ST2VGA Enhanced – Active VGA Adapter for Atari ST/STE/Mega ST/Mega STE

Active VGA adapter for early Atari ST or machines with weak video output

The ST2VGA Enhanced Adapter is the active sibling of the ST2VGA family. It plugs into the Atari monitor port and runs the RGB lines through a dedicated quad video amplifier, an analog low-pass filter and buffered outputs before they reach the VGA cable. The result is a stronger and cleaner image on machines that struggle with a passive adapter: early Atari ST boards without a +12 V rail on the video port, machines with weak or noisy color output, displays prone to vertical jailbars and long-cable setups that fail to lock on the signal. Powered by a 5 V micro-USB supply, so it works on Ataris that cannot feed a passive adapter at all.

Ships from Spain. For the Atari ST, STE, Mega ST and Mega STE.

Key features

• Active quad RGB amplifier: a dedicated quad video amplifier boosts weak Atari analog color levels to a strong, consistent range before the monitor sees them.
• Analog low-pass filtering: removes high-frequency noise outside the useful video bandwidth. Smoother colors, cleaner edges, less shimmer on modern LCDs.
• Buffered RGB outputs: isolates the Atari video circuitry from the VGA cable and monitor input. Better signal stability with long cables and picky LCD inputs.
• Jailbar reduction: the buffered and filtered output reduces, and on many machines eliminates, the vertical jailbar pattern produced by digital noise coupling into the analog RGB lines.
• Works on early ST without +12 V: external 5 V micro-USB power means the adapter does not rely on the Atari +12 V rail. The right pick for very early Atari ST boards that do not expose +12 V on the monitor connector.
• Color and mono slide switch: a slide switch toggles between color modes (ST Low and Medium) and mono mode (ST High) on the fly. No software, no jumpers.

Same practical ST2VGA concept

Despite the added electronics, the Enhanced keeps the same practical concept: direct connection to the Atari monitor port, VGA output for compatible multisync monitors, support for Atari color and mono modes, and original Atari video timings preserved with no scan doubling or scaling. The classic Atari look and timing remain intact, while the analog signal path is improved.

Choose the right ST2VGA

Two adapters, same family, different jobs. Pick the one that fits your machine.

Installation

1. Plug the adapter into the Atari monitor port.
2. Connect a 5 V micro-USB charger to power the adapter.
3. Plug a standard VGA cable into a multisync monitor.
4. Set the slide switch to color or mono, then power on.

No soldering, no modifications, no tools.

Monitor compatibility

The Enhanced preserves the original Atari scan frequencies and does not perform scan conversion or scaling, so a compatible monitor is still required. Color modes (ST Low and ST Medium) require a VGA monitor that accepts a 15 kHz horizontal sync signal. Mono mode (ST High) works on any standard VGA monitor. The 15 kHz reference list is the most practical starting point if you are unsure about a monitor.

Specs

• Weight: under 50 g.
• Dimensions: approximately 38 mm x 45 mm x 36 mm.
• Power: external 5 V via micro-USB.
• Atari connector: DB-13W3 (Atari monitor port).
• Output: VGA-compatible (multisync monitor required for color modes).
• Audio: 3.5 mm stereo jack (mono routed to both channels).
• Active stage: quad video amplifier with analog low-pass filtering and buffered outputs.
• Horizontal sync: 15 kHz (ST Low and Medium), 31 kHz (ST High).

Frequently asked questions

What is the difference between ST2VGA and ST2VGA Enhanced?
The passive ST2VGA Adapter is the right pick for machines whose video output is already strong and stable. The Enhanced version adds an active RGB amplifier, analog low-pass filtering and buffered outputs, so it is better suited for early Atari ST boards, machines with weak or noisy signals, jailbar-prone hardware and long-cable setups.

Is the ST2VGA Enhanced useful for very early Atari ST machines?
Yes. It is especially useful for older Atari ST boards that do not expose +12 V on the monitor port, since the adapter carries its own external 5 V supply over micro-USB.

Is there a 3D printable enclosure?
Yes. Enclosure files and links for the ST2VGA family live in the ST2VGA family enclosures page.

Can this damage my Atari?
No. The adapter is electrically safe and isolates the Atari video circuitry from the VGA cable through its buffered output stage.

Does this device upscale or scan-double the picture?
No. The Enhanced adapter preserves the original Atari timings and scan frequencies. A 15 kHz-capable VGA monitor is still required for color modes.

How do I switch between video modes?
A slide switch on top of the adapter toggles between color modes (ST Low and Medium) and mono mode (ST High) on the fly. No software needed.

Does the Enhanced really get rid of jailbars?
On most machines, yes. The buffered output isolates the RGB lines from the monitor input, and the filtering removes the high-frequency components that show up as the vertical bar pattern on modern LCDs. In the most extreme cases the artifact is heavily reduced rather than eliminated, but the picture is always noticeably cleaner than with a passive adapter.

Why does the Enhanced version need external power?
The integrated video amplifier and buffering stage need a stable 5 V supply to operate correctly. They live outside the Atari video circuitry on purpose, so they cannot draw power from the monitor port.

Is a power supply included?
No. The Enhanced adapter ships without a power supply. You provide a reliable, well-regulated 5 V micro-USB charger and a good-quality cable.

How is audio handled?
The adapter includes a 3.5 mm audio jack. The Atari mono audio signal is duplicated on both left and right channels for easy connection to speakers, amps, capture devices or headphones.

Good to know

• Active adapter, powered by a 5 V micro-USB charger (not included). For color modes you need a 15 kHz-capable multisync monitor.
• If your Atari already produces a strong, clean signal and exposes +12 V on the video port, the passive ST2VGA Adapter is cheaper and enough.
• Homebrew product built for hobbyists, not a sealed appliance.

Certifications and compliance

This product has been assessed for European (CE) and UK (UKCA) conformity. Official Declarations of Conformity and EMC Assessment reports are available for ST2VGA-ENHANCED REV1.0.0: EU / CE Declaration of Conformity and UK / UKCA Declaration of Conformity.