Office & Hobby / bench power supply
Siglent Technologies SPD3303X
D0 No Radio — No radio at all. It cannot phone home.
The unplug test
There is no cloud connection to lose in the first place. The SPD3303X is a three-channel bench power supply operated from its own front panel; its LAN and USB ports exist only to let SCPI commands reach it from a PC on the same bench or network, over the owner's own software (PyVISA, LabVIEW, or one of several independent open-source Python libraries). Unplugging the router changes nothing: the instrument was never talking to anything outside the room.
Why this tier: The SPD3303X ships with no wireless radio of any kind. Its LAN port speaks SCPI — an instrumentation control protocol terminated entirely by the owner's own PC on the owner's own network — and Siglent operates no cloud service the instrument can reach. No radio and no vendor cloud is D0, not D1: D1 exists to describe a device that HAS a radio and still has nowhere to phone home, and this instrument does not have one. An Ethernet port is not a radio, and a wired local control protocol is not a network dependency; the supply does exactly nothing you did not cable it to.
Specifications
| Account required | none |
|---|---|
| Works offline | fully |
| Forced firmware updates | unknown |
| Radios | none |
| FCC ID | not checked |
| Local control | unknown |
| Phones home | none |
| Parts available | unknown |
| Availability | in stock |
| Price band | $600-650 (seen 2026-09-03) |
| Vendor risk | 0 / 3 |
Where to buy
Open questions
- Whether the LAN interface exposes anything beyond raw SCPI (e.g. a browser-based LXI web page) was not confirmed, so local_api is left as 'unknown' rather than asserting a specific protocol from the schema's enum, none of which cleanly names SCPI-over-LXI.
- No FCC check was run: the device has no wireless radio by any source found, making an intentional-radiator grant inapplicable, but this was not independently confirmed via a teardown or FCC filing search.
- Whether the cheaper SPD3303X-E variant (sold alongside this one) omits the LAN port was not directly confirmed in this pass -- do not assume the -E model shares this tier without separately checking it.
- Firmware update mechanism and whether updates can be declined were not established from the sources reviewed.
Sources
Class A is primary (manual, FCC filing, teardown). Class B is corroborated community reporting. Class C is never sufficient alone.
- A https://siglentna.com/power-supplies/spd3303x-spd3303x-e-series-programmable-dc-power-supply/
Manufacturer product page: SPD3303X priced at $631, standard accessories are a USB cable and quick start guide only (no app, account, or wireless adapter of any kind mentioned), and its own application notes describe remote control 'using a standard communications bus like USB or LAN.' — accessed 2026-09-03 - B https://github.com/geissdoerfer/python-spd3303x
Independent open-source Python driver whose README documents connecting to the SPD3303X specifically 'via Ethernet/USB' by IP address (SPD3303X.ethernet_device("192.168.0.4")), confirming the model has a working built-in LAN interface for local SCPI control distinct from the USB path. — accessed 2026-09-03 - B https://raw.githubusercontent.com/Swallowtail-Electronics/SPD3303X-Python-API/main/README.md
A second, independently authored open-source Python interface whose README states plainly: 'This power supply can be controlled over LAN by sending SCPI commands... All you need is the IP address of your power supply,' corroborating the LAN capability from a different project not derived from the first. — accessed 2026-09-03
History
- 2026-09-03 — First published at D1.
- 2026-09-03 — Tier corrected D1 -> D0. The record's own radios field was ['none'] while D1 is defined as a radio being present with no vendor cloud behind it. The LAN/SCPI interface is wired local control, not a radio and not a dependency.
Last verified 2026-09-03 — 3 days ago.