Set Stage 12’s Split Output to Patch back into Stage 1’s External Input. Set Stages 2-11 to THRU. Adjust Stage 12’s Join Gain to just below oscillation. The visual LEDs will race left to right, accelerating as feedback builds. The 12-step display functions as a crude oscillographic phase meter.
In the shadowlands between modular synth rigs, broadcast video routers, and industrial control systems, a unique device has begun to surface: the Visual Audio Splitter Amp-Joiner 12 Serial. At first glance, the name seems contradictory—can a device split and join simultaneously? The answer lies in its 12-lane serial backbone.
This is not merely a distribution amplifier or a passive mixer. It is a hybrid signal processor designed to manage 12 discrete channels of combined visual (CVBS, SDI, or analog video) and audio (line-level or mic) data across a single multi-drop serial infrastructure.
The Model 12 Serial was produced from 1979 to 1983, with approximately 1,200 units made. Three sub-revisions exist: visual audio splitter amp- joiner 12 serial
The "Visual" aspect is only useful if calibrated. Before a show:
The unit is typically 2U rackmount with 12 BNC or DB-15 connectors (one per lane). Each lane has:
Serial control via RS-485 or USB allows remote reconfiguration—critical for broadcast trucks or automated test stands. Set Stage 12’s Split Output to Patch back
The most critical concept is the Serial Join Bus. Unlike a typical splitter (one input to many outputs), the Model 12’s inputs are not all tied to a common node.
Imagine a chain of 12 miniature amplifiers, labeled Stage 1 through Stage 12.
However, each stage also has a Split Output Jack (on the rear panel). This outputs the signal at that exact stage—after its Join Gain has been applied, but before it passes to the next stage. The "Visual" aspect is only useful if calibrated
The heart of the unit is a 12-position serial backplane. Each of the 12 channels functions as an independent bi-directional "lane." A lane can be configured in one of three modes per port:
The "12 Serial" designation means all 12 lanes can operate simultaneously, but they can also be cascaded internally: Lane 1’s output can feed into Lane 2’s joiner, creating complex routing matrices.
