CX Cards

What is a CX Card?

Conexant CX2388x-xx is an 2002 era PCI-based chip, today found with a PCIe bridge chip (Asmedia or ITE) in the 1x PCIe desktop card form factor.

With CXADC it becomes an powerful 28msps 8-bit Analouge to Digital Converter!

CX White (CX23883-39) S-Video/RCA input.

CXADC Driver & CX Card Wiki

This page has overview information, for more in-depth information on the driver and cards click the links below.

Driver - Installation/Usage Readme

Wiki - General Information and hardware information

Ware do I buy a CX Card?

Recommended card type: White CX23883-39

AliExpress is currently the best supplier of the CX White Card at 20~30 USD.

Why PCIe 1x Cards and not any old PCI card?

Standardised PCB layout and predictable and dependably similar performance, allowing for easy modification and standardised guides and sample comparison.

Should I buy more than one card?

For Video8/Hi8/SMPTE-C/SMPTE-B/Beta FM RF capture you will only need one card if it has linear audio only.

Buy 2 or more if you wish to do

• VHS/SVHS/SuperBeta Video + HiFi (now with syncronised timing!)
• Betacam/Betacam SP/MI/MII/W-VHS duel video channel capture.
• Have a flexiable setup or do multible decks at the same time.

Owning an RTLSDR is ideal for calibrating HiFi or If you already have a DomesDay Duplicator is a defacto choise.

The CXADC driver now supports upto 256 cards so setups can be scaled as much as you need, and external timing sources allow it to do clock locked sampling of diffrent signals in the same deck, so zero hardware audio/video drift issues.

Cables & Adapters

On the white card without physical modification, it's recommended to use the S-Video port (Luma or Y signal pin and ground) for FM RF signal capture if you wish to not solder your own cables or modify the card in any way.

• S-Video to BNC Y/C Male
• S-Video to BNC Y/C Female
• S-Video to BNC Male
• RCA to BNC

How to Improve CX Cards

YouTube Modification Video

External Amplification

Due to the limited abilities and additional noise from the internal digital gain amplifier on the CX chips, using an external RMS amplifier is an affordable way to negate the issue, and is a soft mod to the capture chain in most setups for tape formats.

The go to today is the Analog Devices AD8367 / Pot-less AliExpress Link / With Pot AliExpress Link / 4.5v AA Battery Holder / Wiki Setup Link

Cooling Mod

Adding a 40mm heat sync & fan is also recommended. Faster sampling = data output = more heat = shorter hardware life and possible loss of data due to overheating.

File the standard mounts down as not to touch board compoents and glue heatsync/fan unit onto chip, Do NOT forget to use thermal paste and or a pad on the heatsync.

Silicone is recommended over hot glue due to risk of melting, and ease of removal without damaging parts.

Requirements:

• Soldering Iron, Bevel/Conical Tip, Flux, 60/40 Solder
• 40mm heat sync & fan
• Thermal Pad / Thermal Paste
• Silicone Glue

C31 Removal

Note lable on the white card picture above these cards have a bridging capasitor on pad C31 this bridges the 2 input pads for RCA/BNC connectors, and causes worse captures, its best to remove with a iron tap both sides then lightly pressure from one side to kock it off the 2 pads its soldered to, or remove with a gental twist with tweezers/plyers.

RCA to BNC Replacement

With 3 de-soldering taps and a pair of flush cutters, you can replace the RCA connector and or add another input with BNC which is a lot more reliable and flexible than RCA.

AliExpress / Amazon US / Amazon UK / eBay / Walmart Canada

40mhz Crystal Mod - (5-25USD)

• Sampling Speed

This simple "cheep and dirty" modification is just replacing the stock crystal with a soldering iron, an instant drop-in upgrade to 40msps 8-bit capture or 20msps 16-bit capture, though the CX2388x-xx cards are made for upto 54mhz crystal support in testing 40mhz is generally achievable by any card and matches the DomesDayDuplicator, this also improves the SNR of the CX Chips, this mod makes the cards ideal for SVHS/ED-Beta/SMPTE 1" Type-C & LaserDisc capture on a budget.

The Crystal: Generic 40mhz Fundamental or ABRACON ABLS2-40.000MHZ-D4YF-T Digikey / Farnell (can be sorced from most vendors)

Note: adding a 40mm heat sync & fan is also recommended more data = more heat = shorter hardware life and possible loss of data.

External Clock Mod

• Software Defined Crystal Rate
• Hardware Syncroniced Muli-Card Capture
• Hardware Synchronised Linear/Baseband Audio Capture

The most advanced mod avalible today, using an external cystal timing source we can have drift free capture with 2-4 CX Cards and audio feeds.

This allows duel channel video formats such as Betacam to be captured, or Video FM + HiFi FM + Linear for many outher formats like VHS or Betamax.

Possible thanks to cxadc-clock-generator-audio-adc By Rene Wolf

External crystal timing via 2 additional PCB boards, a Jig with an SMA and Mainboard has allowed for under 50USD multi card sync, using 2 or more CX Cards alongside a extra input for synbcroised Linear/Refrance audio capture also has a extra input for headswiching timing signals.

• Raspberry Pi Pico as the interface and control board.

• Adafruit Si5351A for genarating the shared clock source with 5 potential inputs.

• PCM1802 ADC for L/R input Linear/HiFi audio capture.

Audio Inputs and Headswitch Input is on a dedicated bracket you can 3D print.

Clock Speed & Audio is controlled by a CLI application.

LaserDisc Capture

For laserdisc you may want to use the LPF mod (low pass filter) and more information can be read in greater details here:

Tony's CX Hardware mod wiki