1957 Fender Low-Power
Tweed Twin chassis restoration
This amp started like this.
NOTE: This was one of the first major restoration projects I completed with my mentor Jon Bessent of Tonecraft Amp Repair back in 2005.
This 1957 Fender Twin belongs to San Antonio blues legend Curley Mays. Curley rose to fame in the 50s while on tour with Etta James and other acts. He is also the nephew of Clarence "Gatemouth" Brown. This tweed low-power version of the Twin came with two 5U4 rectifier tubes. Curley bought this brand new in 1957, along with a Stratocaster. Curley asked me to "fix" this for him in the summer of 2005. I knew when he pulled her out of the trunk of his Caddy, this amp would be a real challenge.
Looking at the back, true blues history and MOJO, but oh what a mess.
Well, once I pulled of the backpanel, I knew this amp was going to take some serious time to get her right. First, you'll notice that the cabinet is homemade. Curley said that the old box was really rotten, so he had a friend build him a new one. I really don't know how many years ago this was, but seeing how he hasn't played live in more than 20-years ago, it has been a long time that this box has housed his chassis. More on the box later.
You'll notice that the chassis is covered in dirt. Not just dirt, but sticky, old grime. Whew, it was a real tough one to get cleaned up. You'll also see that the power cord has about three different splices on there. Once I looked closer, I also saw original electrolytic caps and that selenium rectifier. All of those are serious hazards when looking at an amp of this vintage. Amp was also missing original tube shields.
Replaced Astrons with Spragues in the tone circuit.
Some Astrons had been replaced. It was a long time ago looking at the cap codes and the amount of film they were coated in. As with any vintage project, I always try and leave as many original parts in the amp as possible. In looking at this amp, I knew there weren't going to be a whole lot of them left.
Oh boy . . . Yikes!
OK. Looking at the back of the chassis, this is what I had to deal with. 7993 Triad Power transformer original, but original wires seriously crumbling. Choke held together with Scotch Tape. Output transformer replaced with a Triad unit form the late 60s. Not a lot really to work with here. But, I had to make some decisions . . . the transformer issue could wait for now.
Circuit board rebuilt.
I started with the circuit board. Replaced all of the electrolytics with Sprague Atoms, and the older Sprague ODs with new ones. The older ones had drifted a bit. At this time, I left what original Astrons were left in the amp. This turned out not to be the best idea. Note all of the grunge cleaned up, selenium rectifier removed, and adjustable bias mod added.
'57 Twin Restoration Page 2
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