one by one (it takes a while).

I call this the L-BMP-1 Fuzz

Edit:
I realized after I whipped this up that it’s pretty similar to a Big Muff. Hence the name. I still feel that it’s pretty original instead of a BMP clone.
 

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Using LPB-1s I sought out to attempt to build a fuzz pedal. I realized that I can add a diode between the collector and base of the transistor to provide some clipping. See original thread. Make sure the anode is in the collector and cathode is going to base.

The first stage is just an LPB-1 with a 470p cap in the feedback loop. The second stage is an LPB-1 with a 1n4148 diode in the feedback loop. From here I put in a spdt switch to select whether or not you want a single clipping stage or double. The second clipping stage has a 1n4001 diode in the feedback loop (collector to base). From here it goes into a Triangle BMP tone stack and then into a recovery stage LPB-1 with the "Boost" control thrown back in there. When I fired this up there was a high pitch oscillation so I put in the 470p cap. Why? Well, if you take a look at this circuit it is essentially 4 transistor boosters. Unless filtered, it will boost ANY signal. The input and output caps take care of a lot of the low end and DC filters. I realized I needed to take the high end and found that the 470p cap does the trick pretty well.

No gain control is needed since your guitar volume will take care of that. If you've got hot pickups there will be a bit of gating if the volume is maxed out. One of the cool things I like about this circuit is that if you hold a note long enough you will eventually hear the clipping stage fizzle out one by one (it takes a while).

I call this the L-BMP-1 Fuzz

Edit:
I realized after I whipped this up that it’s pretty similar to a Big Muff. Hence the name. I still feel that it’s pretty original instead of a BMP clone.
The clipping stage switch is drawn backwards.
 
Just got your breadboard or protoboard in the mail and don't know where to begin? The Test Kitchen's got your back! Let's start with a classic and simple circuit: the LPB-1. This is a simple booster and a basic building block for many circuits out there. Here is a schematic taken from Coda Effects.
View attachment 15802
If you'd like to read their write up about this circuit check this out!
Coda Effects also does a good step by step of this circuit too on a breadboard here.

Let's set up our basics first: guitar input (I used an orange jumper wire), power (+ is red jumper and - is black jumper), the input capacitor C1, and a 2n5088 NPN transistor. Notice the transistor's flat side is facing left in the picture. The pinout for this as read from top to bottom is Emitter (E), Base (B), Collector (C). If you don't have a 2n5088 lying around try another NPN transistor such as a 2n3904 or similar. Just check to make sure the pinouts go this way and if not, simply rotate the transistor 180 degrees.
View attachment 15803

Next we need to add R1 and R2 and then connect that to the Base pin of our transistor. The schematic calls for 430k ohm and 43k ohm transistors, but I chose to use 1m and 100k for 2 reasons. First, I had these values lying around on my workstation and decided to be lazy :p. Secondly, the relationship between R1 and R2 matters more than anything else: R1 is 10 times the value of R2 so you can use nearly any values (just keep r1 pretty high) as long as the relationship stays.

R1 goes from power to the same row as the capacitor and R2 goes from that same row to ground. The result? This is a voltage divider and the "new" voltage created is approx 1/10 of the input. In this case about 0.9v. Yours may differ slightly due to the tolerances of each resistor, but it should be pretty close.

From the row with the 2 resistors and capacitor we jumper this to the base pin. Why do we need to add power to the base? It is called "biasing" a transistor. The transistor needs DC power in order to operate and your guitar signal is AC. So, we add both at the same time to "trick" the transistor into working.
View attachment 15805

OK. 3 more components and we are done with the basic circuit. Let's add R3, R4, and C2.

R3 (390ohms) goes into the row with the emitter (remember, that's the top pin mentioned above) and out to ground. This resistor controls the amount of gain in the circuit. 390 ohms tends to be the sweet spot here, but you can alter it to you liking. Anything above 1k doesn't really work but you can give it a go.
R4 (10k) goes into the row with the collector (bottom pin) and the other end to power (red strip). The body of the resistor is kinda blocking the picture below but trust me on this one.
C2 goes into the same row as the collector and down a few rows. From here you can add your "Boost" potentiometer (it's just a volume pot going to ground) or you can test your circuit by merely adding an output jumper wire. I chose a white one. Be careful: since it's a boost circuit it will get loud!!

If you're looking at the potentiometer with the knob sticking up, the pinout is 1-2-3. 1 goes to ground, 2 goes to your output jack or plug, and 3 goes to the end of C2, right where my white jumper cable is.

I don't have a picture of the Boost pot wired up since I will talk about mods below and you'll see why I skipped this step.
View attachment 15806

And that's it. The LPB-1!!

Let's talk MODS for a bit. You can alter the value of C1: lowering it allows less bass frequencies into the circuit. Going higher than 100n won't have as much of an effect since most guitar signal goes through with 100n, but of course try it and find out!

The write up from Coda Effects (link above) does a pretty good job explaining what each piece does and how you can alter it.

This can easily be turned into a fuzz/distortion pedal!! Let's see how!

If you want to turn this into a fuzz pedal, simply add a diode (I chose a 1n4148) from the collector to the base. The cathode side (it has the black end on it or if you're using an LED it is the shorter end) goes into the row with the base pin of our transistor.
View attachment 15807

When I tried this out I noticed that the fuzz effect doesn't last as long as I like when I hold notes for a period of time. That's simply because of the way diodes work: it needs a certain amount of input or voltage in order to transmit signal.

Want to make this a distortion pedal?

We can add a 1k resistor out of C2 and down a row or two and then add 2 hard clipping diodes: they go in opposite directions and 1 end of each goes to ground. The 1k resistor is merely to protect the diodes.
View attachment 15808

OK. Now were cooking in the test kitchen! I feel like something's missing. Hmm.....let's add a tone control to alter the amount of treble!

A tone control like I will show here is pretty simple. It is merely a low pass filter and you will need a 10k pot and a 22n capacitor. Pin 2 of the pot goes into the same row as our diodes and C2. Pin 3 goes into a different row and this row only has our 22n capacitor (I will call it C3) going to ground. Your output jumper can go here if you'd like to test out your new tone control! You can alter the value of C3 here to suit your tastes: increasing the value will reduce the highs that much quicker. Pin 1 won't be used here.
View attachment 15811

Now, you run over to your amp, hook up your breadboard and your guitar, and fire off a sweet power chord!

Wait a minute? I thought this was supposed to be a boost/dirt pedal. Why is it kinda quiet?
I'll tell you!

Tone controls and hard clipping diodes like this tend to suck out a decent amount of volume. That's just the way these work. So, how can we make this louder? How about we add a booster after it!! Add another LPB-1 circuit block directly after your tone control, keeping the input and output capacitors as well. After the output capacitor here you should wire up your official "Boost" potentiometer like in the schematic: Pin3 to the output cap (100n), Pin 2 to your output jack, and Pin 1 to ground. My output jumper is yellow here. For some reason I kept my white one still on the board.

View attachment 15812

Behold! I present to you an "original" circuit that I'd like to call the L-PB&J Sandwich!! Why a sandwich? Well, because there are LPB-1's in the beginning and end of the circuit and thinking about sandwiches makes me hungry! Once I'm done eating my sandwich I will whip up a schematic for this and post below.

Thanks for making it all the way to the end of this!

BuddyTheReow
Man, you’ve got some great threads! Keep up the awesome work (please)!
 
I am interested in building an LPB-1 with a hi pass filter and a fixed gain compensation for it. Something like the Walrus Plainsman. What is the best way to implement that into the LPB-1 circuit?
 
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I am interested in building an LPB-1 with a hi pass filter and a fixed gain compensation for it. Something like the Walrus Plainsman. What is the best way to implement that into the LPB-1 circuit?
Good question. The short answer is to experiment to find what you like, but I'll show you the building blocks needed to get started.

An LPB-1 is a simple booster and amplifies your signal. The simple high pass filter is passive in nature meaning all "unwanted" signal gets dumped to ground and results in a volume drop but not as much as you may think. The more passive filters you have, the greater the volume drop. Are you looking to have the filter permanent or to toggle it on/off?

When you say 'fixed gain compensation' I am guessing one of 2 things: you want a dB switch or control like the Walrus Plainsman or you are looking for a simple 'recovery' stage to compensate for the lost signal. Hopefully you can clarify here.

IMO, here are the 2 or possibly 3 building blocks you will need depending on how much boost you want.

Here's the simpler one of the two: 2 stage circuit and the one I would mess around with first.

IN->LPB-1 w/o Boost control ->Hi Pass Filter->Boost Control->OUT

And the 3 stage circuit. This will get VERY LOUD. Perhaps too loud.

IN->LPB-1 w/o Boost Control->High Pass Filter->LPB-1->OUT

Let's talk about the tone filter first. Here is the schematic of what one looks like. A capacitor then a resistor to ground.
1633348435207.png
I'm leaving the values for the cap and resistor blank since I'm not quite sure how treble-y you want it to sound. You will have to sub a pot for the resistor here: lug 2 to ground and lug 3 as the other end of the resistor in the above schematic. As you turn the knob more to the left (counter clockwise) the resistance is increasing and more 'raw signal' comes through. The more you turn it clockwise the more bass gets cut. A good starting point for values would be 10n for the capacitor and 100k for the pot. Here is a simple calculator to help you find the frequency you're looking for. Less resistance = more treble. http://www.muzique.com/schem/filter.htm

OK. Now the 'gain compensation'. Here's a circuit analysis from Coda Effects:
LPB1%2Bcircuit%2Bguide.gif


IMO your fixed gain mod will be to change out R3 here, the emitter resistor. 390 ohms is the 'sweet spot' for this circuit for the most gain without adding dirt to the sound. The less resistance the more gain you will have, but anything below 390ohms will have too much gain and the signal will start to break up. My experience with this circuit is anywhere between 0ohms and 1k or possibly a little higher for the full range of gain. The higher the resistance the less gain, and therefore boost, you will get. You will need to have 2 resistors here to make the gain switchable like in the Walrus Plainsman. Here's what it would look like on a schematic. I used 390ohms as the standard and left the other value blank for your experiments. Use a SPDT switch with the middle lug to ground.
1633350169532.png
 
@Travis has a good question out there how to add a boost to a circuit, but when the BOOST knob is dialed all the way back he wants unity gain. So, naturally I put this on a breadboard to experiment. It's an interesting concept to use a boost circuit as a true boost. Anyways, I found in my quick breadboard session to add a 10k resistor from lug 1 of the BOOST pot to ground. Keep in mind when the knob is dialed back there is a bit of tone filtering happening.
 
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