Like large-diaphragm condensers, tube microphones have migrated from the realm of the prohibitively expensive to the modestly priced. Tube mics add even-order harmonics to the audio signal, which, though subtle, deliver a coveted warmth and richness that most solid-state, large-diaphragm condensers can’t match.

AKG has added modern convenience and control to their low-cost tube mic, the Perception 820 Tube ($849.00 MSRP). As the flagship of the Perception line (which includes the P 170 ($279.95) small-diaphragm “pencil” condenser, and the P 120 ($229.95), P 220 ($349.95), and P 420 ($579.95) large-diaphragm models), the Perception 820 is an excellent performer that can be the first-call mic on many kinds of projects, as well as play a specific role in a first-class mic closet.

The Perception 820 Tube has a frequency response of 20 Hz to 20 kHz (±5 dB), and its ability to handle sound pressure levels (SPLs) of up to 155 dB (with the pad engaged) makes it a modern, multifunction tube mic: It can handle chores such as recording drums and guitar amps—traditionally, jobs for dynamic mics—as easily as it does vocals and acoustic instruments.

Look and Feel
The Perception 820 Tube comes in a slick package with everything you need to use the mic anywhere in the world: a black and silver road case that houses a snug, foam interior with cutouts for the mic; a top-shelf spider mount; a 50-foot, 7-pin audio/control cable; and two IEC power cables—one each for 110–120V (US) and 210–240V (European) use. The users manual offers a range of practical recording tips, such as miking up strings, winds, piano, and percussion.

The long audio/control cable connects the Perception 820 Tube to a book-sized control unit, which you then connect to your mixer or audio interface with a standard XLR mic cable (see Fig. 1). The brushed-aluminum controller has a blue power-indicator, mini toggle switches for the 80 Hz rolloff (12 dB/octave) and the –20 dB pad, and a stepped, pattern-control knob that selects omni, cardioid, figure-8, or any of six intermediate patterns. Omni is selected in the fully counter-clockwise position. Rotating the knob clockwise takes you through three detented positions before reaching cardioid at the top, and then three hypercardioid stops on the way to figure-8 at bottom right. The rear of the unit has a 7-pin input connector for the audio/control cable, an XLR output, a ground lift switch, a voltage selector switch, and a power-cable receptacle.

Fig. 1: The control box allows you change the mic’s polar pattern, as well as engage the pad and high-pass switches, remotely.

The mic, itself, features dual 1-inch capsules and comes with an ECC 83 dual-triode tube, which you can replace with the widely available 12AX7 tube (see Fig. 2). Once you’ve connected the mic to its shock mount, all signal adjustments are made on the remote control unit, so the 50-foot cable is an important accessory in letting the engineer choose the best audio setting in the monitoring area, while the singer can adjust the mic physically to his or her heart’s content in the performance area. (If you have only an XLR box between your live room and control room, you may need to run the 7-pin cable under or around a door.)

Getting Connected
Like other tube mics, setting up the Perception 820 Tube is not an immediate plug-and-perform process. As with any piece of tube-based gear, a tube mic needs to warm up to function properly. With your output gain or monitor level set low, it’s best to connect the Perception 820 Tube to the control unit, then the control unit to the mixing board before connecting to the power source. Once everything is properly connected and powered up, you can slowly raise your input and output levels to test the mic.

Fig. 2: A peek at the inside of the Perception 820 from the maintenance manual, showing the position of the tube.

The Perception 820 Tube control unit gave me a brief bit of concern when I first turned it on. Its power indicator is designed not to glow until the “heating voltage” reaches a specified level. Consequently, the blue glow appears about 10 seconds after you hit the power switch, then you need to wait another 20 seconds before actually using the mic. In practice, it’s not a big deal to turn on the control unit as you’re powering up other studio devices or while the singers or musicians are warming up.

Once the mic’s tube had warmed for about 30 minutes, I set it up for some voiceover and acoustic guitar work connecting the control unit to my Mackie Onyx 1220 while monitoring through a pair of KRK Rokit 6’s. Weighing just under two pounds, the Perception 820 Tube has a hefty, professional feel to it: the connectors are solid and snug, the shock mount is excellent (with two extra spider bands included in the case), and the mount attached easily to the mic stand and to the mic. It was great not having to handle the mic while switching between the various polar patterns.

Sonic Perceptions
To audition the Perception 820 Tube, I set the unit’s pattern selector to cardioid and began a standard vocal test. It sounded crisp but seemed to be missing some low-end depth, especially for a tube condenser. Then I noticed the pad was engaged on the control unit. I switched it to the flat position and the monitors filled with the low-end richness you’d expect from a tube mic, but with that AKG flavor—what I always think of as the slight bite you characteristically get from the company’s C 414 models when A-B’d with, say, a Neumann U-87. The Perception 820 maintained a flatter response, with less bass and less proximity effect, than other tube mics have in my studio under similar conditions.

The sound made me think the mic would be great for boomy vocalists or acoustic guitars that needed a lot of EQ tweaking with other tube mics. It would also be useful on male vocalists with deep voices, and it should be great for overheads on drum sessions—any recording job where a little crispness and bass control are called for, but without losing low-end definition.

A view of the Perception 820 Tube's control module's back panel.

I liked how it captured the sound on my acoustic guitar—a Martin D-15 with a mahogany top—especially when recorded with full band tracks. I don’t need any bass frequencies from the guitar in this type of situation, as I would in a solo acoustic-guitar recording, and the Perception 820 Tube allowed the natural crispness of the D-15 to come through. I usually prefer a large-diaphragm condenser with a bit more bass response for this guitar, which is naturally thinner sounding than many dreadnoughts. A decades old Gibson knockoff I have also sounded great when recorded with the Perception 820 Tube.

I also took the mic to a pro session at a friend’s studio in New York, and the Perception 820 Tube was the hit of the date. A growling rock vocalist was coming off muddy with the studio’s condensers, and they were going to resort to recording with a Shure SM58 to let the singer approximate his live style. (They had decided to record the band and vocalist at the same time.) But once they auditioned the Perception 820 Tube, they knew they had found the right mic.

The Perception 820 Tube’s excellent SPL handling let the singer wail, while the band blasted away. After trying various polar-pattern settings, the engineer decided the straight cardioid pattern was best. The recorded vocal maintained more high-end nuance than they would have gotten with the dynamic mic.

Tube Terrific
The Perception 820 Tube is a terrific value and easily competes with tube mics costing hundreds more. It may not be best for every session, but you’d be hard pressed to find a more versatile mic with this quality and in this price range.

The Perception 820 Tube can handle everything from the subtleties of rich acoustic instruments to the not-so-subtle expressions of rock singers, drummers, and guitar players. Don’t even think of buying a solid-state large-diaphragm condenser mic in this price range without checking out a Perception 820.

Pros: Solidly built. Nine polar patterns. Remote switching capability. Nice sound quality.

Cons: No stand-by switch.

Rusty Cutchin is a producer, engineer, and music journalist in the New York City area.