Models
The Selective range
Installation amplifiers built for the same job: driving architectural and invisible loudspeakers from a rack, a cupboard or a shelf, and being configured by whoever is standing in front of them.
- Models
- One
- Chassis
- Half-rack 1U
- Output
- Lo-Z and 70 / 100 V
Current models
SD125.4
Four channels at 125 W, or two 70/100 V lines at 250 W, in a half-rack 1U chassis.
| Output, 4 Ω / 8 Ω | 125 W × 4 |
|---|---|
| 70 / 100 V line | 250 W × 2 |
| Total system power | 500 W |
| Chassis | 1U half-rack |
Common to the range
Lo-Z and 70/100 V from one chassis
Low-impedance channels and constant-voltage lines out of the same unit, with no external transformer between them.
Automatic, across each channel pair
Spare power moves to the channel asking for it, on demand, with nothing for the installer to set.
Set up over the amplifier’s own Wi-Fi
The unit hosts its own access point and interface. No app to install, no cloud account, no laptop required on site.
Half-rack 1U
Two units side by side in a 19 inch rack, or one on a shelf, with rack ears and mounting plates supplied.
Planning an installation
Today the range is the SD125.4, so the practical points below are its own, taken from its user manual.
Sources arrive on RCA phono and Euroblock connectors, with a stereo S/PDIF digital input and a stereo S/PDIF output for daisy-chaining. The amplifier joins the network over RJ45 Ethernet or Wi-Fi, and a GPIO Euroblock connector exposes some of its functions to external control.
Output is either four low-impedance channels, each driving 4 Ω to 16 Ω at 125 W, or two constant-voltage lines at 250 W for 70 V or 100 V distribution — no external transformer in between. Channels 1 and 2 share the supply, as do channels 3 and 4, and in 100 V mode the line runs at −1 dB, about 90 V.
There is no power switch: the unit is operational as soon as mains is connected. It draws 150 W in use and under 0.6 W in standby, and wakes on signal, on a network command or on a 12 V trigger. It is fan-cooled, with the fan off in standby, so allow 80 mm of clearance to the ventilated faces. It is rated for indoor use from 0 to 40 °C, below 2000 m.
Every published figure is on the specifications page; wiring and cable gauges are in the documentation.
Specifying a system?
Selective Amplifiers are sold through custom-installation dealers and specifiers. Tell us the zones, the speaker types, and whether the runs are low impedance or 100 V, and we will confirm the configuration.