FIG. 1: Blue's Robbie mic pre offers a unique design that limits front-panel features to a large gain control and single instrument input, along with a window to the unit's ECC88 twin triode tube.
Blue Microphones has always attracted attention with its splashy industrial designs. Products such as the Ball-series dynamics and the Mouse and Dragonfly mics, which sport rotating capsules, are eye-catchers. The company recently expanded into signal processing and developed its first product — a tube mic preamp called Robbie — that also serves as a DI (see Fig. 1). Robbie's features are basic: a single XLR input and output; a power switch; and buttons for mic or DI use, phase reverse, a -20 dB pad, and 48V phantom power. The front panel has only a ¼-inch instrument input and a big gain-control knob. Robbie's design upholds Blue's reputation for producing products with visual flair. As for the sound, the emphasis is on loads of gain and extreme clarity.
Look and Feel
The Robbie preamp is an homage to Robby the robot from the sci-fi classic Forbidden Planet (the preamp's logo is a caricature of the legendary bot), and Robbie's chassis reflects the curvaceous legacy of '50s-era design. Blue's stated design goal is elegance in appearance and simplicity of use. The preamp's chassis has semicircular sides, which enhance the look of the two main features of the front panel: an oversized chrome potentiometer and a transparent round turret that juts out from the surface. Robbie's ECC88 twin triode tube is housed in this turret, as is a spring that spirals around the tube.
A blue light emanating from behind the front panel surrounds the two front cylinders. The pot's range markers are regularly spaced translucent circles that produce more soft blue light. On our review unit's pot, another smaller blue light glowed when Robbie reached unity gain. According to Blue, however, this light has caused some confusion with customers and is being eliminated from future production runs. The preamp's tube also glows in its turret.
The more I used Robbie, however, the more I felt that the space taken up by the large front-panel cylinders could have been allotted for the switches and connectors, all of which (except for the DI jack) are shunted to the rear panel (see Fig. 2). That won't be a major hassle if you set Robbie on a tabletop, but it's a case of form trumping ergonomic function. For $25, Blue offers a rackmount adapter plate, but a rackmounted Robbie (with its rearmounted switches) would be difficult to fully adjust unless it was on a sliding rack tray. Robbie is also somewhat of a space hog; although it's a half-rackspace unit, it's 3U in height.
Robbie's chassis is set on a circular metal ring with threaded holes for the rackmount adapter screws. The ringed base encompasses slightly more than half of the chassis's total area. That could affect the unit's stability when it's placed on an unusually unlevel surface or if another unit is stacked on top.
Loud and Clear
Robbie's preamp is a Class A discrete tube design that uses high-quality metal film resistors and polystyrene capacitors to lower self-noise and distortion. The attention to detail pays off; you'd have to work at it to make Robbie sound bad.
FIG. 2: Robbie's rear panel houses a power switch and buttons for selecting mic or DI mode, phase reverse,20dB pad, and 48V phantom power.
I first used Robbie in tandem with a Blue Bluebird as a close mic on a Martin dreadnought acoustic guitar. With the Bluebird positioned a foot away, finding an optimal playing position was tricky. Minute changes in position yielded dramatic differences in the sound, perhaps attributable to the Bluebird's response pattern. For a close-mic setup, Robbie's sound was very clear once I located the sweet spot (placing the mic at the eighth fret pointing at a 30-degree angle toward the sound hole). Robbie provided exactly what I was looking for: a sound that was crisp but not overly bright and not too woofy. For some tracks, the guitar player wanted to be able to move around a bit, so I backed the mic off another foot or two. The differences in response to playing position changes decreased (and a bit more ambience crept in), while the clarity of the highs and lows remained even.
I had a matching pair of high-quality tube mics at my disposal during the testing period, enabling me to record male vocals with the same mic model through different preamps simultaneously. With levels matched, Robbie was a bit more compressed sounding, seemingly due to its big, clear low-end response. Without that extended low end, the solid-state pre was sensitive to the singer's every head bob and weave, while Robbie stabilized the audio.
I used a Shure SM57 with Robbie and was amazed; the difference Robbie made with that ubiquitous mic was huge. I compared it directly with another SM57 that was connected to one of my best solid-state pres. Both mics were placed in the same relative position on separate speakers of a 2 × 10 bass cab. Although each sounded good, Robbie would have been a better choice for a situation in which only one mic could be used. Robbie had a more natural and somewhat less electric sound. In addition, Robbie's sound was more like the sound coming from the cab than that of the solid-state pre. The difference was noticeable, and the blending of the two mics yielded an incredible sound.
Robbie produced natural-sounding electric and bass guitar sounds. In addition, Robbie helped effected sounds by taking the edge off the processed sound. That wasn't a by-product of a reduced high-frequency response; rather, it's a by-product of a better low end.
As a DI, Robbie provided clear, round, and even sound. It was much better on guitar than I would have expected (it didn't emphasize the sound's spikiness as do some other DIs). And with its great low-frequency response, Robbie sounded absolutely fantastic with a direct bass guitar. I was somewhat surprised while playing electric guitar, because the output was so strong (even stronger than the bass) that I had to employ the -20 dB pad. I'd have no problem using Robbie as a DI in most situations, and the preamp's portability makes it ideal for DI use.
Although I wasn't that attracted to Robbie's shape and layout, those issues may not be problems for many users. I wouldn't be inclined to rack Robbie; the shape lends itself to mobility. (Use both hands; the round sides are slippery.) The inclusion of great-sounding DI circuitry made me want to take it from the control room to the studio and back again as necessary. In the end, I was using it sideways. There's nothing helpful to look at on the front anyway; the knob on the pot is simple to operate; and I had visual and tactile access to the rear-panel stuff.
I wish Blue had used a stepped attenuator instead of the large-knob potentiometer. The unlabeled dots of light around the pot don't do much to aid repeat setups. One small knob and a ¼-inch jack accomplish same thing in a smaller space. On the other hand, dialing in a level is quick and easy.
What I personally prefer in this kind of device is a plain box with full control, easy access, and excellent sound quality. Ultimately, in evaluating a standalone preamp, good sound is the clincher. Robbie's sound is great, and anyone can appreciate that. If you also appreciate flashy design and don't mind reaching around back to get at some controls, then you'll enjoy working with Robbie.
Rich Wells oversees the Supreme Reality, a recording studio and band in Portland, Oregon.
||(1) balanced XLR (1) unbalanced ¼" inst.
||(1) balanced XLR
|Mic Input Impedance (20 Hz-20 kHz)
||5 kΩ (2 × 2.5 kΩ)
|Hi-Z Input Impedance
||8 dB-68 dB
|Frequency Response (±2 dB)
||10 Hz-100 kHz
|THD + Noise @ 60 dB gain (10 Hz-20 kHz, +22 dBu output)
|Maximum Input Level (8 dB gain, 20 Hz-20 kHz)
||+22 dBu w/o pad
|Maximum Output Level (20 Hz-40 kHz @ 10 k)
||50Ω (2 × 25Ω)
||+48 VDC, ±1.5 VDC
||8.25" (W) × 8.5" (L) × 5.25" (H)
BLUE MICROPHONES Robbie
tube mic pre
OVERALL RATING (1 THROUGH 5): 4
PROS: Great clarity and extended low end.
CONS: No meter. Controls relegated to rear panel.
Blue Microphones www.bluemic.com