Part No. ECHO-SE3-T5

Big Expansion. Small Footprint.

Echo SE III T5

Compact, desktop 3-slot Thunderbolt 5 to PCIe Card Expansion System for Computers with Thunderbolt or USB4 Ports

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

Laptop and mini desktop computers with ultra-high performance Thunderbolt™ 5 ports deliver outstanding onboard processing power, but lack the PCIe slots needed to support adapter cards that add specialized connectivity and processing capabilities.

Echo™ SE III T5 provides the expansion your professional workflow demands. Using the included Thunderbolt 5 cable, this pro Thunderbolt 5 expansion system connects three half-length+ (up to 7.75 inches long) PCIe cards simultaneously to your Thunderbolt 5, 4, or USB4 Mac, Windows PC, or Linux computer. Install nearly any compatible (non-GPU) PCIe card to create the professional setup your workflow demands.

Compact Desktop Expansion

When plugged into one of your computer's Thunderbolt ports, Echo SE III T5 enables you to connect three professional PCIe cards, including video capture, streaming and transcoding; audio DSP; 10Gb and 25Gb Ethernet; SSD storage; SAS host bus adapter; and other specialty types.

Three PCIe 3.1 Slots: 3400 MB/s Aggregate, Bi-directional PCIe Bandwidth

Echo SE III T5 features three PCIe 3.1 x8 slots that support three half-length+, full-height, single-width PCIe cards, or one single-width card plus one double-width card. When connected to a Thunderbolt 5 computer, the system provides up to 3400 MB/s aggregate, bi-directional PCIe bandwidth. It supports single- and double-width PCIe 4.0, 3.1, 2.0, and 1.1 cards, including video capture, streaming, and transcoding; audio DSP; 10Gb and 25Gb Ethernet; SSD storage; SAS host bus adapters; and other specialty cards.

Double-width?
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.

Comprehensive Support for Professional PCIe Cards

Echo SE III T5 is large enough to support the majority of Thunderbolt compatible, non-GPU cards. Not sure if a card you own or are considering is compatible? We’ve created a PCI Card Compatibility PDF that lists many cards conforming to Thunderbolt technology requirements and organized by fit and power compatibility with specific expansion systems.

Design Smarts: Aluminum Enclosure. Auto Power On/Off.

Echo SE III T5 is wrapped in a compact and rugged aluminum outer shell, resulting in a lightweight system small enough to carry in your backpack, yet durable enough to protect the installed PCIe cards securely. Designed without a power switch, the Echo SE III T5 powers on and off automatically with the connected computer to help conserve energy. And with no power switch, you can’t forget to turn off the system!

Power to Spare
Echo SE III T5 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.

Ultra-quiet Operation

Featuring a Noctua fan, Echo SE III T5 is designed to deliver ultra-quiet operation so that it can be comfortably used in noise-sensitive environments. Rated at 17 dBA — below the 20 dBA ceiling prescribed for use in recording and broadcast studios — the fan spreads the spectrum of its noise to minimize the impact at any single frequency. To further ensure negligible noise levels, the fan is temperature-controlled, automatically speeding up and slowing down smoothly as needed, and the Echo system enclosure is engineered to optimize airflow over the installed cards to effectively and efficiently cool the system.

Secure Connections for High Performance

Thunderbolt 5 Cable and ThunderLok Included. Sonnet includes a Thunderbolt 5 cable that supports Thunderbolt’s maximum bandwidth and is fully compatible with Thunderbolt 5, 4, and 3 computers. Sonnet also provides ThunderLok, a Thunderbolt connector cable lock, that prevents accidental cable disconnections.

ThunderLok Advantage: Many Sonnet Thunderbolt products featuring Thunderbolt ports come equipped with threaded mounting holes to securely attach a Sonnet ThunderLok connector lock, preventing Thunderbolt cables from accidentally disconnecting.

Thunderbolt 5: More Than Just the Fastest External Interface Available

Echo SE III T5 features an ultra-high-speed Thunderbolt 5 interface that delivers the PCIe bandwidth needed to support demanding cards at high performance. The system includes two Thunderbolt 5 ports: one connects to the computer, while the second enables you to connect an additional Thunderbolt or USB peripheral device:

Powers Peripherals. 15 watts is provided to bus-powered USB or Thunderbolt devices requiring extra power through the secondary Thunderbolt port.

Connect One 5K Display Using Spare Bandwidth. Maximize the utilization of one computer Thunderbolt port, connecting a 5K display while retaining full PCIe bandwidth.

Key Features & Specifications

• Connect PCIe Cards – Use three high-performance PCIe cards with your computer without expansion slots via one Thunderbolt 5 cable.
• Three PCIe 3.1 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.
• Thunderbolt 5 to PCIe Device – Provides 3400 MB/s aggregate, bi-directional PCIe bandwidth to the installed cards when connected to a Thunderbolt 5 computer port.
• 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.
• Remarkably Quiet – Dual temperature-controlled, variable-speed Noctua fans rated at 17dBA automatically and quietly cool the cards.
• Rugged 2U Steel Housing + Optional Expansion Space – Provides robust and secure protection in server and DIT racks; space for an additional Sonnet expansion module (sold separately).
• Connect an Additional Device – Secondary Thunderbolt port provides 15W of power for an additional Thunderbolt or USB device.
• Mac Compatibility – Mac with Thunderbolt 5, Thunderbolt 4, or Thunderbolt/USB4 ports. OS support: macOS 15+; compatible with macOS 27.
• Windows Compatibility – Windows computer with Thunderbolt 5, Thunderbolt 4, or USB4 ports. OS support: Windows 11 25H2+ and Windows Server 2025.
• Linux Compatibility – Linux computer with Thunderbolt 5, Thunderbolt 4, or USB4 ports. OS support: Supported Linux kernel, 6.6 or later.
• PCIe Card Compatibility – For a list of compatible PCIe cards, see PCIe Card Compatibility PDF for details.
• Dimensions (WxDxH) – 6.5 x 11 x 4.6 in. (16.5 x 27.9 x 11.7 cm).
• Weight – 3.7 lbs. (1.7 kg).
• Package Contents – Echo SE III T5 Thunderbolt 5 Expansion System; universal power adapter; region-specific power cable; 6-pin PCIe auxiliary power cable; 0.8-meter Thunderbolt 5 cable; ThunderLok-A connector lock (for securing Thunderbolt cable); product documentation.
• Warranty – 2-year product warranty.
• Customer Support – Lifetime technical support.
• The Sonnet Advantage – Innovating technology since 1986.

Note:Computers and accessories featured in photos are not included with the product. Product specifications are subject to change without notice.

Compatibility Charts

• PCIe card compatibility chart (Thunderbolt expansion systems)
• All Sonnet compatibility charts

Manuals & Firmware

• Quick start guide (echo_se_iii_t5_qsg.pdf)
• Sonnet support articles for this product