DIYstompboxes.com

DIY Stompboxes => Building your own stompbox => Topic started by: ibanezts808 on November 20, 2004, 02:11:15 PM

Title: Signal Drop, not Significant, but should be amplified.
Post by: ibanezts808 on November 20, 2004, 02:11:15 PM
Okay, I'm a beginner and I want to know what I'm doing Wrong.  I'm sure it is something basic:

My input goes to the base on a transistor, the battery goes to a switch and the switch goes to collector, and the emitter goes to output.  Everything is correctly grounded.

When I plug the guitar into the pedal I can hear it through the amp, and very well too.  But when I plug the amp directly into the guitar, no alterations made, the volume is noticeably higher, shouldn't it be the other way around.  Keep in mind, I'm not using any resistors, caps, or anything else in the circuit, which I'm wondering if that is where I went wrong.  Thank you.
Title: Re: Signal Drop, not Significant, but should be amplified.
Post by: guitarhacknoise on November 20, 2004, 02:38:26 PM
Quote from: ibanezts808Keep in mind, I'm not using any resistors, caps, or anything else in the circuit, which I'm wondering if that is where I went wrong.  Thank you.
Hello,
I'm not sure what it is you are trying to build!
but I would guess that you need some more components.
check out the boosters in the schematics section, or even better, check out aron's begginer project. It's really simple and sounds cool. plus it's step by step with ton's of members questions and answers.
-matthias
Title: Honestly...
Post by: ibanezts808 on November 20, 2004, 02:51:33 PM
Honestly I don't even know what I'm making, I just want to see what each compnent does, and I figured, lets see if I can make a transistor amplify my signal... and well, I figured that answer out.  LOL!  Yeah, I think I will follow the beginner project.
Title: ...
Post by: petemoore on November 20, 2004, 04:43:38 PM
Hello 808 !!! Glad you're posting !!!
 Excellent choice !!!
Title: Signal Drop, not Significant, but should be amplified.
Post by: aaronkessman on November 20, 2004, 04:45:25 PM
talk about a bare bones approach. that's probably the best way to start! battery and a transistor!
Title: Re: Signal Drop, not Significant, but should be amplified.
Post by: davebungo on November 20, 2004, 04:56:06 PM
Quote from: ibanezts808Okay, I'm a beginner and I want to know what I'm doing Wrong.  I'm sure it is something basic:

My input goes to the base on a transistor, the battery goes to a switch and the switch goes to collector, and the emitter goes to output.  Everything is correctly grounded.

When I plug the guitar into the pedal I can hear it through the amp, and very well too.  But when I plug the amp directly into the guitar, no alterations made, the volume is noticeably higher, shouldn't it be the other way around.  Keep in mind, I'm not using any resistors, caps, or anything else in the circuit, which I'm wondering if that is where I went wrong.  Thank you.

What you have done effectively is made a "sort of" emitter follower with the emitter resistance being the input of your amplifier but it won't work well.  The transistor is basically a current amplifying device so your guitar signal drives a current into the base and an amplified current appears at the collector.  In order to produce a *voltage* amplification, you need to put a resistor (try something like 10K) from the supply rail to the collector (to develop a voltage signal) and take your output from the collector.  It's not quite as simple as this as you have to bias the transistor so it can swing up and down in response to your input signal, but try it out and you may see an improvement.  Good luck!