SOB (COB Pro) vs COB LED Strip: Key Differences and How to Choose
By DENO LED Lighting ·
Compare SOB (also called COB Pro by some suppliers) and COB LED strips by structure, optics, power, copper, run length, cut unit, control, and project fit.
Short answer: neither SOB nor COB is the automatic winner for every project. Both can create a continuous, dot-free line of light, but they reach that result through different package and circuit structures. Choose by comparing the exact model, optical target, power density, thermal path, run length, cut unit, control method and installation conditions—not the three-letter name alone.
What SOB and COB Mean in This Guide
COB (Chip-on-Board) LED strip mounts bare flip-chip dies directly on the flexible circuit board and covers them with a shared phosphor layer. The dense die layout and continuous coating can create a smooth light line without the visible points associated with conventional, widely spaced SMD tape.
SOB (Solder-on-Board) uses small, individually encapsulated LED packages soldered to the flexible circuit board, followed by a continuous optical coating. DENO's package specification uses 99.99% gold bonding wire. Some buyers and suppliers also quote this product direction as COB Pro, FOB, S-COB or SCOB. Those terms are market aliases; DENO's product name is SOB LED strip.
The distinction matters because “dot-free” describes an optical result, not one universal construction. Package protection, copper build, circuit topology, coating, LED pitch, diffuser depth and viewing angle all influence the finished installation. A good specification therefore names the product model and operating conditions instead of assuming every COB or every SOB strip behaves identically.
SOB vs COB LED Strip: A Project-Level Comparison
| Selection factor | COB LED strip | SOB LED strip |
|---|---|---|
| Light-source structure | Bare flip-chip dies mounted on the board beneath a shared phosphor layer | Individually encapsulated, gold-wire-bonded SMD packages soldered to the board beneath a continuous optical coating |
| Dot-free appearance | Achieved through dense die placement and the shared coating | Achieved through package pitch, optical geometry and the continuous coating |
| Power and output | Available in multiple power classes; compare a specific model and test report | DENO has verified builds up to 24 W/m at 24 V DC, 25 °C ambient and with aluminum-profile mounting |
| Copper and thermal path | Varies by model; DENO catalog examples include 1.3 oz boards | Varies by model; DENO catalog examples include 3 oz boards, while the R2R platform supports copper up to 105 µm or thicker by project |
| Color specification | High-CRI and controlled-bin options exist; verify CCT, CRI and binning on the selected model | DENO's standard binning target is SDCM ≤3, with tighter selection available; CRI still varies by model |
| Run length | Depends on voltage, wattage, conductor cross-section and feed topology; some DENO COB models are designed for long runs | Depends on the same variables; standard and constant-current long-run SOB models must not be treated as one specification |
| Cut unit | Model-specific; dense COB does not automatically mean the shortest cut unit | Model-specific; DENO model 14159 is listed with a 3.33 mm cut unit |
| Best starting point | Shorter, lower-load or cost-sensitive continuous-light applications, subject to model verification | Projects prioritizing high load, fine cutting, package protection or specialized long-run circuits, subject to model verification |
1. Start With the Optical Result, Not the Label
Both technologies can look continuous when the strip, profile and diffuser are selected as one optical system. LED pitch is only one variable. The distance from the emitter to the diffuser, diffuser transmittance, beam angle, surface finish and viewing direction can reveal or hide brightness modulation. A shallow profile that looks uniform head-on may show structure at a grazing angle.
For a fair approval, install the candidate COB and SOB samples in the same profile with the same diffuser. Use the same CCT, output target, camera exposure and observation distance. Photograph powered and unpowered samples, then inspect the full run for local bright or dark areas. Do not compare a low-output sample in a deep profile with a higher-output sample in a shallow profile and call the result a technology verdict.
2. Compare Power, Output and Thermal Conditions Together
Wattage per metre, lumens per metre and luminous efficacy answer different questions. Wattage describes electrical load, lumens per metre describe delivered light, and lumens per watt describe conversion efficiency. A specification that lists only one of these cannot establish which strip will meet the lux target or thermal limit.
DENO has a verified SOB capability of up to 24 W/m under stated conditions: 24 V DC, 25 °C ambient and installation in an aluminum profile. That is a conditional production capability, not a claim that every SOB model runs at 24 W/m or that every COB product is limited to one lower figure. The selected model's photometric report, operating current, CCT, CRI, encapsulation and profile must be reviewed together.
For example, DENO SOB model 16828 is listed as a 24 V, 10 mm CCT-tunable strip with 544 LEDs/m, a 29.412 mm cut unit, 3 oz copper and a listed 12–24 W power range. That makes it a useful high-load candidate when independent white-channel control is required. It should be compared against a COB model that meets the same control, CCT, CRI and output brief—not against an unrelated single-color economy strip.
3. Treat Copper as Part of the Electrical and Thermal Design
The flexible circuit carries current and helps move heat away from the LED junction area. More copper cross-section can reduce conductor resistance and spread heat, but the installed result also depends on trace geometry, current, total length, ambient temperature, adhesive interface and aluminum profile. Copper thickness alone is not a complete thermal report.
DENO's Roll-to-Roll FPCB platform supports electroplated copper up to 105 µm, with thicker builds available by project. Product records express individual constructions in ounces: for example, SOB models 14159, 16828 and 15927 are listed with 3 oz copper, while several catalogued COB models use 1.3 oz boards. Those are model examples, not universal definitions of either category.
4. Separate Manufacturing Length, Reel Length and Electrical Run Length
A continuous FPCB can be manufactured without an intermediate PCB splice joint inside the reel, but this does not mean the complete reel can be powered from one point. Four terms must remain separate: continuous FPCB length, finished reel length, electrical run length and cut unit. Electrical run length is governed by voltage drop, power density, conductor geometry and whether power is fed from one end, both ends or a mid-strip tap.
DENO's R2R process supports a continuous FPCB length of up to 50 m per reel without an intermediate soldered PCB joint. The acceptable powered distance still belongs to the individual circuit. Standard constant-voltage models and constant-current long-run models can have very different limits, even when both carry the SOB name.
Model 15927, for example, is listed as a 48 V constant-current SOB strip with 300 LEDs/m, a 50 mm cut unit, 3 oz copper and a 4.8–19.2 W listed power range. Its long-run behavior must be approved with the proposed wattage, feed method and allowable end-of-run performance. On the COB side, DENO's 360-series catalog entries are listed with 24 V, 360 LEDs/m, 1.3 oz copper and model-specific long-run configurations. These examples show why “COB is always short-run” and “SOB is always long-run” are both inaccurate shortcuts.
5. Use Cut Unit and Installation Geometry to Avoid Site Waste
Cut length becomes critical around display shelves, furniture returns, stairs, coves and repeated modules. A strip with excellent output but a long cut unit may force a dark gap or excess material at the end of each section. Connector dimensions, solder-pad access, waterproof finishing and the minimum bending radius also affect whether the specified strip can be installed cleanly.
DENO SOB model 14159 is a useful model-level example: the database lists a 24 V, 8 mm strip with 300 LEDs/m, 3 oz copper, a 4–20 W power range and a 3.33 mm cut unit. For a fine cabinet detail, that cutting precision may matter more than the technology name. A COB alternative should be assessed using its actual cut unit, board width and termination method rather than its LED density alone.
COB remains a practical choice where a slim continuous light line, gentle curves and cost control dominate the brief. SOB becomes a strong candidate when the project also needs fine cut control, higher-load options or an encapsulated package architecture. Neither choice removes the need to respect bending direction, pad geometry, profile dimensions and environmental protection.
6. Match Color and Control Requirements to a Real Circuit
CRI, R9, CCT tolerance and batch consistency must be specified per model and order. DENO's verified standard color-consistency target is SDCM ≤3, with tighter selection available, but the requested bin must appear in the quotation and approval sample. The catalog contains different CRI grades, so “all SOB is CRI 95” and “COB cannot provide high CRI” are not acceptable specifications.
Control architecture also changes the comparison. Single-color, tunable-white, dim-to-warm, RGB, RGBW and addressable strips use different channel counts and controllers. For dim-to-warm, the driver or gateway must follow the selected circuit's channel behavior; for tunable white, independent CCT and intensity control may be required. Compare equivalent functions before comparing package technologies.
The SOB dim-to-warm range is the appropriate starting point for warm-dimming projects, while the COB tunable-white range serves projects that require adjustable white from a COB platform. Submit the dimming protocol, controller, minimum dim level and desired CCT path with the request.
7. Which Technology Should You Choose?
Choose a COB model when:
- The project needs a smooth light line at a moderate load and short or model-approved run length.
- A slim, flexible construction and competitive system cost are priorities.
- The selected COB model already meets the required CRI, CCT, cut unit and environmental rating.
- You can validate the visual result in the intended profile and diffuser.
Start with an SOB model when:
- The project requires an encapsulated-package construction and DENO's gold-wire package specification.
- The load, thermal environment or fine cut requirement points to a specific SOB build.
- A specialized constant-current long-run, micro-cut, tunable-white, dim-to-warm or color circuit is required.
- The quotation can state the exact copper build, binning, power, profile and feed conditions.
In both cases, ask for the model drawing, photometric data, approved sample and installation limits. If two candidates are being compared, align the test conditions first. The right result is a documented model choice, not a category slogan.
Frequently Asked Questions
What is the difference between SOB and COB LED strips?
COB mounts bare flip-chip dies directly on the board beneath a shared phosphor layer. SOB uses individually encapsulated, gold-wire-bonded SMD packages soldered to the board beneath a continuous optical coating. Both can create a continuous light line, but the construction and available circuit options differ.
Is SOB always better than COB?
No. SOB is a strong option for encapsulated-package construction, higher-load models, fine cut units and specialized long-run circuits. COB remains practical for many shorter, lower-load, slim or cost-sensitive continuous-light applications. Compare exact models under equal conditions.
Can SOB operate at 24 W/m?
DENO has verified SOB builds up to 24 W/m at 24 V DC and 25 °C ambient when installed in an aluminum profile. This is not the rating of every SOB model; confirm the selected product and operating conditions.
Does a 50 m continuous FPCB mean a 50 m single-feed electrical run?
No. A continuous FPCB manufacturing length and an electrical run length are different specifications. The powered distance depends on voltage drop, power density, conductor geometry and feed topology.
How should copper specifications be compared?
Use the exact model drawing and its stated units. Copper thickness, trace geometry, current, ambient temperature and the aluminum profile all affect electrical and thermal performance.
Which conditions should be aligned before comparing samples?
Use the same CCT, output target, profile, diffuser, viewing angle, camera exposure, ambient temperature, powered length and feed method. Then review the data and installation constraints for each exact model.
A Practical RFQ Checklist
Send the following information so DENO can narrow the SOB and COB options without guessing:
- Application, installation environment and required IP protection;
- Total run length, segment lengths and allowed power-feed locations;
- Target CCT, CRI, R9, color tolerance and dimming or control protocol;
- Required lumens per metre or illuminance target, plus maximum W/m;
- Profile dimensions, diffuser type, viewing angle and available thermal path;
- Minimum cut unit, board width, connector or lead-wire requirements;
- Required approvals, sample quantity and project schedule.
Review the DENO SOB LED strip series and the DENO COB LED strip series, or send your project requirements for a model-level recommendation and sample plan.