Introduction: Small Tube Guitar Amplifier

About: I am a researcher/ scientist in pressure metrology, in my spare time i play guitar, building thing, breaking thing,

Tube Guitar Amplifier is used by most many guitar player,it preferred because it produce sound that more "natural sound' in clean or distorted,it sound different compare to solid state guitar amp. Normally this amp will contain heavy transformer and a tube glass that very fragile.of course its not portable because that two reasons .But why need to make small amp because it practical to move around (portable)and make decent sound .Or if you are beginner and want to make small practice that not make neighbor get mad and angry this project is perfect for you. Also this amp is cute.

DIY Small guitar amp already made by other like using firefly tube amp schematic or in P1(please see my other instructable )it power rating from 1 to 5 watt. Or you can just buy zvex amp or orange tiny terror that hybrid.

Usually guitar amp contain Preamp , tone control, and power amp. In preamp you can use matsumin schematic, real mactube, P1 preamp, or firefly preamp. in tone control for small amp it not provide like in

My amp combine preamp from P1 preamp and modified firefly power amp. preamp usually use 12ax7 tube preamp, and using 12 au7 as power amp in firefly schematic. I use 12BH7 because I only have output transformer.

Disclaimer:this project contain HIGH VOLTAGE up to 400V dc that DANGEROUS if not properly handle. please if you not know what your doing ,DO NOT follow this project.I'm not responsible for what mistake that happen regarding following this project.

Step 1: Parts and Tools

Part List

1.Chassis (this chassis actually for Nano amp )


3.Power Transformer 0.7 A 220/110V to 18/12/9/6 V


5. Output Transformer : 8 k Ohm to 8 Ohm

6. 12AU7

7. 12BH7

8. .Power Transformer 0.3 A 220/110V to 12 V

9. Resistor

10 Capacitor


12 Tube socket


*All the part I purchase in south Korea.


1.Soldering Iron

2.Solder tin

Step 2: Schematic and First to Do List

As I mention in the introduction, I combine the small amp tube amplifier that woks because I don't have all the necessary component such as Power transformer.

the list of small tube amplifier /Pre-amplifier as my reference

1. Firefly Amplifier

2.P1,P1 extreme from

3. Preamp Matsumin valve caster

4. Mac tube Preamp

Fist I solder all based on Matsumin pre-Amp and power section as in firefly , I got someone already success build this one Please watch this video first

I try to make the same as but it failed because high voltage section i made from this make some oscillation and the volume is to low.

Step 3: Try and Error

First I try B+ 12 V. there no sound when increase the B+ above 260 V with no load but when it connect with tube on it The B+ voltage drop until 100 V. and LM 7812 is very hot I add heat sink on it.

Change by adding transformer as reverse direction. you can find this method using mac tube preeamp.

Step 4: Little Sucsess

Step 5: Video

Sound Check of my amp. It connect to 8 inch jensen speaker output.

Input connect to My vintage modern Fender guitar with EHX soul of food as pre-amp/boost.