Sonnet Echo III HDX Edition Desktop Thunderbolt Three-Slot Full-Length PCIe Card Expansion System (Original size)

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Sonnet Echo III HDX Edition Desktop Thunderbolt Three-Slot Full-Length PCIe Card Expansion System (Original size)


Sonnet Echo III HDX Edition Desktop Thunderbolt Three-Slot Full-Length PCIe Card Expansion System (Original size)

3-slot Desktop Thunderbolt 3 Expansion System for PCIe Cards, Optimized for Use with Multiple Pro Tools | HDX PCIe Cards

Connect Three Full-length PCIe Cards to Computers with Thunderbolt 3 Ports

For pros working in the creative fields, a computer’s processing power alone is not enough to get the job done. Prime examples are the latest MacBook Pro®, and Mac mini®, which, while offering great performance, lacks the PCIe expansion slots necessary to support specialty cards that connect pro video and audio inputs, transcode data, and connect to high-speed storage and networks. Instead of slots, these computers include high-performance Thunderbolt™ 3 ports to support peripherals. Sonnet’s Echo™ Express III-D (Thunderbolt 3 HDX Edition) is a pro-level, desktop Thunderbolt™ 3 to PCIe card expansion system that enables you to connect your computer to three full-length PCIe cards at the same time.

Qualified for Pro Tools

No extra parts or configuration necessary – ready right out of the box for up to three Pro Tools | HDX PCIe cards

Optimized to support up to three Pro Tools | HDX PCIe cards, Sonnet's Echo Express III-D (Thunderbolt 3 HDX Edition) is Avid qualified, compatible and ready for use out of the box, no extra parts or special configuration necessary! It has been tested and approved for use with Pro Tools HD 12 software, and is qualified by the Avid Audio group for use with Pro Tools HDX and HD Native systems. See this Sonnet FAQ and the Avid website for ProTools System Requirements and Compatibility.

Every Thunderbolt 3 Compatible, Non-GPU Card Supported

Echo Express III-D supports three single-width, full-length PCIe cards, or one double-width, full-length card plus one single-width card, enabling it to support every Thunderbolt 3 compatible, non-GPU PCIe 1.1, PCIe 2.0, and PCIe 3.0 card available. Do you have a card in mind but aren’t sure it’s compatible? We’ve put together a list in our supporting PCIe Card Thunderbolt Compatibility Chart (PDF). There you’ll find cards identified as conforming to Thunderbolt technology requirements, and organized by fit and power compatibility with specific expansion system.

Three PCIe 2.0 Slots

Sonnet’s Echo Express III-D supports three full-size PCIe cards, up to 12.28 inches (full-length) long. The III-D integrates a universal 300W power supply and includes a 75W PCIe power connector for cards that require supplementary power, such as the Avid Pro Tools | HDX. Even with all that power, the III-D is enviro-friendly; it automatically powers on or off whenever the connected computer powers on (or wakes), or powers off or sleeps, respectively.

Included at No Extra Charge

Thunderbolt 3 Cable. ThunderLok 3.

Sonnet includes a 0.7-meter Thunderbolt 3 (40Gbps) cable that supports Thunderbolt 3’s full 2750 MB/s PCIe bandwidth. Sonnet also provides a ThunderLok 3 Thunderbolt connector retainer clip(1) that prevents accidental cable disconnections—just slide it over one end of the cable, and then plug in the connector and secure it to the chassis by turning a thumbscrew. Because of its unique design, ThunderLok remains on the cable so it won’t get lost when not in use.

Technical Specifications


Mac Compatibility

Windows Compatibility

  • PC with Thunderbolt 3 ports
  • Windows 10 (64-bit Edition Version 1809 or greater, see note)
  • Important Note: Windows computers require the latest BIOS and Thunderbolt drivers to support this product. Check with your computer manufacturer for update information.

Linux Compatibility

  • Linux® computer with Thunderbolt 3 ports
  • Linux Kernel 5.0+


Part Number



  • 2-year

Form Factor

  • Desktop expansion system

External Connectors

  • Two Thunderbolt 3 ports
  • 12V power port

Internal Connector

  • 6-pin Mini-Fit Jr (same type as on legacy Mac Pro motherboard; provides up to 75W of power for PCIe cards that require supplemental power)

Expansion Slots (Facing Rear, Left to Right)

  • One x8 mechanical (x4 electrical) PCIe 2.0
  • One x16 mechanical (x8 electrical) PCIe 2.0
  • One x8 mechanical (x4 electrical) PCIe 2.0

PCIe Cards Supported

  • One full-length, full-height, double-width PCIe card, plus one single-width card or
  • Three full-length, full-height, single-width PCIe cards

Power Supply

  • Universal 300W, 115-230V AC, 50-60 Hz(5)

Operating Temperature

  • 0ºC to 35ºC (32ºF to 95ºF)

Dimensions (WxDxH)

  • 3.8 x 16 x 10.2 in. (9.7 x 40.5 x 25.9 cm)


  • 7.5 lbs (3.4 kg)

RoHS Compliant

  • Yes

Package Contents

  • Echo Express III-D (Thunderbolt 3 HDX Edition)
  • Power cord
  • 0.7-meter Thunderbolt 3 (40Gbps) cable
  • ThunderLok 3 Thunderbolt Connector Retainer Clip(1)
  • Documentation

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