Juke Coda Amp

By Leon Chalnick

Intro
Dig that warm, clear, vintage amp tone? Do you like an amp that really responds to your hands and guitar volume knob? Are you into amps that include iconic features from amps of the 50s and 60s, like spring reverb, tremolo and pitch-shifting vibrato? Do you love lightweight, portable little amps…but only if they sound really big? If any of those qualities appeal to you, you’re going to absolutely love the Juke Coda.

If you’re somewhat familiar with small, “boutique” amplifier builders, you may have heard of Juke amps before. The proprietor, Gary Croteau, of Troy, New Hampshire, has been around making Juke amps for about 15 years and has been working on amps for…well…many, many years. It’s almost an understatement to say that Gary is very well versed in the designs popularized by Gibson, Ampeg, Fender, Magnatone, Valco and other American musical instrument amplifier companies. And the knowledge has been put to good use developing the Jukes’ unique circuits.

Technical and Design Features
The 1x12 combo amp that I reviewed came in a white pine cabinet, measuring 17½” tall by 22” wide by 10” deep. The cab is covered in some very attractive and sturdy-feeling red garnet / bronco type tolex, with eight black metal corner protectors. The 12” speaker is a Jensen Tornado (neodymium magnet) 12/100. The cab features a ⅜” birch-ply baffle with a sturdy, wicker cane grill “cloth” which I imagine helps tame some high-end frequencies.

The amp I reviewed runs on a pair of 5881s (though you can use 6L6s if you prefer). The Coda comes with a switch that allows you to change between pentode and triode operation of the power tubes. The amp can be built to run either fixed (Class AB) or cathode-biased (Class A) power tube configuration. With the Coda configured for cathode bias, it puts out 18W in pentode and 6W in triode. When configured for fixed bias, the amp puts out 30W in pentode and 10W in triode. (You can also order—at extra cost—a switch that enables you to switch between fixed and cathode-bias configuration.) While these features enable you to change the overall volume/performance level of the amp a bit, another benefit is that they allow you to change its personality and utility in different performance settings and for different instruments (e.g., harmonica).

The Coda is tube-rectified with a 5AR4. It utilizes two 12AX7s in the preamp, a 12AU7 for driving the reverb and for modulation, another 12AX7 for reverb recovery, a 12DW7 for oscillator and vibrato inversion and another 12AX7 for the phase inverter.

This is a very well-built amp. You note this quality in the perfect solder joints, ceramic tube sockets and immaculate workmanship. The reverb tank is tucked securely in a jacket held in place by screw. A thick elastic cord is provided to hold the AC cable and foot pedal in place when transporting the amp.

As I mentioned, the amp being reviewed is powered by a pair of 5881s but Juke will custom design/build the amp for you with other power tubes if you prefer (e.g., 7591, 6V6s or EL84s).

The Coda employs a long-tailed phase inverter circuit. The location of the master volume in the circuit can be modified so that it can be put before or after the phase inverter. (Gary can employ a variety of master volume designs based on the customer’s tonal predilections.)

The Coda's control panel faces forward and is well laid out and useful

The tremolo circuit uses pre-amp bias modulation, like in some old Gibsons and Fenders. The vibrato is similar to the Bonham-design made famous in Magnatones, though it is not identical. The Coda’s modulation circuit goes further than Bonham’s to isolate frequency modulation (FM) from the amplitude modulation (AM) that is part of this type of circuit. By providing separate knobs for amplitude and frequency modulation, you have more control over the balance of the two effects on your sound. And you can blend the AM and FM to achieve something very close to Magnatone-like vibrato.

The reverb circuit is very old-school—capacitor-driven. This is similar to the wonderful reverb that you find in some Magnatone and Ampeg models. It’s not the boingy, splashy style reverb we’re accustomed to hearing in Fender type reverb designs; it’s more subtle.

You can also order cabs with different size speakers or different configurations. Juke builds the Coda in 1x12, 2x10 and 1x15 cabs. Configured as this one is, it weighs in at an easily managed 36 lbs.

One thing that I cannot emphasize enough—and I know this matter a lot to some folks—this amp is one of the most finely built products I’ve ever seen. The attention to each and every detail is truly noteworthy—from the workmanship on the cabinet, tolex and baffles down to the quality of the circuit-board layout, parts and every solder joint. This is the second Juke amp I’ve gotten to inspect in detail and the workmanship is truly a thing of beauty.

Juke amps are sold direct at 30% off retail list. With the Jensen Tornado, the list price is $2,600.00 for either fixed or cathode bias. The up-charge for switchable biasing is $100.00. You can also order the amp cab in a two tone design for an up-charge of $75.00.

Player Features
The amp features some very useful and well thought-out old-time features. Like other Juke models, the Coda provides both tremolo and vibrato. As mentioned above, you can you use one or the other or simultaneously use both. The speed knob is very useful as well as it offers a wide range. You slow the modulation down quite a bit—notably slower than the Magnatones I’ve tried.

The spring reverb is controlled by 3 knobs – Color, Dwell and Depth – rather than just the typical depth control. Dwell drives the voltage to the springs thus allowing you to control the length of the reverberation. Color allows you to change the tone of the reverberations, darkening them a bit when turned counter-clockwise, taking some of the “sproingy” edge out. Depth controls the mix of reverberated to dry signal. It’s interesting to note that the reverb signal does not go through the vibrato; its circuit goes around the vibrato.

Closer to the front-end, you have Treble, Bass and Contour controls. They are all quite useful because they are not simple cut controls. Though they are not active, they do cut/boost the frequency at hand, like many old Ampegs and some Magnatones. So at 12:00, you’re getting the natural, un-eq’ed signal. Turn the knob down and you’re cutting; turn the knob up and you’re boosting.

The Contour control was influenced by some old stereo amplifiers; some may remember this type of control in a few old Gibson amps too. It’s really a kind of a midrange knob and has an easily identified impact on gain as well. When you turn it all the way counter-clockwise, you get a bit thinner, more scooped sound. When you push it up past 2:00 or so, you start hearing the gain come up and more of a midrange orientation. This knob is extremely useful in changing the amp’s personality.

Sounds
One thing I want to make very clear – while the amp has a lot of features, Gary has done an excellent job of keeping the amp simple to use and easy to dial in. Its basic tone is clear, pure and natural sounding, even with all these features.

The sound is very musical whether operating at very loud or very soft volume levels and anything from ultra-clean to very dirty distortion. You can get it sounding very tweedy by cranking up the Contour up, backing the Treble down a bit and leaving the Bass near flat. If you back the Bass down, you’ll find the low-end tightening up. Back down the Countour and you wind up with something closer to the Blackface sound.

In my experience, many guitarists are accustomed to playing with their tone knobs wide open. If you should try out a Coda, I would suggest that before you start playing; turn the tone knobs on your guitar down a little bit. The amp seems to be EQed with the assumption that you’ll do so. This is actually a logical idea if you think about it; it makes a bit more sense to set the amp a little brighter and back your tone knobs down—this way you have some “brightness headroom.” As I’m a fan of Gibson guitars from the 60s with T-Top humbuckers, I’ve learned to do this anyway.

The master volume (labeled Volume) is excellent and can be used to very effectively lower the volume without killing the feel of the amp. I found the amp remarkably responsive to changes in guitar volume and pick attack. Even with the Level (pre-amp gain) and the Contour dimed, the amp cleans up quite well from the volume knob on my Gibson ES-345 guitar. This is really the kind of amp that you can control from your guitar, freeing you to focus on your playing.

If overdrive, distortion or booster pedals are part of your sound, you’ll be equally happy with the Coda. It ate up everything I put in front of it – I had great luck with my Timmy, Ibanez Tube Screamer, Blues Breaker, Okko Diablo and MI Audio Crunch Box. My favorite is always the Diablo and this little Coda just ripped when paired with the Diablo. I was getting screaming harmonic feedback anywhere I wanted it. Click the pedal off and the little Coda’s glorious big, clean sound was equally enjoyable. It should be noted, however, that with humbuckers, you simply don’t need pedals to get some ripping harmonic feedback, as you’ll see in some of my video demos on YouTube.

(My third sound clip of the Coda features the amp with the Level all the way, Contour all the way up and the volume at about 3:00. I used a slight boost from a Bluesbreaker clone pedal as the amp was isolated in a separate, sound-proof room.)

And speaking of big sound, I have to say this is one of the fullest, biggest sounding little amps I’ve played. Considering its size and weight, it’s remarkable. The bass is very present but not boomy. If you want it looser, turn the bass up a little. If you want to tighten it up a bit, cut the knob back a bit.

I played extensively through the amp with a variety of guitars/pickups. I used a ‘68 ES-345, a John Mayer Stratocaster, a DeArmond M77t and a ’61 Epiphone Coronet with a dog-ear P90. The amp responded wonderfully with each of these guitars. I was amazed at how great the Strat sounded through the amp. With the Coda just about dimed, the bass and treble backed down a bit and Contour wide open, I was able to achieve an almost Marshall-esque Jeff-Beck-ish tone with no pedals. And if I put a pedal in front and turned the Level down a bit, I could easily push it into “Brittish screamer” territory.

As for gain levels and propensity for certain types of music, the Coda covers a lot of ground but is clearly not for everyone. It’s safe to say it was not designed for folks looking for a high-gain, modern sound. But it’ll put out a very hard-driving sound if you want it. There’s plenty of gain there for classic rock lovers and blues players. The amp’s basic clean tone is deep and gorgeous and has a really nice rubbery bounce to it which I think anyone who loves a great clean sound is really going to appreciate.

Clip 1 – a jazzy blues clip. The DeArmond M77T guitar was plugged straight into the amp. The reverb is the Coda’s onboard reverb.

Clip 2 – a blues rocker features a ’68 Les Paul Custom plugged straight into the amp.

Clip 3 – this clip features the Coda’s tremolo, with a wee bit of pitch modulation and reverb as well. The rhythm guitar is a Strat plugged straight in. The lead guitar is a Thorn Master Artisan with humbuckers. It was plugged into a Bluesbreaker clone pedal. There is some delay added in the mix on the lead guitar.

Summary

Gary Croteau has a real winner here. While this Juke Coda is loaded with some very thoughtfully-implemented features, its basic sound remains pure, exciting and familiar. It’s going to make a lot of people happy in terms of its performance capabilities and usability. The amp really covers a lot of tonal ground, yet it’s small, light and very portable, making it very, very practical. Without a doubt, one of the best sounding and most unique boutique offerings I’ve tried in many years.