Showing posts with label vintage gibson amp. Show all posts
Showing posts with label vintage gibson amp. Show all posts

Wednesday, September 16, 2020

1940's Kalamazoo KEA

 Curious little bargain tube amp that I got to bring back from the dead..... a 1940's Kalamazoo KEA.





This is one circuit that I'll admit I have little idea of how it works. It has a single 6SJ7 driving a pair of 6V6 tubes. How this is achieved I do not know. It's not parallel single ended. Look at the schematic!


The other challenge was finding a 10" speaker that is shallow enough to fit in such a tight space. This project sat around and almost made the 'sold for parts as-is' pile. Nothing fit! But fortunately I was able to find an old CTS speaker in the bowels of Southside Guitars deep in the basement under discarded case parts...... It was dead so we had it re-coned. Speaker had the perfect holes to mount the output trasformer.



In the end it's a fantastic little amp. Not a fuzz box, very clear and defined. These are financially not worth the effort, you'll likely lose money doing what I did. But we were all so blown away by it's charming tone that an employee bought it and will be tracking with it! I have an affinity for the 6SJ7 tube. My favorite preamp of all time so it's not surprising how much I like this amp. 


Did the usual, changed the caps etc. Fortunately both transformers were good. I do not think this amp would work well without that odd asymmetrical output transformer. So make sure that part is happy before you commit to one of these. 


J






Tuesday, November 20, 2018

1950 (or so) Gibson BR6F

The first good small tube amp I bought was a Gibson BR6F. I found it at Guitar Exchange in Catonsville, Maryland back in 1992.

I....love....these....amps!

6SJ7 driving a 6SN7 phase inverter feeding 2 hungry little 6V6 tubes. 5Y3 rectifier. 10 watts into a 10" field coil speaker.

A word about the field coil speakers. They often sound lovely. Don't do what I did to mine: run a bunch of pedals into it and blast off for hours. I killed mine and once that speaker is dead, that's it. It'll never be the same. You want to treat the elderly nice and gentle, with respect. Leave those dumb ass pedals in the bag and learn to play better!

I probably could have had that speaker rebuilt, but I blew mine up in 1995. No internet in those days and tough to find someone to rebuild it properly

If you do blow it up, check these cats out:

http://www.thespeakershop.com/home/speakerrepair.html

his one was at Southside Guitars. It's long sold. I re-capped it and replaced the power cable. I hope the new owner just plugs in and plays it!

And a video of my friend Eric playing it.....

https://www.youtube.com/watch?v=_PUzJnwjELg

The amp: