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Sonnet Echo Express SE IIIe 3-Slot Thunderbolt 3 Expansion Chassis for PCIe Cards

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Product code: ECHO-EX-SE3E-T3

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Connect Three PCIe Cards to Any Mac with Thunderbolt 3 Ports.

Your price: $1,219.99

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Echo Express SE IIIe

3-slot Desktop Thunderbolt to PCIe Card Expansion System for Computers with Thunderbolt 4 or Thunderbolt 3 Ports

Connect Three Full-height, Half-length+ PCIe Cards

Although Mac®, Windows®, and Linux® computers with Thunderbolt™ 4 or Thunderbolt 3 ports offer processing power to spare, for many users (such as pros in the creative fields) onboard processing power alone is not enough. The computers lack the PCIe expansion slots needed to install specialty cards that add video and audio inputs, transcode data, and connect to high-speed shared storage and networks. Sonnet’s Echo™ Express SE IIIe is a compact, desktop Thunderbolt to PCIe card expansion system that enables you to connect three professional PCIe cards to your computer at the same time, via a single Thunderbolt cable.

Key Features

Connect PCIe Cards

Use multiple high-performance PCIe cards with any computer with a Thunderbolt 4 or Thunderbolt 3 port.

Three PCIe 3.0 x8 Slots

Supports three full-height, half-length+ (up to 7.75 inches long), single-width cards, or one double-width card plus one single-width card.

40Gbps Thunderbolt System

Offers 2750 MB/s of PCIe bandwidth to the installed card. 

Pro Performance. Compact Design.

Takes up little space on the desktop, but large enough to support nearly every Thunderbolt-compatible non-GPU PCIe card at full performance.

Two Thunderbolt Ports

One port connects to computer; second port supports daisy-chaining of up to five additional Thunderbolt peripheral devices.

Remarkably Quiet

Temperature-controlled, variable-speed fan automatically and quietly cools the cards.

Energy Saver Mode

Powers on/off automatically with the computer.

Rugged Aluminum Housing

Provides robust and secure protection.

Pro Power

Auxiliary PCIe power connector for a power-hungry card; daisy chain port provides up to 15W of power to connected peripherals.

Apple® M1 Series Compatible

Supports M1, M1 Pro, and M1 Max Macs (with PCIe cards that have M1 compatible drivers).

Intel® Mac & Windows Compatible

Supports Intel Macs with Thunderbolt 3 ports, and Thunderbolt 2 ports (with adapter and Thunderbolt 2 cable, both sold separately); and Windows computers with Thunderbolt 3 ports.

Linux Compatible

Supports Linux computers with Thunderbolt 4 and Thunderbolt 3 ports.

Nearly Every Thunderbolt-Compatible, Non-GPU PCIe Card Supported

Smaller than the 3-slot Echo III Desktop, the Echo Express SE IIIe is still large enough to support nearly every Thunderbolt compatible, non-GPU card available. With its three x8 slots, the SE IIIe supports PCIe 3.0, PCIe 2.0, and PCIe 1.1 cards up to 7.75 inches long. 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 3.0 Slots for Demanding Professional Needs

Echo Express SE IIIe’s PCIe 3.0 x8 slots support three half-length+, full-height, single-width PCIe cards, or one single-width card plus one double-width card.



Some specialty cards, such as RME’s HDSPe MADI FX, Blackmagic Design’s DeckLink 4K Extreme, and the Lynx AES16e 50, include a daughter card that mates with and provides additional external connections to the main card.


Power to Spare

Echo Express SE IIIe includes an auxiliary PCIe power connector, enabling you to install a card requiring extra power, such as the AJA® Kona® 5 or Blackmagic DeckLink 4K Extreme 12G, and Bluefish444’s Epoch and KRONOS SDI cards.

 Mac Compatibility

  • Mac (M1, M1 Pro, M1 Max) with PCIe cards that have M1 compatible drivers
  • Mac (Intel®) with Thunderbolt 3 ports
  • Mac (Intel) with a Thunderbolt 2 or Thunderbolt 1 port with an Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter plus a Thunderbolt 2 cable (both sold separately)
  • macOS® 10.12.6+
  • macOS Monterey compatible


Windows Compatibility

  • Windows 10 computer with Thunderbolt 4 or Thunderbolt 3 ports
  • Windows 11 does not support multiple-slot Thunderbolt expansion systems. We are working with Microsoft to resolve the issue.


Linux Compatibility

  • Linux computer with Thunderbolt 4 or Thunderbolt 3 ports
  • Linux Kernel 5.0+


PCIe Card Compatibility

For a list of compatible PCIe cards, view the PDF of Sonnet's PCIe Card Thunderbolt Compatibility Chart

Compatibility Chart



Part Number




  • 2-year


Form Factor

  • Thunderbolt desktop enclosure


External Connectors

  • Two Thunderbolt ports
  • 12V power port


Internal Connector

  • 6-pin Mini-Fit Jr (same type as on legacy Mac Pro motherboard; provides power for PCIe card that requires supplemental power)


Expansion Slots

  • One x8 mechanical (x4 electrical) PCIe 3.0
  • Two x8 mechanical (x8 electrical) PCIe 3.0


PCIe Cards Supported

  • One half-length+ (up to 7.75 inches long), double-width, full-height x8 PCIe card, plus one single-width card or
  • Three half-length+, single-width, full-height x8 PCIe cards


Power Adapter

  • Universal 120W, 100-240V, 50-60 Hz
  • NRTL Certified



  • Noctua NF-R8 redux-1800 at 17.1dBA


Operating Temperature

  • 0ºC to 35ºC (32ºF to 95ºF)


Dimensions (WxDxH)

  • 6.5 x 11 x 4.6 in. (16.5 x 27.9 x 11.7 cm)



  • 2.6 lbs. (1.18 kg)



  • RoHS 3 (Directive 2015/863)
  • EC62368-1 and IEC62368-2 Safety


Package Contents

  • Echo Express SE IIIe Desktop Enclosure
  • Universal power adapter
  • Power cord
  • 0.7-meter Thunderbolt cable
  • ThunderLok 3 Thunderbolt connector retainer clip(1)
  • Documentation


Support Links

Product Manual

Product Manual

Technical Notes


  1. ThunderLok 3 compatible specifically with Sonnet 0.5- and 0.7-meter Thunderbolt cables; Sonnet 1- and 2-meter Thunderbolt cables require ThunderLok 3L.
  2. While the Echo Express SE IIIe features a 40Gbps Thunderbolt interface, some computers equipped with Thunderbolt 3 use an x2 PCIe lane implementation of Thunderbolt 3 technology that limits PCIe performance to 20Gbps.
  3. Full performance requires the use of the included or comparable 40Gbps Thunderbolt cables; look for the Thunderbolt icon AND the number 3 on the connector housings to identify these cables. Full performance supported by any Thunderbolt 4 cable.
  4. Second Thunderbolt port supports USB 3.1 Gen 1 (5Gb) or Gen 2 (10Gb) devices when connected with proper cable or adapter (sold separately).

Additional Information

Colour Black
Type No
Connection Thunderbolt 3 (40Gb/s)
Interface No
Form Factor PCI Express
Suitable for No
Model Identifier No
Manufacturer Sonnet
Manufacturer P/N ECHO-EXP-SE3-T3
UPC 732311012303
Shipping Restriction --Please Select--

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