Building a Tube Amp from Scratch: Crazy!

9-6-2010 This amp had some used power tubes that finally quit working efficiently. They rattled and buzzed, which makes me think one of them had some loose parts. I am going to take this amp apart and rewire it later on when I get some time. It began to hum very badly.

8-12-2009 This amp still works great. I have played it at least 2 hours a week with great pleasure.

homemade tube amplifierhomemade tube amplifier


1-18-2009 – Yep. The amp sounds great. Although trumped by my dad’s 85 watt fender tube amp, this amp holds its ground with warm tone and great distortion. I left out the negative feedback loop that was in the Instructable, but I have a blank drilled for the switch and a set of turrets for the resistor. This amp is definitely a warm hug of beautiful tone. It is quiet like wind blowing through the pines on a cold winter night. It has just a slight hum, but not enough to make you go insane. I am very pleased with this project now that I have it finished and working. I was having a hard time seeing the light at the end of the tunnel last week, but I see now that just little things make it difficult.

It is never good to forget to make connections. I left 2 wires out that disconnected the preamp and the power amp.

tube amplifier tube glow

1-17-2009 – I finally finished the amp today. It sounds great. I do not have my electric guitar at home, but I played my acoustic through it, and it was so cool! I will try it out tomorrow with my tele knock-off.

12-27-2008 – I had an idea to build a guitar amplifier sometime in November 2008. I found a few designs centered around those 15 watt TO-220 IC packages. The Fender Amp-Can was something like what I had in mind. I did a few Google searches and came across a project on Instructables.com that was a tube amplifier. I heard the sound clips and had to have it. Little did I know…

So far I have read the article about 20 times, gone back a few times to page 19 for the links, bought a book on tube amps that was $30+ dollars, and bought parts from several websites. I had it completely assembled on December 24, 2008, but it had “demons!” The demons screeched and warbled me into madness. Too many wires crossing paths, circuit board traces too close to others, and really bad layout caused the amp to be beyond repair. That’s okay because I did learn from my mistakes.

Mistake 1: I tried to make this amp with printed circuit boards.
Fix: I will build it on a turret board. Tube amps were made with something close to point-to-point wiring.

Mistake 2: The power switch was routed too far from the plug causing major hummmmmm.
Fix: Power plug and switch will be in the back.

Mistake 3: Heater wires were too close to the signal wires.
Fix: Heater wires will be routed towards the back of the case.

Parts Links:
Digikey.com – Caps, Resistors
Edcorusa.com – Transformers
Hoffmanamps.com – Parts and Turret board supplies/tools
Mouser.com – Caps, Pots, Resistors, Switches
Newark.com – Chokes
Tubesandmore.com – Wide selection of tube amp parts

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About robbie

I am an electronics enthusiest and a ham radio operator (W1RCP). I like to play with electronics. It's fun and educational. I looked forward to working in the engineering field in the future. I have a BS in Electronics Engineering Technology from DeVry University. I also have an Associate's degree in Marketing Management from Moultrie Tech, and a diploma in Electronics from MTC.

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  1. Pingback: The baby is asleep, and the 6W tube amp is quiet… « Tech Tut