ST2VGA Adapter – Clean VGA Output for Your Atari ST
The ST2VGA adapter (Revision 3) allows classic Atari ST computers to connect directly to compatible VGA monitors while preserving the original video timings of the machine. Designed specifically for the Atari ST, STE, Mega ST, and Mega STE, this adapter converts the native video signals into a format that multisync VGA monitors can understand.
New Revision 3 introduces important electrical improvements that deliver cleaner signals, improved stability, and sharper video output, ensuring your retro system looks better than ever on modern displays.
Key Features
Universal Atari ST Compatibility
The ST2VGA adapter works with the full Atari ST family. Tested on:
- Atari 520ST / STF / STFM / STE
- Atari 1040ST / STF / STFM / STE
- Atari Mega ST
- Atari Mega STE
Simply connect the adapter to the Atari video port and attach a VGA monitor.
Improved Signal Integrity with a 4-Layer PCB
Revision 3 introduces a 4-layer printed circuit board, a major upgrade over typical hobbyist designs.
Video signals—especially RGB video and synchronization signals—are high-speed analog signals. Poor routing or noisy power distribution can cause visible issues such as:
- Color bleeding
- Signal ringing
- Noise or shimmer in the image
- Crosstalk between channels
A 4-layer PCB improves signal integrity by providing:
- Dedicated ground planes that act as stable reference layers
- Shorter and more controlled signal paths
- Better shielding between traces, reducing interference
- Improved power distribution and noise suppression
The result is a cleaner and more stable video signal, which translates directly into a sharper and more reliable image on your monitor.
New RGB Low-Pass Filters for Cleaner Video
Revision 3 also introduces dedicated low-pass filters on the RGB lines.
The Atari ST’s video output can contain high-frequency components and digital edge noise that modern displays may amplify or interpret poorly. These unwanted frequencies can cause:
- Pixel edge noise
- Color artifacts
- Slight shimmer or harsh transitions
The integrated analog low-pass filters gently remove frequencies above the useful video bandwidth while preserving the actual image content.
Benefits include:
- Smoother color transitions
- Reduced noise in solid colors
- Cleaner edges and more stable picture
This filtering stage helps the VGA monitor receive a properly conditioned analog video signal, closer to what CRT monitors originally expected.
Simple Mode Switching
A built-in slide switch allows you to toggle between Atari video modes:
- Color modes (ST Low / Medium)
- Mono mode (ST High)
Switching modes is instant and requires no configuration.
Authentic Atari Video Timing
The ST2VGA adapter does not perform scan doubling or scaling.
Instead, it preserves the original Atari video frequencies, meaning:
- The classic look of Atari graphics is preserved
- No additional processing latency
- Perfect compatibility with software expecting original timings
Because of this, color modes require a VGA monitor capable of handling a 15kHz horizontal sync signal.
Integrated Audio Output
A convenient 3.5 mm audio jack is included.
The Atari’s mono audio signal is duplicated to both left and right channels, allowing easy connection to:
- Speakers
- Amplifiers
- Capture devices
- Headphones
No additional adapters are required.
No External Power Required
The ST2VGA adapter operates entirely from the signals provided by the Atari video port.
- No external power supply
- No USB power cable
- Minimal load on the Atari hardware
Simply plug it in and use it.
Compact and Durable
The adapter features a compact and robust PCB design, making it ideal for permanent installation in a retro setup.
Lightweight, reliable, and designed to withstand years of use.
Experience Atari on Modern Displays
Whether you’re exploring retro development, playing classic games, or restoring vintage hardware, the ST2VGA adapter provides a clean and practical bridge between Atari systems and modern displays.
Revision 3 improves upon previous designs with better signal quality, improved electrical design, and refined video conditioning, ensuring the best possible output from your Atari hardware.
Note: To enjoy color modes, ensure your VGA monitor supports a 15KHz HSYNC signal. This isn’t a scan doubler; it maintains the authentic scan frequency of your Atari, eliminating flicker while preserving its vintage charm.
Upgrade your retro setup today and rediscover the magic of Atari with the ST2VGA adapter—the smart, reliable bridge between classic computing and modern display technology.
Frequently Asked Questions
How difficult is it to install the ST2VGA adapter?
Installation is extremely simple. Just plug the adapter into the Atari’s video port and connect a VGA monitor using a standard VGA cable. No soldering or modification is required.
Which Atari models are compatible?
The adapter has been tested and is compatible with the following Atari models:
- Atari 520ST / STF / STFM / STE
- Atari 1040ST / STF / STFM / STE
- Atari Mega ST
- Atari Mega STE
Note: Some very early Atari ST models may lack the +12V line required for the adapter to function. In that case, check our new ST2VGA ENHANCED model, which needs an external power supply.
Is there a 3D printable enclosure for ST2VGA?
Yes. You can download the enclosure here: ST2VGA Enclosure – Sidecartridge on Printables.
How do I switch between video modes?
The ST2VGA adapter offers an easy mode switching mechanism with a slide switch on top of the device to toogle between color modes (ST Low/Med) and mono mode (ST High) on-the-fly.
What video modes are available, and what are the monitor requirements?
The adapter supports both color and mono video modes:
- Color Modes (ST Low/Med): Require a monitor that supports a 15KHz HSYNC signal (multisync). If your monitor does not support 15KHz, you will not be able to use color mode.
- Mono Mode (ST High): Can be used with any compatible monitor but retains the vintage scan frequency without additional processing.
Where can I find information about compatible monitors?
For color modes, you will need a monitor that supports a 15KHz HSYNC signal. You can find a list of compatible monitors online in this website.
Note: This device is not a scan doubler; it simply provides a clean, flicker-free output by preserving the original scan frequency.
For Mono mode, any VGA monitor should work.
Is this a scan doubler?
No.
The adapter does not upscale or convert the scan frequency. It simply outputs a clean analog signal that preserves the original Atari timings.
How is audio handled?
The adapter includes a 3.5mm audio output jack.
The Atari’s mono signal is routed to both left and right channels, allowing easy connection to standard audio equipment.
Does the adapter require external power?
No.
The device runs directly from the Atari video port and does not require an external power supply.
Note: Some very early Atari ST models may lack the +12V line required for the adapter to function. In that case, check our new ST2VGA ENHANCED model, which needs an external power supply.
Are special VGA cables required?
A standard VGA cable works perfectly.
For best results, a cable with ferrite noise filters is recommended.
What is the weight?
Less than 50 grams.
What are the dimensions?
Approximately 38 mm × 45 mm × 36 mm.
Can this damage my Atari?
No.
The ST2VGA adapter is designed to be electrically safe and places minimal load on the Atari video circuitry.
Is this product for me?
This is a homebrew product designed for hobbyists with a keen interest in experimenting with their computers. If you seek a seamless, Apple-like experience, it will not meet your expectations.
Why can’t I access the store or Discord even though you ship to my country?
Access to our products and community spaces requires basic respect. We have zero tolerance for harassment, personal attacks, abusive behavior, or defamatory content toward our team or community. We operate under a simple principle: don’t be abusive. If that principle is violated, access will be revoked. We build for people who enjoy experimenting, not creating hostility.
More information
- 3D printable enclosure: ST2VGA Enclosure – Sidecartridge on Printables
