The LaST Upgrade Part 48 - ST RGB to VGA adapter

June 23, 2023 - Last updated February 6, 2024

 

Introducing the exxos ST2VGA adapter – a groundbreaking solution that redefines the standards of signal transmission for your computer, offering unmatched performance, durability, and compatibility at an affordable price.

Designed with a forward-thinking approach, the exxos adapter ditches conventional mechanical switches in favor of a digital multiplexer IC, ensuring stability over time and eliminating signal distortions and color loss. This low-cost ST to VGA adapter boasts switchable RGB color and MONO modes through a digital switching mechanism via a select jumper on top of the board, providing a seamless transition between modes.

Noteworthy is the inclusion of colour voltage correction resistors, a unique feature addressing the prevalent issue of elevated RGB output from your computer. Bid farewell to color saturation problems and welcome vibrant, accurate colors on your monitor. To complement its versatile features, the adapter also includes a standard 3.5mm audio jack, enhancing your overall multimedia experience.

What truly sets the exxos ST2VGA adapter apart is its seamless compatibility with the MEGA ST series of computers. Unlike other adapters, it is tailored to meet the specific requirements of MEGA ST systems, ensuring a perfect fit without compromising functionality.

 

UNIQUE CONSTRUCTION

Other adapters, like the one mentioned below in the left image, lack compatibility with MEGA ST computers. These non-compatible adapters obstruct two other ports, necessitating an alternative design, preferably taller, to restore compatibility with MEGA ST systems.

In attempts to enhance durability, such problematic adapters are often encased, providing additional rigidity. While this approach seems logical in theory, adapter cases are typically assumed to be flush with the bottom of the machine, which may not be the actual scenario. Furthermore, issues arise when feet are missing, squashed, or damaged, causing the entire weight of the computer to bear down on the adapter case. This places significant strain on the socket and can lead to potential damage over time.

 

Moreover, it is important to note that certain alternative adapters opt for the integration of switches in the selection of RGB colors, a decision closely linked to potential signal complications. Typically employed as a cost-effective and convenient solution during the initial design phase, these switches might overlook the lasting impact on the device's durability and signal stability.

Mechanical switches, intended for signal routing or alteration, may encounter issues like contact bounce, where the switch toggles rapidly and unintentionally as contacts make or break connection. This behavior introduces unwanted noise and inconsistencies in transmitted signals, potentially leading to disruptions or complete failures in signal transmission. Additionally, mechanical switches are susceptible to environmental factors such as dust, moisture, and temperature fluctuations. The accumulation of debris or the influence of changing environmental conditions can compromise the precision and reliability of mechanical switch operations, exacerbating signal instability.This wear and tear can lead to signal distortions and total color loss.

In contrast, the exxos style adapter's transition to a digital multiplexer IC reflects a forward-looking approach, prioritizing sustained performance and signal integrity over time. This emphasizes the significance of considering not only immediate benefits but also the long-term implications when choosing components for signal processing and transmission systems.

In contrast, electronic components like digital multiplexer ICs, when integrated into specific signal transmission systems, do not grapple with the same physical wear issues as mechanical switches. Their solid-state nature, devoid of moving parts, enhances resilience against wear and environmental factors, providing a more stable and durable solution for signal processing and transmission. This alternative technology presents users seeking stable signal transmission with a more robust solution.

In attempts to enhance durability, such problematic adapters are often encased, providing additional rigidity. While this approach seems logical in theory, adapter cases are typically assumed to be flush with the bottom of the machine, which may not be the actual scenario. Furthermore, issues arise when case feet are missing, squashed, or damaged, causing the entire weight of the computer to bear down on the adapter case. This places significant strain on the socket and can lead to potential damage over time.

The exxos ST2VGA adapter incorporates color voltage correction resistors in its design. This addition is essential to address a common issue associated with the RGB output of the computer, specifically the higher-than-normal voltage levels. The typical RGB output from the computer's port tends to exceed the compatibility threshold for many monitors. As a result, this elevated voltage can lead to problems such as color saturation, as well as washed-out and faded colors when displayed on the monitor.

The purpose of the color voltage correction resistors in the exxos ST2VGA adapter is to mitigate these undesirable effects. By introducing these resistors into the circuit, the adapter effectively adjusts the voltage levels of the RGB signals, bringing them within the acceptable range for monitors. This correction ensures that the colors displayed on the monitor remain accurate, vibrant, and free from the distortions caused by excessively high voltage levels.

In summary, the inclusion of color voltage correction resistors in the exxos ST2VGA adapter is a deliberate measure to optimize the compatibility between the computer's RGB output and monitors, ultimately enhancing the quality and fidelity of the displayed. All at a fraction of the cost of other VGA adapters!

WHERE TO BUY

https://www.exxosforum.co.uk/atari/store2/#0170

3D STL CASE FILES (by forum user Plagued)

https://www.exxosforum.co.uk/forum/viewtopic.php?f=62&t=3037

 

FAQ

Q) Does the adapter need a external power supply ?
A) No. The adapter obtains power from pin 8 of the monitor port which is a 12V feed from the power supply (via a 1.2K resistor).

Q) Won't the PCB break above the socket as its thin ?
A) No.I couldn't break it even in a vice. It would take considerable force to break the circuit board. If such forces are present then it will likely destroy the socket on the computer well before the adapter itself.

Q) Can I use RGB and MONO on the same monitor ?
A) The monitor must support 15khz to support colour resolutions, otherwise it will be mono only compatible. A example of such monitors can be found here http://15khz.wikidot.com/

Q) How to I connect audio ?
A) Use a standard 3.5mm audio lead to active desktop PC type speakers or soundbar etc.

Q) Is there a cased version ?
A) Not currently via the exxos store. However the exxos community have produced STL files for the adapter HERE.

 

 

HOME