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Advanced Audio Microphones CM-28

Detachable-Capsule Pencil Tube Condenser Microphone

The Advanced Audio CM28 is a small-diaphragm tube condenser with detachable capsules.

The CM28 ships with three capsules: Omni; Cardioid; Hypercardioid. A wide cardioid capsule is available separately.

The mic actually uses both vacuum tube and FET circuitry to optimize headroom and gain, see quote below.

Dave Thomas

Our circuit provides at least 6db more headroom than traditional fet/transformer circuits. We do this with a fet front end designed to capture all the detail of the capsule, which is then coupled into a 6J1b tube driving our BV11 transformer. This approach takes full advantage of a low noise fet circuit. The tube stage then needs to provide very little gain so it is configured as a Low Z driver. The tube provides the fet with a very high impedance load so the fet’s headroom can be maximized.

Switches on the mic body provide -15dB attenuation and LF rolloff (not specified). The mic attaches to the external power supply by 7-pin XLR.

Tape Op - 2011

The thing I keep realizing when using Advanced Audio’s mics, is that they are really well balanced. I never find any sonic anomalies in the response. This is again true with the CM-28.
…
Furthermore, the CM-28 does not display any of the “cheaper condenser zing” that can get so quickly tiring. It also doesn’t have quite as much top end as some SDCs that I’ve tried, but that is not to say that it is at all dull or lifeless.

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Specifications

Compatible Capsules

Advanced Audio Microphones CM-28 Cardioid Cardioid capsule Sensitivity: 14 mV/Pa CHARTFreq. Resp.: 20 - 20,000 Hz MSRP: $59 | Still In Production Advanced Audio Microphones CM-28 Hypercardioid Hypercardioid capsule Sensitivity: 14 mV/Pa CHARTFreq. Resp.: 20 - 20,000 Hz MSRP: $59 | Still In Production Advanced Audio Microphones CM-28 Omni Omnidirectional capsule Sensitivity: 14 mV/Pa CHARTFreq. Resp.: 20 - 20,000 Hz MSRP: $59 | Still In Production Advanced Audio Microphones CM-28 Wide Cardioid Wide Cardioid capsule Sensitivity: 14 mV/Pa Freq. Resp.: 20 - 20,000 Hz MSRP: $59 | Still In Production

Pads & Filters	Impedance	SPL/Noise
Pad: -15dB (Via Switch) Filter: LF Rolloff (Via Switch)	200 Ohms (Low)	Max SPL: 135 dB Self-noise: 18.0 dB(A)

Weight	Length	Max Diameter	Interface(s)
119g (4.20oz)	140mm (5.51'')	21mm (0.83'')	3-pin XLR male (1)

Power Specifications
Includes tube power supply

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