Rane AD 22B

The Rane AD 22B is a two-channel audio delay in a single rack space, made by Rane Corporation. It belongs to the world of installed and live sound rather than the delay pedal on a pedalboard: instead of stompbox knobs it has a five-digit LED display, push buttons and rear-panel XLRs, and its job is precise time alignment, delaying each channel independently in steps as fine as 10 microseconds¹.

Rane built the AD 22 family for installers who need to align speakers in rooms, and the AD 22B is the balanced-XLR version of the design. It can run as two independent delay channels, as a stereo pair, or be jumpered internally into a mono configuration with double the delay range²³.

What it does

Each channel of the AD 22B delays an audio signal by an amount you set on the front panel. The two channels can operate independently, or the unit can be treated as a stereo pair edited together. Internally, three jumpers reconfigure it as a Mono device with twice the normal delay, 655.34 milliseconds; in that mode the Channel 2 Input and Output connectors go unused, the CHAN button is disabled, and Channel 2 sits in Bypass with its BYPASS button disabled².

On power-up the display reports the software revision level and the internal Stereo/Mono configuration, shown as "2CHAN" for Stereo and "1CHAN" for Mono².

Display, sensitivity and memories

The heart of the front panel is a five-digit LED display showing the current delay value for the selected channel, or the smaller of the two values when both channels are selected².

Delay increments are always in 1 millisecond and 10 microsecond steps, regardless of the display mode, so switching to feet or meters changes only what you read, not the resolution of the adjustment².

The feet and meters readings depend on the speed of sound, so the AD 22B includes a temperature setting. It is factory set for 22°C (71.6°F) and adjustable in 1°C steps (or 1.8°F steps); the 1 ms/Coarse buttons display Celsius and the 10 µsec/Fine buttons display Fahrenheit. The setting is used with a constant 30% humidity to calculate the speed of sound for converting delay times into distance. Changing the temperature changes the displayed distance values only, not the actual delay times²³.

Each channel holds two nonvolatile Memories, A and B, so a setting survives power cycles and can be swapped at the push of the RECALL button².

Bypass

The AD 22B passes audio while it is unpowered by virtue of its fail-safe bypass relays; when a channel is Bypassed it functions like a wire². One detail worth knowing for installed use: the default setting of the internal jumpers disables Bypass in Front Panel Lockout mode, a mode intended to keep hands off the settings once a system is tuned³.

Connections and grounding

The Inputs and Outputs are electronically balanced, using balanced XLRs with pin 2 hot per AES standards, and shields on pin 1 connect to chassis ground. Rane's manual is direct about wiring: use only balanced wiring².

Because the unit does not get chassis ground through its AC cord, a #6-32 screw and toothed washer is provided on the rear as a chassis ground point for systems that need one².

Power

The AD 22B uses an 18 volt AC center-tapped transformer only, fed to the POWER input connector. Rane specifies a model RS 1 or another remote AC power supply approved by Rane, and the manual notes the connector is an AC input, not a telephone jack².

The 230 VAC model carries CE marking under the EMC directive 89/336/EEC, and the 230 VAC supply meets LVD 73/23/EEC³.

Where it sits in Rane's delay line

Rane made several versions of this design. The AD 22B is the balanced-XLR model; the AD 22 used screw terminals on its inputs, preferring #6 spade connectors, with balanced line drivers on its outputs. Rane also built the earlier Rane AD 13, a single-channel delay with a 0 to 655 ms range and 20 microsecond or 1 millisecond steps toggled by holding the INCREASE or DECREASE button and tapping CHANNEL SELECT⁶². The AD 22B's 10 microsecond fine steps and its feet/meters display are the refinements over that earlier unit.

Questions