Video DAC for Commodore 128/128D, IBM CGA, and Tandy CGA Plus

The BIT-C-128 Video DAC with a Gonbes video converter and power adapter is the cheapest and easiest combination to display high-quality 80-column video from a Commodore 128 or IBM CGA on newer VGA displays, including lightweight LCD flat panels.

Designed especially for Commodore 128 and 128D computers, the BIT-C-128 Video DAC has been carefully tuned to match the colors on the Commodore 1084S-D display and designed for manufacturing using modern design tools and surface-mounted components.

Key features:

Inexpensive to get running quickly and to build onto later
– from pre-VGA (<17 kHz) color in 80-columns, add VGA, 40-column modes, even HDMI!
Multiple uses
– attach directly or via 9-pin extension cable, loose or in an enclosure
Very easy to use – ships assembled, no tools required!
Better color and sharpness than DACs having only digital ICs – especially on analog displays
Safe and environmentally-friendly
– lead-free product, complies with EU RoHS (no US FCC certification required)
Satisfaction guaranteed!

Please see the links at the top of this page for more information about applications and how to get started, or to buy the video DAC and accessories.

For questions about this product, please contact me (John Carlsen).

News

2024 April 9: The US Postal Service has increased rates, removing the lowest rate class for international shipments.

2024 January 11: Sales resume in 2024 via the new BIT-C-128 store on Square. Please note that orders placed in January may require up to two weeks to process, which should return to the usual three days thereafter. (Also, this site now offers secure browsing via https and a new SSL certificate.)

2023 May: I’ve decided to stop using PayPal. I don't know how long it will take to migrate. Please reach out to me via the contact page if you would like to make a purchase.

2022 March: The BIT-C-128 Video DAC circuit board is now in its seventh printing. Thank you for making BIT-C-128 the world's best selling video DAC for Commodore 128 and IBM CGA!

Due to Russia’s ongoing attack of Ukraine, delivery to Russia and selected Russian allies are now suspended.

Small-parcel international shipping rates have increased slightly due to postal system rate increases.

2020 April: Due to restricted movement during the COVID-19 pandemic, shipping may be slightly delayed. Thank you for your patience, and please stay safe!

Also, I added a page for frequently-asked questions (FAQs).

2019 January: I added a brief survey. Would you please give a little feedback on what you like and what you would like? Thanks!

Also, I added instructions on how to convert to HDMI.

2017 April-May: Enclosures are now being made for the BIT-C-128 Video DAC and/or the Gonbes GBS-8200 or GBS-8220. For details, see the How to Buy page.

2016 June: To celebrate its first anniversary, I'm publishing a 3-D PDF design proof of the BIT-C-128 Video DAC that I created a year ago. This file contains a three-dimensional model that may be viewed and turned in three dimensions with a modern Adobe PDF reader. (Older versions will display only a white page.)

Details

Details of the key features:

Cheap to get running quickly and to build onto!
1. For Commodore 128 80-column or IBM CGA display: Start with a BIT-C-128 Video DAC (about $50), a good 5-volt AC power adapter (about $15), and
  1. If using an analog RGB display (such as a 15kHz CRT): Suitable cable (such as a HD-DE-15P-to-BNC) and cable adapters (for video and power), or
  2. If using a VGA display (usually LCD): Add a Gonbes GBS-8220 or GBS-8200 to convert analog RGB to VGA (about $26)
2. To add grayscale 40-column display: Connect a Commodore DIN-to-composite video cable to the Gonbes unit's component Y input
3. To add color 40-column display: Add an Ambry SDV1composite-to-component converter (about $95) and 3 RCA cables to connect component signal to the Gonbes unit
4. To add HDMI output: Add a Gana Link VGA to HDMI converter (about $11), a USB power adapter, and VGA and HDMI cables
Multiple uses:
- Plugs into Commodore 128/128D/128D(CR) or IBM CGA
- Connect DE-9 directly or through extension cable
- Reproduces Commodore colors accurately and IBM CGA very closely
- Drives analog VGA display via Gonbes video converter or pre-VGA (<17 kHz) displays directly
Very easy to use:
- No tools needed: ships fully assembled, push-button terminal block easily and neatly connects all wires supplied with Gonbes GBS-8200 or GBS-8220
- Power indicator LED
- Power diode protects circuit from accidental polarity reversal
Fully-buffered analog output, assuring better color and sharpness than DACs having only digital ICs, especially when using analog displays
Safe, environmentally-friendly lead-free product, complies with EU RoHS (no FCC certification required)
Satisfaction guaranteed

More Information

Want to know more about Syncopated Systems?

Contact me