


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.
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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.
Permalink: Advanced Audio Microphones CM-28
Specifications
Compatible Capsules | ||||||||
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Pads & Filters | Impedance | SPL/Noise |
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200 Ohms (Low) | Max SPL: 135 dB Self-noise: 18.0 dB(A) |
Weight | Length | Max Diameter | Interface(s) |
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119g (4.20oz) | 140mm (5.51'') | 21mm (0.83'') |
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Power Specifications |
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