On the Bench: 1959 Fender 5F1 Champ

There is an element of time travel in opening up an amp to find original circuitry from decades prior. As an amp repair technician, there are few things better than finding that circuit untouched. And that feeling is enhanced when the amp has sentimental value. In this case, I received a 1959 Fender 5F1 Champ that belonged to my client’s grandfather, who used it along with his Fender Champion lap steel guitar. He was a Polish immigrant who worked in the coal mines of Pennsylvania and enjoyed teaching himself a range of subjects from mathematics to music.
The 5F1 “narrow-panel” Champ was produced from 1956-1964. All of the tweed-era amps were special, but the 5F1 is a quintessential amp of that period. It’s a simple circuit, with only one volume control. This is as pure as it gets, allowing the unfiltered guitar signal to really breathe through the speaker and into our ears.
When you think about early rock ’n’ roll, and that warm and crunchy guitar tone, you’re hearing a tweed Champ. Eric Clapton, Joe Walsh, and Keith Richards were all known to use a 5F1 in the studio. At low volumes, a guitar sounds smooth and rich. As the amp’s volume gets cranked, it starts to growl, filling the room with pure grit.
“It was customary for the amp’s builder to sign their name on this piece of tape, and in many cases during this time, the builder was a woman.”At first glance, I was impressed with the overall condition of the amp. The tweed and grill cloth are in beautiful shape, with barely any flaws. Opening up the amp only entails the removal of 4 screws. I held my breath as I placed the asbestos-lined panel—which was meant to act as a heat shield—outside. I then sealed it with a clear lacquer, to avoid disturbing the material.
Immediately, my eye was drawn to the tiny piece of masking tape that had been placed inside the chassis. It was customary for the amp’s builder to sign their name on this piece of tape, and in many cases during this time, the builder was a woman. Sometimes that piece of tape is missing or illegible, but I was happy to see the name “Lily” clearly visible in this amp.This Champ still has its original speaker, an 8' Oxford, which is dated the 3rd week of 1959. Sadly, but not surprisingly, the speaker did need a re-cone. Over time, it’s common for the paper cone to crack or tear, which was visually obvious in this case. If we were to put a signal through the speaker as it was, it would sound horribly blown.
The circuit itself is pristine, sporting all of the original components that had kept the amp alive for the last 66 years. The orange Astron filter and cathode bypass capacitors caught my attention as soon as I saw them.The filter capacitors are an important part of the amp, as they smooth or “filter” noise out of the power supply. Eventually, these capacitors dry out and can cause loud humming or other issues. The cathode resistor sets the bias for each cathode-biased tube, which, in the 5F1, includes the output tube. The cathode bypass capacitor works in parallel with this resistor to resurrect the gain and tonal color that tends to flatten out through this process. When these capacitors start to drift from factory specification, they can cause strange tone or signal issues.
It’s disappointing to have to replace parts on such an original specimen, but in order to make the amp usable and reliable, the leaky and drifted capacitors need to go. Thankfully, there is a way to preserve the aesthetic beauty of the orange Astrons and keep the amp appearing as original as possible. I carefully opened up each capacitor, removed the outer orange cardboard, and pulled out the capacitor itself, which is typically silver in color. I then installed the new, quality F&T filter capacitors inside of the original cardboard covering. I did the same with the bypass capacitors, using Sprague as a replacement.
This process takes a bit of finesse, but the results are worth it. There is nothing like seeing that orange color inside of a tweed Fender amp.
Safety standards have changed significantly since the 1950s. Instead of the original 2-prong power cord, I will always install a grounded 3-prong power cord. I will also remove the “death cap,” which is a capacitor connected from the AC power line to ground. These were originally used to reduce noise, but are completely obsolete with a grounded power cord. If this capacitor shorts, the chassis could become electrified, resulting in an unpleasant shock hazard. With the installation of a modern power cord and the removal of the “death cap,” the amp is safe to use.
After a basic service and tube install, I was finally able to hear the amp in its full glory. The owner and I agreed that NOS tubes would suit this beauty well. I happily tested the amp for a while, buttoned it up, and sent it on its way to thrive for another 65 years.