TUTORIAL Amentum Boost

BuddytheReow

Breadboard Baker
Here is a step by step tutorial how to build the Amentum Boost from pedalpcb.com on a breadboard.

Here is the link for the build doc https://docs.pedalpcb.com/project/Amentum.pdf

Here is the schematic found in the build doc. This is a simple, one transistor booster circuit. There are 4 resistors, 4 capacitors, 1 electrolytic capacitor, a potentiometer, and a BJT Transistor (2N5089)
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My first step is to block out the circuit on my breadboard. Here we really only have 2 circuit blocks: the power and the booster.
Usually I make my power section the upper right hand corner of my breadboard, but wherever you'd like to place it is up to you. Vcc in the power section is connected to 2 capacitors: C100 and C4. Both of these also go to ground.

The transistor is a 2N5089. I have the flat side facing the left so the pinout is EBC. Here is the pinout.
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Now to add some jumpers and R2/R3. The input power, both capacitors, and an output jumper will go in the same row to complete your power section. This out jumper will be placed at an arbitrary place further down.

R2 goes from the emitter to ground. The emitter is the top pin in my breadboard pic. R3 has one lead into the collector (bottom pin in the picture) and goes up toward the input section of the circuit.
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Now to add the potentiometer.
Pin 3 goes to the collector of the transistor and before R3. So, from left to right in this row it will be pin 3 jumper wire, R3, then the collector.
Pin 2 is our "output" wire and we will place it below this circuit block to get ready for the real output.
Pin 1 goes to our power source. As I'm writing this I realized the red jumper wire going from the power section to the pin 1 jumper is unnecessary. You may plug my pin 1 jumper (blue in the pic) directly to the power row or follow along the pic itself. Either way will work.
1629739358607.png

Since we've gotten the output section ready to go let's finish that first before we head back and wire up the input section. My black jumper wire from pot lug 2 is attached to C3. The other lead of C3 we can point it down. In this row there are 2 more connections: a 100k resistor to ground and our output wire. I have chosen a yellow one.
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Ok. The end of the circuit is done. Let's go back to the input section.

We need to add a jumper wire from the base pin (middle in my picture) to the "free" lead of R3.
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Where R3 and the yellow jumper wire added we have to add the butt end of C2. The front end is place a row or 2 upwards. From the front end we have to add 3 connections: R1, C1, and our input cable. R1 and C1 both go to ground. The input cable is also plugged into this row as well (it is green in my picture).
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And there you have it! The Amentum Boost from pedalPCB.com. A nice and simple circuit. When and if you decide to start down the road of circuit design this would be a great in/out booster section.

Feel free to leave questions or comments.

Thanks Everyone!

BuddyTheReow
 
Am I correct that this tutorial omits the Schottky diode? I tried building this from schematic only yesterday and failed. The only real difference I can see between my circuit and yours is the diode. I wonder if I hooked it up to the wrong rail
 
Recheck your breadboard against the schematic. If you want help troubleshooting then we will need to see pix of your build.

How experienced are you at assembling breadboards?

Did you sub any parts?

Do you have a DMM?
 
Recheck your breadboard against the schematic. If you want help troubleshooting then we will need to see pix of your build.

How experienced are you at assembling breadboards?

Did you sub any parts?

Do you have a DMM?

I'm mostly curious if I am correct that the tut above doesn't include the diode. I searched "diode" on the page via CTRL+F and didn't find it, so it looks like it's just the capacitors.

Fairly. The skill I am currently working on is assembling from schematic only so there's a bit of a learning curve that can't be helped by anything other than working stuff out.

No part substitutions.

I do, a really nice one actually. It was late and I had to stop. At work now so I can't take any photos
 
Am I correct that this tutorial omits the Schottky diode? I tried building this from schematic only yesterday and failed. The only real difference I can see between my circuit and yours is the diode. I wonder if I hooked it up to the wrong rail
that diode is there for polarity protection, not to get the circuit functional. If you’re working from the protoboard you can omit it since it’s already installed
 
OK, cool. I was tracing things out on my board and it all seemed good except for the power section. I'll check to see if the diode is reversed, or going to the wrong rail. It's probably something stupid. My transistor measured ~560hFE, using the recommended 5089
 
How loud should the circuit be? I tried out a bunch of different transistors for fun, and only 2N5089s seem to work (at least without changing any other parts). The EQ effect is good and nice, but the volume knob isn't doing much. More of a dark to bright thing than a volume thing. There is SOME boost, but not a lot. Transistor gain is 600hFE
 
Let’s see a pic of your board.
How loud should the circuit be? I tried out a bunch of different transistors for fun, and only 2N5089s seem to work (at least without changing any other parts). The EQ effect is good and nice, but the volume knob isn't doing much. More of a dark to bright thing than a volume thing. There is SOME boost, but not a lot. Transistor gain is 600hFE
 
White is in, green is out.

For the pot, red is power, yellow/black is the wiper to output, black is to ground.

Power section is in the top left corner if you're looking at photo 1

Sorry in advance for the crappy resistor colors. I have to measure them instead of reading them most times. Some have extra bands, weird colors, etc. Cheap.
 

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White is in, green is out.

For the pot, red is power, yellow/black is the wiper to output, black is to ground.

Power section is in the top left corner if you're looking at photo 1

Sorry in advance for the crappy resistor colors. I have to measure them instead of reading them most times. Some have extra bands, weird colors, etc. Cheap.
You're transistor is wired backwards. Turn it 180 degrees.
1696427473083.png
 
Oh yeah, I forgot why I posted this in the first place! I had the transistor the other way around, but nothing was happening. Faint sound would come through the amplifier, but nothing much. Turning down the volume pot all the way gave me some signal back. Flipping the transistor around in frustration made things louder. Not quite unity gain, but nearly. I meant to flip it back around and try it again but life got in the way.

Based on what I described, do you think it could be something else? The transistor orientation is the only thing I have changed with the circuit
 
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