Recommended Adapters, Sync Solutions & Transcoders - ZFEbHVUE/Batocera-CRT-Script GitHub Wiki
There are many VGA-to-SCART adapters and sync solutions available, each with their own pros and cons. This page outlines various popular devices, with commentary based on testing and community feedback (primarily from the GroovyArcade and Batocera CRT communities).
📚 Table of Contents (click to expand)
Before looking at specific products, it’s important to clarify the categories:
🔹 Not a converter — just a direct pin-to-pin cable that connects RGBHV (VGA) to RGBS (SCART), assuming the GPU is outputting a compatible 15kHz signal.
🧩 Requires correct timings (e.g., 320x240p or 640x480i) and sync polarity for the display to work.
🔌 Some of these cables include:
- A USB cable for supplying 5V to SCART pin 16 (RGB mode) and pin 8 (AV switch)
- A Molex connector for providing 5V and/or 12V
- A 3.5mm audio male connector to route audio into SCART
They rely entirely on your GPU outputting a clean, compatible 15kHz signal (RGBHV, with HSync used directly as CSync).
However, despite appearing feature-rich, many are:
- Unshielded or poorly grounded
- Lacking proper sync attenuation or filtering
- Prone to interference and noise (both visual and audible)
🔹 These devices combine Horizontal + Vertical sync into Composite Sync (CSync), and may:
- Supply blanking voltage to SCART pin 16 (forces RGB mode)
- Include basic signal filtering or line drivers
🧠 These are not full converters, but they make VGA output more compatible with TVs and SCART equipment.
Examples: UMSA, RetroTINK VGA2SCART, Mike Chi’s open source design
🔹 These are active devices that translate one analog signal format to another, such as:
- VGA (RGBHV) → Component (YPbPr)
- SCART (RGBS) → Component (YPbPr)
- VGA (RGBHV) → RGBS
- RGBS → Composite Sync (CSync) (in some niche tools)
🧠 These units go beyond passive adapters or sync combiners — they convert signal formats to ensure compatibility with consumer CRTs or PVMs.
| Device | Vendor / Creator | Notes |
|---|---|---|
| VideoAMP | njz3 & Bandicoot | Advanced VGA amplifier with active sync filtering, EDID emulation, SCART output, and audio routing. Compatible with 15/24/31kHz displays. Flyer |
| HD15-2-SCART | Rondo Products | Does not supply SCART pin 16 (RGB mode). Relies on TV auto-detection or manual override. |
| UMSA (Ultimate SCART Adapter) | Arcade Forge | Classic design; limited stock; lacks advanced sync protection. |
| VGA2SCART Sync Converter | Retro Upgrades | Based on Mike Chi’s open-source design. Includes USB-powered SCART pin 16 blanking voltage. |
| RetroTINK VGA to SCART | Mike Chi (Open Source) | Lacks pin 16 voltage; RGB mode must be forced manually. |
| The Ultimate VGA to SCART Adapter | Scart Vader (Hackaday) | Uses PIC microcontroller for sync filtering. Has issues with slow sync recovery. DIY build available. |
| VGA to SCART Adapter | Tim Worthington | Has sync protection that blocks out-of-range signals, causing TVs to switch inputs. |
| The Ultimate VGA to SCART Adapter - Arcade Express Version | Arcade Express | Known grounding issues; reported ground loop noise in picture/audio. |
| VGA-SCART CONVERTER F-15 | sirMagb (Hackaday) | Enhanced take on the Scart Vader design with improved sync handling. DIY only. |
| MonochromeRGB | Aitor Gómez García (Hackaday) | VGA to SCART adapter for monochrome displays. DIY only. |
| MonochromeVGA | Aitor Gómez García (Hackaday) | VGA to monochrome VGA adapter. DIY only. |
| Low-Quality Prebuilt VGA to SCART Cables | Various (RetroCables ES, Arcade Express, etc.) | Often include 5V (USB or Molex) for SCART pins 8 and 16, but suffer from poor shielding, weak sync integrity, and audio interference. |
Transcoders convert RGB signals (like VGA or SCART) into other analog formats, such as YPbPr (Component), Composite, or S-Video.
These are useful when your CRT or capture device only supports one of those inputs.
| Device | Signal | Notes |
|---|---|---|
| GreenAntz RGB to Component Transcoder | SCART/VGA → Component | Open-source build with active sync filtering. See ArcadeControls thread and Facebook post. |
|
RGB VGA to YPbPr Component by linuxbot3000 |
VGA → Component | Available via eBay. Simple and reliable transcoder for 15kHz/31kHz signals. |
| RetroTINK RGB2COMP | SCART → Component | Official site. Premium transcoder with built-in sync and color level handling. |
| Bitfunx RGBS VGA/SCART to YPBPR/YCBCR | SCART/VGA → Component | See AliExpress listing. Known working, but color wiring is non-standard: • Green → Pb • Red → Y • Blue → Pr |
|
SCART RGBS to YPbPr Transcoder (AliExpress) |
SCART → Component |
AliExpress listing. Known working, but color wiring is non-standard: • Green → Pb • Red → Y • Blue → Pr |
| Arcade Express SCART to YPbPr Converter | SCART → Component + S-Video | Product link. Can also be found by searching AliExpress for “SCART RGBS to YUV YCBCR Video Converter”. |
| Device | Signal | Notes |
|---|---|---|
|
VGA → Composite / S-Video by Antonio Villena |
VGA (RGBHV) → Composite / S-Video |
Product page. 🟢 Best overall quality. Uses AD723 encoder for superior composite sharpness. |
|
RGB VGA to NTSC S-Video / Composite by linuxbot3000 |
VGA (RGBHV) → Composite / S-Video | Available on eBay. Uses CXA2075 encoder. Lower quality than Villena’s AD723-based model, but functional and reliable. |
| AxunWorks RGB to Composite & S-Video v2.0 | SCART (RGBS) → Composite / S-Video | Product page. Accepts SCART RGBS. Solid performer for consumer TVs needing legacy video inputs. |
📝 Encoder Chip Comparison
- AD723 (Antonio Villena): Sharper image and cleaner color burst. Considered one of the best analog encoders for RGB → Composite/S-Video.
- CXA2075 (linuxbot3000): Cheaper Sony chip, still decent but less crisp; more color bleeding.
📝 Note:
These transcoders do not upscale or digitize the signal. They maintain analog output at the same horizontal refresh rates and resolutions (e.g. 15kHz 240p).
Be mindful of sync levels and color phase if mixing SCART/VGA sources into YPbPr workflows.
When out-of-range sync is detected, the adapter blocks the signal entirely. This may cause some TVs to:
- Switch back to a TV channel
- Mute video until sync resumes
"The thing about cutting the video signal in the absence of a sync signal is apparently not a universal thing — only 1 of my 5 CRTs does that. This mod is useless it turns out."
"Hi Rion,
You want to look at an out-of-sync picture instead? I don't think you'll like that either, but it can be easily accomplished by closing solder jumper JP1 to disable the protection circuit.What I think you actually want to do is blank the screen when the signal is out of sync. The current hardware cannot do this as the circuits to drive SCART pins 8 and 16 are tied together.
To blank the screen you must drive pin 16 without driving pin 8. What you can do is open JP2 (this disconnects SCART pin 16) and drive SCART pin 16 with a 12V supply (it's best to put in a 1k resistor in series for safety). This way the TV will remain in AV mode always."
The Scart Vader–style adapters (e.g. from Hackaday or Arcade Express) often use a PIC16F18313 to:
- Filter sync
- Generate 12V from 9V
- Prevent invalid signals from reaching the display
Unfortunately:
- These filters are too slow, cutting sync during game resolution switches
- No updated firmware was released to fix these issues
- Arcade Express units had soldering defects causing noise due to missing ground wires
If you're looking for an all-in-one solution with advanced filtering, switching, and audio support — the VideoAMP is unmatched.
- Active HSync filter for sync protection
- VGA IN / VGA OUT passthrough (EDID emulation possible)
- SCART output with proper RGBS handling
- AUDIO IN (3.5mm jack) routed to SCART
- GunCon IN (support for lightgun sync)
- Switchable RGBHV / RGBS modes
- Audio L/R ↔ R/L flip
- Fully shielded and properly grounded
More info:
📎 https://www.arcade-projects.com/threads/vga-video-amplifier-board-for-arcade-monitor-with-sync-filter.24936/#post-375822
📎 https://www.gamoover.net/Forums/index.php?topic=44224.0
When choosing an adapter, sync combiner, or transcoder:
- 🧠 Avoid sync-blocking designs unless you fully understand your CRT’s behavior
- 🛡️ Always choose devices with proper shielding and solid grounding
- 🔌 Look for adapters that supply blanking voltage on SCART pin 16 when needed
⚠️ Be cautious of cheap cables with poor shielding or noisy sync lines
- VideoAMP — Full-featured sync-safe amplifier with audio routing and EDID passthrough
- sirMagb’s F-15 — Reliable, improved version of the Scart Vader with better sync handling
- UMSA (Ultimate SCART Adapter) — Classic and trusted
- VGA2SCART Sync Converter (Retro Upgrades) — USB-powered design with good voltage handling
Each of these has been tested by the community and offers a stable signal path for CRT use with minimal fuss.
-
GreenAntz RGB to Component Transcoder
Offers the best video quality in this category, with robust signal handling and accurate colors.
🔗 Forum thread detailing the latest PCB revisions -
RGB VGA to YPbPr Component
by linuxbot3000 (Available on eBay)
A reliable transcoder with solid community feedback. -
Bitfunx RGBS VGA/SCART to YPBPR/YCBCR
Affordable and accessible SCART/VGA to component transcoder sold via AliExpress and resellers.
Note: Color channel labeling differs slightly (e.g. Green = Pb, Red = Y, Blue = Pr)
Each of these options has been tested or vetted by retro gaming communities such as GroovyArcade, Batocera, and ArcadeControls, ensuring reliability for CRT setups.
The GreenAntz RGB → Component transcoder is one of the most highly recommended options for converting RGB (SCART or VGA) to YPbPr component video. It offers a clean analog signal path, zero lag, and precise control over video output characteristics.
- Accepts both RGBS and RGBHV inputs
- Built-in sync combiner with superior sync-tip filtering
- Outputs YPbPr component video with excellent signal integrity
- Adjustable potentiometers for fine-tuning Pr and Y levels
- Powered by USB-C (convenient for modern setups)
- Compact, high-quality PCB with clear labeling
- No digital processing or scaling — zero input lag
- Sync integration is cleaner than most BA7230-based units
- Produces brighter, clearer images with more vibrant colors
- Several users note it's visually indistinguishable from native RGB on 15kHz CRTs
- Particularly well-suited for use with consumer CRTs that only accept component input
“I’d struggle to tell the difference between RGB and YPbPr.”
“GreenAntz sync integration with luma has tighter sync‑tip filtering… image is brighter, clearer and has stronger colours.”
➡️ If you need the best quality RGB → Component output for CRT use, GreenAntz is a top-tier analog transcoder solution.
According to Andrew (“Zebidee”), the creator of the GreenAntz RGB to Component Transcoder:
The Bitfunx unit is a direct clone of an older, pre-GreenAntz design that we originally shared as a hobby project on AussieArcade.com and GitHub back in 2018. Bitfunx added a basic sync circuit — based on the well-known "Tom Engdahl composite sync" design from the 1990s — but otherwise made no meaningful technical improvements.
🛠️ Key Differences and Issues with Bitfunx:
- No voltage regulation: Bitfunx lacks proper regulation circuitry, which results in inconsistent signal levels.
- Poor color saturation and "flickeriness": This is especially noticeable on games with large uniform color areas (Time Pilot, Alex Kidd, Wonder Boy, etc.).
- Outdated sync logic: The composite sync is generated using an older logic IC, which may not be compatible with some GPUs (especially those outputting TTL-level sync signals).
- No sync-tip clamping: The sync circuit used by Bitfunx does not inject properly clamped sync into the Y (luma) signal. This can lead to wandering sync and fluctuating Y levels, reducing image stability and quality.
- Visual artifacts: While the difference can be subtle, color reproduction on Bitfunx units may appear washed out — described as “butter scraped over too much bread”. Once noticed, the issue becomes difficult to ignore.
📚 Note from Andrew:
“The reason Bitfunx handles sync differently is because we hadn’t sorted sync out properly yet in 2018 — the older schematics didn’t cover that part. I worked it out later after a lot of testing. Learned a lot with this project!”
Despite its flaws, the Bitfunx unit remains widely available and budget-friendly, which explains its popularity. However, users who compare it side-by-side with GreenAntz often notice a significant quality difference and end up upgrading.
“Some people DO notice — and they come to me for GreenAntz.”
— Andrew (“Zebidee”)
-
VGA → Composite / S-Video
by Antonio Villena
Uses the AD723 encoder — widely regarded as producing the cleanest composite output among modern adapters.
🔧 Be sure to select the version with sync combiner if converting from RGBHV.
🔗 Product page -
RGB VGA to NTSC S-Video / Composite
by linuxbot3000
Based on the CXA2075 encoder chip. Offers decent image quality and is widely available via eBay.
🔗 eBay listing (availability may vary) -
RGB to Composite & S-Video Ver2.0
by AxunWorks
Also uses the CXA2075 (same chip as linuxbot3000’s design), in a more enclosed and polished form factor.
🔗 AxunWorks product page
These are useful when converting 15kHz RGBHV or RGBS into legacy display formats such as Composite or S-Video, for use with older consumer CRTs, VHS capture devices, or TVs without SCART/component inputs.
| Feature | AD723 (Antonio Villena) | CXA2075 (linuxbot3000) |
|---|---|---|
| Target use | VGA (RGBHV) sources at 15 kHz | Console RGB (RGBS), not optimized for VGA |
| Clock input | Accepts digital 4FSC clock | Requires analog subcarrier (sine wave) |
| Input compatibility | Handles VGA 15 kHz directly | Needs sync conditioning for VGA (or may distort) |
| Built-in filters | Has luminance trap (Y-TRAP) for dot crawl | Has chroma trap and flicker filter (for 240p RGBS) |
| Output quality | Clean, soft, stable for PC/VGA to CRT | Sharper but more prone to artifacts when misused |
| Real-world results | Smoother picture, fewer artifacts with VGA input | Higher sharpness, but can show flicker, color bleed |
Although the CXA2075 is technically more advanced (wider bandwidth, sharper output), it was designed for clean RGBS signals from consoles, not VGA sources. It expects proper sync levels, analog subcarrier input, and ideal signal conditions—something VGA doesn’t always provide directly.
The AD723, by contrast, was made for VGA to TV output. It accepts RGBHV, includes dot crawl reduction via a Y-trap filter, and provides smooth, stable composite and S-Video out with fewer compatibility issues.
In summary:
- AD723 (Antonio Villena adapter) is better suited for VGA sources, resulting in cleaner, softer, and more artifact-free video on CRTs.
- CXA2075 (linuxbot3000 adapter) can offer sharper detail, but may introduce flicker, color bleed, or instability if not paired with properly conditioned RGBS.
These are useful when converting 15kHz RGBHV or RGBS into legacy display formats such as Composite or S-Video, for use with older consumer CRTs, VHS capture devices, or TVs without SCART/component inputs.