Demonstrating another amplifier build, a Tweed Bassman copy
Hello, all you steemians out there, and welcome to my blog, eh!
In this post, I'm going to talk about an amp that I built for a friend. He brings me old amp parts, and sometimes a complete older tube amp from the PA system in a store or a school, some place like that, and I rebuild them into guitar amps. I built several of them for him last winter, and I'm starting on my next build now that it's cold outside.
The amp that I'm going to talk about in this post is one that I built for him last winter, and have been storing for him since then. I live in the upper Great Lakes area and he lives in Oregon, so he doesn't have a lot of opportunities to pick the amps up once they're built, but that is a story for another day.
This amp was built from a chassis with transformers that he brought me, it had apparently been someone's home built music amp. I rebuilt the amp using the schematic from a late 1950s Fender Tweed Bassman amplifier, the 5F6-A chassis. Interestingly enough, this chassis is also what the first Marshall guitar amps were designed from. The circuits are almost identical.
This is what the amp looks like. It's not real pretty, but it's the chassis that I was given to use. With the proper tools, a decent cabinet could be built to put it into.
The inside from the top. The amp uses two 12AX7 preamp tubes, a 12AT7 driver tube, two 6L6GC power tubes, and a 5U4 rectifier tube.
The circuit wiring. This type of wiring is known as point to point wiring. There are no circuit boards, just connector strips and the tube sockets. I used mostly new parts to build this amp, except for the transformers. Those are the only really expensive parts in a tube amplifier. This view shows the inside of the front of the amp with the controls.
This view shows the inside of the back of the amp with the power hookup, fuse holder, power switches, and the speaker output jacks and assorted parts. One of the good things about building this amp was that there's lots of room for the parts. A lot of tube amps have all the parts crammed into a small space, making working on them more "interesting".
I made a video to demonstrate the sound of this amp, using both my bass guitar and my 6 string electric. I think the volume of the amp overloaded the mic built into the camera several times when I turned the amp up, but I think you'll get the idea of how this amp sounds.
Well, that's about it for this post, I hope you found it interesting!
Thanks for stopping by and checking out my post, eh!
As always, feel free to leave a comment or a question if you'd like.
May the steem nuggets ever be in your favor!
Man that Bass sound amazing!! great job engineer friend :) \m/ you rock!
It's so cool that you can do this, to me it's just a mess of wires and thingy-things.
Great post! Now I know who to call for amp repairs 🙂
Thank you!
You're welcome
Old amplifiers... well, there is something to be said for the new, and there is something to be said for the old.
Like, you can't get your computer to modify everything like you could with an equalizer. And the everything in one chip makes wiring really easy.
But, you can't put power through it like a tube amp. The transistor also has such a tiny part of its curve where it is amplifying. Where as the tube has tons.
I enjoyed the pictures.
Thank you!