Sunday, February 1, 2015

My 1st DIY SET AMP 2A3/45 Part 1

It's ALIVE!!!!! Welll.. Sort of....

 I've always wanted to build my own tube amp so when I was in New York in May hanging with Jeffrey and Dave they sent me home with a schematic and enough parts to get started on a Stereo 45/2A3 amp. I have been moving toward this project at a glacial pace. I had a bit of help from my friend Chris on layout and the use of his drill press. Metal is so so messy..... 
 I like the looks even if it isn't perfectly symmetrical. That makes me abit crazy... loll

 So how did it go? 
Well after my friend Chris went over my work yesterday he only found one issue with a wrong resistor rating which he happened to have so he dropped them by for me today. I completed my homework and plugged it in and turned it on.
Some hum.... Only one channel working.... Sound is coming out.
But no smoke no burning no smoke 8-)
 I wasn't going to post until it was working perfectly but that wouldn't be very honest or fun. We learn the most from mistakes anyway.
Stay tuned for part 2. 

EDIT Part 1.34
It turns out parts like LED's have polarity and if one is reversed it does not work. Now I have both channels working and the amp is stable. However it just sounds terrible. Tomorrow I'll dive in to take measurements to see what else I have done wrong and buggered up. 


  1. Very cool!
    I've been considering venturing into the tube equipment,
    probably a running dynaco though to start.
    There's a handy tool called a "dim bulb tester",
    it's basically a cord with a weak light bulb in line,
    and if there's a short the light glows.
    Saved me from a smoke out on a solid state amp!
    Anyway I'll be watching progress!

  2. Well done! For the first project very well. Ideally - if you will understand as it has to work. Then there will be no questions - as it has to look. Don't stop!

  3. Nice work Iain! OMG that's a lot of iron. What are the James-looking cans? Outputs? Interstage?


    1. Thank you...

      The back is power transformer rectifier tubes power supply choke with another under the chassis. Then James output transformers with hammond interstage transformers in front of them.

      I hope to get back to it this weekend and get the hum figured out.

    2. Looks great for a first try. Love the Stereo badge! Good luck with the hum.

  4. nice,sound of vacuum tube others like that......


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