iAMP 800 Review - Bass Player Online

Some bass-gear manufacturers stand out from the crowd by way of a characteristic sound-but Euphonic Audio wants to be the sonic equivalent of the Invisible Man. Its amp heads, not to mention its combo amps and cabinets (see sidebar), are designed to be as sonically transparent as possible, faithfully reproducing your instrument s sound with little or no coloration. The iAMP 800 is the latest and most powerful of EA s line of iAMP heads, which began with the original iAMP (500 watts into 4ohms, reviewed in February 00. At 19 pounds, it s also one of the lightest high-powered heads available.

The iAMP 800 got a visual facelift from the original iAMP s design, with better graphics and a sophisticated black-faced front panel. As on the original, the controls are laid out in five logical, well-labeled sections. The only thing that seems misplaced is the SPEAKER IN/OUT (mute) button, which is buried among the myriad TONE SHAPING controls. Staff opinions were mixed regarding the controls themselves; everyone loved the meaty, smooth-turning LEVEL and MAIN knobs, and the smaller knobs feel good as well-but some staffers thought the buttons and sliders felt chintzy. But "Chiclet"-style push buttons have been used on bass amps for many years, and manufacturers who use them report very few long-term durability problems. My only gripe with the 800 s push buttons is that it can be tough to tell if their positions are in or out. Pressing the DEEP, CONTOUR I, and CONTOUR II buttons (as well as TONE/FLAT) produced a slightly annoying click through the speakers, though the HI button was quiet. [Euphonic Audio responds: "The click happens because we don t use buffers, which would detract from the amp s hi-fi sound."]

The iAMP 800 uses a Class D digital power amplifier (see Bass Tech, February 02). Class D amps are highly efficient, which is why the iAMP 800 can operate without a fan; it generates little waste heat, so passive heat sinks are sufficient to keep its key components cool. However, while most Class D amps also use a switching power-supply, Euphonic Audio decided to go with a more conventional toroidal power transformer. Although this adds about ten pounds to the amp s relatively light weight, the benefit is more current reserve-and more current reserve means more headroom. In bass amplification good headroom is important in faithfully amplifying a signal-particularly at the attacks of notes, where waveforms voltage swings are the quickest and most extreme.

Power rating: 500 watts RMS into 8 ohms; 800 watts RMS into 4 ohms; 1,000 watts RMS into 2 ohms

Frequency response: 20Hz-20kHz ± 3dB

Front-panel jacks: ACTIVE and PASSIVE 1/4" inputs, 1/8" STEREO IN, 1/4" TUNER out, 1/4" PHONES out, XLR DI out, 1/4" EFFECTS SEND and RETURN

Rear-panel jacks: Two Speakon outs

Tone controls: LO (±15dB @ 40Hz-180Hz w/TONE/FLAT switch), LO-MID (±15dB @ 180Hz-1kHz w/1 OCTAVE or 1/2 octave Q switch), HI-MID (±15dB @ 880Hz-8kHz w/1 OCTAVE or 1/2 octave Q switch), and HI (±15dB @ 1kHz-8kHz) semi-parametric EQ sections; DEEP, CONTOUR I, CONTOUR II, and BRIGHT switches

Other controls: Input LEVEL knob, STEREO IN level knob, SPEAKER ON/OFF switch, MAIN volume knob, effect-loop LEVEL knob, DI level knob, DI ON/OFF and PRE/POST EQ switches, TUNER ON/OFF switch, 110V/220V voltage-selector switch (rear panel)

Option: Jensen JT-11-DMCF transformer (£ POA)
Dimensions: 19" x 3w" x 10q" (2U)
Weight: 19 lbs (8.6 kg)

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Made in: U.S.A.
Warranty: Three years limited (transferable)

I like Euphonic s unique semiparametric EQ layout. Instead of using two knobs per frequency region, EA uses a more intuitive upward-slanting slider to determine each region s center frequency. The EQ is highly musical and useful. My favorite control was LO-MID; a small boost around 350Hz results in intense presence and note definition, without necessarily sounding like an EQ boost. The two mid regions also have bandwidth switches (one or one-half octave). You ll likely leave these controls in one position, depending on your tone-shaping taste. Both of the CONTOUR buttons subtly remove midrange "honk" and add muscular bottom; CONTOUR II is voiced with more edge, while CONTOUR I has more low-mid heft.

Another handy feature is the STEREO IN jack and level knob, which lets you plug in an external audio source and play along. Onstage you could also plug a sampler, DAT machine, or even a keyboard mix into this input if you re also saddled with non-bass duties. The effect-loop and DI sections are full-featured. No ground-lift switch? Actually, the 800 s DI is permanently ground-lifted; at user request, EA replaced the original iAMP s ground-lift switch with the 800 s DI ON/OFF switch. As an option EA offers a Jensen transformer that electrically isolates the DI completely, eliminating the possibility of ground-loop-induced hum.

I Think, Therefore iAMP
Since Euphonic Audio aims for sonic transparency with its amps, I wanted to test the iAMP 800 with a bass whose sound I know intimately. I used my Atlansia Stealth 4-string, which I ve been recording with (usually direct) for the past 12 years. I tried the head with a Euphonic Audio CxL112 1x12, Aguilar GS412 4x12, Bergantino NV610 6x10, Hartke 4200 4x10, and an Epifani T-410UL 4x10. Through the Euphonic, Aguilar, and Bergantino cabs (with the iAMP s EQ flat), it was great to hear my bass s direct sound amplified so loudly and faithfully. Through the tweeterless Bergantino my month-old strings sounded a bit lifeless; a tweak of the iAMP s tone controls helped inject presence into my sound. The iAMP s power is exceptionally robust: Even cranked really loud, it never sounded like it was flinching. Some staffers thought the amp sounded a little dry with the EQ flat-not surprising for a hi-fi solid-state circuit-although it faithfully represented every bass we tried. The powerful EQ was useful for warming up the sound or bringing out particular tone colors.

One staffer tried the 800 on his New Orleans-style swamp-funk gig with Aguilar GS112 and Bergantino HT322 cabs. The amp sounded very quick and clean onstage. When he needed to tune between songs, since he was also sending a direct line to the house, he realized a bit too late that he had to hit the DI ON/OFF switch as well as SPEAKER ON/OFF. A single, better-placed mute switch (perhaps in addition to the other mutes) might be a user-friendly addition to the 800. [Euphonic Audio responds: "The separate DI and speaker mute switches are there only because users requested them."] Still, he loved the onboard Sabine tuner. The front panel tuner-out jack almost seems unnecessary; a back-panel jack might be better suited for players who wish to use their own rackmount tuner.

Considering its relatively low price, the iAmp 800 is packed with handy features and big power. But like almost every piece of gear, the iAMP 800 isn t for everyone: Without the versatile EQ engaged, the iAmp doesn t have a strong characteristic tone of its own, which some players prefer. The iAMP 800 is for players who believe a bass amp should be like a good bass player-it does its job well without calling attention to itself. Paired with the proper speaker cabinet, that s exactly what it ll do for you.

See also: EA iampWZ Combo / WZ-112P | WZ-112 passive cabinet | Bass Player Online