Hands-On Review:Ampeg J20 Jet Guitar Combo
Vintage tube tone in an attractive, affordable package
By Mike Fitch
Musician’s Friend Staff Writer
As a guitar player who’s also a huge digital technology freak, I’ve heard some impressive digital vintage amp models over the last several years. But when it comes to tube amplifier tone, as the song said, “ain’t nothing like the real thing.” Until recently, finding an authentic tube amp meant tracking down a heavily-used vintage box or paying top dollar for a large British-type combo that sounds great but is too loud for most real-world venues.
The Ampeg J20 Jet Guitar Combo is for those who prefer the genuine article—a point-to-point hand-wired, all-tube amplifier that brings back the power and fun saturation that filled the airwaves in the glory days of vintage rock and soul. And it delivers those tasty tones at a comfortable volume that won’t send your audience running for the exits, especially in the small-to-medium clubs in which you’ll find the average working player gigging at most weekends.
The J20 Jet is a straightforward 20-watt, class AB combo amplifier with tremolo, a single 12" speaker, plus an included footswitch for turning the tremolo on and off. The Jet’s design evokes the 5E3 circuitry found in a range of classic amplifiers manufactured some thirty to forty years ago, but provides more headroom for a better, more coherent sound.
The J20 shares the characteristic blue-checked retro appearance found on the rest of Ampeg’s Diamond Blue Amplifier Series, a look that originates from the classic Ampeg amps of the ’60s. The J20 harkens back to an earlier age when the average guy could be his own car mechanic, beats were played instead of “programmed,” and amps had simple controls that didn’t take a computer engineer to understand.
If you remove the back panel from the J20, you will discover something missing that’s usually ubiquitous in amplifiers today—a circuit board. That’s because, rather than using integrated circuits, the J-20’s “point-to-point” wiring is soldered by hand in a labor-intensive process that’s usually found only in very pricey boutique amplifiers.
First I plugged my dual-humbucker guitar into the normal input on the J20, and turned the volume up about 1/4. The sound immediately hit me as very tight and clean, with none of the annoying fraction-of-a-second delay one sometimes hears in an amp. And the sucker is LOUD given its relatively modest size and wattage. The in-your-face tone brought to mind Booker T & the MGs, Steve Cropper, Muscle Shoals, Stax, Motown, and other classic ’60s rock and soul guitar sounds. I found myself inexorably drawn to playing the scratchy funk rhythms and rumbling rock chords that seem to come so naturally to the J20.
When I turned it up halfway, the tube compression kicked in for a pleasing vintage crunch, but the tone kept its integrity and didn’t start to disintegrate as sometimes happens with inferior amps—a credit to the quality of the 12" alnico speaker that pumps out the J20’s sound.
The other “bright” input gave the sound an edge that cut like a freshly sharpened machete. Most players would generally opt for the normal input, although jazzers who play large, hollowbody electrics would doubtless find the bright input useful for getting a harder-edged sound.
To hear how it handled a more high-gain distorted sound, I plugged in my overdrive pedal. The tone retained its brightness and presence well, even when I cranked the distortion to a level verging on anarchy.
The J20’s single onboard effect is tremolo, and it’s a nicely done modulation accomplished without using the modern shortcut of photo resisters. There’s a satisfying depth to the oscillation. Rate and depth controls allow you to dial-in the variety of tremolo you desire, ranging from Dick Dale-style surf to spaghetti western. Overall the effect gets high marks and its inclusion is very much in keeping with the amp’s vibe and performance.
Three distinct types of tubes are built into the J20’s architecture, including three 12AX7 preamp tubes, two 6V6s operating in fixed-bias mode, plus a 5AR4 rectifier tube. The power configuration closely resembles that of the classic tube amplifiers of the ’60s and ’70s. All this tube power creates more volume than the 20-watt specs would lead you to expect—I seldom find myself turning the volume up halfway, even while performing with my electric blues band, which gets pretty loud.
An external speaker output jack gives you the option of running an external cabinet, and those who want greater coverage for larger rooms might want to take advantage of this option. Another strategy would be to buy a pair of J20s and run both of them with an audio splitter.
Volume and tone control knobs of the classic “stove-top” design make dialing in your desired sound and amount of edge a piece of cake.
Get amped up
If you’re looking for a small combo amp that delivers powerful, clean, and authentic tube sound that’s dressed down in an attractively retro package with undeniable stage presence, you’ll definitely want to check out the Ampeg J20. The sound is full, brilliant, and maintains its tonal integrity and focus when you pump up the volume. The handmade construction techniques give it the authority of a meticulously well-made object. Easily fitting into the back seat of a compact car, and at 25 pounds presenting no problem to haul around, the J20 should find itself a niche among club date guitarists. For the vintage-tone loving rock, jazz, blues, funk, or soul player, the sound alone should make owning the J20 a very attractive proposition.
Features & Specs
- RMS Power Output:
- 15W (Cathode bias) 20W (Fixed bias)
- Class AB Speaker: 1 x 12" alnico
- Preamp tubes: (3 x 12AX7)
- Power Amp tubes: (2 x 6V6)
- Rectifier Tube: (5AR4)
- Controls: Volume, Tone
- Effects: Bias-vary Tremolo
- Footswitch: Tremolo On/Off
- Speaker Output: 1/4" jack
- 20W" x 17-1/2"H x 9-3/4"D
- Weight: 25 lbs.