low watt

Check out the big amp tones from a little box that won't bust your eardrums (or your bankroll).

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I primarily use it as a practice amp at home, typically at lower volumes, and I’d love to get tones similar to a Fender Tonemaster. Is that possible?


Produced between 1987 and 1992, the Fender Champ 12 is a 12-watt, 1x12 combo with a single 6L6 power tube and a pair of 7025 preamp tubes. Photo courtesy of telecaster.com

Hi Jeff,
I have a Fender Champ 12 from the late ’80s that I’m curious about. The input jack is broken, and it has never been re-tubed or probably even serviced since it was new. I’ve given up on trying to get any useful, adjustable gain out of it, and the reverb is pretty much just full on or off. I primarily use it as a practice amp at home, typically at lower volumes, and I’d love to get tones similar to a Fender Tonemaster. Is that possible?
Thanks,
Leonard



Hi Leonard,
When a customer brought his Champ 12 in for service years ago, a couple of this amp’s unique “innovations” had me scratching my head. There are aspects of the electronic design I’ve not seen in any other Fender amp.

The Champ 12 I repaired had multiple problems: Its output was low and distorted, and it wouldn’t switch channels. Before pulling a schematic on the unit, I took a few minutes to troubleshoot it. Sure enough, the output looked very bad on the oscilloscope, and there was no low voltage for the switching circuitry. When I started tracing the wiring associated with the switching circuitry, it unexpectedly led me to the output stage! I figured this can’t be right—someone must have already gotten their inexperienced, grubby little paws into the amp and moved some wires.

It was then I realized what was actually going on. The amp had been designed to tap voltage off of the cathode circuit in the cathode-biased output stage as a low-voltage source for the switching circuitry. Wow, I hadn’t seen that before. I checked the resistors in the cathode circuit, and then replaced one that was way out of tolerance. That was it—the switching circuitry now had voltage and the output of the amp was great. Okay, I won’t forget that the next time a Champ 12 comes in with the same set of problems. But let’s move on to your amp and see if we can address some of your concerns.

The first thing I’d suggest is to re-tube the amp, especially if that has never been done before. You may hear a noticeable improvement. Also, be sure to have the cathode resistors in the output stage checked, as we already know what kinds of problems they can cause. I’d also recommend having the broken input jack replaced. It’s generally the number 1 input jack that breaks and typically that’s the most useable input for guitar.

Being a 10–12 watt amp, the Champ 12 is, of course, never going to sound as big and bold as the 100-watt Tonemaster, nor will it have that kind of distortion unless the entire circuit is completely rebuilt. So what I’m shooting for is to bring the amp’s tone closer to the Tonemaster.

We’ll start with the tone stacks, as they’re noticeably different in these two amps. Locate the three main capacitors in the Champ’s tone circuit—C3, C4, and C5. Replace the 250 pF ceramic cap (C3) with a 150 pF with at least a 250V rating. Next, replace the 0.1 μF (C4) with a .047 μF 400-600V. Feel free to use the original C5 cap here, as C5 will be replaced by a 0.022 μF 400-600V cap. This should set up the tonal characteristics to be closer to the Tonemaster.

You mentioned the amp didn’t have much gain adjustability. This may be due to the type of “shunt-to-ground” volume controls (something I generally don’t care for) used in the Champ 12, but if you’ve found the gain is a bit too loose and broken up, I’d suggest changing the value of C1. Using a 25 μF capacitor on the first gain stage can sometimes provide too much amplification of the lower frequencies, which can muddy up the overdrive. I’d suggest switching the locations of C1 (25 μF) and C8 (0.68 μF). Install the 0.68 μF capacitor in the cathode stage of V1A and the 25 μF capacitor in the cathode stage of V1B.

Another option would be to switch the locations of C1 and C12, instead of C8. This would place the 25 μF cap one stage further down the line.

You mentioned that the reverb is delivering all or nothing, but this may be due to an incorrect adjustment. The reverb in these amps is the other unique “innovation” I mentioned earlier. It’s actually driven by the signal going to the speaker!

I had seen this done before in early amps from a different manufacturer, but not in a Fender. It seems this unique design requires the proper adjustment of an internal pot to work properly. I won’t go into the procedure for this because you can find it on Fender’s supplied schematic for this amp. If you have this adjusted properly, it may make your reverb a bit more useable, although I wouldn’t expect full reverb bliss from this frugal design.

Last and definitely not the least, I’d encourage you to change the speaker. The Tonemaster came stock with either a Celestion Vintage 30 or Celestion G12- 80, both of which would sound substantially different from the stock Fender blue-label speaker currently in your amp. I hope these suggestions make your amp a real Tone Champ!

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The 1968 360/12 pictured here has the features most often associated with classic Deluxe Rickenbacker models of the ’60s.


This stunning fireglo 1968 Rickenbacker 360/12 features a semi-hollow maple body with a single slash soundhole and a pair of “toaster” single-coils.

In the 1920s, Adolph Rickenbacker began a successful tool-and-die business in Los Angeles, and eventually his outfit began providing metal parts for various guitar companies, including National. Together with two former National employees—George Beauchamp and Paul Barth—Rickenbacker designed and marketed the first “Frying Pan” electrified lap-steel guitar.

F.C. Hall, owner of Radio & Television Equipment Co. (Radio-Tel) purchased the Electro String Company from Adolph Rickenbacker in 1953. Hall revamped the business and focused on electric standard guitars, rather than steels. These electric guitars were slow sellers at first, but they continued to increase in popularity as the 1950s progressed. In early 1954, German guitar maker Roger Rossmeisl was hired, and his unique “old world” designs gave Rickenbacker guitars a distinctive look that continues today.

The folk music trend of the early ’60s and its reliance on flattop 12-string guitars inspired Rickenbacker to fashion an electric 12-string in 1963. Although other companies (notably Gibson and Danelectro) had made earlier attempts, the Rickenbacker 12-string electric became the most sought-after because of its association with George Harrison. (He received the second one made in early 1964.)

The 1968 360/12 pictured here has the features most often associated with classic Deluxe Rickenbacker models of the ’60s. These include a bound maple neck, gloss finished rosewood fretboard with large triangle- shaped inlays, two “toaster” single-coil pickups, a maple body with checkerboard binding on the back, a slash soundhole, and a distinctive “R” tailpiece.


Rickenbacker’s innovative tuner arrangement allows for a smaller headstock and also reduces tuning confusion—tuners for the six standard strings are mounted on the side of the headstock, while the tuners for the octave and doubled top strings are mounted on the back. RIGHT: The rear-mounted tuners for the doubled top and octave strings.

This example has a deep, unfaded version of Rickenbacker’s most popular color—fireglo. The 1966 list price was $524.50. The current value for one in excellent all-original condition is $5,000.

The exact model name of the amp behind the guitar is unknown to us. It resembles the description in the 1957 Rickenbacker catalog of a Model M-11A. It is equipped with tremolo and a Jensen 12" speaker dating to 1968. The current value for the amp is $400.


LEFT: Rickenbacker’s distinctive tailpiece. RIGHT: The maple back sports checkerboard binding.

Sources for this article include Rickenbacker Electric 12-String: The Story of the Guitars, the Music, and the Great Players by Tony Bacon, Rickenbacker by Richard R. Smith, and The Rickenbacker Book: A Complete History of Rickenbacker Electric by Tony Bacon and Paul Day. If you’re into chimey 12-string sounds, you’ll enjoy exploring any of these well-researched, lavishly illustrated books.

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