My first and last DIY tube amp !

[HFGuy]

I thought I would share my little tube amp story with all you folks before I powered it up for the first time (just in case). About 5 years ago i started looking for a tube amp for my 2ch setup, i found some good sounding stuff. But what I really wanted as a statement type of amp. What I really wanted was a CJ premier 12 (or was it the 11?). I spent months looking for a used one. But after shipping and all it was just out of my price range.

I had previously built a 1W pure class A discrete BJT headphone amp (Still being used daily !) so I had alittle confidence and decided to build my own tube amp. Well the whole project started simple and just got alittle out of hand. I figured if i was going to go through all the hassle of building an amp of my own i didnt want to regret any of choices (yes I am aware how ironic this is now). I settled pretty early on that i wanted a PP kT88/6550 amp, i didn't want to limit my future speaker selection. After looking around it became obvious that I would use some kind of williamson type amp. I eventually settled on the schematic on the Plitron website. My tube expert buddy recommended some changes to it (wishing now I just left it stock), unfortunately he has disappeared on me. So with that settled I started picking components and decided I didn't want to use any electrolytic caps (I was young and stupid at the time, now I am old and bitter ).

I know this is very superficial but I spent the most time and effort on the chassis. I looked around this site for a long time and just didn't see anything I would stare at and admire while listening to music (nothing personal). I simply refused to use a Hammond box, I spent alot of time looking around for chassis that would live up to my "standards" and didn't find anything I could afford. So I decided to build my own chassis by hand (my only concession was a drill press) from scrap aluminum. My only real goal was to have a minimal number of bolts and/or nuts showing. The only hardware I wanted to show was that nessessary for the construction of the chassis itself. I didnt want to see any hardware from the mounting of internal electric components. Basically this meant retarded thickness of alum and drilling/tapping work.

Well building this chassis killed me. I lost ALL interest in both finishing the amp and audio in general. I switched over to a new hobby, one that I still love and devote way to much of my free time to. But the hobby is a good weather hobby so I found myself this winter wanting to finish my tube amps. So the amp is more or less ready for testing. Here it is in its current state.



If you guys haven't already heard enough from me and want to see more photos of the amp at various stages of construction Ill post some tomorrow.

[vinylkid58]

That's a very nice looking amp. You might as well give us all the gory details, now that the cat's out of the bag, so to speak.

jeff

[DigitalJunkie]

"My first and last DIY tube amp !" -You say that now,but it's highly addictive to some people.

[piano3]

I know what you mean about chassis building! One time, after sawing by hand many pieces of 6mm thick aluminium channel outside in the hot sun trying to keep to a line with the sweat running in my eyes, I couldn't even think about the project for some weeks.
I must say though,you have made a lovely job.

[kavermei]

That's a gorgeous amp! Chassis work is such a PITA. Turns me off every time, and yet it takes the majority of the time

Maybe in a couple of years from now, you'll feel "the urge" returning

[quikie22]

beautiful work there.

Chassis work sucks esp to me who has no woodworking/metalworking skills. So far, I managed to find a PA amp chassis to use and also a blank chassis. My next project will use a re-purposed drawer.... hmmm...

[maxw]

Good job! I too feel your pain in building a decent chassis. Would you mind posting a couple more pics of the chassis and the internals of the amp?

[Pano]

That's very, very pretty. Kudos!

I'll cast my vote with the rest. Chassis work sucks. No wonder you went off the hobby. But your work is quite lovely.

[6L6]

Your work looks amazing! We would all love to see more photos.

Once you have your creations fired up and tuned in, I think you will not be so down on DIY audio!

[chops]

Extremely impressive work! That amp looks great!

I wish I had the knowledge and resources to do such work. If I did, I'd be in business building amps and preamps all day long. My father is like that and can build shortwave radios, amplifiers, etc, etc without even looking at a schematic. He just starts building and in a few weeks he has a wonderfully working piece of equipment on his bench.

Maybe one of these days I'll grow enough knowledge and balls to build my own gear. You should be greatfull you can do such wonderful work.