Rigol DHO804 vs Siglent SDS804X HD: The Definitive Comparison

If you want the better user experience out of the box: buy the Rigol DHO804. If you want the cleaner analog front end and better ADC performance: buy the Siglent SDS804X HD. Both are excellent 12-bit, 4-channel scopes in the mid-$400s, and honestly, you won't regret either one.

The Reddit community is genuinely split on this, which tells you something important — neither scope has a decisive advantage across the board. Your choice comes down to whether you prioritize display and interface (Rigol) or raw signal quality and hackability (Siglent).

I've spent significant time with both, and this guide breaks down every dimension that actually matters.

On paper, these scopes are remarkably similar. The SDS804X HD has a higher sample rate (2 GSa/s vs 1.25 GSa/s), which matters for capturing fast transients and aliasing avoidance. But the real differences are in the details that don't show up on a spec sheet.

Both scopes have 7-inch IPS touchscreens, but the experience isn't identical. Rigol's DHO series interface is more polished and phone-like — it was clearly designed by someone who uses modern mobile devices. The pinch-to-zoom is smooth, the menus are logically organized, and the overall responsiveness feels snappier.

Siglent's SDS804X HD touchscreen works well but feels slightly more utilitarian. The interface is functional and logical, but it doesn't have the same consumer-electronics polish. Some users actually prefer this — it feels more like a proper instrument and less like a tablet pretending to be a scope.

For beginners who've never used an oscilloscope, Rigol's interface has a lower learning curve. For experienced users switching from older scopes, the difference is negligible — you'll adapt to either in a day.

One area where Rigol clearly wins: the overall UI animation smoothness. The DHO804 feels like it has more processing power dedicated to the interface. The SDS804X HD occasionally shows slight lag when navigating deep menu trees, though this has improved with firmware updates.

This is where the Siglent SDS804X HD has a genuine technical edge, and it's the single biggest reason the Reddit community recommends it for precision analog work.

Siglent's parent company acquired LeCroy's oscilloscope technology, and it shows in the analog front end. The SDS804X HD consistently measures a lower noise floor than the DHO804 at equivalent sensitivity settings. If you're working with small signals — millivolt-level sensor outputs, low-level audio, or precision power supply ripple measurements — the Siglent will give you cleaner captures.

The 12-bit ADC in both scopes is a massive upgrade over traditional 8-bit oscilloscopes. You get 16x the vertical resolution, which means you can actually see small signals riding on top of larger ones. But the ADC is only as good as the analog front end feeding it, and Siglent's front end introduces less noise.

For most hobbyist work — debugging Arduino projects, checking PWM signals, verifying power supplies — the noise floor difference won't matter. Both scopes are excellent. But if you're doing precision analog design or audio electronics, the Siglent's cleaner front end is a meaningful advantage.

Both scopes include SPI, I2C, and UART decoding out of the box. For most hobbyist embedded work, this covers the essentials. The decoding quality is comparable — both will reliably decode serial bus traffic at reasonable baud rates.

Neither scope includes CAN or LIN decoding at the base price. If you need automotive protocol support, you'll need to step up to the Siglent SDS1104X-U ($419 with CAN/LIN included) or pay for Rigol's optional license.

The Siglent's protocol decoding interface is slightly more mature, with better triggering options on decoded data. Rigol's decoding works well but the trigger-on-decoded-content feature is less refined. For basic decode-and-display usage, they're equivalent.

This is where things get interesting, and where the Reddit community has very strong opinions.

The Rigol DHO804 has a well-documented firmware unlock that can bump its bandwidth from 70MHz to higher levels, effectively giving you a more expensive scope's capabilities for $439. The Rigol hacking community is large, active, and has made the process accessible. We won't provide step-by-step instructions here, but the community has thoroughly documented the process.

The Siglent SDS804X HD is also unlockable — the community has documented methods to increase bandwidth to 200MHz. Siglent's unlock scene is smaller but active, and the SDS800X HD series has been a popular target.

Both scopes benefit from active communities that push firmware boundaries. If hackability is important to you, both are good choices, but Rigol's larger hacking community means more documentation, more tools, and faster updates when new firmware versions are released.

The DHO804's fan noise is the number one complaint on Reddit, and it's legitimate. The internal fan runs continuously and is audible in a quiet room. Some users describe it as a low hum, others call it genuinely annoying. There are community-documented fan modification or replacement procedures that can help, but out of the box, the DHO804 is not a silent instrument.

The SDS804X HD runs noticeably quieter. Siglent's thermal design appears to be more conservative, resulting in less fan activity. In a quiet home lab, this difference is noticeable and appreciated during long debugging sessions.

Build quality is comparable on both — solid plastic enclosures, decent weight, proper BNC connectors. Neither feels cheap. The DHO804's front panel layout is slightly more spacious due to Rigol's emphasis on the touchscreen over physical controls. The SDS804X HD has more physical buttons, which some users prefer for quick adjustments without lifting a probe hand.

Buy the Rigol DHO804 if:

• You're a beginner who values an intuitive, phone-like interface
• You plan to unlock the bandwidth via firmware modification
• You want the larger Rigol community for troubleshooting and tutorials
• Display quality and UI responsiveness are your top priorities
• You can tolerate some fan noise or are willing to mod the fan

Buy the Siglent SDS804X HD if:

• You do precision analog work where noise floor matters
• Fan noise in a quiet home lab would bother you
• You prefer more physical buttons and a traditional instrument feel
• You value the LeCroy analog front-end heritage
• You want the higher 2 GSa/s sample rate for better signal fidelity

Either scope is excellent for:

• Arduino and embedded development
• Basic power supply debugging
• Learning oscilloscope fundamentals
• General hobbyist electronics work

Which has better value for the money?
They're essentially tied. The DHO804 is about $10 cheaper and has a slightly more polished UI. The SDS804X HD has a better sample rate and lower noise floor. Pick the one that matches your priorities — neither is a bad deal.

Can both be unlocked to higher bandwidth?
Yes, both have active firmware unlock communities. The Rigol unlock scene is larger and more documented. The Siglent SDS804X HD can be unlocked to 200MHz, which is a significant upgrade from 70MHz.

Is the fan noise on the DHO804 really that bad?
It depends on your environment. In a garage workshop, you'll never notice it. In a quiet bedroom lab at midnight, it's noticeable. Many users replace the fan with a quieter aftermarket option — the community has documented compatible replacements.

Should I just buy the DHO924S instead?
If you can stretch to $899 for the DHO924S, you get 250MHz bandwidth without any hacking. But you lose the 12-bit ADC — the DHO924S is 8-bit. If vertical resolution matters more than bandwidth, the 12-bit DHO804 or SDS804X HD is the better choice.

Which one does Reddit recommend more?
It's genuinely split. Threads asking this question consistently produce advocates for both sides. The Siglent camp tends to emphasize the cleaner analog front end. The Rigol camp emphasizes the UI and community size. Both sides have valid points.