Comp2DVI

The Comp2DVI is an open-source (CERN OHLv2) device, designed for 15KHz (240p & 480i) retro gaming signals.  The gerbers, as well as the Eagle design files can be downloaded here.  This device has been tested, and we found a small mistake: Pb and Pr are being sent through without bias, which might affect the colors, but won’t harm your equipment.  An updated revision will be available soon, but for now here’s the current rev:  http://retrorgb.com/assets/dvi/Comp2DVIv1.1.zip

 

Introduction

This device is powered by USB  and has a toggle switch for the built in low-pass filter.  I’d expect in most cases you’d need the LPF on, but as a rule, you only want one LPF in any chain.  I suggest starting with it off and try toggling to see if it removes noise.  Detailed information can be found here:  http://www.retrorgb.com/datapathcapture.html

 

DVI-I Cable / Connector

This can connect to your capture card via a DVI-I cable or coupler.  Make sure whatever your connection is using has the analog pins, otherwise it won’t work!

DVI-I Cables:
https://amzn.to/2Ndxglu
https://amzn.to/2T2QuQb

DVI-I Coupler:
https://ebay.to/2DUk9BD
https://www.mycablemart.com/store/cart.php?m=product_detail&p=5987

 

Case / Enclosure

Jacob Proctor created a small plexi case for the Comp2DVIv1.0 & 1.1.  The design files are available here:  http://retrorgb.com/assets/dvi/COMP2DVI_2_PanelsV1.svg
You can have them made here:  https://www.ponoko.com/design-your-own/products/comp2dvi-2-panels-15298

 

Other Cables & Accessories

If you’re keeping the Comp2DVI close to your capture card for the least amount of signal loss, you’ll want some short cables.  I also like to have a cable tie, to help with strain relief when a coupler is used:

1Ft Micro USB Cable: https://amzn.to/2WsrG35
Cable tie:  https://amzn.to/2GShtrc
RCA to 3.5mm adapter for audio:  https://amzn.to/2IqadW9

 

Full Bill Of Materials

Here’s some component links, to try and make your ordering easier!

3x Output Capacitor:  https://www.digikey.com/product-detail/en/avx-corporation/TAJC227K006RNJ/478-1713-1-ND/564745

1x Red RCA Connector:  https://www.digikey.com/product-detail/en/cui-inc/RCJ-012/CP-1401-ND/408488

1x Green RCA Connector:  https://www.digikey.com/product-detail/en/RCJ-016/CP-1405-ND/408492/

1x Blue RCA Connector:  https://www.digikey.com/product-detail/en/RCJ-015/CP-1404-ND/408491

4x Capacitor 0.1uF (100nF):  https://www.digikey.com/product-detail/en/CL10F104ZO8NNNC/1276-1258-1-ND/3889344/

1x Capacitor 100uF:  https://www.digikey.com/product-detail/en/panasonic-electronic-components/EEE-0JA101WR/PCE3853CT-ND/766229

1x Inductor:  https://www.digikey.com/product-detail/en/MPZ1608S331ATA00/445-5221-1-ND/2117955/

1x MicroUSB Port:  https://www.digikey.com/product-detail/en/wurth-electronics-inc/629105150521/732-5960-2-ND/5047751

7x Resistor 75ohm:  https://www.digikey.com/product-detail/en/rohm-semiconductor/ESR03EZPF75R0/RHM75.0ADCT-ND/1983773

1x MicroSwitch:  https://www.digikey.com/product-detail/en/c-k/JS202011AQN/401-2000-ND/1640096

1x THS7374:  https://www.digikey.com/product-detail/en/texas-instruments/THS7374IPWR/296-41661-1-ND/5224405

1x SCART Connector, female:   
https://www.ebay.com/itm/321474089583
https://console5.com/store/female-scart-jp21-through-hole-pcb-mount-21-pin-connector-right-angle.html

1x DVI Input Port:  https://www.digikey.com/product-detail/en/molex-llc/0743201004/WM5600-ND/356066

Cheaper links, but either long or expensive shipping (better for 5 or more though!):
https://lcsc.com/product-detail/Audio-Video-Connectors_CONNFLY-Elec-DS1091-VN0X_C77847.html
https://www.aliexpress.com/item/Free-shipping-10pcs-DVI-29Pin-to-PCB-90-Degree-Female-Connector-Plug-24-5-Pin-Female/32224360849.html

2x Screws (need to double check):  https://www.digikey.com/product-detail/en/te-connectivity-amp-connectors/5207953-3/5207953-3-ND/1121976

 

I’d like to look into improving this device any way possible.  The first thing on my list would be to have a switchable low-pass filter that can handle multiple frequencies for use across all analog resolutions (240p – 1080i).  I’d also like to see a VGA version, but held off on making one until the filtering options were solved, as most VGA uses would be 480p and up.

People with the necessary knowledge are encouraged to edit and modify this as they find ways to improve or change the design.

 

A detailed guide on how to use this device with your capture setup can be found here: