Anywhere you need...
- To Switch Line-Level Sources
- To Select Between Two Balanced Lines
- Silent Audio Switching
- Audio Switching for Audio Muting
- Fast Switching for Audio Muting
- Switching by Open-Collector Logic
APPLICATION: The ST-SSR1 is part of a group of products in the STICK-ON series from Radio Design Labs. The durable bottom adhesive permits quick, permanent mounting nearly anywhere, or use it with RDL's racking accessories. The ST-SSR1 offers the ultimate in totally solid state audio switching, with the big PLUS...you can put it right where you need it!
FUNCTIONAL DESCRIPTION: The ST-SSR1 has two line level audio inputs and a single line level audio output. In the absence of a control input, the NORMAL input feeds the module output. When the TRIG control terminal is pulled to ground, the SELECT input is switched to the output and the NORMAL output is switched off. When the TRIG terminal is again allowed to go HI, then the SELECT input is turned off and the NORMAL input is switched to the output. The module contains no mechanical relay. The audio inputs are applied to a low-noise preamplifier. The control circuits utilize solid state switching to apply either of these signals to a balanced line driver.
The ST-SSR1 has user-selectable switching rates. The module can be used in muting applications where audio must be switched off extremely fast. This could be required to prevent feedback in automatic microphone mixing installations. For muting, typically, an input would only be connected to the NORMAL input, and the ST-SSR1 would be used to turn this line OFF. In this mode, the audio off-time switching is accomplished in <100 µs. Although necessary in some circumstances, this fast a switching transition can appear harsh to the ear and would be undesirable where the module is being used to select inputs to a high power amplifier or in high quality studio applications. Installation of a jumper between the SOFT terminal and GROUND slows the switching transition by implementing a soft knee and ramping the audio to the ON or OFF condition. This still sounds INSTANT to the ear, but is slowed sufficiently to remove any unpleasant edge from the switch transition. For most applications, the module is used in the SOFT mode.
The control current required at the TRIG terminal is so minimal (0.5 mA) that the ST-SSR1 can be controlled from nearly any source...from switches to logic circuits. The TRIG input feeds a comparator which switches with a threshold of 2 volts, permitting open-collector switching, or switching directly from circuits operating from a 5 volt supply!
The exceptional low noise and low distortion performance of the ST-SSR1 makes it the ideal choice for noiseless line-level audio switching in both sound system or recording installations. Used in conjunction with other STICK-ON audio and control modules, the ST-SSR1 can be the foundation for many high quality, innovative audio systems!
Power supply is required.
