Euphonic Audio iAMP

While most manufacturers of Class D amps keep their products’ weight and cost at a minimum by employing a switching power supply, the designers at Euphonic Audio believe that a conventional linear power supply with a toroidal power transformer yields better sound-a smoother, fuller tone without brittle midrange. To wit, in the realm of high-fidelity instrument amplification, Euphonic Audio stands out from the rest of the pack. The company’s pursuit for perfect tone that has led it to create what may well be the best-sounding Class D amps on the market, if not the most lightweight.

Bassists are the target market for EA’s iAMP-200 head unit, but I was pleasantly surprised to hear how great my archtop guitar sounded through it. The 200 can be paired with any speaker cabinet, including EA’s own WZ112 Wizzy or WZ112P powered cabinet, by way of a link output. Both of those four-ohm cabinets get the full 200 watts from the iAMP-200. Plugging the iAMP-200 into my eight-ohm cabinet yielded 165 watts, more than enough for most jazz guitarists. If headroom is an issue, EA also offers the iAMP-500 and iAMP-800, which are slightly heavier but plenty powerful. The iAMP heads range from eight-and-a-half to 19 pounds, and each occupies three spaces in a rack setup to insure proper ventilation. Guitarists would want to add a reverb unit to the rack and then pair it with a small cabinet, making a great-sounding portable amp.

I brought the iAMP-200 to a weekly gig in a “difficult” room with high ceilings and hard surfaces. With previous amps I could control which input I plugged into and had treble, bass and midrange pots at my command. Some of these amps had bright switches, notch filters and special “sonic circuits.” I even tried outboard EQ boxes, and often I could improve the sound in this particular room, but I was seldom ever completely happy with it. Things were looking up after hearing the sound of the iAMP in this environment-and the EQ was set completely flat. Finally I conquered the room’s acoustic obstacles with only a few strategic turns of the iAMP’s parametric EQ.

That EQ is part of a tone-shaping section that’s the same across all three amps in the iAMP line. In addition to the four-band parametric EQ there are four presets: Deep, Contour I and II, and Bright. You can choose to keep all controls flat and use only presets, or mix the presets with a bit of EQ tweaking. Designed with the most exacting musician in mind, this has to be the most detailed amp EQ on the market. But that’s not to say it’s difficult to operate. To get a newbie started, the operating manual offers two favorite settings: Fat Tube, which gives this solid state amp a warm, tube-like tone; and the Jaco setting, which adds a bit more midrange growl.

In addition to the iAMP-200, I tested EA’s iAMP-500C combo amp. With the EQ set flat I was able to get a nice tone from acoustic and electric bass, archtop guitar and keyboards-and with just a little bit of fine-tuning I achieved a perfect balance in tone. In a group setting, I made minor tone adjustments and found that the 500C allowed all instruments to cut through nicely and remain balanced in all registers. What stood out were individual notes in the chords I played. Each had great definition, sounded “round” and hit with a punch along the full spectrum. This amp’s low end is particularly stunning. EA believes that that’s due in part to its transmission-line cabinets. As the EA Web site states, “in a transmission line, the sound wave from the back of the woofer is channeled down a long pathway filled with a fibrous bundle of wool or another synthetic material. Transmission-line cabinets can be designed to have a smoother and more extended low-frequency output than a corresponding vented enclosure given the same internal volume.”

Another contributing factor to the 500C’s ultra-high fidelity is its use of a dual cone system. The Wizzy’s 12-inch driver and “Whizzer” cone produce both low and high frequency signals from a single voice coil. Aside from its sound-enhancing features, the 44-pound combo has a front-panel output section with a variety of great features including a tuner jack, headphone jack, a DI output level, an output clip LED, a power amp level adjustment and an XLR output plug that’ll please many a recording engineer and soundman. The designers at EA have responded to musicians’ needs and concerns-the combo also sports a tilt-back handle on its bottom surface-and have also taught musicians a few things about what should go into a high-end amplification system.

There will no doubt be musicians who will look at all of the knobs and sliders on the iAMP and opt out. But for many others having this much control over an amplified sound is where it’s at. Tone is in the hands of the player, and the iAMP will accurately reproduce the sound of an instrument with ample tone-shaping possibilities far beyond the scope of most other amps.

Originally Published September 1, 2005