Download Example 1
Smooth Tremolo
Download Example 2
Fast Harmonic Vibrato-Stereo
Download Example 3
Slow Harmonic Vibrato-Stereo
Clips recorded with Anderson Cobra Special-S and Clark Beaufort and Allen Old Flame (for stereo). No other effects.
Holding this compact light green box in my hand, I have to ask the age-old question: “What makes this little tremolo box different from all other little tremolo boxes?” Scanning the top panel from left to right and top to bottom, the answer appears immediately. The first control encountered is a mini-toggle Mode switch that toggles between Tremolo and Harmonic Vibrato. I don’t recall ever seeing another pedal with this term. So, you may ask, wha’sup with harmonic vibrato?

Back to the Future
To answer that question, we need to take the time machine back about half a century to sleepy (at the time) Southern California. The folks at Fender have been cranking out amps for several years now and are sitting pretty atop the pro market. There are other small companies such as Standel, Carvin, Valco and Danelectro vying for market share and special niches. One of these companies is the Magna Amplifier Co. They have a brilliant engineer who has developed not a tremolo but a true vibrato which is making waves (pun intended) in the marketplace. They have an artist in their stable named Lonnie Mack who is topping the charts with superb guitar instrumentals and a distinctive sound never heard before, and Robert Ward has brought that sound to the Blues airwaves. They have definitely attracted the attention of Leo Fender.

Magnatone amps are heavy, expensive, and volume challenged, but they are selling; they also have a patent application pending for their vibrato system (later granted). Fender engineers try to meet the challenge with a tremolo system they call “Harmonic Vibrato.” Yes, it is a tremolo system misnamed by Fender as a vibrato, but it is broadly welcomed along with the new “Brownface” front panel controls, white/brown Tolex covering, and new circuitry. By general consensus, it sounds great, but does require a lot of new circuitry and expense. Is it worth it?

History shows the harmonic vibrato going away along with the Magnatone amp at the advent of outboard effects pedals. Interestingly, no commercial stompbox has ever really duplicated the Magnatone sound, though many have tried.

Wobbly Tone 101
To understand this better, let’s explore the difference between tremolo, vibrato, and harmonic vibrato. Tremolo is amplitude modulation—louder and softer, as in taking your pinkie and pulsing the volume control on your guitar. Vibrato is frequency modulation, as in wiggling the whammy bar (known correctly as a vibrato bar), changing the frequency of the sounded tone. “Harmonic Vibrato” is purely an electronic construct in which the preamp signal is split into high and low frequency bands, run through a phase inverter, which puts the two bands out of phase, an oscillator to add the pulse, and then usually recombines them into one signal.

However, one of the other major distinguishing features of the Pipeline is that after phase inversion the high-frequency band and low-frequency band may be split into a “stereo” output, i.e., each band has a separate out which may be routed to separate amps. Each amp will enable separate control of the two bands. Great design for the true tremolo lover.